Full Code of t3nsor/quora-backup for AI

Repository: t3nsor/quora-backup
Branch: master
Commit: 1032cbef56c6
Files: 5
Total size: 45.6 KB

Directory structure:
gitextract_bfuioo1s/

├── .gitignore
├── LICENSE
├── README.md
├── converter.py
└── crawler.py

================================================
FILE CONTENTS
================================================

================================================
FILE: .gitignore
================================================
*.swp


================================================
FILE: LICENSE
================================================
GNU GENERAL PUBLIC LICENSE
                       Version 2, June 1991

 Copyright (C) 1989, 1991 Free Software Foundation, Inc., <http://fsf.org/>
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

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Public License instead of this License.



================================================
FILE: README.md
================================================
## Installation

You need Python 3, version 3.2 or higher, with the `html5lib` library installed. Pick up a copy [here](https://github.com/html5lib/html5lib-python).

This software is only known to work on Linux. It can probably be made to work in Windows too, but I haven't tried it. Patches welcome.

No installation is required, but make sure that `converter.py` and `crawler.py` are executable. (Or you can just run them by invoking `python3` explicitly.)

## Basic usage: downloading all your answers

To view all your answers, go to the answers section of [Your Content](https://www.quora.com/content?content_types=answers) and scroll all the way down until there are no more answers to load.

Type the following into your browser's URL bar:

    javascript:window.open().document.write(JSON.stringify(Array.prototype.map.call(document.querySelectorAll('.UserContentList .pagedlist_item'), function (e) { return [e.getElementsByTagName('a')[0].href, e.getElementsByClassName('metadata')[0].innerHTML] })))

**Note:** You can copy and paste the code above, but your browser might automatically remove the `javascript:` prefix from the URL when you do so. If that happens, you'll have to type in the `javascript:` part yourself. Alternatively, you can just use the browser console to execute the javascript code.

(You need popups enabled in order for this to work. If your popup blocker blocks the window, disable it and try again.)

This creates a popup window or new tab containing a list of your answers, in a format that looks something like this:

`[["https://www.quora.com/Do-classical-mechanics-work-beyond-the-speed-of-light/answer/Brian-Bi","Added Fri"],["https://www.quora.com/Are-competitive-programmers-happy-when-working-as-software-engineers/answer/Brian-Bi","Added Thu"],["https://www.quora.com/How-did-Brian-Bi-not-know-it-was-Chinese-New-Year-today/answer/Brian-Bi","Added Thu"],["https://www.quora.com/How-many-hours-of-studies-did-Brian-Bi-put-in-per-day-in-order-to-prepare-for-the-IChO/answer/Brian-Bi","Added Thu"]`...

Copy and paste the entire contents of the window or tab into a text editor and save it as a file, `answers.json`.

Go back to your browser, type in the following URL, and press Enter:

`javascript:window.open().document.write(new Date().valueOf() + '<br>' + new Date().getTimezoneOffset())`

(The same caveats as before apply.)

Again a new window or tab should pop up, showing the date in a numeric format, with two lines. The first line shows the current timestamp in numeric format. The second shows the offset of your time zone from UTC in minutes. Take note of both of these numbers.

Suppose you installed the scripts in `/home/brian/quora-backup`. You can run the crawler as follows:

`/home/brian/quora-backup/crawler.py answers.json /home/brian/quora-answers --origin_timestamp=${TIMESTAMP} --origin_timezone=${OFFSET}`

replacing `${TIMESTAMP}` with the timestamp value previously obtained from the browser, and `${OFFSET}` with the time zone offset value.

This creates a new directory, `/home/brian/quora-answers`, and populates it with the answers specified, after downloading them from Quora. It also generates a timestamp in YYYY-MM-DD format for each answer.

## Converting answers to a standalone format

The converter can be run as follows:

`/home/brian/quora-backup/converter.py /home/brian/quora-answers /home/brian/quora-answers-cooked`

This creates the directory `/home/brian/quora-answers-cooked` and copies each answer downloaded into `/home/brian/quora-answers` into the new directory after processing it to remove everything other than the answer content itself. If this step succeeds, then the answer will still be readable even if Quora disappears from the face of the Web.

## What the crawler does

The crawler is pretty simple: its job is to download the URLs you provide. But it also has a slightly nontrivial task, which is to determine the date on which each answer was written (give or take a day). This is done by reading the timestamps provided on the Your Content page itself. But the more recent timestamps given are relative, not absolute (for example, "Fri" if you wrote answer last Friday). That's why the crawler needs to be told at what time you accessed that page and in what time zone, so it can resolve those strings into absolute dates.

