# 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 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 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): 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): super(HDDeflater, self).__init__() def __dealloc__(self): 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 = \ 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 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. ''' cnghttp2.nghttp2_hd_deflate_set_no_refset(&self._ctx, no_refset) 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): rv = cnghttp2.nghttp2_hd_inflate_init(&self._ctx, side) if rv != 0: raise Exception(_strerror(rv)) def __init__(self, side): super(HDInflater, self).__init__() def __dealloc__(self): 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 *nva cdef ssize_t rv rv = cnghttp2.nghttp2_hd_inflate_hd(&self._ctx, &nva, data, len(data)) if rv < 0: raise Exception(_strerror(rv)) try: res = [(nva[i].name[:nva[i].namelen], nva[i].value[:nva[i].valuelen]) for i in range(rv)] finally: cnghttp2.nghttp2_nv_array_del(nva) cnghttp2.nghttp2_hd_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')))