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nghttp2/_sources/apiref.txt

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API Reference
=============
Includes
--------
To use the public APIs, include ``nghttp2/nghttp2.h``::
#include <nghttp2/nghttp2.h>
The header files are also available online: :doc:`nghttp2.h` and
:doc:`nghttp2ver.h`.
Remarks
-------
Do not call `nghttp2_session_send`, `nghttp2_session_recv` or
`nghttp2_session_mem_recv` from the nghttp2 callback functions
directly or indirectly. It will lead to the crash. You can submit
requests or frames in the callbacks then call `nghttp2_session_send`,
`nghttp2_session_recv` or `nghttp2_session_mem_recv` outside of the
callbacks.
Macros
------
.. macro:: NGHTTP2_VERSION
Version number of the nghttp2 library release
.. macro:: NGHTTP2_VERSION_NUM
Numerical representation of the version number of the nghttp2 library
release. This is a 24 bit number with 8 bits for major number, 8 bits
for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
.. macro:: NGHTTP2_PROTO_VERSION_ID
The protocol version identification of this library supports.
.. macro:: NGHTTP2_PROTO_VERSION_ID_LEN
The length of :macro:`NGHTTP2_PROTO_VERSION_ID`.
.. macro:: NGHTTP2_VERSION_AGE
The age of :type:`nghttp2_info`
.. macro:: NGHTTP2_PRI_DEFAULT
The default priority value
.. macro:: NGHTTP2_PRI_LOWEST
The lowest priority value
.. macro:: NGHTTP2_MAX_WINDOW_SIZE
The maximum window size
.. macro:: NGHTTP2_INITIAL_WINDOW_SIZE
The initial window size for stream level flow control.
.. macro:: NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE
The initial window size for connection level flow control.
.. macro:: NGHTTP2_MAX_HEADER_TABLE_SIZE
The maximum header table size.
.. macro:: NGHTTP2_CLIENT_CONNECTION_HEADER
The client connection header.
.. macro:: NGHTTP2_CLIENT_CONNECTION_HEADER_LEN
The length of :macro:`NGHTTP2_CLIENT_CONNECTION_HEADER`.
.. macro:: NGHTTP2_INITIAL_MAX_CONCURRENT_STREAMS
Default maximum concurrent streams.
Enums
-----
.. type:: nghttp2_error
Error codes used in this library. The code range is [-999, -500],
inclusive. The following values are defined:
.. macro:: NGHTTP2_ERR_INVALID_ARGUMENT
(``-501``)
Invalid argument passed.
.. macro:: NGHTTP2_ERR_UNSUPPORTED_VERSION
(``-503``)
The specified protocol version is not supported.
.. macro:: NGHTTP2_ERR_WOULDBLOCK
(``-504``)
Used as a return value from :type:`nghttp2_send_callback` and
:type:`nghttp2_recv_callback` to indicate that the operation
would block.
.. macro:: NGHTTP2_ERR_PROTO
(``-505``)
General protocol error
.. macro:: NGHTTP2_ERR_INVALID_FRAME
(``-506``)
The frame is invalid.
.. macro:: NGHTTP2_ERR_EOF
(``-507``)
The peer performed a shutdown on the connection.
.. macro:: NGHTTP2_ERR_DEFERRED
(``-508``)
Used as a return value from
:func:`nghttp2_data_source_read_callback` to indicate that data
transfer is postponed. See
:func:`nghttp2_data_source_read_callback` for details.
.. macro:: NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE
(``-509``)
Stream ID has reached the maximum value. Therefore no stream ID
is available.
.. macro:: NGHTTP2_ERR_STREAM_CLOSED
(``-510``)
The stream is already closed; or the stream ID is invalid.
.. macro:: NGHTTP2_ERR_STREAM_CLOSING
(``-511``)
RST_STREAM has been added to the outbound queue. The stream is in
closing state.
.. macro:: NGHTTP2_ERR_STREAM_SHUT_WR
(``-512``)
The transmission is not allowed for this stream (e.g., a frame
with END_STREAM flag set has already sent).
.. macro:: NGHTTP2_ERR_INVALID_STREAM_ID
(``-513``)
The stream ID is invalid.
.. macro:: NGHTTP2_ERR_INVALID_STREAM_STATE
(``-514``)
The state of the stream is not valid (e.g., DATA cannot be sent
to the stream if response HEADERS has not been sent).
.. macro:: NGHTTP2_ERR_DEFERRED_DATA_EXIST
(``-515``)
Another DATA frame has already been deferred.
.. macro:: NGHTTP2_ERR_START_STREAM_NOT_ALLOWED
(``-516``)
Starting new stream is not allowed. (e.g., GOAWAY has been sent
and/or received.
.. macro:: NGHTTP2_ERR_GOAWAY_ALREADY_SENT
(``-517``)
GOAWAY has already been sent.
.. macro:: NGHTTP2_ERR_INVALID_HEADER_BLOCK
(``-518``)
The received frame contains the invalid header block. (e.g.,
There are duplicate header names; or the header names are not
encoded in US-ASCII character set and not lower cased; or the
header name is zero-length string; or the header value contains
multiple in-sequence NUL bytes).
.. macro:: NGHTTP2_ERR_INVALID_STATE
(``-519``)
Indicates that the context is not suitable to perform the
requested operation.
.. macro:: NGHTTP2_ERR_GZIP
(``-520``)
The gzip error.
.. macro:: NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE
(``-521``)
The user callback function failed due to the temporal error.
.. macro:: NGHTTP2_ERR_FRAME_SIZE_ERROR
(``-522``)
The length of the frame is invalid, either too large or too small.
.. macro:: NGHTTP2_ERR_HEADER_COMP
(``-523``)
Header block inflate/deflate error.
.. macro:: NGHTTP2_ERR_FLOW_CONTROL
(``-524``)
Flow control error
.. macro:: NGHTTP2_ERR_INSUFF_BUFSIZE
(``-525``)
Insufficient buffer size given to function.
.. macro:: NGHTTP2_ERR_PAUSE
(``-526``)
Callback was paused by the application
.. macro:: NGHTTP2_ERR_TOO_MANY_INFLIGHT_SETTINGS
(``-527``)
There are too many in-flight SETTING frame and no more
transmission of SETTINGS is allowed.
.. macro:: NGHTTP2_ERR_PUSH_DISABLED
(``-528``)
The server push is disabled.
.. macro:: NGHTTP2_ERR_FATAL
(``-900``)
The errors < :macro:`NGHTTP2_ERR_FATAL` mean that the library is
under unexpected condition and cannot process any further data
reliably (e.g., out of memory).
.. macro:: NGHTTP2_ERR_NOMEM
(``-901``)
Out of memory. This is a fatal error.
.. macro:: NGHTTP2_ERR_CALLBACK_FAILURE
(``-902``)
The user callback function failed. This is a fatal error.
.. type:: nghttp2_frame_type
The control frame types in HTTP/2.0.
.. macro:: NGHTTP2_DATA
(``0``)
The DATA frame.
.. macro:: NGHTTP2_HEADERS
(``1``)
The HEADERS frame.
.. macro:: NGHTTP2_PRIORITY
(``2``)
The PRIORITY frame.
.. macro:: NGHTTP2_RST_STREAM
(``3``)
The RST_STREAM frame.
.. macro:: NGHTTP2_SETTINGS
(``4``)
The SETTINGS frame.
