boards/templatetags/board.py

import re
from django.shortcuts import get_object_or_404
from django import template

ELLIPSIZER = '...'

REGEX_LINES = re.compile(r'(<div class="br"></div>)', re.U | re.S)
REGEX_TAG = re.compile(r'<(/)?([^ ]+?)(?:(\s*/)| .*?)?>', re.S)


register = template.Library()

actions = [
    {
        'name': 'google',
        'link': 'http://google.com/searchbyimage?image_url=%s',
    },
    {
        'name': 'iqdb',
        'link': 'http://iqdb.org/?url=%s',
    },
]


@register.simple_tag(name='post_url')
def post_url(*args, **kwargs):
    post_id = args[0]

    post = get_object_or_404('Post', id=post_id)

    return post.get_url()


@register.simple_tag(name='image_actions')
def image_actions(*args, **kwargs):
    image_link = args[0]
    if len(args) > 1:
        image_link = 'http://' + args[1] + image_link # TODO https?

    result = ''

    for action in actions:
        result += '[<a href="' + action['link'] % image_link + '">' + \
                  action['name'] + '</a>]'

    return result


# TODO Use get_view of a post instead of this
@register.inclusion_tag('boards/post.html', name='post_view')
def post_view(post, moderator=False, need_open_link=False, truncated=False,
              **kwargs):
    """
    Get post
    """

    if 'is_opening' in kwargs:
        is_opening = kwargs['is_opening']
    else:
        is_opening = post.is_opening()

    thread = post.get_thread()

    if 'can_bump' in kwargs:
        can_bump = kwargs['can_bump']
    else:
        can_bump = thread.can_bump()

    opening_post_id = thread.get_opening_post_id()

    return {
        'post': post,
        'moderator': moderator,
        'is_opening': is_opening,
        'thread': thread,
        'bumpable': can_bump,
        'need_open_link': need_open_link,
        'truncated': truncated,
        'opening_post_id': opening_post_id,
    }


@register.filter(is_safe=True)
def truncate_lines(text, length):
    if length <= 0:
        return ''

    html4_singlets = (
        'br', 'col', 'link', 'base', 'img',
        'param', 'area', 'hr', 'input'
    )

    # Count non-HTML chars/words and keep note of open tags
    pos = 0
    end_text_pos = 0
    current_len = 0
    open_tags = []

    while current_len <= length:
        m = REGEX_LINES.search(text, pos)
        if not m:
            # Checked through whole string
            break
        pos = m.end(0)
        if m.group(1):
            # It's an actual non-HTML word or char
            current_len += 1
            if current_len == length:
                end_text_pos = m.start(0)
            continue
        # Check for tag
        tag = REGEX_TAG.match(m.group(0))
        if not tag or current_len >= length:
            # Don't worry about non tags or tags after our truncate point
            continue
        closing_tag, tagname, self_closing = tag.groups()
        # Element names are always case-insensitive
        tagname = tagname.lower()
        if self_closing or tagname in html4_singlets:
            pass
        elif closing_tag:
            # Check for match in open tags list
            try:
                i = open_tags.index(tagname)
            except ValueError:
                pass
            else:
                # SGML: An end tag closes, back to the matching start tag,
                # all unclosed intervening start tags with omitted end tags
                open_tags = open_tags[i + 1:]
        else:
            # Add it to the start of the open tags list
            open_tags.insert(0, tagname)

    if current_len <= length:
        return text
    out = text[:end_text_pos]

    if not out.endswith(ELLIPSIZER):
        out += ELLIPSIZER
    # Close any tags still open
    for tag in open_tags:
        out += '</%s>' % tag
    # Return string
    return out