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https://github.com/9001/copyparty.git
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cromulent rfc2388/rfc6266 parser
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ed
parent
afa4216591
commit
c53413d57c
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@ -2,6 +2,9 @@
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# coding: utf-8
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from __future__ import print_function
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import re
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import hashlib
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class Unrecv(object):
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"""
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@ -25,3 +28,289 @@ class Unrecv(object):
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def unrecv(self, buf):
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self.buf = buf + self.buf
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class MultipartParser(object):
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def __init__(self, log_func, sr, http_headers):
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self.sr = sr
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self.log = log_func
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self.headers = http_headers
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self.re_ctype = re.compile(r"^content-type: *([^;]+)", re.IGNORECASE)
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self.re_cdisp = re.compile(r"^content-disposition: *([^;]+)", re.IGNORECASE)
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self.re_cdisp_field = re.compile(
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r'^content-disposition:(?: *|.*; *)name="([^"]+)"', re.IGNORECASE
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)
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self.re_cdisp_file = re.compile(
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r'^content-disposition:(?: *|.*; *)filename="(.*)"', re.IGNORECASE
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)
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def _read_header(self):
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"""
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returns [fieldname, filename] after eating a block of multipart headers
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while doing a decent job at dealing with the absolute mess that is
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rfc1341/rfc1521/rfc2047/rfc2231/rfc2388/rfc6266/the-real-world
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(only the fallback non-js uploader relies on these filenames)
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"""
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for ln in read_header(self.sr):
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self.log(ln)
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m = self.re_ctype.match(ln)
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if m:
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if m.group(1).lower() == "multipart/mixed":
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# rfc-7578 overrides rfc-2388 so this is not-impl
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# (opera >=9 <11.10 is the only thing i've ever seen use it)
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raise Exception(
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"you can't use that browser to upload multiple files at once"
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)
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continue
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# the only other header we care about is content-disposition
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m = self.re_cdisp.match(ln)
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if not m:
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continue
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if m.group(1).lower() != "form-data":
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raise Pebkac("not form-data: {}".format(ln))
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try:
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field = self.re_cdisp_field.match(ln).group(1)
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except:
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raise Pebkac("missing field name: {}".format(ln))
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try:
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fn = self.re_cdisp_file.match(ln).group(1)
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except:
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# this is not a file upload, we're done
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return field, None
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try:
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is_webkit = self.headers["user-agent"].lower().find("applewebkit") >= 0
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except:
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is_webkit = False
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# chromes ignore the spec and makes this real easy
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if is_webkit:
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# quotes become %22 but they don't escape the %
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# so unescaping the quotes could turn messi
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return field, fn.split('"')[0]
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# also ez if filename doesn't contain "
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if not fn.split('"')[0].endswith("\\"):
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return field, fn.split('"')[0]
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# this breaks on firefox uploads that contain \"
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# since firefox escapes " but forgets to escape \
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# so it'll truncate after the \
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ret = u""
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esc = False
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for ch in fn:
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if esc:
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if ch in [u'"', u"\\"]:
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ret += u'"'
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else:
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ret += esc + ch
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esc = False
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elif ch == u"\\":
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esc = True
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elif ch == u'"':
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break
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else:
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ret += ch
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return [field, ret]
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def _read_data(self):
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blen = len(self.boundary)
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bufsz = 32 * 1024
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while True:
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buf = self.sr.recv(bufsz)
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if not buf:
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# abort: client disconnected
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raise Exception("client disconnected during post")
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while True:
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ofs = buf.find(self.boundary)
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if ofs != -1:
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self.sr.unrecv(buf[ofs + blen :])
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yield buf[:ofs]
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return
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d = len(buf) - blen
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if d > 0:
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# buffer growing large; yield everything except
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# the part at the end (maybe start of boundary)
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yield buf[:d]
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buf = buf[d:]
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# look for boundary near the end of the buffer
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for n in range(1, len(buf) + 1):
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if not buf[-n:] in self.boundary:
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n -= 1
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break
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if n == 0 or not self.boundary.startswith(buf[-n:]):
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# no boundary contents near the buffer edge
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break
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if blen == n:
