mirror of
https://github.com/Grasscutters/mitmproxy.git
synced 2024-11-23 08:11:00 +00:00
379 lines
12 KiB
Python
379 lines
12 KiB
Python
from __future__ import absolute_import, print_function, division
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import time
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import sys
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import re
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from netlib.http import request
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from netlib.http import response
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from netlib.http import headers
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from netlib.http import url
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from netlib import utils
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from netlib import exceptions
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def get_header_tokens(headers, key):
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"""
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Retrieve all tokens for a header key. A number of different headers
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follow a pattern where each header line can containe comma-separated
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tokens, and headers can be set multiple times.
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"""
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if key not in headers:
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return []
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tokens = headers[key].split(",")
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return [token.strip() for token in tokens]
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def read_request(rfile, body_size_limit=None):
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request = read_request_head(rfile)
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expected_body_size = expected_http_body_size(request)
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request.data.content = b"".join(read_body(rfile, expected_body_size, limit=body_size_limit))
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request.timestamp_end = time.time()
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return request
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def read_request_head(rfile):
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"""
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Parse an HTTP request head (request line + headers) from an input stream
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Args:
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rfile: The input stream
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Returns:
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The HTTP request object (without body)
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Raises:
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exceptions.HttpReadDisconnect: No bytes can be read from rfile.
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exceptions.HttpSyntaxException: The input is malformed HTTP.
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exceptions.HttpException: Any other error occured.
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"""
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timestamp_start = time.time()
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if hasattr(rfile, "reset_timestamps"):
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rfile.reset_timestamps()
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form, method, scheme, host, port, path, http_version = _read_request_line(rfile)
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headers = _read_headers(rfile)
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if hasattr(rfile, "first_byte_timestamp"):
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# more accurate timestamp_start
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timestamp_start = rfile.first_byte_timestamp
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return request.Request(
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form, method, scheme, host, port, path, http_version, headers, None, timestamp_start
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)
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def read_response(rfile, request, body_size_limit=None):
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response = read_response_head(rfile)
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expected_body_size = expected_http_body_size(request, response)
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response.data.content = b"".join(read_body(rfile, expected_body_size, body_size_limit))
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response.timestamp_end = time.time()
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return response
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def read_response_head(rfile):
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"""
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Parse an HTTP response head (response line + headers) from an input stream
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Args:
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rfile: The input stream
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Returns:
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The HTTP request object (without body)
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Raises:
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exceptions.HttpReadDisconnect: No bytes can be read from rfile.
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exceptions.HttpSyntaxException: The input is malformed HTTP.
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exceptions.HttpException: Any other error occured.
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"""
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timestamp_start = time.time()
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if hasattr(rfile, "reset_timestamps"):
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rfile.reset_timestamps()
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http_version, status_code, message = _read_response_line(rfile)
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headers = _read_headers(rfile)
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if hasattr(rfile, "first_byte_timestamp"):
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# more accurate timestamp_start
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timestamp_start = rfile.first_byte_timestamp
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return response.Response(http_version, status_code, message, headers, None, timestamp_start)
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def read_body(rfile, expected_size, limit=None, max_chunk_size=4096):
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"""
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Read an HTTP message body
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Args:
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rfile: The input stream
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expected_size: The expected body size (see :py:meth:`expected_body_size`)
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limit: Maximum body size
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max_chunk_size: Maximium chunk size that gets yielded
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Returns:
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A generator that yields byte chunks of the content.
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Raises:
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exceptions.HttpException, if an error occurs
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Caveats:
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max_chunk_size is not considered if the transfer encoding is chunked.
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"""
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if not limit or limit < 0:
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limit = sys.maxsize
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if not max_chunk_size:
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max_chunk_size = limit
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if expected_size is None:
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for x in _read_chunked(rfile, limit):
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yield x
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elif expected_size >= 0:
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if limit is not None and expected_size > limit:
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raise exceptions.HttpException(
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"HTTP Body too large. "
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"Limit is {}, content length was advertised as {}".format(limit, expected_size)
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)
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bytes_left = expected_size
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while bytes_left:
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chunk_size = min(bytes_left, max_chunk_size)
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content = rfile.read(chunk_size)
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if len(content) < chunk_size:
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raise exceptions.HttpException("Unexpected EOF")
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yield content
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bytes_left -= chunk_size
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else:
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bytes_left = limit
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while bytes_left:
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chunk_size = min(bytes_left, max_chunk_size)
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content = rfile.read(chunk_size)
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if not content:
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return
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yield content
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bytes_left -= chunk_size
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not_done = rfile.read(1)
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if not_done:
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raise exceptions.HttpException("HTTP body too large. Limit is {}.".format(limit))
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def connection_close(http_version, headers):
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"""
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Checks the message to see if the client connection should be closed
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according to RFC 2616 Section 8.1.
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"""
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# At first, check if we have an explicit Connection header.
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if "connection" in headers:
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tokens = get_header_tokens(headers, "connection")
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if "close" in tokens:
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return True
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elif "keep-alive" in tokens:
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return False
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# If we don't have a Connection header, HTTP 1.1 connections are assumed to
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# be persistent
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return http_version != "HTTP/1.1" and http_version != b"HTTP/1.1" # FIXME: Remove one case.
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def expected_http_body_size(request, response=None):
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"""
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Returns:
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The expected body length:
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- a positive integer, if the size is known in advance
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- None, if the size in unknown in advance (chunked encoding)
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- -1, if all data should be read until end of stream.
