mitmproxy/netlib/http.py
Aldo Cortesi 7d01d5c797 Don't read all from server by default.
This can cause us to hang waiting for data. More research is needed to
establish the right course of action here.
2012-06-24 23:13:09 +12:00

277 lines
8.2 KiB
Python

import string, urlparse
import odict
class HttpError(Exception):
def __init__(self, code, msg):
self.code, self.msg = code, msg
def __str__(self):
return "HttpError(%s, %s)"%(self.code, self.msg)
def parse_url(url):
"""
Returns a (scheme, host, port, path) tuple, or None on error.
"""
scheme, netloc, path, params, query, fragment = urlparse.urlparse(url)
if not scheme:
return None
if ':' in netloc:
host, port = string.rsplit(netloc, ':', maxsplit=1)
try:
port = int(port)
except ValueError:
return None
else:
host = netloc
if scheme == "https":
port = 443
else:
port = 80
path = urlparse.urlunparse(('', '', path, params, query, fragment))
if not path.startswith("/"):
path = "/" + path
return scheme, host, port, path
def read_headers(fp):
"""
Read a set of headers from a file pointer. Stop once a blank line
is reached. Return a ODictCaseless object.
"""
ret = []
name = ''
while 1:
line = fp.readline()
if not line or line == '\r\n' or line == '\n':
break
if line[0] in ' \t':
# continued header
ret[-1][1] = ret[-1][1] + '\r\n ' + line.strip()
else:
i = line.find(':')
# We're being liberal in what we accept, here.
if i > 0:
name = line[:i]
value = line[i+1:].strip()
ret.append([name, value])
return odict.ODictCaseless(ret)
def read_chunked(code, fp, limit):
"""
Read a chunked HTTP body.
May raise HttpError.
"""
content = ""
total = 0
while 1:
line = fp.readline(128)
if line == "":
raise HttpError(code, "Connection closed prematurely")
if line != '\r\n' and line != '\n':
try:
length = int(line, 16)
except ValueError:
# FIXME: Not strictly correct - this could be from the server, in which
# case we should send a 502.
raise HttpError(code, "Invalid chunked encoding length: %s"%line)
if not length:
break
total += length
if limit is not None and total > limit:
msg = "HTTP Body too large."\
" Limit is %s, chunked content length was at least %s"%(limit, total)
raise HttpError(code, msg)
content += fp.read(length)
line = fp.readline(5)
if line != '\r\n':
raise HttpError(code, "Malformed chunked body")
while 1:
line = fp.readline()
if line == "":
raise HttpError(code, "Connection closed prematurely")
if line == '\r\n' or line == '\n':
break
return content
def has_chunked_encoding(headers):
for i in headers["transfer-encoding"]:
for j in i.split(","):
if j.lower() == "chunked":
return True
return False
def read_http_body(code, rfile, headers, all, limit):
"""
Read an HTTP body:
code: The HTTP error code to be used when raising HttpError
rfile: A file descriptor to read from
headers: An ODictCaseless object
all: Should we read all data?
limit: Size limit.
"""
if has_chunked_encoding(headers):
content = read_chunked(code, rfile, limit)
elif "content-length" in headers:
try:
l = int(headers["content-length"][0])
except ValueError:
# FIXME: Not strictly correct - this could be from the server, in which
# case we should send a 502.
raise HttpError(code, "Invalid content-length header: %s"%headers["content-length"])
if limit is not None and l > limit:
raise HttpError(code, "HTTP Body too large. Limit is %s, content-length was %s"%(limit, l))
content = rfile.read(l)
elif all:
content = rfile.read(limit if limit else -1)
else:
content = ""
return content
def parse_http_protocol(s):
"""
Parse an HTTP protocol declaration. Returns a (major, minor) tuple, or
None.
"""
if not s.startswith("HTTP/"):
return None
_, version = s.split('/')
if "." not in version:
return None
major, minor = version.split('.')
major = int(major)
minor = int(minor)
return major, minor
def parse_init_connect(line):
try:
method, url, protocol = string.split(line)
except ValueError:
return None
if method != 'CONNECT':
return None
try:
host, port = url.split(":")
except ValueError:
return None
port = int(port)
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return host, port, httpversion
def parse_init_proxy(line):
try:
method, url, protocol = string.split(line)
except ValueError:
return None
parts = parse_url(url)
if not parts:
return None
scheme, host, port, path = parts
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return method, scheme, host, port, path, httpversion
def parse_init_http(line):
"""
Returns (method, url, httpversion)
"""
try:
method, url, protocol = string.split(line)
except ValueError:
return None
if not (url.startswith("/") or url == "*"):
return None
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return method, url, httpversion
def request_connection_close(httpversion, headers):
"""
Checks the request to see if the client connection should be closed.
"""
if "connection" in headers:
for value in ",".join(headers['connection']).split(","):
value = value.strip()
if value == "close":
return True
elif value == "keep-alive":
return False
# HTTP 1.1 connections are assumed to be persistent
if httpversion == (1, 1):
return False
return True
def response_connection_close(httpversion, headers):
"""
Checks the response to see if the client connection should be closed.
"""
if request_connection_close(httpversion, headers):
return True
elif (not has_chunked_encoding(headers)) and "content-length" in headers:
return False
return True
def read_http_body_request(rfile, wfile, headers, httpversion, limit):
"""
Read the HTTP body from a client request.
"""
if "expect" in headers:
# FIXME: Should be forwarded upstream
if "100-continue" in headers['expect'] and httpversion >= (1, 1):
wfile.write('HTTP/1.1 100 Continue\r\n')
wfile.write('\r\n')
del headers['expect']
return read_http_body(400, rfile, headers, False, limit)
def read_http_body_response(rfile, headers, all, limit):
"""
Read the HTTP body from a server response.
"""
return read_http_body(500, rfile, headers, all, limit)
def read_response(rfile, method, body_size_limit):
line = rfile.readline()
if line == "\r\n" or line == "\n": # Possible leftover from previous message
line = rfile.readline()
if not line:
raise HttpError(502, "Blank server response.")
parts = line.strip().split(" ", 2)
if len(parts) == 2: # handle missing message gracefully
parts.append("")
if not len(parts) == 3:
raise HttpError(502, "Invalid server response: %s."%line)
proto, code, msg = parts
httpversion = parse_http_protocol(proto)
if httpversion is None:
raise HttpError(502, "Invalid HTTP version: %s."%httpversion)
try:
code = int(code)
except ValueError:
raise HttpError(502, "Invalid server response: %s."%line)
headers = read_headers(rfile)
if code >= 100 and code <= 199:
return read_response(rfile, method, body_size_limit)
if method == "HEAD" or code == 204 or code == 304:
content = ""
else:
content = read_http_body_response(rfile, headers, False, body_size_limit)
return httpversion, code, msg, headers, content