httpie/downloads.py
"""
Download mode implementation.
"""
import mimetypes
import os
import re
from mailbox import Message
from time import monotonic
from typing import IO, Optional, Tuple
from urllib.parse import urlsplit
import requests
from .models import HTTPResponse, OutputOptions
from .output.streams import RawStream
from .context import Environment
PARTIAL_CONTENT = 206
class ContentRangeError(ValueError):
pass
def parse_content_range(content_range: str, resumed_from: int) -> int:
"""
Parse and validate Content-Range header.
<https://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.
"""
if content_range is None:
raise ContentRangeError('Missing Content-Range')
pattern = (
r'^bytes (?P<first_byte_pos>\d+)-(?P<last_byte_pos>\d+)'
r'/(\*|(?P<instance_length>\d+))$'
)
match = re.match(pattern, content_range)
if not match:
raise ContentRangeError(
f'Invalid Content-Range format {content_range!r}')
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(
f'Invalid Content-Range returned: {content_range!r}')
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(
f'Unexpected Content-Range returned ({content_range!r})'
f' for the requested Range ("bytes={resumed_from}-")'
)
return last_byte_pos + 1
def filename_from_content_disposition(
content_disposition: str
) -> Optional[str]:
"""
Extract and validate filename from a Content-Disposition header.
:param content_disposition: Content-Disposition value
:return: the filename if present and valid, otherwise `None`
"""
# attachment; filename=jakubroztocil-httpie-0.4.1-20-g40bd8f6.tar.gz
msg = Message(f'Content-Disposition: {content_disposition}')
filename = msg.get_filename()
if filename:
# Basic sanitation.
filename = os.path.basename(filename).lstrip('.').strip()
if filename:
return filename
def filename_from_url(url: str, content_type: Optional[str]) -> str:
fn = urlsplit(url).path.rstrip('/')
fn = os.path.basename(fn) if fn else 'index'
if '.' not in fn and content_type:
content_type = content_type.split(';')[0]
if content_type == 'text/plain':
# mimetypes returns '.ksh'
ext = '.txt'
else:
ext = mimetypes.guess_extension(content_type)
if ext == '.htm':
ext = '.html'
if ext:
fn += ext
return fn
def trim_filename(filename: str, max_len: int) -> str:
if len(filename) > max_len:
trim_by = len(filename) - max_len
name, ext = os.path.splitext(filename)
if trim_by >= len(name):
filename = filename[:-trim_by]
else:
filename = name[:-trim_by] + ext
return filename
def get_filename_max_length(directory: str) -> int:
max_len = 255
if hasattr(os, 'pathconf') and 'PC_NAME_MAX' in os.pathconf_names:
max_len = os.pathconf(directory, 'PC_NAME_MAX')
return max_len
def trim_filename_if_needed(filename: str, directory='.', extra=0) -> str:
max_len = get_filename_max_length(directory) - extra
if len(filename) > max_len:
filename = trim_filename(filename, max_len)
return filename
def get_unique_filename(filename: str, exists=os.path.exists) -> str:
attempt = 0
while True:
suffix = f'-{attempt}' if attempt > 0 else ''
try_filename = trim_filename_if_needed(filename, extra=len(suffix))
try_filename += suffix
if not exists(try_filename):
return try_filename
attempt += 1
class Downloader:
def __init__(
self,
env: Environment,
output_file: IO = None,
resume: bool = False
):
"""
:param resume: Should the download resume if partial download
already exists.
:param output_file: The file to store response body in. If not
provided, it will be guessed from the response.
:param progress_file: Where to report download progress.
"""
self.finished = False
self.status = DownloadStatus(env=env)
self._output_file = output_file
self._resume = resume
self._resumed_from = 0
def pre_request(self, request_headers: dict):
"""Called just before the HTTP request is sent.
Might alter `request_headers`.