.. macro:: NGHTTP2_PUSH_PROMISE
(``5``)
The PUSH_PROMISE frame.
.. macro:: NGHTTP2_PING
(``6``)
The PING frame.
.. macro:: NGHTTP2_GOAWAY
(``7``)
The GOAWAY frame.
.. macro:: NGHTTP2_WINDOW_UPDATE
(``9``)
The WINDOW_UPDATE frame.
.. type:: nghttp2_flag
The flags for HTTP/2.0 frames. This enum defines all flags for
frames, assuming that the same flag name has the same mask.
.. macro:: NGHTTP2_FLAG_NONE
(``0``)
No flag set.
.. macro:: NGHTTP2_FLAG_END_STREAM
(``0x1``)
The END_STREAM flag.
.. macro:: NGHTTP2_FLAG_END_HEADERS
(``0x4``)
The END_HEADERS flag.
.. macro:: NGHTTP2_FLAG_PRIORITY
(``0x8``)
The PRIORITY flag.
.. macro:: NGHTTP2_FLAG_END_PUSH_PROMISE
(``0x4``)
The END_PUSH_PROMISE flag.
.. macro:: NGHTTP2_FLAG_ACK
(``0x1``)
The ACK flag.
.. type:: nghttp2_settings_id
The SETTINGS ID.
.. macro:: NGHTTP2_SETTINGS_HEADER_TABLE_SIZE
(``1``)
SETTINGS_HEADER_TABLE_SIZE
.. macro:: NGHTTP2_SETTINGS_ENABLE_PUSH
(``2``)
SETTINGS_ENABLE_PUSH
.. macro:: NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS
(``4``)
SETTINGS_MAX_CONCURRENT_STREAMS
.. macro:: NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE
(``7``)
SETTINGS_INITIAL_WINDOW_SIZE
.. macro:: NGHTTP2_SETTINGS_FLOW_CONTROL_OPTIONS
(``10``)
SETTINGS_FLOW_CONTROL_OPTIONS
.. macro:: NGHTTP2_SETTINGS_MAX
(``10``)
Maximum ID of :type:`nghttp2_settings_id`.
.. type:: nghttp2_error_code
The status codes for the RST_STREAM and GOAWAY frames.
.. macro:: NGHTTP2_NO_ERROR
(``0``)
No errors.
.. macro:: NGHTTP2_PROTOCOL_ERROR
(``1``)
PROTOCOL_ERROR
.. macro:: NGHTTP2_INTERNAL_ERROR
(``2``)
INTERNAL_ERROR
.. macro:: NGHTTP2_FLOW_CONTROL_ERROR
(``3``)
FLOW_CONTROL_ERROR
.. macro:: NGHTTP2_SETTINGS_TIMEOUT
(``4``)
SETTINGS_TIMEOUT
.. macro:: NGHTTP2_STREAM_CLOSED
(``5``)
STREAM_CLOSED
.. macro:: NGHTTP2_FRAME_SIZE_ERROR
(``6``)
FRAME_SIZE_ERROR
.. macro:: NGHTTP2_REFUSED_STREAM
(``7``)
REFUSED_STREAM
.. macro:: NGHTTP2_CANCEL
(``8``)
CANCEL
.. macro:: NGHTTP2_COMPRESSION_ERROR
(``9``)
COMPRESSION_ERROR
.. macro:: NGHTTP2_CONNECT_ERROR
(``10``)
CONNECT_ERROR
.. macro:: NGHTTP2_ENHANCE_YOUR_CALM
(``420``)
ENHANCE_YOUR_CALM
.. type:: nghttp2_headers_category
The category of HEADERS, which indicates the role of the frame. In
HTTP/2.0 spec, request, response, push response and other arbitrary
headers (e.g., trailers) are all called just HEADERS. To give the
application the role of incoming HEADERS frame, we define several
categories.
.. macro:: NGHTTP2_HCAT_REQUEST
(``0``)
The HEADERS frame is opening new stream, which is analogous to
SYN_STREAM in SPDY.
.. macro:: NGHTTP2_HCAT_RESPONSE
(``1``)
The HEADERS frame is the first response headers, which is
analogous to SYN_REPLY in SPDY.
.. macro:: NGHTTP2_HCAT_PUSH_RESPONSE
(``2``)
The HEADERS frame is the first headers sent against reserved
stream.
.. macro:: NGHTTP2_HCAT_HEADERS
(``3``)
The HEADERS frame which does not apply for the above categories,
which is analogous to HEADERS in SPDY.
.. type:: nghttp2_opt
Configuration options for :type:`nghttp2_session`.
.. macro:: NGHTTP2_OPT_NO_AUTO_STREAM_WINDOW_UPDATE
(``1``)
This option prevents the library from sending WINDOW_UPDATE for a
stream automatically. If this option is set to nonzero, the
library won't send WINDOW_UPDATE for a stream and the application
is responsible for sending WINDOW_UPDATE using
`nghttp2_submit_window_update`. By default, this option is set to
zero.
.. macro:: NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE
(``1 << 1``)
This option prevents the library from sending WINDOW_UPDATE for a
connection automatically. If this option is set to nonzero, the
library won't send WINDOW_UPDATE for a connection and the
application is responsible for sending WINDOW_UPDATE with stream
ID 0 using `nghttp2_submit_window_update`. By default, this
option is set to zero.
.. macro:: NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS
(``1 << 2``)
This option sets the SETTINGS_MAX_CONCURRENT_STREAMS value of
remote endpoint as if it is received in SETTINGS frame. Without
specifying this option, before the local endpoint receives
SETTINGS_MAX_CONCURRENT_STREAMS in SETTINGS frame from remote
endpoint, SETTINGS_MAX_CONCURRENT_STREAMS is unlimited. This may
cause problem if local endpoint submits lots of requests
initially and sending them at once to the remote peer may lead to
the rejection of some requests. Specifying this option to the
sensible value, say 100, may avoid this kind of issue. This value
will be overwritten if the local endpoint receives
SETTINGS_MAX_CONCURRENT_STREAMS from the remote endpoint.
Types (structs, unions and typedefs)
------------------------------------
.. type:: nghttp2_session
The primary structure to hold the resources needed for a HTTP/2.0
session. The details of this structure are intentionally hidden
from the public API.
.. type:: nghttp2_info
This struct is what `nghttp2_version()` returns. It holds
information about the particular nghttp2 version.
.. member:: int age
Age of this struct. This instance of nghttp2 sets it to
:macro:`NGHTTP2_VERSION_AGE` but a future version may bump it and
add more struct fields at the bottom
.. member:: int version_num
the :macro:`NGHTTP2_VERSION_NUM` number (since age ==1)
.. member:: const char *version_str
points to the :macro:`NGHTTP2_VERSION` string (since age ==1)
.. member:: const char *proto_str
points to the :macro:`NGHTTP2_PROTO_VERSION_ID` string this
instance implements (since age ==1)
.. type:: nghttp2_nv
The name/value pair, which mainly used to represent header fields.
.. member:: uint8_t *name
The *name* byte string, which is not necessarily ``NULL``
terminated.
.. member:: uint8_t *value
The *value* byte string, which is not necessarily ``NULL``
terminated.
.. member:: uint16_t namelen
The length of the *name*.
.. member:: uint16_t valuelen
The length of the *value*.
.. type:: nghttp2_frame_hd
The frame header.
.. member:: uint16_t length
The length field of this frame, excluding frame header.