## What the converter does

The converter has three main functions:

1. It removes everything on the page other than the answer content. No bar at the top, no sidebar with related answers, no box indicating why the answer was collapsed (if it was); your name is not shown, nor are upvotes, the timestamp, view count, comments, or the upvote and downvote buttons. All that's left is answer content. This also reduces the size of the HTML considerably.
2. It downloads a copy of each image embedded in your answer. These images are
all hosted on Quora's servers; after running the converter, you'll have a copy on local disk, so you'll still be able to view the images even if Quora disappears. (This functionality can be disabled using the `-n` flag.)
3. It removes extraneous HTML elements and attributes, simplifying the HTML as much as possible.

## FAQ

**Why did you write your own Quora backup tool when there are already a zillion of them?**

Because I believe this tool is unique in that it allows you to reliably and easily download ALL your answers, even if you have thousands of them, AND to ensure that they still display properly even if Quora completely disappears.

**What if I only want to download some of my answers?**

To download only some of your answers, just remove all the entries from `answers.json` you don't want. If you also just want to download some recent answers, you don't have to scroll all the way down on the "Your Content" page. Yes, I realize this is really user-unfriendly. It would be nice to have a GUI. Patches welcome.

**Won't Quora flag me for using a script to automatically download answers?**

It depends on how many answers you're downloading. If it's less than a thousand, you'll probably be fine, but I take no responsibility if something bad happens to you. If you have a LOT of answers, you might want to take advantage of the built-in rate limiting options. Both the crawler and converter support a `--delay` flag; for example, `--delay=1` tells the script to pause for a second after every download. Don't ask me what value to use here; I don't know. Use this software at your own risk.

**Why is this licensed under the GPL? I noticed you usually prefer more permissive licenses.**

Because I want to make sure that all changes get merged back into my repository. There is a very good reason for this: there is only one Quora, and they'll probably change the way they generate HTML, which means this software will periodically stop working properly. I want to maintain a single version that's fully up to date with all the patches other people submit, rather than having multiple versions running around with patches for different kinds of elements.

## Errors and bugs
A message starting with [FATAL] signals that the script cannot function at all. [ERROR] means that processing of a single answer was aborted due to an unrecoverable error; [WARNING] means an error condition arose which prevented some feature from working properly but did not abort the processing of an answer. If you run with the `-v` flag, you'll also see [DEBUG] messages.

The converter will emit a [WARNING] message if it doesn't understand the HTML found in the answer. I have tested the converter against my entire set of answers, so I believe that as of the time of this release, this should never happen. But the format of Quora's HTML is likely to change in the future, which means the converter will stop working properly. If this happens, you're likely to see [WARNING] messages. Those should be reported.

If you want to report such a bug in the converter, try re-running with the "-v" flag, and include with your report everything between the closest "Filename:" lines before and after the [WARNING] message. (This doesn't mean other kinds of bugs shouldn't be reported; I am just giving instructions on how to report the most common kind of bug I expect.)


================================================
FILE: converter.py
================================================
#!/usr/bin/env python3
import argparse
import errno
from html5lib import (HTMLParser, serializer, treebuilders, treewalkers)
import os
import re
import sys
import time
import urllib.error
import urllib.request
from xml.dom.minidom import Node

def log_if_v(msg):
    if args.verbose:
        print('[DEBUG] %s' % msg, file=sys.stderr)

def get_title_node(document):
    for node in document.getElementsByTagName('title'):
        return node
    return None

def get_text_content(node):
    text = ''
    for text_node in node.childNodes:
        if text_node.nodeType == Node.TEXT_NODE:
            text += text_node.data
    return text

