nghttp2/python/nghttp2.pyx

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# nghttp2 - HTTP/2.0 C Library
# Copyright (c) 2013 Tatsuhiro Tsujikawa
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cimport cnghttp2
from libc.stdlib cimport malloc, free
from libc.string cimport memcpy, memset
from libc.stdint cimport uint8_t, uint16_t, uint32_t, int32_t
HD_SIDE_REQUEST = cnghttp2.NGHTTP2_HD_SIDE_REQUEST
HD_SIDE_RESPONSE = cnghttp2.NGHTTP2_HD_SIDE_RESPONSE
HD_DEFLATE_HD_TABLE_BUFSIZE_MAX = 4096
HD_ENTRY_OVERHEAD = cnghttp2.NGHTTP2_HD_ENTRY_OVERHEAD
class HDTableEntry:
def __init__(self, name, namelen, value, valuelen, ref):
self.name = name
self.namelen = namelen
self.value = value
self.valuelen = valuelen
self.ref = ref
def space(self):
return self.namelen + self.valuelen + HD_ENTRY_OVERHEAD
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cdef class _HDContextBase:
cdef cnghttp2.nghttp2_hd_context _ctx
def __init__(self):
pass
def change_table_size(self, hd_table_bufsize_max):
'''Changes header table size to |hd_table_bufsize_max| byte.
An exception will be raised on error.
'''
cdef int rv
rv = cnghttp2.nghttp2_hd_change_table_size(&self._ctx,
hd_table_bufsize_max)
if rv != 0:
raise Exception(_strerror(rv))
def get_hd_table(self):
'''Returns copy of current dynamic header table.'''
cdef int length = self._ctx.hd_table.len
cdef cnghttp2.nghttp2_hd_entry *entry
res = []
for i in range(length):
entry = cnghttp2.nghttp2_hd_table_get(&self._ctx, i)
k = _get_pybytes(entry.nv.name, entry.nv.namelen)
v = _get_pybytes(entry.nv.value, entry.nv.valuelen)
res.append(HDTableEntry(k, entry.nv.namelen,
v, entry.nv.valuelen,
(entry.flags & cnghttp2.NGHTTP2_HD_FLAG_REFSET) != 0))
return res
cdef _get_pybytes(uint8_t *b, uint16_t blen):
# While the |blen| is positive, the |b| could be NULL. This is
# because deflater may deallocate the byte strings its local table
# space.
if b == NULL and blen > 0:
val = None
else:
val = b[:blen]
return val
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cdef class HDDeflater(_HDContextBase):
'''Performs header compression. The header compression algorithm has
to know the header set to be compressed is request headers or
response headers. It is indicated by |side| parameter in the
constructor. The constructor also takes |hd_table_bufsize_max|
parameter, which limits the usage of header table in the given
amount of bytes. This is necessary because the header compressor
and decompressor has to share the same amount of header table and
the decompressor decides that number. The compressor may not want
to use all header table size because of limited memory
availability. In that case, the |hd_table_bufsize_max| can be used
to cap the upper limit of talbe size whatever the header table
size is chosen. The default value of |hd_table_bufsize_max| is
4096 bytes.
The following example shows how to compress request header sets:
import binascii, nghttp2
deflater = nghttp2.HDDeflater(nghttp2.HD_SIDE_REQUEST)
res = deflater.deflate([(b'foo', b'bar'),
(b'baz', b'buz')])
print(binascii.b2a_hex(res))
'''
def __cinit__(self, side,
hd_table_bufsize_max = HD_DEFLATE_HD_TABLE_BUFSIZE_MAX):
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rv = cnghttp2.nghttp2_hd_deflate_init2(&self._ctx, side,
hd_table_bufsize_max)
if rv != 0:
raise Exception(_strerror(rv))
def __init__(self, side,
hd_table_bufsize_max = HD_DEFLATE_HD_TABLE_BUFSIZE_MAX):
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super(HDDeflater, self).__init__()
def __dealloc__(self):
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cnghttp2.nghttp2_hd_deflate_free(&self._ctx)
def deflate(self, headers):
'''Compresses the |headers|. The |headers| must be sequence of tuple
of name/value pair, which are sequence of bytes (not unicode
string).
This function returns the encoded header block in byte string.
An exception will be raised on error.
'''
cdef cnghttp2.nghttp2_nv *nva = <cnghttp2.nghttp2_nv*>\
malloc(sizeof(cnghttp2.nghttp2_nv)*\
len(headers))
cdef cnghttp2.nghttp2_nv *nvap = nva
for k, v in headers:
nvap[0].name = k
nvap[0].namelen = len(k)
nvap[0].value = v
nvap[0].valuelen = len(v)
nvap += 1
cdef uint8_t *out = NULL
cdef size_t outcap = 0
cdef ssize_t rv
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rv = cnghttp2.nghttp2_hd_deflate_hd(&self._ctx, &out, &outcap,
0, nva, len(headers))
free(nva)
if rv < 0:
raise Exception(_strerror(rv))
cdef bytes res
try:
res = out[:rv]
finally:
cnghttp2.nghttp2_free(out)
return res
def set_no_refset(self, no_refset):
'''Tells the compressor not to use reference set if |no_refset| is
nonzero. If |no_refset| is nonzero, on each invocation of
deflate(), compressor first emits index=0 to clear up
reference set.
'''
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cnghttp2.nghttp2_hd_deflate_set_no_refset(&self._ctx, no_refset)
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cdef class HDInflater(_HDContextBase):
'''Performs header decompression.
The following example shows how to compress request header sets:
data = b'0082c5ad82bd0f000362617a0362757a'
inflater = nghttp2.HDInflater(nghttp2.HD_SIDE_REQUEST)
hdrs = inflater.inflate(data)
print(hdrs)
'''
def __cinit__(self, side):
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rv = cnghttp2.nghttp2_hd_inflate_init(&self._ctx, side)
if rv != 0:
raise Exception(_strerror(rv))
def __init__(self, side):
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super(HDInflater, self).__init__()
def __dealloc__(self):
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cnghttp2.nghttp2_hd_inflate_free(&self._ctx)
def inflate(self, data):
'''Decompresses the compressed header block |data|. The |data| must be
byte string (not unicode string).
'''
cdef cnghttp2.nghttp2_nv nv
cdef int final
cdef ssize_t rv
cdef uint8_t *buf = data
cdef size_t buflen = len(data)
res = []
while True:
rv = cnghttp2.nghttp2_hd_inflate_hd(&self._ctx, &nv, &final,
buf, buflen)
if rv < 0:
raise Exception(_strerror(rv))
if final:
break
buf += rv
buflen -= rv
# may throw
res.append((nv.name[:nv.namelen], nv.value[:nv.valuelen]))
cnghttp2.nghttp2_hd_inflate_end_headers(&self._ctx)
return res
cdef _strerror(int liberror_code):
return cnghttp2.nghttp2_strerror(liberror_code).decode('utf-8')
def print_hd_table(hdtable):
'''Convenient function to print |hdtable| to the standard output. This
function does not work if header name/value cannot be decoded using
UTF-8 encoding.
s=N means the entry occupies N bytes in header table. if r=y, then
the entry is in the reference set.
'''
idx = 0
for entry in hdtable:
idx += 1
print('[{}] (s={}) (r={}) {}: {}'\
.format(idx, entry.space(),
'y' if entry.ref else 'n',
'**DEALLOCATED**' if entry.name is None else entry.name.decode('utf-8'),
'**DEALLOCATED**' if entry.value is None else entry.value.decode('utf-8')))