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#!/usr/bin/env python3
# Copyright 2015 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Read from stdin a set of colon separated http headers:
:path: /foo/bar
content-type: application/grpc
Write a set of strings containing a hpack encoded http2 frame that
represents said headers."""
import argparse
import json
import sys
def append_never_indexed(payload_line, n, count, key, value):
payload_line.append(0x10)
assert (len(key) <= 126)
payload_line.append(len(key))
payload_line.extend(ord(c) for c in key)
assert (len(value) <= 126)
payload_line.append(len(value))
payload_line.extend(ord(c) for c in value)
def append_inc_indexed(payload_line, n, count, key, value):
payload_line.append(0x40)
assert (len(key) <= 126)
payload_line.append(len(key))
payload_line.extend(ord(c) for c in key)
assert (len(value) <= 126)
payload_line.append(len(value))
payload_line.extend(ord(c) for c in value)
def append_pre_indexed(payload_line, n, count, key, value):
payload_line.append(0x80 + 61 + count - n)
_COMPRESSORS = {
'never': append_never_indexed,
'inc': append_inc_indexed,
'pre': append_pre_indexed,
}
argp = argparse.ArgumentParser('Generate header frames')
argp.add_argument('--set_end_stream',
default=False,
action='store_const',
const=True)
argp.add_argument('--no_framing',
default=False,
action='store_const',
const=True)
argp.add_argument('--compression',
choices=sorted(_COMPRESSORS.keys()),
default='never')
argp.add_argument('--hex', default=False, action='store_const', const=True)
args = argp.parse_args()
# parse input, fill in vals
vals = []
for line in sys.stdin:
line = line.strip()
if line == '':
continue
if line[0] == '#':
continue
key_tail, value = line[1:].split(':')
key = (line[0] + key_tail).strip()
value = value.strip()
vals.append((key, value))
# generate frame payload binary data
payload_bytes = []
if not args.no_framing:
payload_bytes.append([]) # reserve space for header
payload_len = 0
n = 0
for key, value in vals:
payload_line = []
_COMPRESSORS[args.compression](payload_line, n, len(vals), key, value)
n += 1
payload_len += len(payload_line)
payload_bytes.append(payload_line)
# fill in header
if not args.no_framing:
flags = 0x04 # END_HEADERS
if args.set_end_stream:
flags |= 0x01 # END_STREAM
payload_bytes[0].extend([
(payload_len >> 16) & 0xff,
(payload_len >> 8) & 0xff,
(payload_len) & 0xff,
# header frame
0x01,
# flags
flags,
# stream id
0x00,
0x00,
0x00,
0x01
])
hex_bytes = [ord(c) for c in "abcdefABCDEF0123456789"]
def esc_c(line):
out = "\""
last_was_hex = False
for c in line:
if 32 <= c < 127:
if c in hex_bytes and last_was_hex:
out += "\"\""
if c != ord('"'):
out += chr(c)
else:
out += "\\\""
last_was_hex = False
else:
out += "\\x%02x" % c
last_was_hex = True
return out + "\""
# dump bytes
if args.hex:
all_bytes = []
for line in payload_bytes:
all_bytes.extend(line)
print(('{%s}' % ', '.join('0x%02x' % c for c in all_bytes)))
else:
for line in payload_bytes:
print((esc_c(line)))
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