"""
# Ask the server not to encode the content so that we can resume, etc.
request_headers['Accept-Encoding'] = 'identity'
if self._resume:
bytes_have = os.path.getsize(self._output_file.name)
if bytes_have:
# Set ``Range`` header to resume the download
# TODO: Use "If-Range: mtime" to make sure it's fresh?
request_headers['Range'] = f'bytes={bytes_have}-'
self._resumed_from = bytes_have
def start(
self,
initial_url: str,
final_response: requests.Response
) -> Tuple[RawStream, IO]:
"""
Initiate and return a stream for `response` body with progress
callback attached. Can be called only once.
:param initial_url: The original requested URL
:param final_response: Initiated response object with headers already fetched
:return: RawStream, output_file
"""
assert not self.status.time_started
# FIXME: some servers still might sent Content-Encoding: gzip
# <https://github.com/httpie/cli/issues/423>
try:
total_size = int(final_response.headers['Content-Length'])
except (KeyError, ValueError, TypeError):
total_size = None
if not self._output_file:
self._output_file = self._get_output_file_from_response(
initial_url=initial_url,
final_response=final_response,
)
else:
# `--output, -o` provided
if self._resume and final_response.status_code == PARTIAL_CONTENT:
total_size = parse_content_range(
final_response.headers.get('Content-Range'),
self._resumed_from
)
else:
self._resumed_from = 0
try:
self._output_file.seek(0)
self._output_file.truncate()
except OSError:
pass # stdout
output_options = OutputOptions.from_message(final_response, headers=False, body=True)
stream = RawStream(
msg=HTTPResponse(final_response),
output_options=output_options,
on_body_chunk_downloaded=self.chunk_downloaded,
)
self.status.started(
output_file=self._output_file,
resumed_from=self._resumed_from,
total_size=total_size
)
return stream, self._output_file
def finish(self):
assert not self.finished
self.finished = True
self.status.finished()
def failed(self):
self.status.terminate()
@property
def interrupted(self) -> bool:
return (
self.finished
and self.status.total_size
and self.status.total_size != self.status.downloaded
)
def chunk_downloaded(self, chunk: bytes):
"""
A download progress callback.
:param chunk: A chunk of response body data that has just
been downloaded and written to the output.
"""
self.status.chunk_downloaded(len(chunk))
@staticmethod
def _get_output_file_from_response(
initial_url: str,
final_response: requests.Response,
) -> IO:
# Output file not specified. Pick a name that doesn't exist yet.
filename = None
if 'Content-Disposition' in final_response.headers:
filename = filename_from_content_disposition(
final_response.headers['Content-Disposition'])
if not filename:
filename = filename_from_url(
url=initial_url,
content_type=final_response.headers.get('Content-Type'),
)
unique_filename = get_unique_filename(filename)
return open(unique_filename, buffering=0, mode='a+b')
class DownloadStatus:
"""Holds details about the download status."""
def __init__(self, env):
self.env = env
self.downloaded = 0
self.total_size = None
self.resumed_from = 0
self.time_started = None
self.time_finished = None
def started(self, output_file, resumed_from=0, total_size=None):
assert self.time_started is None
self.total_size = total_size
self.downloaded = self.resumed_from = resumed_from
self.time_started = monotonic()
self.start_display(output_file=output_file)
def start_display(self, output_file):
from httpie.output.ui.rich_progress import (
DummyDisplay,
StatusDisplay,
ProgressDisplay
)
message = f'Downloading to {output_file.name}'
if self.env.show_displays:
if self.total_size is None:
# Rich does not support progress bars without a total
# size given. Instead we use status objects.
self.display = StatusDisplay(self.env)
else:
self.display = ProgressDisplay(self.env)
else:
self.display = DummyDisplay(self.env)
self.display.start(
total=self.total_size,
at=self.downloaded,
description=message
)
def chunk_downloaded(self, size):
assert self.time_finished is None
self.downloaded += size
self.display.update(size)
@property
def has_finished(self):
return self.time_finished is not None
@property
def time_spent(self):
if (
self.time_started is not None
and self.time_finished is not None
):
return self.time_finished - self.time_started
else:
return None
def finished(self):
assert self.time_started is not None
assert self.time_finished is None
self.time_finished = monotonic()
if hasattr(self, 'display'):
self.display.stop(self.time_spent)
def terminate(self):
if hasattr(self, 'display'):
self.display.stop(self.time_spent)