92 lines
3.1 KiB
Python
92 lines
3.1 KiB
Python
"""
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Image Tag
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---------
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This implements a Liquid-style image tag for Pelican,
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based on the liquid img tag which is based on the octopress image tag [1]_
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Syntax
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------
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{% b64img [class name(s)] [http[s]:/]/path/to/image [width [height]] [title text | "title text" ["alt text"]] %}
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Examples
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--------
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{% b64img /images/ninja.png Ninja Attack! %}
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{% b64img left half http://site.com/images/ninja.png Ninja Attack! %}
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{% b64img left half http://site.com/images/ninja.png 150 150 "Ninja Attack!" "Ninja in attack posture" %}
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Output
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------
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<img src="data:;base64,....">
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<img class="left half" src="data:;base64,..." title="Ninja Attack!" alt="Ninja Attack!">
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<img class="left half" src="data:;base64,..." width="150" height="150" title="Ninja Attack!" alt="Ninja in attack posture">
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[1] https://github.com/imathis/octopress/blob/master/plugins/image_tag.rb
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"""
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import re
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import base64
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try:
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import urllib.request as urllib2
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except ImportError:
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import urllib2
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from .mdx_liquid_tags import LiquidTags
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import six
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SYNTAX = '{% b64img [class name(s)] [http[s]:/]/path/to/image [width [height]] [title text | "title text" ["alt text"]] %}'
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# Regular expression to match the entire syntax
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ReImg = re.compile("""(?P<class>\S.*\s+)?(?P<src>(?:https?:\/\/|\/|\S+\/)\S+)(?:\s+(?P<width>\d+))?(?:\s+(?P<height>\d+))?(?P<title>\s+.+)?""")
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# Regular expression to split the title and alt text
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ReTitleAlt = re.compile("""(?:"|')(?P<title>[^"']+)?(?:"|')\s+(?:"|')(?P<alt>[^"']+)?(?:"|')""")
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def _get_file(src):
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""" Return content from local or remote file. """
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try:
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if '://' in src or src[0:2] == '//': # Most likely this is remote file
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response = urllib2.urlopen(src)
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return response.read()
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else:
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with open(src, 'rb') as fh:
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return fh.read()
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except Exception as e:
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raise RuntimeError('Error generating base64image: {}'.format(e))
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def base64image(src):
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""" Generate base64 encoded image from srouce file. """
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return base64.b64encode(_get_file(src))
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@LiquidTags.register('b64img')
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def b64img(preprocessor, tag, markup):
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attrs = None
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# Parse the markup string
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match = ReImg.search(markup)
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if match:
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attrs = dict([(key, val.strip())
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for (key, val) in six.iteritems(match.groupdict()) if val])
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else:
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raise ValueError('Error processing input. '
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'Expected syntax: {0}'.format(SYNTAX))
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# Check if alt text is present -- if so, split it from title
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if 'title' in attrs:
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match = ReTitleAlt.search(attrs['title'])
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if match:
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attrs.update(match.groupdict())
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if not attrs.get('alt'):
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attrs['alt'] = attrs['title']
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attrs['src'] = 'data:;base64,{}'.format(base64image(attrs['src']))
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# Return the formatted text
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return "<img {0}>".format(' '.join('{0}="{1}"'.format(key, val)
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for (key, val) in six.iteritems(attrs)))
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#----------------------------------------------------------------------
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# This import allows image tag to be a Pelican plugin
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from .liquid_tags import register
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