def image_preview(request, app_label, model, id, size):
"""
Grab all image link within a peice of content
and generate thumbnails of largest image
"""
# get page object; protect size
try:
content_type = ContentType.objects.get(app_label=app_label, model=model)
instance = content_type.get_object_for_this_type(id=id)
except:
return HttpResponseNotFound("Image not found.", mimetype="text/plain")
keys = [settings.CACHE_PRE_KEY, IMAGE_PREVIEW_CACHE, model, str(instance.id), size]
key = '.'.join(keys)
response = cache.get(key)
original_size = size
if not response:
from base.utils import parse_image_sources, make_image_object_from_url, image_rescale
from pages.models import Page
from articles.models import Article
from news.models import News
# set sizes
size_min = (30,30)
size_cap = (512,512)
size_tuple = size.split('x')
if len(size_tuple) == 2: size = int(size_tuple[0]), int(size_tuple[1])
else: size = int(size), int(size)
if size > size_cap: size = size_cap
image_urls = []
# siphon image urls; make fake image (starting image)
if isinstance(instance,Page):
image_urls = parse_image_sources(instance.content)
if isinstance(instance,Article):
image_urls = parse_image_sources(instance.body)
if isinstance(instance,News):
image_urls = parse_image_sources(instance.body)
image = Pil.new('RGBA',size_min)
# find biggest image, dimension-wise
for image_url in image_urls:
image_candidate = make_image_object_from_url(image_url)
if image_candidate:
if image_candidate.size > image.size:
image = image_candidate
if image.size[1] > size_min[1]:
# rescale, convert-to true-colors; return response
image = image_rescale(image, size)
if image.mode != "RGB":
image = image.convert("RGB")
response = HttpResponse(mimetype='image/jpeg')
image.save(response, "JPEG", quality=100)
keys = [settings.CACHE_PRE_KEY, IMAGE_PREVIEW_CACHE, model, str(instance.id), size]
key = '.'.join(keys)
cache.set(key, response)
return response
else: # raise http 404 error (returns page not found)
return HttpResponseNotFound("Image not found.", mimetype="text/plain")
else:
return response