.. member:: uint8_t type
The type of this frame. See `nghttp2_frame`.
.. member:: uint8_t flags
The flags.
.. member:: int32_t stream_id
The stream identifier (aka, stream ID)
.. type:: nghttp2_data_source
This union represents the some kind of data source passed to
:type:`nghttp2_data_source_read_callback`.
.. member:: int fd
The integer field, suitable for a file descriptor.
.. member:: void *ptr
The pointer to an arbitrary object.
.. type:: typedef ssize_t (*nghttp2_data_source_read_callback) (nghttp2_session *session, int32_t stream_id, uint8_t *buf, size_t length, int *eof, nghttp2_data_source *source, void *user_data)
Callback function invoked when the library wants to read data from
the *source*. The read data is sent in the stream *stream_id*. The
implementation of this function must read at most *length* bytes of
data from *source* (or possibly other places) and store them in
*buf* and return number of data stored in *buf*. If EOF is reached,
set *\*eof* to 1. If the application wants to postpone DATA frames,
(e.g., asynchronous I/O, or reading data blocks for long time), it
is achieved by returning :macro:`NGHTTP2_ERR_DEFERRED` without
reading any data in this invocation. The library removes DATA
frame from the outgoing queue temporarily. To move back deferred
DATA frame to outgoing queue, call `nghttp2_session_resume_data()`.
In case of error, there are 2 choices. Returning
:macro:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close the stream
by issuing RST_STREAM with :macro:`NGHTTP2_INTERNAL_ERROR`.
Returning :macro:`NGHTTP2_ERR_CALLBACK_FAILURE` will signal the
entire session failure.
.. type:: nghttp2_data_provider
This struct represents the data source and the way to read a chunk
of data from it.
.. member:: nghttp2_data_source source
The data source.
.. member:: nghttp2_data_source_read_callback read_callback
The callback function to read a chunk of data from the *source*.
.. type:: nghttp2_headers
The HEADERS frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: nghttp2_nv *nva
The name/value pairs.
.. member:: size_t nvlen
The number of name/value pairs in *nva*.
.. member:: nghttp2_headers_category cat
The category of this HEADERS frame.
.. member:: int32_t pri
The priority.
.. type:: nghttp2_priority
The PRIORITY frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: int32_t pri
The priority.
.. type:: nghttp2_rst_stream
The RST_STREAM frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: nghttp2_error_code error_code
The error code. See :type:`nghttp2_error_code`.
.. type:: nghttp2_settings_entry
The SETTINGS ID/Value pair. It has the following members:
.. member:: int32_t settings_id
The SETTINGS ID. See :type:`nghttp2_settings_id`.
.. member:: uint32_t value
The value of this entry.
.. type:: nghttp2_settings
The SETTINGS frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: size_t niv
The number of SETTINGS ID/Value pairs in *iv*.
.. member:: nghttp2_settings_entry *iv
The pointer to the array of SETTINGS ID/Value pair.
.. type:: nghttp2_push_promise
The PUSH_PROMISE frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: nghttp2_nv *nva
The name/value pairs.
.. member:: size_t nvlen
The number of name/value pairs in *nva*.
.. member:: int32_t promised_stream_id
The promised stream ID
.. type:: nghttp2_ping
The PING frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: uint8_t opaque_data[8]
The opaque data
.. type:: nghttp2_goaway
The GOAWAY frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: int32_t last_stream_id
The last stream stream ID.
.. member:: nghttp2_error_code error_code
The error code. See :type:`nghttp2_error_code`.
.. member:: uint8_t *opaque_data
The additional debug data
.. member:: size_t opaque_data_len
The length of *opaque_data* member.
.. type:: nghttp2_window_update
The WINDOW_UPDATE frame. It has the following members:
.. member:: nghttp2_frame_hd hd
The frame header.
.. member:: int32_t window_size_increment
The window size increment.
.. type:: nghttp2_frame
This union includes all frames to pass them to various function
calls as nghttp2_frame type. The DATA frame is intentionally
omitted from here.
.. member:: nghttp2_frame_hd hd
The frame header, which is convenient to inspect frame header.
.. member:: nghttp2_headers headers
The HEADERS frame.
.. member:: nghttp2_priority priority
The PRIORITY frame.
.. member:: nghttp2_rst_stream rst_stream
The RST_STREAM frame.
.. member:: nghttp2_settings settings
The SETTINGS frame.
.. member:: nghttp2_push_promise push_promise
The PUSH_PROMISE frame.
.. member:: nghttp2_ping ping
The PING frame.
.. member:: nghttp2_goaway goaway
The GOAWAY frame.
.. member:: nghttp2_window_update window_update
The WINDOW_UPDATE frame.
.. type:: typedef ssize_t (*nghttp2_send_callback) (nghttp2_session *session, const uint8_t *data, size_t length, int flags, void *user_data)
Callback function invoked when *session* wants to send data to the
remote peer. The implementation of this function must send at most
*length* bytes of data stored in *data*. The *flags* is currently
not used and always 0. It must return the number of bytes sent if
it succeeds. If it cannot send any single byte without blocking,
it must return :macro:`NGHTTP2_ERR_WOULDBLOCK`. For other errors, it
must return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`. The *user_data*
pointer is the third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
.. type:: typedef ssize_t (*nghttp2_recv_callback) (nghttp2_session *session, uint8_t *buf, size_t length, int flags, void *user_data)
Callback function invoked when *session* wants to receive data from
the remote peer. The implementation of this function must read at
most *length* bytes of data and store it in *buf*. The *flags* is
currently not used and always 0. It must return the number of bytes
written in *buf* if it succeeds. If it cannot read any single byte
without blocking, it must return :macro:`NGHTTP2_ERR_WOULDBLOCK`. If
it gets EOF before it reads any single byte, it must return
:macro:`NGHTTP2_ERR_EOF`. For other errors, it must return
:macro:`NGHTTP2_ERR_CALLBACK_FAILURE`. Returning 0 is treated as
:macro:`NGHTTP2_ERR_WOULDBLOCK`. The *user_data* pointer is the
third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
.. type:: typedef int (*nghttp2_on_frame_recv_callback) (nghttp2_session *session, const nghttp2_frame *frame, void *user_data)
Callback function invoked by `nghttp2_session_recv()` when a
non-DATA frame is received. The *user_data* pointer is the third
argument passed in to the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
If the application uses `nghttp2_session_mem_recv()`, it can return
:macro:`NGHTTP2_ERR_PAUSE` to make `nghttp2_session_mem_recv()`
return without processing further input bytes. The *frame*
parameter is retained until `nghttp2_session_continue()` is
called. The application must retain the input bytes which was used
to produce the *frame* parameter, because it may refer to the
memory region included in the input bytes. The application which
returns :macro:`NGHTTP2_ERR_PAUSE` must call
`nghttp2_session_continue()` before `nghttp2_session_mem_recv()`.
