Changes between Initial Version and Version 1 of CustomUploadAndFilters

Timestamp:

Aug 23, 2006, 11:44:30 AM (18 years ago)

Author:

Enrico <rico.bl@…>

Comment:

--

CustomUploadAndFilters

@@ +1 @@
+= Custom Upload Fields and Filters =
+
+I've made custom file upload fields with some extra features:
+
+* automatic upload_to path (based on app/model/field names)
+* automatic renaming the filename based on the primary key
+* maximum width and/or height for images
+
+Also, I've created filters to automatically resize/crop images directly from templates.
+
+The original idea came from [http://trac.studioquattro.biz/djangoutils/wiki/Thumbnail/ ImageWithThumbnailField], I've recreated as an exercise and to adapt it to my taste.
+
+There are similar approaches by [http://www.verdjn.com/ VERDJN].
+
+== Custom upload fields: AutoFileField and AutoImageField ==
+
+{{{
+#!python
+from django.db.models import ImageField, FileField, signals
+from django.dispatch import dispatcher
+from django.conf import settings
+import shutil, os, glob
+
+# Helpers
+from imaging import fit,fit_crop
+from fs import change_basename
+
+def auto_rename(file_path, new_name):
+    """
+    Renames a file, keeping the extension.
+    
+    Parameters:
+        - file_path: the file path relative to MEDIA_ROOT
+        - new_name: the new basename of the file (no extension)
+    
+    Returns the new file path on success or the original file_path on error.
+    """
+    
+    # Return if no file given
+    if file_path == '':
+        return ''
+    #
+    
+    # Get the new name
+    new_path = change_basename(file_path, new_name)
+    
+    # Changed?
+    if new_path != file_path:
+        # Try to rename
+        try:
+            shutil.move(os.path.join(settings.MEDIA_ROOT, file_path), os.path.join(settings.MEDIA_ROOT, new_path))
+        except IOError:
+            # Error? Restore original name
+            new_path = file_path
+        #
+    #
+    
+    # Return the new path replacing backslashes (for Windows)
+    return new_path
+# def auto_rename
+
+def auto_resize(file_path, max_width=None, max_height=None, crop=False):
+    """
+    Resize an image to fit an area.
+    Useful to avoid storing large files.
+    
+    If set to crop, will resize to the closest size and then crop.
+    
+    At least one of the max_width or max_height parameters must be set.
+    """
+    
+    # Return if no file given or no maximum size passed
+    if (not file_path) or ((not max_width) and (not max_height)):
+        return
+    #
+    
+    # Get the complete path using MEDIA_ROOT
+    real_path = os.path.join(settings.MEDIA_ROOT, file_path)
+    
+    if (crop):
+        fit_crop(real_path, max_width, max_height)
+    else:
+        fit(real_path, max_width, max_height)
+    #
+# def auto_resize
+
+def init_path(self, **kwargs):
+    """
+    Create a flag if there's an 'upload_to' parameter.
+    If not found, fill with a dummy value.
+    The flag will be used to create an automatic value on "post_init" signal.
+    """
+    
+    # Flag to auto-fill the path if it is empty
+    self.fill_path = ('upload_to' not in kwargs)
+    
+    if self.fill_path:
+        # Dummy value to bypass attribute requirement
+        kwargs['upload_to'] = '_'
+    #
+    
+    return kwargs
+# def init_path
+
+def set_field_path(self, instance = None):
+    """
+    Set up the "upload_to" for AutoFileField and AutoImageField or "path" for AutoFilePathField.
+    Set a path based on the field hierarchy (app/model/field).
+    """
+    
+    # Use the automatic path?
+    if self.fill_path:
+        setattr(self, 'upload_to', os.path.join(instance._meta.app_label, instance.__class__.__name__, self.name).lower())
+    #
+# def set_field_path
+
+class AutoFileField(FileField):
+    """
+    File field with:
+    * automatic primary key based renaming
+    * automatic upload_to (if not set)
+    """
+    
+    def __init__(self, **kwargs):
+        # Adjust the upload_to parameter
+        kwargs = init_path(self, **kwargs)
+        
+        super(AutoFileField, self).__init__(**kwargs)
+    # def __init__
+    
+    def _post_init(self, instance=None):
+        set_field_path(self, instance)
+    # def _post_init
+    
+    def _save(self, instance=None):
+        if instance == None:
+            return
+        filename = auto_rename(getattr(instance, self.attname), '%s' % instance._get_pk_val())
+        setattr(instance, self.attname, filename)
+    # def _save
+    
+    def contribute_to_class(self, cls, name):
+        super(AutoFileField, self).contribute_to_class(cls, name)
+        dispatcher.connect(self._post_init, signals.post_init, sender=cls)
+        dispatcher.connect(self._save, signals.pre_save, sender=cls)
+    # def contribute_to_class
+    
+    def get_internal_type(self):
+        return 'FileField'
+    # def get_internal_type
+# class AutoFileField
+
+class AutoImageField(ImageField):
+    """
+    Image field with:
+    * automatic primary key based renaming
+    * automatic upload_to (if not set)
+    * optional resizing to a maximum width and/or height
+    """
+    
+    def __init__(self, max_width=None, max_height=None, crop=False, **kwargs):
+        # Adjust the upload_to parameter
+        kwargs = init_path(self, **kwargs)
