Documents: Document image API transformations

Add transformations support to the document image API.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -12,6 +12,8 @@
   as a dependency.
 - Appearance: Remove unused form_empty_label flag.
 - Appearance: Allow subclassing the text area widget.
+- Documents: Add transformation support to document image API with serialized
+  transformations. 
 
 3.1.9 (2018-11-01)
 ==================

mayan/apps/documents/api_views.py

@@ -2,8 +2,11 @@ from __future__ import absolute_import, unicode_literals
 
 import logging
 
+from furl import furl
+
 from django.http import HttpResponse
 from django.shortcuts import get_object_or_404
+from django.utils.encoding import force_bytes
 from django.views.decorators.cache import cache_control, patch_cache_control
 
 from django_downloadview import DownloadMixin, VirtualFile
@@ -184,6 +187,33 @@ class APIDocumentPageImageView(generics.RetrieveAPIView):
 
     @cache_control(private=True)
     def retrieve(self, request, *args, **kwargs):
+        transformation_dict = {
+            'kwargs': {},
+            'name': {}
+        }
+        transformation_list = []
+
+        querystring = furl()
+        querystring.args.update(self.request.GET)
+        querystring.args.update(self.request.POST)
+
+        for key, value in querystring.args.items():
+            if key.startswith('transformation_'):
+                literal, index, element = key.split('_')
+                transformation_dict[element][index] = value
+
+        for order, identifier in transformation_dict['name'].items():
+            if order in transformation_dict['kwargs'].keys():
+                kwargs = {}
+                for kwargs_entry in transformation_dict['kwargs'][order].split(','):
+                    key, value = kwargs_entry.split(':')
+                    kwargs[key] = float(value)
+
+                transformation_list.append({
+                    'name': identifier,
+                    'kwargs': kwargs
+                })
+
         width = request.GET.get('width')
         height = request.GET.get('height')
         zoom = request.GET.get('zoom')
@@ -199,7 +229,8 @@ class APIDocumentPageImageView(generics.RetrieveAPIView):
         task = task_generate_document_page_image.apply_async(
             kwargs=dict(
                 document_page_id=self.get_object().pk, width=width,
-                height=height, zoom=zoom, rotation=rotation
+                height=height, zoom=zoom, rotation=rotation,
+                transformation_list=transformation_list
             )
         )
 

mayan/apps/documents/models.py

@@ -865,10 +865,12 @@ class DocumentPage(models.Model):
         if document page images.
         """
         transformations_hash = BaseTransformation.combine(
-            self.get_combined_transformation_list(*args, **kwargs)
+            transformations=self.get_combined_transformation_list(
+                *args, **kwargs
+            )
         )
 
-        kwargs.pop('transformations', None)
+        transformations = kwargs.pop('transformations', None)
 
         final_url = furl()
         final_url.args = kwargs
@@ -878,6 +880,13 @@ class DocumentPage(models.Model):
             )
         )
         final_url.args['_hash'] = transformations_hash
+        count = 1
+        for transformation in transformations or []:
+            name, kwargs = transformation.serialize().split(';')
+
+            final_url.args['transformation_{}_name'.format(count)] = name
+            final_url.args['transformation_{}_kwargs'.format(count)] = kwargs
+            count = count +1
 
         return final_url.tostr()