-
Notifications
You must be signed in to change notification settings - Fork 0
/
http_parser.py
384 lines (335 loc) · 13.1 KB
/
http_parser.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
# -*- coding: utf-8 -*-
from enum import Enum, auto
from typing import Dict, Tuple, Union
from string import ascii_letters, digits, punctuation
import urllib.parse as urlparse
from utils import Ref
# https://tools.ietf.org/html/rfc2616#page-17
_token_charset = (ascii_letters + digits + "-!#$%&'*+-.^_`|~").encode("ascii")
_uri_charset = (ascii_letters + digits + punctuation).encode("ascii")
class HTTPLocation(urlparse.ParseResult):
"""
An HTTP location.
"""
def __init__(self):
super().__init__()
class HTTPRequestHeader:
"""
Parsing result of an HTTPHeaderParser.
"""
def __init__(self):
self.method: bytes = None
self.location: HTTPLocation = None
self.version: bytes = None
"""This version string contains the whole HTTP/x.y part."""
self.headers: Dict[bytes, Tuple[int, bytes]] = []
"""Key: (Order, Value)"""
self.consumed: bytes = b""
self.uri: bytes = b""
def unproxify(self):
"""
Transform this proxy HTTPRequestHeader to none-proxy HTTPRequestHeader.
"""
order_host = self.headers[b"Host"][0] if b"Host" in self.headers else len(self.headers)
self.headers[b"Host"] = (order_host, self.location.netloc.encode("ascii"))
self.uri = urlparse.urlunsplit(["", "", self.location.path, self.location.query, self.location.fragment]).encode("ascii")
def reconstruct(self)->bytes:
"""
Reconstructing the header in string.
"""
result = b""
result += b"%s %s %s\r\n" % (self.method, self.uri, self.version)
# Reorder the headers
headers = [None] * len(self.headers)
for (k, (i, v)) in self.headers.items():
headers[i] = (k, v)
for (k, v) in headers:
result += b"%s: %s\r\n" % (k, v)
result += b"\r\n"
return result
class HTTPParseStatus(Enum):
PARTIAL = auto()
"""Incomplete, waiting for more."""
ERROR = auto()
SUCCEED = auto()
class HTTPBodyEncoding(Enum):
NONE = auto()
CONTENT_LENGTH = auto()
CHUNKED = auto()
class HTTPBodyParser:
def __init__(self, header: HTTPRequestHeader):
try:
if b"Content-Length" in header.headers:
self._encoding = HTTPBodyEncoding.CONTENT_LENGTH
self._content_length = int(header.headers[b"Content-Length"][1])
elif header.version == b"HTTP/1.1" and header.headers.get(b"Content-Encoding") == b"chunked":
self._encoding = HTTPBodyEncoding.CHUNKED
self._len_buffer = b""
# When chunk length is 0, this means we have just finished reading a chunk/fresh start.
# When chunk length is -1, this means we have started reading length, and are still waiting for length.
# When chunk length is -2, this means we have gotten \r for ending length, and are waiting for \n.
# When chunk length is -3, this means we have gotten 0-len for ending body, and are waiting for \r.
# When chunk length is -4, this means we have gotten 0-len and \r for ending body, and are waiting for \n.
# Otherwise, it's the remaining length of this chunk.
self._chunk_length = 0
else:
self._encoding: HTTPBodyEncoding = HTTPBodyEncoding.NONE
except:
self._encoding: HTTPBodyEncoding = HTTPBodyEncoding.NONE
def feed(self, s: bytes)->Union[HTTPParseStatus, int]:
"""
Feed a byte string to the parser.
:return HTTPParseStatus.PARTIAL if more are expected; HTTPParseStatus.ERROR
if an error occured; an integer n if only n characters are consumed, and the rest belongs to the next
request.
:raises RuntimeError when called after a result has been returned.