# The HTML can mostly be saved as-is. The main changes we want to make are:
# 1) Remove most <span>s and attributes since they are not needed anymore.
# 2) Rewrite relative paths ("/Brian-Bi") to full URLs
# 3) Download a copy of each embedded image
def cleanup_tree(doc, src, dest):
    for child in src.childNodes:
        if child.nodeType == Node.TEXT_NODE:
            # Text nodes can simply be left as-is
            dest.appendChild(child.cloneNode(False))
            continue
        if child.nodeType != Node.ELEMENT_NODE:
            # ???
            raise ValueError()
        # Otherwise, it's an element node.
        if child.tagName in ['br', 'hr']:
            dest.appendChild(child.cloneNode(False))
        elif child.tagName in ['b', 'i', 'u', 'h2', 'ol', 'ul', 'li', 'blockquote', 'wbr', 'p']:
            # This node doesn't need to be modified but its children might.
            # Also, we won't copy over any of its attributes.
            new_node = doc.createElement(child.tagName)
            cleanup_tree(doc, child, new_node)
            dest.appendChild(new_node)
        elif child.getAttribute('data-embed') != '':
            # This is a video. We want to copy the data-embed value, which is HTML for an iframe node.
            # So, we have to parse it into a separate document and import the node.
            iframe_html = child.getAttribute('data-embed')
            parser = HTMLParser(tree=treebuilders.getTreeBuilder('dom'))
            iframe_doc = parser.parse(iframe_html)
            try:
                iframe = iframe_doc.documentElement.childNodes[1].firstChild
                if iframe.tagName != 'iframe':
                    raise ValueError()
                new_node = doc.importNode(iframe, False)
                # Quora uses a protocol-relative URL (//youtube.com/...) so let's make sure we rewrite this.
                src = new_node.getAttribute('src')
                if src.startswith('//'):
                    new_node.setAttribute('src', 'http:' + src)
                # The video will look really bad if we don't explicitly set the dimensions.
                new_node.setAttribute('width', '525')
                new_node.setAttribute('height', '295')
                dest.appendChild(new_node)
            except Exception:
                print('[WARNING] Failed to parse video embed code', file=sys.stderr)
                # Bail out by just copying the original HTML
                dest.appendChild(child.cloneNode(True))
        elif child.tagName == 'code':
            # Inline code block. Strip the attributes.
            new_node = doc.createElement('code')
            dest.appendChild(new_node)
            cleanup_tree(doc, child, new_node)
        elif 'ContentFooter' in child.getAttribute('class') or 'hidden' in child.getAttribute('class'):
            # These are nodes we just want to skip.
            continue
        elif child.tagName in ['span', 'div']:
            # don't insert a span or div; just insert its contents
            cleanup_tree(doc, child, dest)
        elif child.tagName == 'a':
            # A link. We only want to copy the href, and pass the rest through.
            new_node = doc.createElement('a')
            href = child.getAttribute('href')
            if href.startswith('/'):
                href = 'http://quora.com' + href
            new_node.setAttribute('href', href)
            dest.appendChild(new_node)
            cleanup_tree(doc, child, new_node)
        elif child.tagName == 'img':
            src = child.getAttribute('master_src')
            if src == '':
                src = child.getAttribute('src')
            new_node = doc.createElement('img')
            new_node.setAttribute('src', src)
            new_node.setAttribute('alt', child.getAttribute('alt'))
            if args.no_download:
                dest.appendChild(new_node)
                continue
            # Save a copy of the image locally.
            # If an error occurs, just leave the src pointing to Quora.
            try:
                m = re.search('/([^/?]+)(\?|$)', src)
                if m is None:
                    raise ValueError()
                filename = m.group(1)
                if not filename.endswith('.png'):
                    filename += '.png'
                try:
                    img_fd = os.open(args.output_dir + '/' + filename, os.O_WRONLY | os.O_CREAT | os.O_EXCL)
                except OSError as error:
                    if error.errno == errno.EEXIST:
                        log_if_v('Image %s has already been saved; skipping' % filename)
                        new_node.setAttribute('src', filename)
                        continue
                    else:
                        raise
                log_if_v('Downloading image from %s' % src)
                closed = False
                try:
                    img = urllib.request.urlopen(src).read()
                    time.sleep(args.delay)
                    os.write(img_fd, img)
                    os.close(img_fd)
                    closed = True
                except Exception:
                    os.close(img_fd)
                    closed = True
                    try:
                        os.remove(args.output_dir + '/' + filename)
                    except:
                        print('[WARNING] Failed to remove incomplete file %s' % filename, file=sys.stderr)
                    raise
                finally:
                    if not closed:
                        os.close(img_fd)
                    # Don't leave the file there; we will retry it next time.
                # If everything went according to plan, rewrite the src to the local file.
                new_node.setAttribute('src', filename)
            except urllib.error.URLError as error:
                print('[WARNING] Failed to download image from URL %s (%s)' % (src, error.reason), file=sys.stderr)
            except OSError as error:
                print('[WARNING] Failed to save image from URL %s to file %s (%s)' % (src, filename, error.strerror), file=sys.stderr)
            except ValueError:
                print('[WARNING] Failed to determine image name from URL %s' % src, file=sys.stderr)
            finally:
                dest.appendChild(new_node)
        elif child.tagName == 'pre':
            # Block (not inline) code. Quora's HTML already has the desired <pre><code> structure,
            # so we just need to strip the attributes from the <pre>.
            new_node = doc.createElement('pre')
            dest.appendChild(new_node)
            cleanup_tree(doc, child, new_node)
        else:
            print('[WARNING] Unrecognized node', file=sys.stderr)
            # Bail out by just copying the original HTML
            dest.appendChild(child.cloneNode(True))

