previews.py 文件源码

def fetch_oembed_preview(content, urls):
    """Fetch first oembed content for a list of urls."""
    for url in urls:
        # See first if recently cached already
        if OEmbedCache.objects.filter(url=url, modified__gte=now()-datetime.timedelta(days=7)).exists():
            oembed = OEmbedCache.objects.get(url=url)
            Content.objects.filter(id=content.id).update(oembed=oembed)
            return oembed
        # Fetch oembed
        options = {}
        if url.startswith("https://twitter.com/"):
            # This probably has little effect since we fetch these on the backend...
            # But, DNT is always good to communicate if possible :)
            options = {"dnt": "true"}
        try:
            oembed = PyEmbed(discoverer=OEmbedDiscoverer()).embed(url, **options)
        except (PyEmbedError, PyEmbedDiscoveryError, PyEmbedConsumerError, ValueError):
            continue
        if not oembed:
            continue
        # Ensure width is 100% not fixed
        oembed = re.sub(r'width="[0-9]*"', 'width="100%"', oembed)
        oembed = re.sub(r'height="[0-9]*"', "", oembed)
        try:
            with transaction.atomic():
                oembed = OEmbedCache.objects.create(url=url, oembed=oembed)
        except IntegrityError:
            # Some other process got ahead of us
            oembed = OEmbedCache.objects.get(url=url)
            Content.objects.filter(id=content.id).update(oembed=oembed)
            return oembed
        Content.objects.filter(id=content.id).update(oembed=oembed)
        return oembed
    return False