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bfe_meta_opengraph_image.py
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Wed, Jul 3, 08:05

bfe_meta_opengraph_image.py
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# -*- coding: utf-8 -*-
#
# This file is part of Invenio.
# Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2013 CERN.
#
# Invenio is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# Invenio is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Invenio; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""BibFormat element - return an image for the record"""
from invenio.config import CFG_SITE_URL, CFG_SITE_SECURE_URL, CFG_CERN_SITE
from invenio.bibdocfile import BibRecDocs, get_superformat_from_format
from invenio.config import CFG_WEBSEARCH_ENABLE_OPENGRAPH
def format_element(bfo, max_photos='', one_icon_per_bibdoc='yes', twitter_card_type='photo', use_webjournal_featured_image='no'):
"""Return an image of the record, suitable for the Open Graph protocol.
Will look for any icon stored with the record, and will fallback to any
image file attached to the record. Returns nothing when no image is found.
Some optional structured properties are not considered, for optimizing both generation of the page
and page size.
@param max_photos: the maximum number of photos to display
@param one_icon_per_bibdoc: shall we keep just one icon per bibdoc in the output (not repetition of same preview in multiple sizes)?
@param twitter_card_type: the type of Twitter card: 'photo' (single photo) or 'gallery'. Fall back to 'photo' if not enough pictures for a 'gallery'.
@param use_webjournal_featured_image: if 'yes', use the "featured image" (as defined in bfe_webjournal_articles_overview) as image for the Twitter Card
"""
if not CFG_WEBSEARCH_ENABLE_OPENGRAPH:
return ""
bibarchive = BibRecDocs(bfo.recID)
bibdocs = bibarchive.list_bibdocs()
tags = []
images = []
if max_photos.isdigit():
max_photos = int(max_photos)
else:
max_photos = len(bibdocs)
for doc in bibdocs[:max_photos]:
found_icons = []
found_image_url = ''
found_image_size = 0
for docfile in doc.list_latest_files(list_hidden=False):
if docfile.is_icon():
found_icons.append((docfile.get_size(), docfile.get_url()))
elif get_superformat_from_format(docfile.get_format()).lower() in [".jpg", ".gif", ".jpeg", ".png"]:
found_image_url = docfile.get_url()
found_image_size = docfile.get_size()
found_icons.sort()
# We might have found several icons for the same file: keep
# middle-size one
if found_icons:
if one_icon_per_bibdoc.lower() == 'yes':
found_icons = [found_icons[len(found_icons)/2]]
for icon_size, icon_url in found_icons:
images.append((icon_url, icon_url.replace(CFG_SITE_URL, CFG_SITE_SECURE_URL), icon_size))
# Link to main file too (?)
if found_image_url:
images.append((found_image_url, found_image_url.replace(CFG_SITE_URL, CFG_SITE_SECURE_URL), found_image_size))
if CFG_CERN_SITE:
# Add some more pictures from metadata
dummy_size = 500*1024 # we don't we to check image size, we just make one (see Twitter Card limit)
additional_images = [(image_url, image_url.replace("http://mediaarchive.cern.ch/", "https://mediastream.cern.ch"), dummy_size) for image_url in bfo.fields("8567_u") if image_url.split('.')[-1] in ('jpg', 'png', 'jpeg', 'gif') and 'A5' in image_url]
images.extend(additional_images)
tags = ['<meta property="og:image" content="%s" />%s' % (image_url, image_url != image_secure_url and '\n<meta property="og:image:secure_url" content="%s" />' % image_secure_url or "") for image_url, image_secure_url, image_size in images]
# Twitter Card
if use_webjournal_featured_image.lower() == 'yes':
# First look for the prefered image, if available. Note that
# it might be a remote one.
try:
from invenio.bibformat_elements import bfe_webjournal_articles_overview
image_url = bfe_webjournal_articles_overview._get_feature_image(bfo)
image_secure_url = image_url.replace('http:', 'https:')
image_size = 500 * 1024 # TODO: check for real image size
if image_url.strip():
images.insert(0, (image_url, image_secure_url, image_size))
except:
pass
# Filter out images that would not be compatible
twitter_compatible_images = [image_url for image_url, image_secure_url, image_size in images if \
image_size < 1024*1024][:4] #Max 1MB according to Twitter Card APIs, max 4 photos
twitter_card_tags = []
if len(twitter_compatible_images) == 4 and twitter_card_type == 'gallery':
twitter_card_tags = ['<meta name="twitter:image%i" content="%s" />' % \
(twitter_compatible_images.index(image_url), image_url) \
for image_url in twitter_compatible_images]
elif twitter_compatible_images:
twitter_card_tags = ['<meta name="twitter:image" content="%s" />' % twitter_compatible_images[0]]
tags = twitter_card_tags + tags
return "\n".join(tags)
def escape_values(bfo):
"""
Called by BibFormat in order to check if output of this element
should be escaped.
"""
return 0

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