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httpie-cli/httpie/downloads.py
2013-04-12 08:59:33 -03:00

375 lines
11 KiB
Python

# coding=utf-8
"""
Download mode implementation.
"""
from __future__ import division
import os
import re
import sys
import errno
import mimetypes
import threading
from time import time
from datetime import timedelta
from .output import RawStream
from .models import HTTPResponse
from .utils import humanize_bytes
from .compat import urlsplit
PARTIAL_CONTENT = 206
CLEAR_LINE = '\r\033[K'
PROGRESS = ('{percentage: 6.2f}% ({downloaded})'
' of {total} ({speed}/s) ETA {eta}')
PROGRESS_NO_CONTENT_LENGTH = '{downloaded} ({speed}/s) ETA {eta}'
SUMMARY = 'Done. {downloaded} of {total} in {time:0.5f}s ({speed}/s)\n'
SPINNER = '|/-\\'
class ContentRangeError(ValueError):
pass
def _parse_content_range(content_range, resumed_from):
"""
Parse and validate Content-Range header.
<http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html>
:param content_range: the value of a Content-Range response header
eg. "bytes 21010-47021/47022"
:param resumed_from: first byte pos. from the Range request header
:return: total size of the response body when fully downloaded.
"""
pattern = (
'^bytes (?P<first_byte_pos>\d+)-(?P<last_byte_pos>\d+)'
'/(\*|(?P<instance_length>\d+))$'
)
match = re.match(pattern, content_range)
if not match:
raise ContentRangeError(
'Invalid Content-Range format %r' % content_range)
content_range_dict = match.groupdict()
first_byte_pos = int(content_range_dict['first_byte_pos'])
last_byte_pos = int(content_range_dict['last_byte_pos'])
instance_length = (
int(content_range_dict['instance_length'])
if content_range_dict['instance_length']
else None
)
# "A byte-content-range-spec with a byte-range-resp-spec whose
# last- byte-pos value is less than its first-byte-pos value,
# or whose instance-length value is less than or equal to its
# last-byte-pos value, is invalid. The recipient of an invalid
# byte-content-range- spec MUST ignore it and any content
# transferred along with it."
if (first_byte_pos >= last_byte_pos
or (instance_length is not None
and instance_length <= last_byte_pos)):
raise ContentRangeError(
'Invalid Content-Range returned: %r' % content_range)
if (first_byte_pos != resumed_from
or (instance_length is not None
and last_byte_pos + 1 != instance_length)):
# Not what we asked for.
raise ContentRangeError(
'Unexpected Content-Range returned (%r)'
' for the requested Range ("bytes=%d-")'
% (content_range, resumed_from)
)
return last_byte_pos + 1
class Download(object):
def __init__(self, output_file=None,
resume=False, progress_file=sys.stderr):
"""
:param resume: Should the download resume if partial download
already exists.
:type resume: bool
:param output_file: The file to store response body in. If not
provided, it will be guessed from the response.
:type output_file: file
:param progress_file: Where to report download progress.
:type progress_file: file
"""
self._output_file = output_file
self._resume = resume
self._resumed_from = 0
self._progress = Progress()
self._progress_reporter = ProgressReporter(
progress=self._progress,
output=progress_file
)
def pre_request(self, request_headers):
"""Called just before the HTTP request is sent.
Might alter `request_headers`.
:type request_headers: dict
"""
# Disable content encoding so that we can resume, etc.
request_headers['Accept-Encoding'] = None
if self._resume:
try:
bytes_have = os.path.getsize(self._output_file.name)
except OSError as e:
if e.errno != errno.ENOENT:
raise
else:
# Set ``Range`` header to resume the download
# TODO: Use "If-Range: mtime" to make sure it's fresh?
request_headers['Range'] = 'bytes=%d-' % bytes_have
self._resumed_from = bytes_have
def start(self, response):
"""
Initiate and return a stream for `response` body with progress
callback attached. Can be called only once.
:param response: Initiated response object with headers already fetched
:type response: requests.models.Response
:return: RawStream, output_file
"""
assert not self._progress.time_started
try:
total_size = int(response.headers['Content-Length'])
except (KeyError, ValueError):
total_size = None
if self._output_file:
if self._resume and response.status_code == PARTIAL_CONTENT:
content_range = response.headers.get('Content-Range')
if content_range:
total_size = _parse_content_range(
content_range, self._resumed_from)
else:
self._resumed_from = 0
self._output_file.seek(0)
self._output_file.truncate()
else:
# TODO: Should the filename be taken from response.history[0].url?
# Output file not specified. Pick a name that doesn't exist yet.
content_type = response.headers.get('Content-Type', '')
self._output_file = open(
self._get_unique_output_filename(
url=response.url,
content_type=content_type,
),
mode='a+b'
)
self._progress.started(
resumed_from=self._resumed_from,
total_size=total_size
)
stream = RawStream(
msg=HTTPResponse(response),
with_headers=False,
with_body=True,
on_body_chunk_downloaded=self._on_progress,
# TODO: Find the optimal chunk size.
# The smaller it is the slower it gets, but gives better feedback.
chunk_size=1024 * 8
)
self._progress_reporter.output.write(
'Saving to "%s"\n' % self._output_file.name)
self._progress_reporter.report()
return stream, self._output_file
def finish(self):
assert not self._output_file.closed
self._output_file.close()
self._progress.finished()
@property
def interrupted(self):
return (
self._output_file.closed
and self._progress.total_size
and self._progress.total_size != self._progress.downloaded
)
def _on_progress(self, chunk):
"""
A download progress callback.
:param chunk: A chunk of response body data that has just
been downloaded and written to the output.
:type chunk: bytes
"""
self._progress.chunk_downloaded(len(chunk))
def _get_unique_output_filename(self, url, content_type):
suffix = 0
while True:
fn = self._get_output_filename(url, content_type, suffix)
if not os.path.exists(fn):
return fn
suffix += 1
def _get_output_filename(self, url, content_type, suffix=None):
suffix = '' if not suffix else '-' + str(suffix)
fn = urlsplit(url).path.rstrip('/')
fn = os.path.basename(fn) if fn else 'index'
if '.' in fn:
base, ext = os.path.splitext(fn)
else:
base = fn
ext = mimetypes.guess_extension(content_type.split(';')[0]) or ''
return base + suffix + ext
class Progress(object):
def __init__(self):
self.downloaded = 0
self.total_size = None
self.resumed_from = 0
self.total_size_humanized = '?'
self.time_started = None
self.time_finished = None
def started(self, resumed_from=0, total_size=None):
assert self.time_started is None
if total_size is not None:
self.total_size_humanized = humanize_bytes(total_size)
self.total_size = total_size
self.downloaded = self.resumed_from = resumed_from
self.time_started = time()
def chunk_downloaded(self, size):
assert self.time_finished is None
self.downloaded += size
@property
def has_finished(self):
return self.time_finished is not None
def finished(self):
assert self.time_started is not None
assert self.time_finished is None
self.time_finished = time()
class ProgressReporter(object):
def __init__(self, progress, output, tick=.1, update_interval=1):
"""
:type progress: Progress
:type output: file
"""
self.progress = progress
self.output = output
self._prev_bytes = 0
self._prev_time = time()
self._speed = 0
self._spinner_pos = 0
self._tick = tick
self._update_interval = update_interval
self._status_line = ''
super(ProgressReporter, self).__init__()
def report(self):
if self.progress.has_finished:
self.sum_up()
else:
self.report_speed()
# TODO: quit on KeyboardInterrupt
threading.Timer(self._tick, self.report).start()
def report_speed(self):
now = time()
if now - self._prev_time >= self._update_interval:
downloaded = self.progress.downloaded
if self.progress.total_size:
template = PROGRESS
percentage = (
downloaded / self.progress.total_size * 100)
else:
template = PROGRESS_NO_CONTENT_LENGTH
percentage = None
try:
# TODO: Use a longer interval for the speed/eta calculation?
speed = ((downloaded - self._prev_bytes)
/ (now - self._prev_time))
eta = int((self.progress.total_size - downloaded) / speed)
eta = str(timedelta(seconds=eta))
except ZeroDivisionError:
speed = 0
eta = '?'
self._status_line = template.format(
percentage=percentage,
downloaded=humanize_bytes(downloaded),
total=self.progress.total_size_humanized,
speed=humanize_bytes(speed),
eta=eta,
)
self._prev_time = now
self._prev_bytes = downloaded
self.output.write(
CLEAR_LINE
+ SPINNER[self._spinner_pos]
+ ' '
+ self._status_line
)
self.output.flush()
self._spinner_pos = (
self._spinner_pos + 1
if self._spinner_pos + 1 != len(SPINNER)
else 0
)
def sum_up(self):
actually_downloaded = (
self.progress.downloaded - self.progress.resumed_from)
time_taken = self.progress.time_finished - self.progress.time_started
self.output.write(CLEAR_LINE)
self.output.write(SUMMARY.format(
downloaded=humanize_bytes(actually_downloaded),
total=humanize_bytes(self.progress.downloaded),
speed=humanize_bytes(actually_downloaded / time_taken),
time=time_taken,
))
self.output.flush()