The implementation of this function must return 0 if it
succeeds. It may return :macro:`NGHTTP2_ERR_PAUSE`. If the other
nonzero value is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_invalid_frame_recv_callback) (nghttp2_session *session, const nghttp2_frame *frame, nghttp2_error_code error_code, void *user_data)
Callback function invoked by `nghttp2_session_recv()` when an
invalid non-DATA frame is received. The *error_code* is one of the
:macro:`nghttp2_error_code` and indicates the error. When this
callback function is invoked, the library automatically submits
either RST_STREAM or GOAWAY frame. The *user_data* pointer is the
third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_data_chunk_recv_callback) (nghttp2_session *session, uint8_t flags, int32_t stream_id, const uint8_t *data, size_t len, void *user_data)
Callback function invoked when a chunk of data in DATA frame is
received. The *stream_id* is the stream ID this DATA frame belongs
to. The *flags* is the flags of DATA frame which this data chunk is
contained. ``(flags & NGHTTP2_FLAG_END_STREAM) != 0`` does not
necessarily mean this chunk of data is the last one in the
stream. You should use :type:`nghttp2_on_data_recv_callback` to
know all data frames are received. The *user_data* pointer is the
third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
If the application uses `nghttp2_session_mem_recv()`, it can return
:macro:`NGHTTP2_ERR_PAUSE` to make `nghttp2_session_mem_recv()`
return without processing further input bytes. The *frame*
parameter is retained until `nghttp2_session_continue()` is
called. The application must retain the input bytes which was used
to produce the *frame* parameter, because it may refer to the
memory region included in the input bytes. The application which
returns :macro:`NGHTTP2_ERR_PAUSE` must call
`nghttp2_session_continue()` before `nghttp2_session_mem_recv()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_data_recv_callback) (nghttp2_session *session, uint16_t length, uint8_t flags, int32_t stream_id, void *user_data)
Callback function invoked when DATA frame is received. The actual
data it contains are received by
:type:`nghttp2_on_data_chunk_recv_callback`. The *user_data*
pointer is the third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_before_frame_send_callback) (nghttp2_session *session, const nghttp2_frame *frame, void *user_data)
Callback function invoked before the non-DATA frame *frame* is
sent. This may be useful, for example, to know the stream ID of
HEADERS and PUSH_PROMISE frame (see also
`nghttp2_session_get_stream_user_data()`), which is not assigned
when it was queued. The *user_data* pointer is the third argument
passed in to the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_frame_send_callback) (nghttp2_session *session, const nghttp2_frame *frame, void *user_data)
Callback function invoked after the non-DATA frame *frame* is sent.
The *user_data* pointer is the third argument passed in to the call
to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_frame_not_send_callback) (nghttp2_session *session, const nghttp2_frame *frame, int lib_error_code, void *user_data)
Callback function invoked after the non-DATA frame *frame* is not
sent because of the error. The error is indicated by the
*lib_error_code*, which is one of the values defined in
:type:`nghttp2_error`. The *user_data* pointer is the third
argument passed in to the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_data_send_callback) (nghttp2_session *session, uint16_t length, uint8_t flags, int32_t stream_id, void *user_data)
Callback function invoked after DATA frame is sent. The *user_data*
pointer is the third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_stream_close_callback) (nghttp2_session *session, int32_t stream_id, nghttp2_error_code error_code, void *user_data)
Callback function invoked when the stream *stream_id* is
closed. The reason of closure is indicated by the *error_code*. The
stream_user_data, which was specified in `nghttp2_submit_request()`
or `nghttp2_submit_headers()`, is still available in this
function. The *user_data* pointer is the third argument passed in
to the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_request_recv_callback) (nghttp2_session *session, int32_t stream_id, void *user_data)
Callback function invoked when the request from the remote peer is
received. In other words, the frame with END_STREAM flag set is
received. In HTTP, this means HTTP request, including request
body, is fully received. The *user_data* pointer is the third
argument passed in to the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_frame_recv_parse_error_callback) (nghttp2_session *session, nghttp2_frame_type type, const uint8_t *head, size_t headlen, const uint8_t *payload, size_t payloadlen, int lib_error_code, void *user_data)
Callback function invoked when the received control frame octets
could not be parsed correctly. The *type* indicates the type of
received non-DATA frame. The *head* is the pointer to the header of
the received frame. The *headlen* is the length of the
*head*. According to the spec, the *headlen* is always 8. In other
words, the *head* is the first 8 bytes of the received frame. The
*payload* is the pointer to the data portion of the received frame.
The *payloadlen* is the length of the *payload*. This is the data
after the length field. The *lib_error_code* is one of the error
code defined in :macro:`nghttp2_error` and indicates the error. The
*user_data* pointer is the third argument passed in to the call to
`nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: typedef int (*nghttp2_on_unknown_frame_recv_callback) (nghttp2_session *session, const uint8_t *head, size_t headlen, const uint8_t *payload, size_t payloadlen, void *user_data)
Callback function invoked when the received frame type is
unknown. The *head* is the pointer to the header of the received
frame. The *headlen* is the length of the *head*. According to the
spec, the *headlen* is always 8. In other words, the *head* is the
first 8 bytes of the received frame. The *payload* is the pointer
to the data portion of the received frame. The *payloadlen* is the
length of the *payload*. This is the data after the length
field. The *user_data* pointer is the third argument passed in to
the call to `nghttp2_session_client_new()` or
`nghttp2_session_server_new()`.
The implementation of this function must return 0 if it
succeeds. If nonzero is returned, it is treated as fatal error and
`nghttp2_session_recv()` and `nghttp2_session_send()` functions
immediately return :macro:`NGHTTP2_ERR_CALLBACK_FAILURE`.
.. type:: nghttp2_session_callbacks
Callback functions.
.. member:: nghttp2_send_callback send_callback
Callback function invoked when the *session* wants to send data
to the remote peer.
.. member:: nghttp2_recv_callback recv_callback
Callback function invoked when the *session* wants to receive
data from the remote peer.
.. member:: nghttp2_on_frame_recv_callback on_frame_recv_callback
Callback function invoked by `nghttp2_session_recv()` when a
non-DATA frame is received.
.. member:: nghttp2_on_invalid_frame_recv_callback on_invalid_frame_recv_callback
Callback function invoked by `nghttp2_session_recv()` when an
invalid non-DATA frame is received.
.. member:: nghttp2_on_data_chunk_recv_callback on_data_chunk_recv_callback
Callback function invoked when a chunk of data in DATA frame is
received.
.. member:: nghttp2_on_data_recv_callback on_data_recv_callback
Callback function invoked when DATA frame is received.
.. member:: nghttp2_before_frame_send_callback before_frame_send_callback
Callback function invoked before the non-DATA frame is sent.
.. member:: nghttp2_on_frame_send_callback on_frame_send_callback
Callback function invoked after the non-DATA frame is sent.
.. member:: nghttp2_on_frame_not_send_callback on_frame_not_send_callback
The callback function invoked when a non-DATA frame is not sent
because of an error.
.. member:: nghttp2_on_data_send_callback on_data_send_callback
Callback function invoked after DATA frame is sent.
.. member:: nghttp2_on_stream_close_callback on_stream_close_callback
Callback function invoked when the stream is closed.
.. member:: nghttp2_on_request_recv_callback on_request_recv_callback
Callback function invoked when request from the remote peer is
received.
.. member:: nghttp2_on_frame_recv_parse_error_callback
Callback function invoked when the received non-DATA frame octets
could not be parsed correctly.
.. member:: nghttp2_on_unknown_frame_recv_callback on_unknown_frame_recv_callback
Callback function invoked when the received frame type is
unknown.
.. type:: nghttp2_opt_set
Struct to store option values for nghttp2_session.