+        
+        # Image resizing properties
+        self.max_width, self.max_height, self.crop = max_width, max_height, crop
+        
+        # Set fields for width and height
+        self.width_field, self.height_field = 'width', 'height'
+        
+        super(AutoImageField, self).__init__(**kwargs)
+    # def __init__
+    
+    def save_file(self, new_data, new_object, original_object, change, rel):
+        # Original method
+        super(AutoImageField, self).save_file(new_data, new_object, original_object, change, rel)
+        
+        # Get upload info
+        upload_field_name = self.get_manipulator_field_names('')[0]
+        field = new_data.get(upload_field_name, False)
+        
+        # File uploaded?
+        if field:
+            # Resize image
+            auto_resize(getattr(new_object, self.attname), max_width=self.max_width, max_height=self.max_height, crop=self.crop)
+        #
+    # def save_file
+    
+    def delete_file(self, instance):
+        """
+        Deletes left-overs from thumbnail or crop template filters
+        """
+        
+        super(AutoImageField, self).delete_file(instance)
+        
+        if getattr(instance, self.attname):
+            # Get full path
+            file_name = getattr(instance, 'get_%s_filename' % self.name)()
+            # Get base dir, basename and extension
+            basedir = os.path.dirname(file_name)
+            base, ext = os.path.splitext(os.path.basename(file_name))
+            
+            # Delete left-overs from filters
+            for file in glob.glob(os.path.join(basedir, base + '_*' + ext)):
+                os.remove(os.path.join(basedir, file))
+            #
+        #
+    # def delete_file
+    
+    def _post_init(self, instance=None):
+        set_field_path(self, instance)
+    # def _post_init
+    
+    def _save(self, instance=None):
+        if instance == None:
+            return
+        filename = auto_rename(getattr(instance, self.attname), '%s' % instance._get_pk_val())
+        setattr(instance, self.attname, filename)
+    # def _save
+    
+    def contribute_to_class(self, cls, name):
+        super(AutoImageField, self).contribute_to_class(cls, name)
+        dispatcher.connect(self._post_init, signals.post_init, sender=cls)
+        dispatcher.connect(self._save, signals.pre_save, sender=cls)
+    # def contribute_to_class
+
+    def get_internal_type(self):
+        return 'ImageField'
+    # def get_internal_type
+# class AutoImageField
+}}}
+
+== Template filters: thumb and crop ==
+
+Remember to adjust your paths to your project.
+
+{{{
+#!python
+from django import template
+from django.conf import settings
+import os
+
+# Adjust your paths to 'imaging' and 'fs'
+from project.custom.imaging import fit,fit_crop
+from project.custom.fs import add_to_basename
+
+def parse_args(args = ''):
+    """
+    Parse filter arguments in the format:
+        keyword_1=value_1,keyword_2=value_2
+    
+    Returns a keyword list
+    """
+    kwargs = {}
+    
+    if args:
+        for arg in args.split(','):
+            kw, val = arg.split('=', 1)
+            kwargs[kw.lower()] = val
+        # for
+    #
+    
+    return kwargs
+# def parse_args
+
+def resize(url, args = '', crop = False):
+    """
+    On-the-fly thumbnail or crop creation
+    """
+    
+    kwargs = parse_args(args)
+    call_kwargs = {}
+
+    if ('width' not in kwargs) and ('height' not in kwargs):
+        return url
+    #
+    
+    if crop:
+        # Mark as a cropped image
+        extra = '_c_'
+    else:
+        # Mark as a thumbnailed image
+        extra = '_t_'
+    #
+    
+    # Setup width and/or height
+    if 'width' in kwargs:
+        extra += 'w' + kwargs['width']
+        call_kwargs['max_width'] = kwargs['width']
+    #
+    if 'height' in kwargs:
+        extra += 'h' + kwargs['height']
+        call_kwargs['max_height'] = kwargs['height']
+    #
+    
+    # Remove MEDIA_URL
+    url = url.replace(settings.MEDIA_URL, '')
+    
+    new_url = add_to_basename(url, extra)
+    call_kwargs['save_as'] = os.path.join(settings.MEDIA_ROOT, new_url)
+    
+    if crop:
+        # Make the cropping
+        ok = fit_crop(os.path.join(settings.MEDIA_ROOT, url), **call_kwargs)
+    else:
+        # Create the thumbnail
+        ok = fit(os.path.join(settings.MEDIA_ROOT, url), **call_kwargs)
+    #
+    
+    # Something wrong with the image processing?
+    if not ok:
+        # Silently restore the original url
+        new_url = url
+    #
+    
+    # Add MEDIA_URL back to the URL and return
+    return settings.MEDIA_URL + new_url
+    
+# def resize
+
+def thumb(url, args=''):
+    """
+    On-the-fly thumbnail creation
+    
+    Usage:
+        {{ url|thumb:"width=10,height=20" }}
+        {{ url|thumb:"width=10" }}
+        {{ url|thumb:"height=20" }}
+    """
+    
+    return resize(url, args)
+#
+
+def crop(url, args=''):
+    """
+    On-the-fly image cropping
+    
+    Usage:
+        {{ url|crop:"width=10,height=20" }}
+        {{ url|crop:"width=10" }}
+        {{ url|crop:"height=20" }}
+    """
+    
+    return resize(url, args, crop=True)
+#
+
+register = template.Library()
+
+register.filter('thumb', thumb)
+register.filter('crop', crop)
+}}}