Add the ability to extract image URL information when drag-and-dropping image URL from a browser window

- Can't do anything with it yet...
- Code is almost there but leaving for now

InvenTree/part/templates/part/part_base.html

@@ -106,37 +106,29 @@
 
         var transfer = event.originalEvent.dataTransfer;
 
+        var formData = new FormData();
+
         if (isFileTransfer(transfer)) {
-
-            var file = transfer.files[0];
-    
-            inventreeFileUpload(
-                "{% url 'part-image-upload' part.id %}",
-                file,
-                {},
-                {
-                    success: function(data, status, xhr) {
-                        location.reload();
-                    },
-                    error: function(xhr, status, error) {
-                        showAlertDialog('Error uploading image', renderErrorMessage(xhr));
-                    }
-                }
-            );
+            formData.append('image_file', transfer.files[0]);
         } else if (isOnlineTransfer(transfer)) {
-
-            getImageUrlFromTransfer(transfer);
-            /*
-            for (var i = 0; i < 12; i++) {
-                transfer.items[i].getAsString(function(text) {
-                    console.log('item ' + i + ' - ' + text);
-                });
-            }
-            */
+            formData.append('image_url', getImageUrlFromTransfer(transfer));
         } else {
             console.log('Unknown transfer');
+            return;
         }
-
+ 
+        inventreeFormDataUpload(
+            "{% url 'part-image-upload' part.id %}",
+            formData,
+            {
+                success: function(data, status, xhr) {
+                    location.reload();
+                },
+                error: function(xhr, status, error) {
+                    showAlertDialog('Error uploading image', renderErrorMessage(xhr));
+                }
+            }
+        );
     });
 
     $("#show-qr-code").click(function() {

InvenTree/part/views.py

@@ -7,6 +7,9 @@ from __future__ import unicode_literals
 
 from django.shortcuts import get_object_or_404
 
+from django.core.validators import URLValidator
+from django.core.exceptions import ValidationError
+
 from django.http import JsonResponse
 from django.urls import reverse_lazy
 from django.views.generic import DetailView, ListView
@@ -30,7 +33,7 @@ from .forms import EditSupplierPartForm
 from InvenTree.views import AjaxView, AjaxCreateView, AjaxUpdateView, AjaxDeleteView
 from InvenTree.views import QRCodeView
 
-from InvenTree.helpers import DownloadFile, str2bool, TestIfImage
+from InvenTree.helpers import DownloadFile, str2bool, TestIfImage, TestIfImageURL
 
 
 class PartIndex(ListView):
@@ -270,7 +273,20 @@ class PartImage(AjaxUpdateView):
 
 
 class UploadPartImage(AjaxView):
-    """ View for uploading a Part image """
+    """ View for uploading a Part image via AJAX request.
+    e.g. via a "drag and drop" event.
+
+    There are two ways to upload a file:
+
+    1. Attach an image file as request.FILES['image_file']
+        - Image is validated saved
+        - Part object is saved
+    2. Attach an iamge URL as request.POST['image_url']
+        NOT YET IMPLEMENTED
+        - Image URL is valiated
+        - Image is downloaded and validated
+        - Part object is saved
+    """
 
     model = Part
 
@@ -285,18 +301,63 @@ class UploadPartImage(AjaxView):
             response['error'] = 'Part not found'
             return JsonResponse(error_dict, status=404)
 
-        uploaded_file = request.FILES['file']
+        # Direct image upload
+        if 'image_file' in request.FILES:
+            image = request.FILES['image_file']
 
-        if TestIfImage(uploaded_file):
-            part.image = uploaded_file
-            part.clean()
-            part.save()
+            if TestIfImage(image):
+                part.image = image
+                part.clean()
+                part.save()
 
-            response['success'] = 'File was uploaded successfully'
-        else:
-            response['error'] = 'Not a valid image file'
-            status = 400
+                response['success'] = 'File was uploaded successfully'
+                status = 200
+            else:
+                response['error'] = 'Not a valid image file'
+                status = 400
 
+            return JsonResponse(response, status=status)
+
+        elif 'image_url' in request.POST:
+            image_url = request.POST['image_url']
+
+            validator = URLValidator()
+
+            try:
+                validator(image_url)
+            except ValidationError: 
+                response['error'] = 'Invalid image URL'
+                response['url'] = image_url
+
+                return JsonResponse(response, status=400)
+
+            # Test the the URL at least looks like an image
+            if not TestIfImageURL(image_url):
+                response['error'] = 'Invalid image URL'
+                return JsonResponse(response, status=400)
+
+            response['error'] = 'Cannot download cross-site images (yet)'
+            response['url'] = image_url
+            response['apology'] = 'deepest'
+
+            return JsonResponse(response, status=400)
+
+            # TODO - Attempt to download the image file here
+
+            """
+            head = requests.head(url, stream=True, headers={'User-agent': 'Mozilla/5.0'})
+
+            if head.headers['Content-Length'] < SOME_MAX_LENGTH:
+
+                image = requests.get(url, stream=True, headers={'User-agent': 'Mozilla/5.0'})
+
+                file = io.BytesIO(image.raw.read())
+
+                - Save the file?
+
+            """
+
+        # Default response
         return JsonResponse(response, status=status)