parser = argparse.ArgumentParser(description = 'Convert answers downloaded from Quora into a more portable HTML format')
parser.add_argument('input_dir', nargs='?', default='./quora-answers', help='directory containing "raw" answers downloaded from Quora')
parser.add_argument('output_dir', nargs='?', default='./quora-answers-cooked', help='where to store the images and converted answers')
parser.add_argument('-d', '--delay', default=0, type=float, help='Time to sleep between downloads, in seconds')
parser.add_argument('-n', '--no_download', action='store_true', help='Do not save images')
parser.add_argument('-v', '--verbose', action='store_true', help='be verbose')

global args
args = parser.parse_args()

# Get a list of answers to convert...
filenames = list(filter(lambda f: f.endswith('.html'), os.listdir(args.input_dir)))
filenames.sort()
if len(filenames) == 0:
    sys.exit('[FATAL] No .html files found in directory %s', args.input_dir)
print('Found %d answers' % len(filenames), file=sys.stderr)

log_if_v('Creating directory %s' % args.output_dir)
try:
    os.mkdir(args.output_dir, 0o700)
except OSError as error:
    if error.errno == errno.EEXIST:
        log_if_v('Directory already exists')
    else:
        # This is the top level, and we have nothing else to do if we failed
        raise

for filename in filenames:
    sys.stderr.flush()
    print('Filename: ' + filename, file=sys.stderr)
    try:
        with open(args.input_dir + '/' + filename, 'rb') as page:
            page_html = page.read()
    except IOError as error:
        print('[ERROR] Failed to read %s (%s)' % (filename, error.strerror))
        continue

    # Get the HTML element containing just the answer itself.
    # Also get the title.
    parser = HTMLParser(tree=treebuilders.getTreeBuilder('dom'))
    document = parser.parse(page_html, default_encoding='utf-8')
    title_node = get_title_node(document) 
    log_if_v('Title: ' + ('(could not be determined)' if title_node is None else get_text_content(title_node)))

    answer_node = None
    for node in document.getElementsByTagName('div'):
        if 'ExpandedAnswer' in node.getAttribute('class').split():
            answer_node = node
            break
    if answer_node is None:
        print('[WARNING] Failed to locate answer on page (filename: %s)' % filename, file=sys.stderr)
        continue

    # Construct our new page...
    new_page = document.createElement('html')
    head_node = document.createElement('head')
    if not title_node is None:
        head_node.appendChild(title_node)
    meta_node = document.createElement('meta')
    meta_node.setAttribute('charset', 'utf-8')
    head_node.appendChild(meta_node)
    css = ("blockquote { border-left: 2px solid #ddd; color: #666; margin: 0; padding-left: 16px; } "
           "code, pre { background: #f4f4f4; } "
           "pre, h2 { margin: 0; } "
           "ul { margin: 0 0 0 16px; padding: 8px 0; } "
           "ol { margin: 0 0 0 28px; padding: 8px 0; } "
           "li { margin: 0 0 8px; } ")
    style_node = document.createElement('style')
    style_node.setAttribute('type', 'text/css')
    style_node.appendChild(document.createTextNode(css))
    head_node.appendChild(style_node)
    # Quora now uses MathJax, so set up the configuration object:
    script_node = document.createElement('script')
    script_text = document.createTextNode('window.MathJax = {"showMathMenu":false,"messageStyle":"none","errorSettings":{"style":{"color":"#000000","font-style":"normal"}},"HTML-CSS":{"linebreaks":{"automatic":true,"width":"container"},"EqnChunk":150,"EqnChunkDelay":20},"tex2jax":{"inlineMath":[["[math]","[/math]"]],"displayMath":[],"ignoreClass":"edit_latex|qtext_editor_content|ignore_latex","processClass":"render_latex","processEnvironments":false,"preview":"none"},"TeX":{"noUndefined":{"attributes":{"mathcolor":"red"}},"noErrors":{"multiLine":true,"style":{"max-width":"100%","overflow":"hidden"}},"Macros":{"C":"{\\mathbb{C}}","N":"{\\mathbb{N}}","O":"{\\emptyset}","Q":"{\\mathbb{Q}}","R":"{\\mathbb{R}}","Z":"{\\mathbb{Z}}"}},"fast-preview":{"disabled":true},"Safe":{"allow":{"URLs":"none","classes":"none","cssIDs":"none","styles":"none","fontsize":"none","require":"none"}}};')
    script_node.appendChild(script_text)
    head_node.appendChild(script_node)
    # and then load MathJax:
    script_node = document.createElement('script')
    script_node.setAttribute('type', 'text/javascript')
    script_node.setAttribute('src', 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js?config=TeX-AMS-MML_HTMLorMML,Safe')
    head_node.appendChild(script_node)
    new_page.appendChild(head_node)
    body_node = document.createElement('body')
    # This step processes Quora's HTML into a more lightweight and portable form.
    cleanup_tree(document, answer_node, body_node)
    new_page.appendChild(body_node)
    # Okay! Finally, save the HTML.
    walker = treewalkers.getTreeWalker('dom')(new_page)
    try:
        with open(args.output_dir + '/' + filename, 'wb', 0o600) as saved_page:
            saved_page.write(b'<!DOCTYPE html>')
            saved_page.write(serializer.serialize(new_page, 'dom', 'utf-8', omit_optional_tags=False))
    except IOError as error:
        print('[ERROR] Failed to save to file %s (%s)' % (filename, error.strerror), file=sys.stderr)