"""
if self._encoding == HTTPBodyEncoding.NONE:
return HTTPParseStatus.PARTIAL
elif self._encoding == HTTPBodyEncoding.CONTENT_LENGTH:
if len(s) >= self._content_length:
return self._content_length
else:
self._content_length -= len(s)
return HTTPParseStatus.PARTIAL
elif self._encoding == HTTPBodyEncoding.CHUNKED:
for i in range(len(s)):
c = s[i:i+1]
# Fresh start/just finished a chunk
print(self._chunk_length, c)
if self._chunk_length == 0:
# Ending body
# Treat as length
self._len_buffer += c
self._chunk_length = -1
# In length
elif self._chunk_length == -1:
# Ending length
if c == b'\r':
self._chunk_length = -2
else:
self._len_buffer += c
# Waiting for \n for ending length
elif self._chunk_length == -2:
if c != b'\n':
return HTTPParseStatus.ERROR
if self._len_buffer == b'0':
self._chunk_length = -3
else:
try:
self._chunk_length = int(self._len_buffer, 16) + 2 # 2 more \r\n
self._len_buffer = b''
except ValueError:
return HTTPParseStatus.ERROR
# Waiting for \n for ending body
elif self._chunk_length == -3:
if c != b'\r':
return HTTPParseStatus.ERROR
self._chunk_length = -4
# Waiting for \n for ending body
elif self._chunk_length == -4:
if c != b'\n':
return HTTPParseStatus.ERROR
else:
return i + 1
# Waiting for body
else:
self._chunk_length -= 1
return HTTPParseStatus.PARTIAL
class HTTPParseFailedError(Exception):
"""Thrown when trying to feed more value into a HTTP parser when it has failed."""
pass
class HTTPParseReturnedAlreadyError(Exception):
"""Thrown when trying to feed more value into a HTTP parser when it has returned already."""
pass
class HTTPHeaderParser:
def __init__(self):
self._buf = b""
self._parse_result = HTTPRequestHeader()
self._parse_status = HTTPParseStatus.PARTIAL
self._parse_func = self._start
def _post_process(self):
"""
Post process self._parse_result:
1. Parse location
2. change headers to dict
"""
try:
s_uri = self._parse_result.uri.decode("ascii")
if 'http://' not in s_uri and 'https://' not in s_uri:
s_uri = 'http://' + s_uri
self._parse_result.location = urlparse.urlparse(s_uri)
except (ValueError, UnicodeDecodeError) as e:
self._parse_result = HTTPParseStatus.ERROR
return
header_dict = {}
i = 0
for (k, v) in self._parse_result.headers:
header_dict[k] = (i, v)
i += 1
self._parse_result.headers = header_dict
def feed(self, ref_s: Ref[bytes])->Union[HTTPParseStatus, HTTPRequestHeader]:
"""
Feed the reference of a byte string into the parser for parsing. After this methods complete, if there are
unconsumed characters, they'll be stored back into s.
:param s: Reference of a string to be fed into the parser.
:raises HTTPParseReturnedAlreadyError when called after a result has already been returned.
:raises HTTPParseFailedError when called after parsing has failed.
:return: State of the parsing afterward, or the result.
"""
if self._parse_status == HTTPParseStatus.SUCCEED:
raise HTTPParseReturnedAlreadyError()
elif self._parse_status == HTTPParseStatus.ERROR:
raise HTTPParseFailedError()
i = 0
while i < len(ref_s.v):
c = ref_s.v[i:i+1]
self._parse_result.consumed += c
result = self._parse_func(c)
if result == HTTPParseStatus.ERROR:
self._parse_status = result
return result
elif result == HTTPParseStatus.SUCCEED:
self._parse_status = result
self._post_process()
ref_s.v = ref_s.v[i+1:]