.. member:: uint32_t peer_max_concurrent_streams
:macro:`NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS`
.. member:: uint8_t no_auto_stream_window_update
:macro:`NGHTTP2_OPT_NO_AUTO_STREAM_WINDOW_UPDATE`
.. member:: uint8_t no_auto_connection_window_update
:macro:`NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE`
.. type:: nghttp2_gzip
The gzip stream to inflate data. The details of this structure are
intentionally hidden from the public API.
Functions
---------
.. function:: int nghttp2_session_client_new(nghttp2_session **session_ptr, const nghttp2_session_callbacks *callbacks, void *user_data)
Initializes *\*session_ptr* for client use. The all members of
*callbacks* are copied to *\*session_ptr*. Therefore *\*session_ptr*
does not store *callbacks*. *user_data* is an arbitrary user
supplied data, which will be passed to the callback functions.
The :member:`nghttp2_session_callbacks.send_callback` must be
specified. If the application code uses `nghttp2_session_recv()`,
the :member:`nghttp2_session_callbacks.recv_callback` must be
specified. The other members of *callbacks* can be ``NULL``.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_session_server_new(nghttp2_session **session_ptr, const nghttp2_session_callbacks *callbacks, void *user_data)
Initializes *\*session_ptr* for server use. The all members of
*callbacks* are copied to *\*session_ptr*. Therefore *\*session_ptr*
does not store *callbacks*. *user_data* is an arbitrary user
supplied data, which will be passed to the callback functions.
The :member:`nghttp2_session_callbacks.send_callback` must be
specified. If the application code uses `nghttp2_session_recv()`,
the :member:`nghttp2_session_callbacks.recv_callback` must be
specified. The other members of *callbacks* can be ``NULL``.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_session_client_new2(nghttp2_session **session_ptr, const nghttp2_session_callbacks *callbacks, void *user_data, uint32_t opt_set_mask, const nghttp2_opt_set *opt_set)
Like `nghttp2_session_client_new()`, but with additional options
specified in the *opt_set*. The caller must set bitwise-OR of
:macro:`nghttp2_opt` for given options. For example, if it
specifies :macro:`NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE` and
:macro:`NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS` in the *opt_set*,
the *opt_set_mask* should be
``NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE |
NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS``.
If the *opt_set_mask* is 0, the *opt_set* could be ``NULL`` safely
and the call is equivalent to `nghttp2_session_client_new()`.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_session_server_new2(nghttp2_session **session_ptr, const nghttp2_session_callbacks *callbacks, void *user_data, uint32_t opt_set_mask, const nghttp2_opt_set *opt_set)
Like `nghttp2_session_server_new()`, but with additional options
specified in the *opt_set*. The caller must set bitwise-OR of
:macro:`nghttp2_opt` for given options. For example, if it
specifies :macro:`NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE` and
:macro:`NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS` in the *opt_set*,
the *opt_set_mask* should be
``NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE |
NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS``.
If the *opt_set_mask* is 0, the *opt_set* could be ``NULL`` safely
and the call is equivalent to `nghttp2_session_server_new()`.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: void nghttp2_session_del(nghttp2_session *session)
Frees any resources allocated for *session*. If *session* is
``NULL``, this function does nothing.
.. function:: int nghttp2_session_send(nghttp2_session *session)
Sends pending frames to the remote peer.
This function retrieves the highest prioritized frame from the
outbound queue and sends it to the remote peer. It does this as
many as possible until the user callback
:member:`nghttp2_session_callbacks.send_callback` returns
:macro:`NGHTTP2_ERR_WOULDBLOCK` or the outbound queue becomes empty.
This function calls several callback functions which are passed
when initializing the *session*. Here is the simple time chart
which tells when each callback is invoked:
1. Get the next frame to send from outbound queue.
2. Prepare transmission of the frame.
3. If the control frame cannot be sent because some preconditions
are not met (e.g., request HEADERS cannot be sent after
GOAWAY),
:member:`nghttp2_session_callbacks.on_frame_not_send_callback` is
invoked. Abort the following steps.
4. If the frame is request HEADERS, the stream is opened
here.
5. :member:`nghttp2_session_callbacks.before_frame_send_callback` is
invoked.
6. :member:`nghttp2_session_callbacks.send_callback` is invoked one
or more times to send the frame.
7. If the frame is a control frame,
:member:`nghttp2_session_callbacks.on_frame_send_callback` is
invoked.
8. If the frame is a DATA frame,
:member:`nghttp2_session_callbacks.on_data_send_callback` is
invoked.
9. If the transmission of the frame triggers closure of the stream,
the stream is closed and
:member:`nghttp2_session_callbacks.on_stream_close_callback` is
invoked.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_CALLBACK_FAILURE`
The callback function failed.
.. function:: int nghttp2_session_recv(nghttp2_session *session)
Receives frames from the remote peer.
This function receives as many frames as possible until the user
callback :member:`nghttp2_session_callbacks.recv_callback` returns
:macro:`NGHTTP2_ERR_WOULDBLOCK`. This function calls several
callback functions which are passed when initializing the
*session*. Here is the simple time chart which tells when each
callback is invoked:
1. :member:`nghttp2_session_callbacks.recv_callback` is invoked one
or more times to receive frame header.
2. If the frame is DATA frame:
1. :member:`nghttp2_session_callbacks.recv_callback` is invoked
to receive DATA payload. For each chunk of data,
:member:`nghttp2_session_callbacks.on_data_chunk_recv_callback`
is invoked.
2. If one DATA frame is completely received,
:member:`nghttp2_session_callbacks.on_data_recv_callback` is
invoked. If the frame is the final frame of the request,
:member:`nghttp2_session_callbacks.on_request_recv_callback`
is invoked. If the reception of the frame triggers the
closure of the stream,
:member:`nghttp2_session_callbacks.on_stream_close_callback`
is invoked.
3. If the frame is the control frame:
1. :member:`nghttp2_session_callbacks.recv_callback` is invoked
one or more times to receive whole frame.
2. If the received frame is valid,
:member:`nghttp2_session_callbacks.on_frame_recv_callback` is
invoked. If the frame is the final frame of the request,
:member:`nghttp2_session_callbacks.on_request_recv_callback`
is invoked. If the reception of the frame triggers the
closure of the stream,
:member:`nghttp2_session_callbacks.on_stream_close_callback`
is invoked.
3. If the received frame is unpacked but is interpreted as
invalid,
:member:`nghttp2_session_callbacks.on_invalid_frame_recv_callback`
is invoked.
4. If the received frame could not be unpacked correctly,
:member:`nghttp2_session_callbacks.on_frame_recv_parse_error_callback`
is invoked.
5. If the received frame type is unknown,
:member:`nghttp2_session_callbacks.on_unknown_frame_recv_callback`
is invoked.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_EOF`
The remote peer did shutdown on the connection.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_CALLBACK_FAILURE`
The callback function failed.
.. function:: ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in, size_t inlen)
Processes data *in* as an input from the remote endpoint. The
*inlen* indicates the number of bytes in the *in*.
This function behaves like `nghttp2_session_recv()` except that it
does not use :member:`nghttp2_session_callbacks.recv_callback` to
receive data; the *in* is the only data for the invocation of this
function. If all bytes are processed, this function returns. The
other callbacks are called in the same way as they are in
`nghttp2_session_recv()`.
In the current implementation, this function always tries to
processes all input data unless either an error occurs or
:macro:`NGHTTP2_ERR_PAUSE` is returned from
:member:`nghttp2_session_callbacks.on_frame_recv_callback` or
:member:`nghttp2_session_callbacks.on_data_chunk_recv_callback`.
