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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>
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_PROTO_VERSION_ID
The protocol version identification of this library supports.
.. macro:: NGHTTP2_PROTO_VERSION_ID_LEN
The length of NGHTTP2_PROTO_VERSION_ID.
.. 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_CLIENT_CONNECTION_HEADER
The client connection header.
.. macro:: NGHTTP2_CLIENT_CONNECTION_HEADER_LEN
The length of 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_TOO_LARGE
(``-522``)
The length of the frame is too large.
.. macro:: NGHTTP2_ERR_HEADER_COMP
(``-523``)
Header block inflate/deflate error.
.. macro:: NGHTTP2_ERR_FLOW_CONTROL
(``-524``)
Flow control error
.. 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_PONG
(``0x1``)
The PONG flag.
.. type:: nghttp2_settings_id
The SETTINGS ID.
.. 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_STREAM_CLOSED
(``5``)
STREAM_CLOSED
.. macro:: NGHTTP2_FRAME_TOO_LARGE
(``6``)
FRAME_TOO_LARGE
.. macro:: NGHTTP2_REFUSED_STREAM
(``7``)
REFUSED_STREAM
.. macro:: NGHTTP2_CANCEL
(``8``)
CANCEL
.. macro:: NGHTTP2_COMPRESSION_ERROR
(``9``)
COMPRESSION_ERROR
.. 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, the application is
responsible for sending WINDOW_UPDATE using
`nghttp2_submit_window_update`.
.. macro:: NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE
(``2``)
This option prevents the library from sending WINDOW_UPDATE for a
connection automatically. If this option is set, the application
is responsible for sending WINDOW_UPDATE with stream ID 0 using
`nghttp2_submit_window_update`.
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_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:: int32_t pri
The priority.
.. member:: nghttp2_nv *nva
The name/value pairs.
.. member:: size_t nvlen
The number of name/value pairs in *nva*.
.. 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:: int32_t promised_stream_id
The promised stream ID
.. member:: nghttp2_nv *nva
The name/value pairs.
.. member:: size_t nvlen
The number of name/value pairs in *nva*.
.. 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`.
.. 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`.
.. type:: typedef int (*nghttp2_on_frame_recv_callback) (nghttp2_session *session, nghttp2_frame *frame, void *user_data)
Callback function invoked by `nghttp2_session_recv()` when a
non-DATA frame is received.
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_invalid_frame_recv_callback) (nghttp2_session *session, 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 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 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 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, 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 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, nghttp2_frame *frame, void *user_data)
Callback function invoked after the non-DATA frame *frame* is sent.
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, 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 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 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 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 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 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 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_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:: 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_set_option(nghttp2_session *session, int optname, void *optval, size_t optlen)
Sets the configuration option for the *session*. The *optname* is
one of :type:`nghttp2_opt`. The *optval* is the pointer to the
option value and the *optlen* is the size of *\*optval*. The
required type of *optval* varies depending on the *optname*. See
below.
The following *optname* are supported:
:macro:`NGHTTP2_OPT_NO_AUTO_STREAM_WINDOW_UPDATE`
The *optval* must be a pointer to ``int``. If the *\*optval* is
nonzero, the library will not send WINDOW_UPDATE for a stream
automatically. Therefore, the application is responsible for
sending WINDOW_UPDATE using
`nghttp2_submit_window_update`. This option defaults to 0.
:macro:`NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE`
The *optval* must be a pointer to ``int``. If the *\*optval* is
nonzero, the library will not send WINDOW_UPDATE for connection
automatically. Therefore, the application is responsible for
sending WINDOW_UPDATE using
`nghttp2_submit_window_update`. This option defaults to 0.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *optname* is not supported; or the *optval* and/or the
*optlen* are invalid.
.. 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_ctrl_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_ctrl_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_ctrl_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:
2.1. :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.
2.2. 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:
3.1. :member:`nghttp2_session_callbacks.recv_callback` is invoked
one or more times to receive whole frame.
3.2. If the received frame is valid,
:member:`nghttp2_session_callbacks.on_ctrl_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.
3.3. If the received frame is unpacked but is interpreted as
invalid,
:member:`nghttp2_session_callbacks.on_invalid_ctrl_recv_callback`
is invoked.
3.4. If the received frame could not be unpacked correctly,
:member:`nghttp2_session_callbacks.on_ctrl_recv_parse_error_callback`
is invoked.
3.5. If the received frame type is unknown,
:member:`nghttp2_session_callbacks.on_unknown_ctrl_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 an error occurs.