return self._parse_result
i += 1
# We have consumed every char, so empty the source.
ref_s.v = b""
return HTTPParseStatus.PARTIAL
def _start(self, c:bytes):
if c == b'\r':
self._parse_func = self._prefix_r
elif c in _token_charset:
self._parse_func = self._method
self._parse_result.method = c
else:
return HTTPParseStatus.ERROR
def _prefix_r(self, c: bytes):
if c == b'\n':
self._parse_func = self._start
else:
return HTTPParseStatus.ERROR
def _method(self, c: bytes):
if c in _token_charset:
self._parse_result.method += c
elif c == b' ':
self._parse_func = self._method_
else:
return HTTPParseStatus.ERROR
def _method_(self, c: bytes):
if c in _uri_charset:
self._parse_result.uri += c
self._parse_func = self._m_uri_charset
else:
return HTTPParseStatus.ERROR
def _m_uri_charset(self, c: bytes):
if c in _uri_charset:
self._parse_result.uri += c
elif c == b' ':
self._parse_func = self._m_uri_charset_
else:
return HTTPParseStatus.ERROR
def _m_uri_charset_(self, c: bytes):
if c == b'H':
self._parse_result.version = c
self._parse_func = self._m_url_h
else:
return HTTPParseStatus.ERROR
def _m_url_h(self, c: bytes):
if c == b'T':
self._parse_result.version += c
self._parse_func = self._m_url_ht
else:
return HTTPParseStatus.ERROR
def _m_url_ht(self, c: bytes):
if c == b'T':
self._parse_result.version += c
self._parse_func = self._m_url_htt
else:
return HTTPParseStatus.ERROR
def _m_url_htt(self, c:bytes):
if c == b'P':
self._parse_result.version += c
self._parse_func = self._m_url_http
else:
return HTTPParseStatus.ERROR
def _m_url_http(self, c:bytes):
if c == b'/':
self._parse_result.version += c
self._parse_func = self._m_url_https
else:
return HTTPParseStatus.ERROR
# s = slash
def _m_url_https(self, c: bytes):
if c.isdigit():
self._parse_result.version += c
self._parse_func = self._m_url_httpsd
else:
return HTTPParseStatus.ERROR
# d1 = digit
def _m_url_httpsd(self, c: bytes):
if c == b'.':
self._parse_result.version += c
self._parse_func = self._m_url_httpsdd
else:
return HTTPParseStatus.ERROR
# d1 = digit, d2 = dot
def _m_url_httpsdd(self, c:bytes):
if c.isdigit():
self._parse_result.version += c
self._parse_func = self._m_url_httpsddd
else:
return HTTPParseStatus.ERROR
# d1 = digit, d2 = dot, d3 = digit
def _m_url_httpsddd(self, c: bytes):
if c == b'\r':
self._parse_func = self._line_r
else:
return HTTPParseStatus.ERROR
# Got an non-ending \r
def _line_r(self, c: bytes):
if c == b'\n':
self._parse_func = self._line_rn
else:
return HTTPParseStatus.ERROR
def _line_rn(self, c: bytes):
if c in _token_charset:
self._parse_func = self._header_key
self._parse_result.headers.append([c, b""])
elif c == b'\r':
self._parse_func = self._end_r
else:
return HTTPParseStatus.ERROR
def _header_key(self, c: bytes):
if c == b':':
self._parse_func = self._header_key_c
elif c in _token_charset:
self._parse_result.headers[-1][0] += c
else:
return HTTPParseStatus.ERROR
# c = colon
def _header_key_c(self, c: bytes):
if c == b' ':
pass
elif c in b"\r\n":
return HTTPParseStatus.ERROR
else:
# not completely compliant but fuck the messed up HTTP standards
self._parse_result.headers[-1][1] += c
self._parse_func = self._header_key_c_val
def _header_key_c_val(self, c: bytes):
if c == b'\r':
self._parse_func = self._line_r
else:
self._parse_result.headers[-1][1] += c
# Got an ending \r
def _end_r(self, c: bytes):
if c == b'\n':
self._parse_func = self._end_rn
return HTTPParseStatus.SUCCEED
else:
return HTTPParseStatus.ERROR
def _end_rn(self, c: bytes):
return HTTPParseStatus.ERROR