If :macro:`NGHTTP2_ERR_PAUSE` is used, the return value includes the
number of bytes which was used to produce the data or frame for the
callback.
This function returns the number of processed bytes, or one of the
following negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_CALLBACK_FAILURE`
The callback function failed.
.. function:: int nghttp2_session_continue(nghttp2_session *session)
Perform post-processing after `nghttp2_session_mem_recv()` was
paused by :macro:`NGHTTP2_ERR_PAUSE` from
:member:`nghttp2_session_callbacks.on_frame_recv_callback` or
:member:`nghttp2_session_callbacks.on_data_chunk_recv_callback`.
This function frees resources associated with paused frames. It
may also call additional callbacks, such as
:member:`nghttp2_session_callbacks.on_stream_close_callback`.
If this function succeeds, the application can call
`nghttp2_session_mem_recv()` again.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_CALLBACK_FAILURE`
The callback function failed.
.. function:: int nghttp2_session_resume_data(nghttp2_session *session, int32_t stream_id)
Puts back previously deferred DATA frame in the stream *stream_id*
to the outbound queue.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The stream does not exist or no deferred data exist.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_session_want_read(nghttp2_session *session)
Returns nonzero value if *session* wants to receive data from the
remote peer.
If both `nghttp2_session_want_read()` and
`nghttp2_session_want_write()` return 0, the application should
drop the connection.
.. function:: int nghttp2_session_want_write(nghttp2_session *session)
Returns nonzero value if *session* wants to send data to the remote
peer.
If both `nghttp2_session_want_read()` and
`nghttp2_session_want_write()` return 0, the application should
drop the connection.
.. function:: void* nghttp2_session_get_stream_user_data(nghttp2_session *session, int32_t stream_id)
Returns stream_user_data for the stream *stream_id*. The
stream_user_data is provided by `nghttp2_submit_request()`,
`nghttp2_submit_headers()` or
`nghttp2_session_set_stream_user_data()`. Unless it is set using
`nghttp2_session_set_stream_user_data()`, if the stream is
initiated by the remote endpoint, stream_user_data is always
``NULL``. If the stream does not exist, this function returns
``NULL``.
.. function:: int nghttp2_session_set_stream_user_data(nghttp2_session *session, int32_t stream_id, void *stream_user_data)
Sets the *stream_user_data* to the stream denoted by the
*stream_id*. If a stream user data is already set to the stream, it
is replaced with the *stream_user_data*. It is valid to specify
``NULL`` in the *stream_user_data*, which nullifies the associated
data pointer.
It is valid to set the *stream_user_data* to the stream reserved by
PUSH_PROMISE frame.
This function returns 0 if it succeeds, or one of following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The stream does not exist
.. function:: size_t nghttp2_session_get_outbound_queue_size(nghttp2_session *session)
Returns the number of frames in the outbound queue. This does not
include the deferred DATA frames.
.. function:: int32_t nghttp2_session_get_stream_effective_recv_data_length (nghttp2_session *session, int32_t stream_id)
Returns the number of DATA payload in bytes received without
WINDOW_UPDATE transmission for the stream *stream_id*. The local
(receive) window size can be adjusted by
`nghttp2_submit_window_update()`. This function takes into account
that and returns effective data length. In particular, if the
local window size is reduced by submitting negative
window_size_increment with `nghttp2_submit_window_update()`, this
function returns the number of bytes less than actually received.
If flow control is disabled for that stream, this function returns
0.
This function returns -1 if it fails.
.. function:: int32_t nghttp2_session_get_stream_effective_local_window_size (nghttp2_session *session, int32_t stream_id)
Returns the local (receive) window size for the stream
*stream_id*. The local window size can be adjusted by
`nghttp2_submit_window_update()`. This function takes into account
that and returns effective window size.
This function returns -1 if it fails.
.. function:: int32_t nghttp2_session_get_effective_recv_data_length (nghttp2_session *session)
Returns the number of DATA payload in bytes received without
WINDOW_UPDATE transmission for a connection. The local (receive)
window size can be adjusted by
`nghttp2_submit_window_update()`. This function takes into account
that and returns effective data length. In particular, if the local
window size is reduced by submitting negative window_size_increment
with `nghttp2_submit_window_update()`, this function returns the
number of bytes less than actually received.
If flow control is disabled for a connection, this function returns
0.
This function returns -1 if it fails.
.. function:: int32_t nghttp2_session_get_effective_local_window_size (nghttp2_session *session)
Returns the local (receive) window size for a connection. The local
window size can be adjusted by
`nghttp2_submit_window_update()`. This function takes into account
that and returns effective window size.
This function returns -1 if it fails.
.. function:: int nghttp2_session_fail_session(nghttp2_session *session, nghttp2_error_code error_code)
Submits GOAWAY frame with the given *error_code*.
This function should be called when the connection should be
terminated after sending GOAWAY. If the remaining streams should be
processed after GOAWAY, use `nghttp2_submit_goaway()` instead.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_session_upgrade(nghttp2_session *session, const uint8_t *settings_payload, size_t settings_payloadlen, void *stream_user_data)
Performs post-process of HTTP Upgrade request. This function can be
called from both client and server, but the behavior is very
different in each other.
If called from client side, the *settings_payload* must be the
value sent in ``HTTP2-Settings`` header field and must be decoded
by base64url decoder. The *settings_payloadlen* is the length of
*settings_payload*. The *settings_payload* is unpacked and its
setting values will be submitted using
`nghttp2_submit_settings()`. This means that the client application
code does not need to submit SETTINGS by itself. The stream with
stream ID=1 is opened and the *stream_user_data* is used for its
stream_user_data. The opened stream becomes half-closed (local)
state.
If called from server side, the *settings_payload* must be the
value received in ``HTTP2-Settings`` header field and must be
decoded by base64url decoder. The *settings_payloadlen* is the
length of *settings_payload*. It is treated as if the SETTINGS
frame with that payload is received. Thus, callback functions for
the reception of SETTINGS frame will be invoked. The stream with
stream ID=1 is opened. The *stream_user_data* is ignored. The
opened stream becomes half-closed (remote).
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *settings_payload* is badly formed.
:macro:`NGHTTP2_ERR_PROTO`
The stream ID 1 is already used or closed; or is not available;
or the *settings_payload* does not include both
:macro:`NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS` and
:macro:`NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE`.
.. function:: ssize_t nghttp2_pack_settings_payload(uint8_t *buf, size_t buflen, const nghttp2_settings_entry *iv, size_t niv)
Serializes the SETTINGS values *iv* in the *buf*. The size of the
*buf* is specified by *buflen*. The number of entries in the *iv*
array is given by *niv*. The required space in *buf* for the *niv*
entries is ``8*niv`` bytes and if the given buffer is too small, an
error is returned. This function is used mainly for creating a
SETTINGS payload to be sent with the ``HTTP2-Settings`` header
field in an HTTP Upgrade request. The data written in *buf* is NOT
base64url encoded and the application is responsible for encoding.
This function returns the number of bytes written in *buf*, or one
of the following negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *iv* contains duplicate settings ID or invalid value.
:macro:`NGHTTP2_ERR_INSUFF_BUFSIZE`
The provided *buflen* size is too small to hold the output.
.. function:: const char* nghttp2_strerror(int lib_error_code)
Returns string describing the *lib_error_code*. The
*lib_error_code* must be one of the :macro:`nghttp2_error`.
