path: root/libs/apprise/attachment/AttachHTTP.py

# -*- coding: utf-8 -*-
# BSD 2-Clause License
#
# Apprise - Push Notification Library.
# Copyright (c) 2024, Chris Caron <lead2gold@gmail.com>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

import re
import os
import requests
import threading
from tempfile import NamedTemporaryFile
from .AttachBase import AttachBase
from ..common import ContentLocation
from ..URLBase import PrivacyMode
from ..AppriseLocale import gettext_lazy as _


class AttachHTTP(AttachBase):
    """
    A wrapper for HTTP based attachment sources
    """

    # The default descriptive name associated with the service
    service_name = _('Web Based')

    # The default protocol
    protocol = 'http'

    # The default secure protocol
    secure_protocol = 'https'

    # The number of bytes in memory to read from the remote source at a time
    chunk_size = 8192

    # Web based requests are remote/external to our current location
    location = ContentLocation.HOSTED

    # thread safe loading
    _lock = threading.Lock()

    def __init__(self, headers=None, **kwargs):
        """
        Initialize HTTP Object

        headers can be a dictionary of key/value pairs that you want to
        additionally include as part of the server headers to post with

        """
        super().__init__(**kwargs)

        self.schema = 'https' if self.secure else 'http'

        self.fullpath = kwargs.get('fullpath')
        if not isinstance(self.fullpath, str):
            self.fullpath = '/'

        self.headers = {}
        if headers:
            # Store our extra headers
            self.headers.update(headers)

        # Where our content is written to upon a call to download.
        self._temp_file = None

        # Our Query String Dictionary; we use this to track arguments
        # specified that aren't otherwise part of this class
        self.qsd = {k: v for k, v in kwargs.get('qsd', {}).items()
                    if k not in self.template_args}

        return

    def download(self, **kwargs):
        """
        Perform retrieval of the configuration based on the specified request
        """

        if self.location == ContentLocation.INACCESSIBLE:
            # our content is inaccessible
            return False

        # prepare header
        headers = {
            'User-Agent': self.app_id,
        }

        # Apply any/all header over-rides defined
        headers.update(self.headers)

        auth = None
        if self.user:
            auth = (self.user, self.password)

        url = '%s://%s' % (self.schema, self.host)
        if isinstance(self.port, int):
            url += ':%d' % self.port

        url += self.fullpath

        # Where our request object will temporarily live.
        r = None

        # Always call throttle before any remote server i/o is made
        self.throttle()

        with self._lock:
            if self.exists(retrieve_if_missing=False):
                # Due to locking; it's possible a concurrent thread already
                # handled the retrieval in which case we can safely move on
                self.logger.trace(
                    'HTTP Attachment %s already retrieved',
                    self._temp_file.name)
                return True

            # Ensure any existing content set has been invalidated
            self.invalidate()

            self.logger.debug(
                'HTTP Attachment Fetch URL: %s (cert_verify=%r)' % (
                    url, self.verify_certificate))

            try:
                # Make our request
                with requests.get(
                        url,
                        headers=headers,
                        auth=auth,
                        params=self.qsd,
                        verify=self.verify_certificate,
                        timeout=self.request_timeout,
                        stream=True) as r:

                    # Handle Errors
                    r.raise_for_status()

                    # Get our file-size (if known)
                    try:
                        file_size = int(r.headers.get('Content-Length', '0'))
                    except (TypeError, ValueError):
                        # Handle edge case where Content-Length is a bad value
                        file_size = 0

                    # Perform a little Q/A on file limitations and restrictions
                    if self.max_file_size > 0 and \
                            file_size > self.max_file_size:

                        # The content retrieved is to large
                        self.logger.error(
                            'HTTP response exceeds allowable maximum file '
                            'length ({}KB): {}'.format(
                                int(self.max_file_size / 1024),
                                self.url(privacy=True)))

                        # Return False (signifying a failure)
                        return False

                    # Detect config format based on mime if the format isn't
                    # already enforced
                    self.detected_mimetype = r.headers.get('Content-Type')

                    d = r.headers.get('Content-Disposition', '')
                    result = re.search(
                        "filename=['\"]?(?P<name>[^'\"]+)['\"]?", d, re.I)
                    if result:
                        self.detected_name = result.group('name').strip()

                    # Create a temporary file to work with; delete must be set
                    # to False or it isn't compatible with Microsoft Windows
                    # instances. In lieu of this, __del__ will clean up the
                    # file for us.
                    self._temp_file = NamedTemporaryFile(delete=False)