This function returns the number of processed bytes, or one of the
following negative error codes:
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. 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()` or
`nghttp2_submit_syn_stream()`. If the stream is initiated by the
remote endpoint, stream_user_data is always ``NULL``. If the stream
is initiated by the local endpoint and ``NULL`` is given in
`nghttp2_submit_request()` or `nghttp2_submit_syn_stream()`, then
this function returns ``NULL``. If the stream does not exist, this
function returns ``NULL``.
.. 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:: 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, nghttp2_settings_entry *iv, size_t niv)
Serializes the SETTINGS values *iv* in the *buf*. The number of
entry pointed by *iv* array is given by the *niv*. This function
may reorder the pointers in *iv*. The *buf* must have enough region
to hold serialized data. The required space for the *niv* entries
are ``8*niv`` bytes. This function is used mainly for creating
SETTINGS payload to be sent with ``HTTP2-Settings`` header field in
HTTP Upgrade request. The data written in *buf* is not still
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.
.. 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 char **nv, 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 *nv* contains the name/value pairs. For i >= 0, ``nv[2*i]``
contains a pointer to the name string and ``nv[2*i+1]`` contains a
pointer to the value string. The one beyond last value must be
``NULL``. That is, if the *nv* contains N name/value pairs,
``nv[2*N]`` must be ``NULL``.
The *nv* must include following name/value pairs:
``:method``
HTTP method (e.g., ``GET``, ``POST``, ``HEAD``, etc)
``:scheme``
URI scheme (e.g., ``https``)
``:path``
Absolute path and parameters of this request (e.g., ``/foo``,
``/foo;bar;haz?h=j&y=123``)
``:host``
The hostport portion of the URI for this request (e.g.,
``example.org:443``). This is the same as the HTTP "Host" header
field.
This function creates copies of all name/value pairs in *nv*. It
also lower-cases all names in *nv*.
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 *nv* (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_ctrl_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 *nv* includes empty name or
``NULL`` value.
:macro:`NGHTTP2_ERR_NOMEM`
Out of memory.
.. function:: int nghttp2_submit_response(nghttp2_session *session, int32_t stream_id, const char **nv, const nghttp2_data_provider *data_prd)
Submits response HEADERS frame and optionally one or more DATA
frames against the stream *stream_id*.
The *nv* contains the name/value pairs. For i >= 0, ``nv[2*i]``
contains a pointer to the name string and ``nv[2*i+1]`` contains a
pointer to the value string. The one beyond last value must be
``NULL``. That is, if the *nv* contains N name/value pairs,
``nv[2*N]`` must be ``NULL``.
The *nv* must include following name/value pairs:
``:status``
HTTP status code (e.g., ``200`` or ``200 OK``)
This function creates copies of all name/value pairs in *nv*. It
also lower-cases all names in *nv*.
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 function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *nv* includes empty name or ``NULL`` value.
: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 char **nv, 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 *nv* contains the name/value pairs. For i >= 0, ``nv[2*i]``
contains a pointer to the name string and ``nv[2*i+1]`` contains a
pointer to the value string. The one beyond last value must be
``NULL``. That is, if the *nv* contains N name/value pairs,
``nv[2*N]`` must be ``NULL``.
This function creates copies of all name/value pairs in *nv*. It
also lower-cases all names in *nv*.
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 *nv* includes empty name or
``NULL`` value.
: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, int32_t stream_id, int32_t pri)
Submits PRIORITY frame to change the priority of stream *stream_id*
to the priority value *pri*.
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, 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*.
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, 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`.
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.
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 char **nv)
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 *nv* contains the name/value pairs. For i >= 0, ``nv[2*i]``
contains a pointer to the name string and ``nv[2*i+1]`` contains a
pointer to the value string. The one beyond last value must be
``NULL``. That is, if the *nv* contains N name/value pairs,
``nv[2*N]`` must be ``NULL``.
This function creates copies of all name/value pairs in *nv*. It
also lower-cases all names in *nv*.
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 *nv* includes empty name or ``NULL`` value.
: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 *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.
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, nghttp2_error_code error_code, uint8_t *opaque_data, size_t opaque_data_len)
Submits GOAWAY frame with the error code *error_code*.
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.
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.
This function returns 0 if it succeeds, or one of the following
negative error codes:
:macro:`NGHTTP2_ERR_INVALID_ARGUMENT`
The *delta_window_size* is 0.
: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;
}
....
}
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