print('Done', file=sys.stderr)



================================================
FILE: crawler.py
================================================
#!/usr/bin/env python3
import argparse
import errno
import json
import os
import re
import sys
import time
import urllib.error
import urllib.request

def log_if_v(msg):
    if args.verbose:
        print('[DEBUG] %s' % msg, file=sys.stderr)

# Given origin (timestamp offset by time zone) and string from Quora, e.g.
# "Added 31 Jan", returns a string such as '2015-01-31'.
# Quora's short date strings don't provide enough information to determine the
# exact time, unless it was within the last day, so we won't bother to be any
# more precise.
def parse_quora_date(origin, quora_str):
    days_of_week = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
    months_of_year = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    _, _, date_str = quora_str.partition('Added ')
    date_str = date_str.strip()
    if date_str == '':
        raise ValueError('"%s" does not appear to indicate when answer was added' % quora_str)
    m0 = re.match('just now$', date_str)
    m1 = re.match('(\d+)m ago$', date_str)
    m2 = re.match('(\d+)h ago$', date_str)
    m3 = re.match('(' + '|'.join(days_of_week) + ')$', date_str)
    m4 = re.match('(' + '|'.join(months_of_year) + ') (\d+)$', date_str)
    m5 = re.match('(' + '|'.join(months_of_year) + ') (\d+), (\d+)$', date_str)
    m6 = re.match('(\d+)[ap]m$', date_str)
    if not m0 is None or not m6 is None:
        # Using origin for time in am / pm since the time of the day will be discarded anyway
        tm = time.gmtime(origin)
    elif not m1 is None:
        tm = time.gmtime(origin - 60*int(m1.group(1)))
    elif not m2 is None:
        tm = time.gmtime(origin - 3600*int(m2.group(1)))
    elif not m3 is None:
        # Walk backward until we reach the given day of the week
        day_of_week = days_of_week.index(m3.group(1))
        offset = 1
        while offset <= 7:
            tm = time.gmtime(origin - 86400*offset)
            if tm.tm_wday == day_of_week:
                break
            offset += 1
        else:
            raise ValueError('date "%s" is invalid' % date_str)
    elif not m4 is None:
        # Walk backward until we reach the given month and year
        month_of_year = months_of_year.index(m4.group(1)) + 1
        day_of_month = int(m4.group(2))
        offset = 1
        while offset <= 366:
            tm = time.gmtime(origin - 86400*offset)
            if tm.tm_mon == month_of_year and tm.tm_mday == day_of_month:
                break
            offset += 1
        else:
            raise ValueError('date "%s" is invalid' % date_str)
    elif not m5 is None:
        # may raise ValueError
        tm = time.strptime(date_str, '%b %d, %Y')
    else:
        raise ValueError('date "%s" could not be interpreted' % date_str)
    return '%d-%02d-%02d' % (tm.tm_year, tm.tm_mon, tm.tm_mday)

