1 #!/usr/bin/env python2.7 2 3 # Copyright 2015 gRPC authors. 4 # 5 # Licensed under the Apache License, Version 2.0 (the "License"); 6 # you may not use this file except in compliance with the License. 7 # You may obtain a copy of the License at 8 # 9 # http://www.apache.org/licenses/LICENSE-2.0 10 # 11 # Unless required by applicable law or agreed to in writing, software 12 # distributed under the License is distributed on an "AS IS" BASIS, 13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 # See the License for the specific language governing permissions and 15 # limitations under the License. 16 """Read from stdin a set of colon separated http headers: 17 :path: /foo/bar 18 content-type: application/grpc 19 Write a set of strings containing a hpack encoded http2 frame that 20 represents said headers.""" 21 22 import json 23 import sys 24 import argparse 25 26 27 def append_never_indexed(payload_line, n, count, key, value): 28 payload_line.append(0x10) 29 assert (len(key) <= 126) 30 payload_line.append(len(key)) 31 payload_line.extend(ord(c) for c in key) 32 assert (len(value) <= 126) 33 payload_line.append(len(value)) 34 payload_line.extend(ord(c) for c in value) 35 36 37 def append_inc_indexed(payload_line, n, count, key, value): 38 payload_line.append(0x40) 39 assert (len(key) <= 126) 40 payload_line.append(len(key)) 41 payload_line.extend(ord(c) for c in key) 42 assert (len(value) <= 126) 43 payload_line.append(len(value)) 44 payload_line.extend(ord(c) for c in value) 45 46 47 def append_pre_indexed(payload_line, n, count, key, value): 48 payload_line.append(0x80 + 61 + count - n) 49 50 51 _COMPRESSORS = { 52 'never': append_never_indexed, 53 'inc': append_inc_indexed, 54 'pre': append_pre_indexed, 55 } 56 57 argp = argparse.ArgumentParser('Generate header frames') 58 argp.add_argument( 59 '--set_end_stream', default=False, action='store_const', const=True) 60 argp.add_argument( 61 '--no_framing', default=False, action='store_const', const=True) 62 argp.add_argument( 63 '--compression', choices=sorted(_COMPRESSORS.keys()), default='never') 64 argp.add_argument('--hex', default=False, action='store_const', const=True) 65 args = argp.parse_args() 66 67 # parse input, fill in vals 68 vals = [] 69 for line in sys.stdin: 70 line = line.strip() 71 if line == '': continue 72 if line[0] == '#': continue 73 key_tail, value = line[1:].split(':') 74 key = (line[0] + key_tail).strip() 75 value = value.strip() 76 vals.append((key, value)) 77 78 # generate frame payload binary data 79 payload_bytes = [] 80 if not args.no_framing: 81 payload_bytes.append([]) # reserve space for header 82 payload_len = 0 83 n = 0 84 for key, value in vals: 85 payload_line = [] 86 _COMPRESSORS[args.compression](payload_line, n, len(vals), key, value) 87 n += 1 88 payload_len += len(payload_line) 89 payload_bytes.append(payload_line) 90 91 # fill in header 92 if not args.no_framing: 93 flags = 0x04 # END_HEADERS 94 if args.set_end_stream: 95 flags |= 0x01 # END_STREAM 96 payload_bytes[0].extend([ 97 (payload_len >> 16) & 0xff, 98 (payload_len >> 8) & 0xff, 99 (payload_len) & 0xff, 100 # header frame 101 0x01, 102 # flags 103 flags, 104 # stream id 105 0x00, 106 0x00, 107 0x00, 108 0x01 109 ]) 110 111 hex_bytes = [ord(c) for c in "abcdefABCDEF0123456789"] 112 113 114 def esc_c(line): 115 out = "\"" 116 last_was_hex = False 117 for c in line: 118 if 32 <= c < 127: 119 if c in hex_bytes and last_was_hex: 120 out += "\"\"" 121 if c != ord('"'): 122 out += chr(c) 123 else: 124 out += "\\\"" 125 last_was_hex = False 126 else: 127 out += "\\x%02x" % c 128 last_was_hex = True 129 return out + "\"" 130 131 132 # dump bytes 133 if args.hex: 134 all_bytes = [] 135 for line in payload_bytes: 136 all_bytes.extend(line) 137 print '{%s}' % ', '.join('0x%02x' % c for c in all_bytes) 138 else: 139 for line in payload_bytes: 140 print esc_c(line) 141