.. function:: int nghttp2_submit_request(nghttp2_session *session, int32_t pri, const nghttp2_nv *nva, size_t nvlen, const nghttp2_data_provider *data_prd, void *stream_user_data)
Submits HEADERS frame and optionally one or more DATA frames.
The *pri* is priority of this request. 0 is the highest priority
value and :macro:`NGHTTP2_PRI_LOWEST` is the lowest value.
The *nva* is an array of name/value pair :type:`nghttp2_nv` with
*nvlen* elements. The value is opaque sequence of bytes and
therefore can contain NULL byte (0x0). If the application requires
that the ordering of values for a single header field name
appearing in different header fields, it has to concatenate them
using NULL byte (0x0) before passing them to this function.
HTTP/2.0 specification has requirement about header fields in the
request HEADERS. See the specification for more details.
This function creates copies of all name/value pairs in *nva*. It
also lower-cases all names in *nva*.
If *data_prd* is not ``NULL``, it provides data which will be sent
in subsequent DATA frames. In this case, a method that allows
request message bodies
(http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9) must
be specified with ``:method`` key in *nva* (e.g. ``POST``). This
function does not take ownership of the *data_prd*. The function
copies the members of the *data_prd*. If *data_prd* is ``NULL``,
HEADERS have END_STREAM set. The *stream_user_data* is data
associated to the stream opened by this request and can be an
arbitrary pointer, which can be retrieved later by
`nghttp2_session_get_stream_user_data()`.
Since the library reorders the frames and tries to send the highest
prioritized one first and the HTTP/2.0 specification requires the
stream ID must be strictly increasing, the stream ID of this
request cannot be known until it is about to sent. To know the
stream ID of the request, the application can use
:member:`nghttp2_session_callbacks.before_frame_send_callback`. This
callback is called just before the frame is sent. For HEADERS
frame, the argument frame has the stream ID assigned. Also since
the stream is already opened,
`nghttp2_session_get_stream_user_data()` can be used to get
*stream_user_data* to identify which HEADERS we are processing.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *pri* is invalid; or the *nva* includes empty name, or name
which contains invalid characters.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_response(nghttp2_session *session, int32_t stream_id, const nghttp2_nv *nva, size_t nvlen, const nghttp2_data_provider *data_prd)
Submits response HEADERS frame and optionally one or more DATA
frames against the stream *stream_id*.
The *nva* is an array of name/value pair :type:`nghttp2_nv` with
*nvlen* elements. The value is opaque sequence of bytes and
therefore can contain NULL byte (0x0). If the application requires
that the ordering of values for a single header field name
appearing in different header fields, it has to concatenate them
using NULL byte (0x0) before passing them to this function.
HTTP/2.0 specification has requirement about header fields in the
response HEADERS. See the specification for more details.
This function creates copies of all name/value pairs in *nva*. It
also lower-cases all names in *nva*.
If *data_prd* is not ``NULL``, it provides data which will be sent
in subsequent DATA frames. This function does not take ownership
of the *data_prd*. The function copies the members of the
*data_prd*. If *data_prd* is ``NULL``, HEADERS will have
END_STREAM flag set.
This method can be used as normal HTTP response and server-push
response. When pushing a resource using this function, the
*session* must be configured using `nghttp2_session_server_new()`
or its variants and the target stream denoted by the *stream_id*
must be reserved using `nghttp2_submit_push_promise()`.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *nva* includes empty name or name which contains invalid
characters.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_headers(nghttp2_session *session, uint8_t flags, int32_t stream_id, int32_t pri, const nghttp2_nv *nva, size_t nvlen, void *stream_user_data)
Submits HEADERS frame. The *flags* is bitwise OR of the
following values:
* :macro:`NGHTTP2_FLAG_END_STREAM`
* :macro:`NGHTTP2_FLAG_END_HEADERS`
* :macro:`NGHTTP2_FLAG_PRIORITY`
If *flags* includes :macro:`NGHTTP2_FLAG_END_STREAM`, this frame has
END_STREAM flag set. The library does not support header
continuation and the HEADERS frame always has
:macro:`NGHTTP2_FLAG_END_HEADERS` flag set regardless of the *flags*
value.
If the *stream_id* is -1, this frame is assumed as request (i.e.,
request HEADERS frame which opens new stream). In this case, the
actual stream ID is assigned just before the frame is sent. For
response, specify stream ID in *stream_id*.
The *pri* is priority of this request.
The *nva* is an array of name/value pair :type:`nghttp2_nv` with
*nvlen* elements. The value is opaque sequence of bytes and
therefore can contain NULL byte (0x0). If the application requires
that the ordering of values for a single header field name
appearing in different header fields, it has to concatenate them
using NULL byte (0x0) before passing them to this function.
This function creates copies of all name/value pairs in *nva*. It
also lower-cases all names in *nva*.
The *stream_user_data* is a pointer to an arbitrary data which is
associated to the stream this frame will open. Therefore it is only
used if this frame opens streams, in other words, it changes stream
state from idle or reserved to open.
This function is low-level in a sense that the application code can
specify flags directly. For usual HTTP request,
`nghttp2_submit_request()` is useful.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *pri* is invalid; or the *nva* includes empty name, or name
which contains invalid characters.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_data(nghttp2_session *session, uint8_t flags, int32_t stream_id, const nghttp2_data_provider *data_prd)
Submits one or more DATA frames to the stream *stream_id*. The
data to be sent are provided by *data_prd*. If *flags* contains
:macro:`NGHTTP2_FLAG_END_STREAM`, the last DATA frame has END_STREAM
flag set.
This function does not take ownership of the *data_prd*. The
function copies the members of the *data_prd*.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_STREAM_CLOSED`
The stream is already closed or does not exist.
.. function:: int nghttp2_submit_priority(nghttp2_session *session, uint8_t flags, int32_t stream_id, int32_t pri)
Submits PRIORITY frame to change the priority of stream *stream_id*
to the priority value *pri*.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *pri* is negative.
:macro:`NGHTTP2_ERR_STREAM_CLOSED`
The stream is already closed or does not exist.
.. function:: int nghttp2_submit_rst_stream(nghttp2_session *session, uint8_t flags, int32_t stream_id, nghttp2_error_code error_code)
Submits RST_STREAM frame to cancel/reject the stream *stream_id*
with the error code *error_code*.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_settings(nghttp2_session *session, uint8_t flags, const nghttp2_settings_entry *iv, size_t niv)
Stores local settings and submits SETTINGS frame. The *iv* is the
pointer to the array of :type:`nghttp2_settings_entry`. The *niv*
indicates the number of :type:`nghttp2_settings_entry`.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
This function does not take ownership of the *iv*. This function
copies all the elements in the *iv*.
While updating individual stream's local window size, if the window
size becomes strictly larger than NGHTTP2_MAX_WINDOW_SIZE,
RST_STREAM is issued against such a stream.
SETTINGS with :macro:`NGHTTP2_FLAG_ACK` is automatically submitted
by the library and application could not send it at its will.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *iv* contains invalid value (e.g., attempting to re-enable
flow control).
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_push_promise(nghttp2_session *session, uint8_t flags, int32_t stream_id, const nghttp2_nv *nva, size_t nvlen)
Submits PUSH_PROMISE frame. The *flags* is currently ignored and
the resulting PUSH_PROMISE frame always has
:macro:`NGHTTP2_FLAG_END_PUSH_PROMISE` flag set due to the lack of
header continuation support in the library.