parser = argparse.ArgumentParser(description = 'Download a set of answers from Quora')
parser.add_argument('input_file', help='file containing JSON-encoded list of timestamped URLs to download')
parser.add_argument('output_dir', nargs='?', default='./quora-answers', help='where to store the downloaded answers and images')
parser.add_argument('-d', '--delay', default=0, type=float, help='Time to sleep between answers, in seconds')
parser.add_argument('-t', '--origin_timestamp', default=None, type=int, help='JS time when the list of URLs was fetched')
parser.add_argument('-z', '--origin_timezone', default=None, type=int, help='browser timezone')
parser.add_argument('-v', '--verbose', action='store_true', help='enable debug messages')
parser.add_argument('-o', '--overwrite', action='store_true', help='Overwrite existing answers')

global args
args = parser.parse_args()

# Determine the origin for relative date computation
if args.origin_timestamp is None:
    log_if_v('Using current time')
    args.origin_timestamp = time.time()
else:
    args.origin_timestamp //= 1000
if args.origin_timezone is None:
    log_if_v('Using system time zone')
    args.origin_timezone = time.timezone
else:
    args.origin_timezone *= 60
origin = args.origin_timestamp - args.origin_timezone

# Load the list of answer URLs from the input file.
log_if_v('Loading input file %s' % args.input_file)
with open(args.input_file, 'rb') as input_file:
    answers = json.load(input_file)
print('Found %d answers' % len(answers), file=sys.stderr)

# Check the validity of the input
if type(answers) != list:
    sys.exit('[FATAL] Incorrect input format')
for e in answers:
    if type(e) != list or len(e) != 2 or type(e[0]) != str or type(e[1]) != str:
        sys.exit('[FATAL] Incorrect input format')

log_if_v('Creating directory %s' % args.output_dir)
try:
    os.mkdir(args.output_dir, 0o700)
except OSError as error:
    if error.errno == errno.EEXIST:
        log_if_v('Directory already exists')
    else:
        # This is the top level, and we have nothing else to do if we failed
        raise
os.chdir(args.output_dir)
download_file_count = 0
for e in answers:
    sys.stderr.flush()
    url = e[0]
    print('URL: %s' % url, file=sys.stderr)

    # Determine the date when this answer was written
    try:
        added_time = parse_quora_date(origin, e[1])
    except ValueError as error:
        print('[WARNING] Failed to parse date: %s' % str(error), file=sys.stderr)
        added_time = 'xxxx-xx-xx'
    print('Date: %s' % added_time, file=sys.stderr)

    # Get the part of the URL indicating the question title; we will save under this name
    m1 = re.search('quora\.com/([^/]+)/answer', url)
    # if there's a context topic
    m2 = re.search('quora\.com/[^/]+/([^/]+)/answer', url)
    filename = added_time + ' '
    if not m1 is None:
        filename += m1.group(1)
    elif not m2 is None:
        filename += m2.group(1)
    else:
        print('[ERROR] Could not find question part of URL %s; skipping' % url, file=sys.stderr)
        continue
    # Trim the filename if it's too long. 255 bytes is the limit on many filesystems.
    total_byte_length = len(bytes(filename + '.html', encoding="utf-8"))
    filename_bytes = bytes(filename, encoding="utf-8")
    if total_byte_length > 255:
        filename_bytes = filename_bytes[:255-total_byte_length]
        well_formed = False
        while not well_formed:
            try:
                filename = str(filename_bytes, encoding="utf-8")
                well_formed = True
            except UnicodeDecodeError:
                filename_bytes = filename_bytes[:-1]
        log_if_v('Filename was truncated to at most 255 bytes.')
    filename += '.html'
    log_if_v('Filename: %s' % filename)

    # If overwrite is enabled or the answer doesn't exist
    if args.overwrite or not os.path.isfile(filename):
        # Fetch the URL to find the answer
        log_if_v('Downloading answer from URL %s' % url)
        try:
            page_html = urllib.request.urlopen(url).read()
            with open(filename, 'wb') as f:
                f.write(page_html)
        except urllib.error.URLError as error:
            print('[ERROR] Failed to download answer from URL %s (%s)' % (url, error.reason), file=sys.stderr)
            continue
        except IOError as error:
            print('[ERROR] Failed to save answer to file %s (%s)' % (filename, error.strerror), file=sys.stderr)

        download_file_count += 1
        time.sleep(args.delay)
    else:
        log_if_v('Answer File : %s Already Exists. Skipping' % filename)

print('Done. Downloaded %d files' % download_file_count, file=sys.stderr)