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Raises:
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exceptions.HttpSyntaxException, if the content length header is invalid
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"""
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# Determine response size according to
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# http://tools.ietf.org/html/rfc7230#section-3.3
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if not response:
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headers = request.headers
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response_code = None
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is_request = True
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else:
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headers = response.headers
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response_code = response.status_code
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is_request = False
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if is_request:
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if headers.get("expect", "").lower() == "100-continue":
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return 0
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else:
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if request.method.upper() == "HEAD":
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return 0
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if 100 <= response_code <= 199:
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return 0
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if response_code == 200 and request.method.upper() == "CONNECT":
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return 0
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if response_code in (204, 304):
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return 0
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if "chunked" in headers.get("transfer-encoding", "").lower():
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return None
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if "content-length" in headers:
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try:
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size = int(headers["content-length"])
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if size < 0:
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raise ValueError()
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return size
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except ValueError:
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raise exceptions.HttpSyntaxException("Unparseable Content Length")
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if is_request:
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return 0
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return -1
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def _get_first_line(rfile):
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try:
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line = rfile.readline()
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if line == b"\r\n" or line == b"\n":
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# Possible leftover from previous message
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line = rfile.readline()
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except exceptions.TcpDisconnect:
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raise exceptions.HttpReadDisconnect("Remote disconnected")
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if not line:
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raise exceptions.HttpReadDisconnect("Remote disconnected")
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return line.strip()
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def _read_request_line(rfile):
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try:
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line = _get_first_line(rfile)
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except exceptions.HttpReadDisconnect:
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# We want to provide a better error message.
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raise exceptions.HttpReadDisconnect("Client disconnected")
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try:
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method, path, http_version = line.split()
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if path == b"*" or path.startswith(b"/"):
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form = "relative"
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scheme, host, port = None, None, None
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elif method == b"CONNECT":
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form = "authority"
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host, port = _parse_authority_form(path)
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scheme, path = None, None
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else:
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form = "absolute"
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scheme, host, port, path = url.parse(path)
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_check_http_version(http_version)
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except ValueError:
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raise exceptions.HttpSyntaxException("Bad HTTP request line: {}".format(line))
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return form, method, scheme, host, port, path, http_version
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def _parse_authority_form(hostport):
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"""
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Returns (host, port) if hostport is a valid authority-form host specification.
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http://tools.ietf.org/html/draft-luotonen-web-proxy-tunneling-01 section 3.1
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Raises:
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ValueError, if the input is malformed
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"""
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try:
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host, port = hostport.split(b":")
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port = int(port)
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if not utils.is_valid_host(host) or not utils.is_valid_port(port):
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raise ValueError()
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except ValueError:
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raise exceptions.HttpSyntaxException("Invalid host specification: {}".format(hostport))
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return host, port
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def _read_response_line(rfile):
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try:
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line = _get_first_line(rfile)
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except exceptions.HttpReadDisconnect:
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# We want to provide a better error message.
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raise exceptions.HttpReadDisconnect("Server disconnected")
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try:
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parts = line.split(None, 2)
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if len(parts) == 2: # handle missing message gracefully
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parts.append(b"")
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http_version, status_code, message = parts
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status_code = int(status_code)
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_check_http_version(http_version)
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except ValueError:
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raise exceptions.HttpSyntaxException("Bad HTTP response line: {}".format(line))
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return http_version, status_code, message
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def _check_http_version(http_version):
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if not re.match(br"^HTTP/\d\.\d$", http_version):
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raise exceptions.HttpSyntaxException("Unknown HTTP version: {}".format(http_version))
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def _read_headers(rfile):
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"""
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Read a set of headers.
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Stop once a blank line is reached.
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Returns:
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A headers object
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Raises:
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exceptions.HttpSyntaxException
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"""
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ret = []
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while True:
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line = rfile.readline()
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if not line or line == b"\r\n" or line == b"\n":
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break
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if line[0] in b" \t":
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if not ret:
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raise exceptions.HttpSyntaxException("Invalid headers")
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# continued header
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ret[-1] = (ret[-1][0], ret[-1][1] + b'\r\n ' + line.strip())
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else:
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try:
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name, value = line.split(b":", 1)
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value = value.strip()
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if not name:
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raise ValueError()
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ret.append((name, value))
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except ValueError:
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raise exceptions.HttpSyntaxException(
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"Invalid header line: %s" % repr(line)
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)
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return headers.Headers(ret)
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def _read_chunked(rfile, limit=sys.maxsize):
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"""
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Read a HTTP body with chunked transfer encoding.
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Args:
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rfile: the input file
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limit: A positive integer
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"""
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total = 0
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while True:
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line = rfile.readline(128)
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if line == b"":
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raise exceptions.HttpException("Connection closed prematurely")
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if line != b"\r\n" and line != b"\n":
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try:
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length = int(line, 16)
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except ValueError:
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raise exceptions.HttpSyntaxException("Invalid chunked encoding length: {}".format(line))
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total += length
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if total > limit:
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raise exceptions.HttpException(
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"HTTP Body too large. Limit is {}, "
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"chunked content longer than {}".format(limit, total)
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)
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chunk = rfile.read(length)
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suffix = rfile.readline(5)
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if suffix != b"\r\n":
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raise exceptions.HttpSyntaxException("Malformed chunked body")
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if length == 0:
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return
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yield chunk
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