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__init__.py
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__init__.py
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from __future__ import absolute_import
import re
import requests
from io import BufferedIOBase
from six import PY3
from sys import version_info
__all__ = ["open", "HTTPIOError", "HTTPIOFile"]
# The expected exception from unimplemented IOBase operations
IOBaseError = OSError if PY3 else IOError
def open(url, block_size=-1, **kwargs):
"""
Open a URL as a file-like object
:param url: The URL of the file to open
:param block_size: The cache block size, or `-1` to disable caching.
:param kwargs: Additional arguments to pass to `requests.Request()`
:return: An `httpio.HTTPIOFile` object supporting most of the usual
file-like object methods.
"""
f = HTTPIOFile(url, block_size, **kwargs)
f.open()
return f
class HTTPIOError(IOBaseError):
pass
class SyncHTTPIOFile(BufferedIOBase):
def __init__(self, url, block_size=-1, **kwargs):
super(SyncHTTPIOFile, self).__init__()
self.url = url
self.block_size = block_size
self._kwargs = kwargs
self._cursor = 0
self._cache = {}
self._session = None
self.length = None
self._closing = False
def __repr__(self):
status = "closed" if self.closed else "open"
return "<%s %s %r at %s>" % (status, type(self).__name__, self.url, hex(id(self)))
def __enter__(self):
self.open()
return super(SyncHTTPIOFile, self).__enter__()
def open(self):
self._assert_not_closed()
if not self._closing and self._session is None:
self._session = requests.Session()
response = self._session.head(self.url, **self._kwargs)
response.raise_for_status()
try:
self.length = int(response.headers['Content-Length'])
except KeyError:
raise HTTPIOError("Server does not report content length")
if response.headers.get('Accept-Ranges', '').lower() != 'bytes':
raise HTTPIOError("Server does not accept 'Range' headers")
def close(self):
self._closing = True
self._cache.clear()
if self._session is not None:
self._session.close()
super(SyncHTTPIOFile, self).close()
def flush(self):
self._assert_not_closed()
self.open()
self._cache.clear()
def peek(self, size=-1):
loc = self.tell()
data = self.read1(size)
self.seek(loc)
return data
def read(self, size=-1):
return self._read_impl(size)
def read1(self, size=-1):
return self._read_impl(size, 1)
def readable(self):
return True
def readinto(self, b):
return self._readinto_impl(b)
def readinto1(self, b):
return self._readinto_impl(b, 1)
def seek(self, offset, whence=0):
self._assert_not_closed()
if whence == 0:
self._cursor = offset
elif whence == 1:
self._cursor += offset
elif whence == 2:
self._cursor = self.length + offset
else:
raise HTTPIOError("Invalid argument: whence=%r" % whence)
if not (0 <= self._cursor <= self.length):
raise HTTPIOError("Invalid argument: cursor=%r" % self._cursor)
return self._cursor
def seekable(self):
return True
def tell(self):
self._assert_not_closed()
self.open()
return self._cursor
def write(self, *args, **kwargs):
raise HTTPIOError("Writing not supported on http resource")
def _read_impl(self, size=-1, max_raw_reads=-1):
self._assert_not_closed()
self.open()
if size < 1 or self._cursor + size > self.length:
size = self.length - self._cursor
if size == 0:
return b""
if self.block_size <= 0:
data = self._read_raw(self._cursor, self._cursor + size)
else:
data = b''.join(self._read_cached(size,
max_raw_reads=max_raw_reads))
self._cursor += len(data)
return data
def _readinto_impl(self, b, max_raw_reads=-1):
self._assert_not_closed()
self.open()
size = len(b)
if self._cursor + size > self.length:
size = self.length - self._cursor
if size == 0:
return 0
if self.block_size <= 0:
b[:size] = self._read_raw(self._cursor, self._cursor + size)
return size
else:
n = 0
for sector in self._read_cached(size,
max_raw_reads=max_raw_reads):
b[n:n+len(sector)] = sector
n += len(sector)
return n
def _read_cached(self, size, max_raw_reads=-1):
sector0, offset0 = divmod(self._cursor, self.block_size)
sector1, offset1 = divmod(self._cursor + size - 1, self.block_size)
offset1 += 1
sector1 += 1
# Fetch any sectors missing from the cache
status = "".join(str(int(idx in self._cache))
for idx in range(sector0, sector1))
raw_reads = 0
for match in re.finditer("0+", status):
if max_raw_reads >= 0 and raw_reads >= max_raw_reads:
break
data = self._read_raw(
self.block_size * (sector0 + match.start()),
self.block_size * (sector0 + match.end()))
raw_reads += 1
for idx in range(match.end() - match.start()):
self._cache[sector0 + idx + match.start()] = data[
self.block_size * idx:
self.block_size * (idx + 1)]
data = []
for idx in range(sector0, sector1):
if idx not in self._cache:
break
start = offset0 if idx == sector0 else None
end = offset1 if idx == (sector1 - 1) else None
data.append(self._cache[idx][start:end])
return data
def _read_raw(self, start, end):
headers = {"Range": "bytes=%d-%d" % (start, end - 1)}
headers.update(self._kwargs.get("headers", {}))
kwargs = dict(self._kwargs)
kwargs['headers'] = headers
response = self._session.get(
self.url,
**kwargs)
response.raise_for_status()
return response.content
def _assert_not_closed(self):
if self.closed:
raise HTTPIOError("I/O operation on closed resource")
if version_info[0] > 3 or (version_info[0] == 3 and version_info[1] >= 6):
from .asyncio import AsyncHTTPIOFileContextManagerMixin
class HTTPIOFile (SyncHTTPIOFile, AsyncHTTPIOFileContextManagerMixin):
pass
else:
class HTTPIOFile(SyncHTTPIOFile):
pass