The *stream_id* must be client initiated stream ID.
The *nva* is an array of name/value pair :type:`nghttp2_nv` with
*nvlen* elements. The value is opaque sequence of bytes and
therefore can contain NULL byte (0x0). If the application requires
that the ordering of values for a single header field name
appearing in different header fields, it has to concatenate them
using NULL byte (0x0) before passing them to this function.
This function creates copies of all name/value pairs in *nva*. It
also lower-cases all names in *nva*.
Since the library reorders the frames and tries to send the highest
prioritized one first and the HTTP/2.0 specification requires the
stream ID must be strictly increasing, the promised stream ID
cannot be known until it is about to sent. To know the promised
stream ID, the application can use
:member:`nghttp2_session_callbacks.before_frame_send_callback`. This
callback is called just before the frame is sent. For PUSH_PROMISE
frame, the argument frame has the promised stream ID assigned.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *nva* includes empty name, or name which contains invalid
characters.
:macro:`NGHTTP2_ERR_STREAM_CLOSED`
The stream is already closed or does not exist.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_ping(nghttp2_session *session, uint8_t flags, uint8_t *opaque_data)
Submits PING frame. You don't have to send PING back when you
received PING frame. The library automatically submits PING frame
in this case.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
If the *opaque_data* is non ``NULL``, then it should point to the 8
bytes array of memory to specify opaque data to send with PING
frame. If the *opaque_data* is ``NULL``, zero-cleared 8 bytes will
be sent as opaque data.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_goaway(nghttp2_session *session, uint8_t flags, nghttp2_error_code error_code, uint8_t *opaque_data, size_t opaque_data_len)
Submits GOAWAY frame with the error code *error_code*.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
If the *opaque_data* is not ``NULL`` and *opaque_data_len* is not
zero, those data will be sent as additional debug data. The
library makes a copy of the memory region pointed by *opaque_data*
with the length *opaque_data_len*, so the caller does not need to
keep this memory after the return of this function. If the
*opaque_data_len* is 0, the *opaque_data* could be ``NULL``.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags, int32_t stream_id, int32_t window_size_increment)
Submits WINDOW_UPDATE frame.
The *flags* is currently ignored and should be
:macro:`NGHTTP2_FLAG_NONE`.
If the *window_size_increment* is positive, the WINDOW_UPDATE with
that value as window_size_increment is queued. If the
*window_size_increment* is larger than the received bytes from the
remote endpoint, the local window size is increased by that
difference.
If the *window_size_increment* is negative, the local window size
is decreased by -*window_size_increment*. If
:macro:`NGHTTP2_OPT_NO_AUTO_STREAM_WINDOW_UPDATE` (or
:macro:`NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE` if *stream_id*
is 0) is not set and the library decided that the WINDOW_UPDATE
should be submitted, then WINDOW_UPDATE is queued with the current
received bytes count.
If the *window_size_increment* is 0, the function does nothing and
returns 0.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_FLOW_CONTROL`
The local window size overflow or gets negative.
:macro:`NGHTTP2_ERR_STREAM_CLOSED`
The stream is already closed or does not exist.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_nv_compare_name(const nghttp2_nv *lhs, const nghttp2_nv *rhs)
Compares lhs->name with lhs->namelen bytes and rhs->name with
rhs->namelen bytes. Returns negative integer if lhs->name is found
to be less than rhs->name; or returns positive integer if lhs->name
is found to be greater than rhs->name; or returns 0 otherwise.
.. function:: int nghttp2_select_next_protocol(unsigned char **out, unsigned char *outlen, const unsigned char *in, unsigned int inlen)
A helper function for dealing with NPN in client side. The *in*
contains server's protocol in preferable order. The format of *in*
is length-prefixed and not null-terminated. For example,
``HTTP-draft-04/2.0`` and ``http/1.1`` stored in *in* like this::
in[0] = 17
in[1..17] = "HTTP-draft-04/2.0"
in[18] = 8
in[19..26] = "http/1.1"
inlen = 27
The selection algorithm is as follows:
1. If server's list contains ``HTTP-draft-04/2.0``, it is selected
and returns 1. The following step is not taken.
2. If server's list contains ``http/1.1``, this function selects
``http/1.1`` and returns 0. The following step is not taken.
3. This function selects nothing and returns -1. (So called
non-overlap case). In this case, *out* and *outlen* are left
untouched.
Selecting ``HTTP-draft-04/2.0`` means that ``HTTP-draft-04/2.0`` is
written into *\*out* and its length (which is 17) is
assigned to *\*outlen*.
See http://technotes.googlecode.com/git/nextprotoneg.html for more
details about NPN.
To use this method you should do something like::
static int select_next_proto_cb(SSL* ssl,
unsigned char **out,
unsigned char *outlen,
const unsigned char *in,
unsigned int inlen,
void *arg)
{
int rv;
rv = nghttp2_select_next_protocol(out, outlen, in, inlen);
if(rv == 1) {
((MyType*)arg)->http2_selected = 1;
}
return SSL_TLSEXT_ERR_OK;
}
...
SSL_CTX_set_next_proto_select_cb(ssl_ctx, select_next_proto_cb, my_obj);
Note that the HTTP/2.0 spec does use ALPN instead of NPN. This
function is provided for transitional period before ALPN is got
implemented in major SSL/TLS libraries.
.. function:: int nghttp2_gzip_inflate_new(nghttp2_gzip **inflater_ptr)
A helper function to set up a per request gzip stream to inflate data.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_GZIP`
The initialization of gzip stream failed.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: void nghttp2_gzip_inflate_del(nghttp2_gzip *inflater)
Frees the inflate stream. The *inflater* may be ``NULL``.
.. function:: int nghttp2_gzip_inflate(nghttp2_gzip *inflater, uint8_t *out, size_t *outlen_ptr, const uint8_t *in, size_t *inlen_ptr)
Inflates data in *in* with the length *\*inlen_ptr* and stores the
inflated data to *out* which has allocated size at least
*\*outlen_ptr*. On return, *\*outlen_ptr* is updated to represent
the number of data written in *out*. Similarly, *\*inlen_ptr* is
updated to represent the number of input bytes processed.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_GZIP`
The inflation of gzip stream failed.
The example follows::
void on_data_chunk_recv_callback(nghttp2_session *session,
uint8_t flags,
int32_t stream_id,
const uint8_t *data, size_t len,
void *user_data)
{
...
req = nghttp2_session_get_stream_user_data(session, stream_id);
nghttp2_gzip *inflater = req->inflater;
while(len > 0) {
uint8_t out[MAX_OUTLEN];
size_t outlen = MAX_OUTLEN;
size_t tlen = len;
int rv;
rv = nghttp2_gzip_inflate(inflater, out, &outlen, data, &tlen);
if(rv != 0) {
nghttp2_submit_rst_stream(session, stream_id,
NGHTTP2_INTERNAL_ERROR);
break;
}
... Do stuff ...
data += tlen;
len -= tlen;
}
....
}
.. function:: nghttp2_info *nghttp2_version(int least_version)
Returns a pointer to a nghttp2_info struct with version information about
the run-time library in use. The *least_version* argument can be set to a
24 bit numerical value for the least accepted version number and if the
condition is not met, this function will return a NULL. Pass in 0 to skip
the version checking.
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