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August 29, 2015 13:55
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Django Image field with thumbnail.
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from django.db.models import ImageField | |
from django.db.models import signals | |
from django.db.models.fields.files import ImageFieldFile | |
from PIL import Image | |
import os | |
def name_thumb(str): | |
""" Function for generating thumbnail name from original file. """ | |
parts = str.split(u'.') | |
parts[-2]+=u'_thumb' | |
return u'.'.join(parts) | |
class ImageWithThumbFieldFile(ImageFieldFile): | |
""" Extension to file field. """ | |
def get_thumb_url(self): | |
try: # hack to check if file was passed | |
self.file | |
except: | |
return | |
return name_thumb(u"%s"%self) | |
thumb_url = property(get_thumb_url) | |
class ImageWithThumbField(ImageField): | |
""" Model field for keeping a thumbnail next to actual image """ | |
attr_class = ImageWithThumbFieldFile | |
def db_type(self, connection): | |
return 'Varchar(255)' | |
def __init__(self, verbose_name=None, name=None, twidth=120, theight=80, **kwargs): | |
self.twidth, self.theight = twidth, theight | |
super(ImageWithThumbField, self).__init__(verbose_name=verbose_name, name=name,**kwargs) | |
def _save(self,**kwargs): | |
image = getattr(kwargs['instance'], self.attname) | |
try: # hack to check if file was passed | |
image.file | |
except: | |
return | |
thumb_path = name_thumb(image.path) | |
if os.path.exists(thumb_path) and os.path.getmtime(image.path) > os.path.getmtime(thumb_path): #obsolete? | |
os.unlink(thumb_path) | |
if not os.path.exists(thumb_path): | |
image = Image.open(image.path) | |
image.thumbnail([self.twidth, self.theight], Image.ANTIALIAS) | |
try: | |
image.save(thumb_path, image.format, quality=90, optimize=1) | |
except: | |
image.save(thumb_path, image.format, quality=90) | |
def _delete(self,**kwargs): | |
image = getattr(kwargs['instance'], self.attname) | |
try: # hack to check if file was passed | |
image.file | |
except: | |
return | |
if image.file: | |
thumb_path = name_thumb(image.path) | |
try: | |
os.unlink(image.path) | |
os.unlink(thumb_path) | |
except OSError: | |
pass | |
def contribute_to_class(self, cls, name): | |
super(ImageWithThumbField, self).contribute_to_class(cls, name) | |
signals.post_save.connect(self._save, cls, True) | |
signals.pre_delete.connect(self._delete, cls, True) | |
def get_internal_type(self): | |
return 'ImageField' |
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