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# EOF: found boundary
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yield buf[:-n]
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return
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buf2 = self.sr.recv(bufsz)
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if not buf2:
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# abort: client disconnected
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raise Exception("client disconnected during post")
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buf += buf2
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yield buf
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def _run_gen(self):
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"""
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yields [fieldname, unsanitized_filename, fieldvalue]
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where fieldvalue yields chunks of data
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"""
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while True:
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fieldname, filename = self._read_header()
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yield [fieldname, filename, self._read_data()]
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tail = self.sr.recv(2)
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if tail == b"--":
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# EOF indicated by this immediately after final boundary
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self.sr.recv(2)
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return
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if tail != b"\r\n":
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raise Pebkac("protocol error after field value")
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def _read_value(self, iterator, max_len):
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ret = b""
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for buf in iterator:
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ret += buf
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if len(ret) > max_len:
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raise Pebkac("field length is too long")
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return ret
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def parse(self):
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# spec says there might be junk before the first boundary,
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# can't have the leading \r\n if that's not the case
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self.boundary = b"--" + get_boundary(self.headers).encode("utf-8")
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# discard junk before the first boundary
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for junk in self._read_data():
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self.log(
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u"discarding preamble: [{}]".format(junk.decode("utf-8", "ignore"))
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)
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# nice, now make it fast
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self.boundary = b"\r\n" + self.boundary
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self.gen = self._run_gen()
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def require(self, field_name, max_len):
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"""
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returns the value of the next field in the multipart body,
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raises if the field name is not as expected
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"""
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p_field, _, p_data = next(self.gen)
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if p_field != field_name:
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raise Pebkac('expected field "{}", got "{}"'.format(field_name, p_field))
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return self._read_value(p_data, max_len).decode("utf-8", "ignore")
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def drop(self):
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"""discards the remaining multipart body"""
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for _, _, data in self.gen:
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for _ in data:
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pass
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def get_boundary(headers):
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# boundaries contain a-z A-Z 0-9 ' ( ) + _ , - . / : = ?
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# (whitespace allowed except as the last char)
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ptn = r"^multipart/form-data; *(.*; *)?boundary=([^;]+)"
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ct = headers["content-type"]
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m = re.match(ptn, ct, re.IGNORECASE)
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if not m:
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raise Pebkac("invalid content-type for a multipart post: {}".format(ct))
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return m.group(2)
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def read_header(sr):
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ret = b""
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while True:
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if ret.endswith(b"\r\n\r\n"):
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break
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elif ret.endswith(b"\r\n\r"):
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n = 1
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elif ret.endswith(b"\r\n"):
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n = 2
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elif ret.endswith(b"\r"):
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n = 3
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else:
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n = 4
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buf = sr.recv(n)
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if not buf:
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raise Exception("failed to read headers")
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ret += buf
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return ret[:-4].decode("utf-8", "replace").split("\r\n")
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def sanitize_fn(fn):
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return fn.replace("\\", "/").split("/")[-1].strip()
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def hashcopy(actor, fin, fout):
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u32_lim = int((2 ** 31) * 0.9)
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hashobj = hashlib.sha512()
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tlen = 0
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for buf in fin:
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actor.workload += 1
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if actor.workload > u32_lim:
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actor.workload = 100 # prevent overflow
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tlen += len(buf)
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hashobj.update(buf)
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fout.write(buf)
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return tlen, hashobj.hexdigest()
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def unescape_cookie(orig):
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# mw=idk; doot=qwe%2Crty%3Basd+fgh%2Bjkl%25zxc%26vbn # qwe,rty;asd fgh+jkl%zxc&vbn
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ret = u""
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esc = u""
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for ch in orig:
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if ch == u"%":
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if len(esc) > 0:
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ret += esc
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esc = ch
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elif len(esc) > 0:
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esc += ch
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if len(esc) == 3:
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try:
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ret += chr(int(esc[1:], 16))
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except:
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ret += esc
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esc = u""
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else:
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ret += ch
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if len(esc) > 0:
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ret += esc
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return ret
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class Pebkac(Exception):
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pass
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