                    # Get our chunk size
                    chunk_size = self.chunk_size

                    # Track all bytes written to disk
                    bytes_written = 0

                    # If we get here, we can now safely write our content to
                    # disk
                    for chunk in r.iter_content(chunk_size=chunk_size):
                        # filter out keep-alive chunks
                        if chunk:
                            self._temp_file.write(chunk)
                            bytes_written = self._temp_file.tell()

                            # Prevent a case where Content-Length isn't
                            # provided. In this case we don't want to fetch
                            # beyond our limits
                            if self.max_file_size > 0:
                                if bytes_written > self.max_file_size:
                                    # The content retrieved is to large
                                    self.logger.error(
                                        'HTTP response exceeds allowable '
                                        'maximum file length '
                                        '({}KB): {}'.format(
                                            int(self.max_file_size / 1024),
                                            self.url(privacy=True)))

                                    # Invalidate any variables previously set
                                    self.invalidate()

                                    # Return False (signifying a failure)
                                    return False

                                elif bytes_written + chunk_size \
                                        > self.max_file_size:
                                    # Adjust out next read to accomodate up to
                                    # our limit +1. This will prevent us from
                                    # reading to much into our memory buffer
                                    self.max_file_size - bytes_written + 1

                    # Ensure our content is flushed to disk for post-processing
                    self._temp_file.flush()

                    # Set our minimum requirements for a successful download()
                    # call
                    self.download_path = self._temp_file.name
                    if not self.detected_name:
                        self.detected_name = os.path.basename(self.fullpath)

            except requests.RequestException as e:
                self.logger.error(
                    'A Connection error occurred retrieving HTTP '
                    'configuration from %s.' % self.host)
                self.logger.debug('Socket Exception: %s' % str(e))

                # Invalidate any variables previously set
                self.invalidate()

                # Return False (signifying a failure)
                return False

            except (IOError, OSError):
                # IOError is present for backwards compatibility with Python
                # versions older then 3.3.  >= 3.3 throw OSError now.

                # Could not open and/or write the temporary file
                self.logger.error(
                    'Could not write attachment to disk: {}'.format(
                        self.url(privacy=True)))

                # Invalidate any variables previously set
                self.invalidate()

                # Return False (signifying a failure)
                return False

        # Return our success
        return True

    def invalidate(self):
        """
        Close our temporary file
        """
        if self._temp_file:
            self.logger.trace(
                'Attachment cleanup of %s', self._temp_file.name)
            self._temp_file.close()

            try:
                # Ensure our file is removed (if it exists)
                os.unlink(self._temp_file.name)

            except OSError:
                pass

            # Reset our temporary file to prevent from entering
            # this block again
            self._temp_file = None

        super().invalidate()

    def __del__(self):
        """
        Tidy memory if open
        """
        with self._lock:
            self.invalidate()

    def url(self, privacy=False, *args, **kwargs):
        """
        Returns the URL built dynamically based on specified arguments.
        """

        # Our URL parameters
        params = self.url_parameters(privacy=privacy, *args, **kwargs)

        # Prepare our cache value
        if self.cache is not None:
            if isinstance(self.cache, bool) or not self.cache:
                cache = 'yes' if self.cache else 'no'
            else:
                cache = int(self.cache)

            # Set our cache value
            params['cache'] = cache

        if self._mimetype:
            # A format was enforced
            params['mime'] = self._mimetype

        if self._name:
            # A name was enforced
            params['name'] = self._name

        # Append our headers into our parameters
        params.update({'+{}'.format(k): v for k, v in self.headers.items()})

        # Apply any remaining entries to our URL
        params.update(self.qsd)

        # Determine Authentication
        auth = ''
        if self.user and self.password:
            auth = '{user}:{password}@'.format(
                user=self.quote(self.user, safe=''),
                password=self.pprint(
                    self.password, privacy, mode=PrivacyMode.Secret, safe=''),
            )
        elif self.user:
            auth = '{user}@'.format(
                user=self.quote(self.user, safe=''),
            )

        default_port = 443 if self.secure else 80

        return '{schema}://{auth}{hostname}{port}{fullpath}?{params}'.format(
            schema=self.secure_protocol if self.secure else self.protocol,
            auth=auth,
            hostname=self.quote(self.host, safe=''),
            port='' if self.port is None or self.port == default_port
                 else ':{}'.format(self.port),
            fullpath=self.quote(self.fullpath, safe='/'),
            params=self.urlencode(params),
        )

    @staticmethod
    def parse_url(url):
        """
        Parses the URL and returns enough arguments that can allow
        us to re-instantiate this object.

        """
        results = AttachBase.parse_url(url)

        if not results:
            # We're done early as we couldn't load the results
            return results

        # Add our headers that the user can potentially over-ride if they wish
        # to to our returned result set
        results['headers'] = results['qsd-']
        results['headers'].update(results['qsd+'])

        return results