22_API_UploadingImage_CustomActions.ipynb

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    "## Uploading and deleting images"
   ]
  },
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   "metadata": {},
   "source": [
    "### Serializer\n",
    "\n",
    "Create a separate serializer for **Recipe** model having the image field\n",
    "\n",
    "```python\n",
    "# Recipe serializer with image field\n",
    "class RecipeImageSerializer(serializers.ModelSerializer):\n",
    "    \"\"\"serializer for uploading images to recipes\"\"\"\n",
    "    class Meta:\n",
    "        model = Recipe\n",
    "        fields = ('id', 'image')\n",
    "        read_only_fields = ('id',)\n",
    "```"
   ]
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    "### Writing custom actions to upload and delete image to a recipe\n",
    "\n",
    "Custom action **upload_image** is implemented inside **RecipeViewSet** using **action decorator**\n",
    "\n",
    "> 1) Specify the **append path to url**. Appending **upload-image** to url will look like this\n",
    "```bash\n",
    "/api/recipe/recipes (POINTS TO RecipeViewSet class List View)\n",
    "/api/recipe/recipes/<pk> (POINTS to RecipeViewSet class Detail View)\n",
    "/api/recipe/recipes/<pk>/upload-image (POINTS to custom action with path 'upload-function)\n",
    "```\n",
    "\n",
    "> 2) Specify if **pk** arg is needed. If yes, then set **detail=True**\n",
    "\n",
    "> 3) Specify the **allowed Methods**\n",
    "\n",
    "> we have to encode our own Response. Ie, we have to manually serialize our objects"
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    "<div style=\"border:2px solid;margin:0 20px 0 20px\" ></div> \n",
    "\n",
    "```python\n",
    "# for image upload api view\n",
    "from rest_framework.decorators import action\n",
    "from rest_framework.response import Response\n",
    "\n",
    "class RecipeViewSet(viewsets.ModelViewSet):\n",
    "    ...\n",
    "    ...\n",
    "    # writing custom function on call to specific api with specific request\n",
    "    # This function becomes a custom action = upload_image\n",
    "    # API CALL (recipe-upload-image) : /api/recipe/recipes/<pk>/upload-image\n",
    "    @action(methods=['POST', 'DELETE'], detail=True, url_path='upload-image')\n",
    "    def upload_image(self, request, pk=None):\n",
    "        # we have to encode our own Response\n",
    "        # ie, we have to manually serialize our objects\n",
    "        recipe = self.get_object()\n",
    "        if(request.method == 'POST'):\n",
    "            # modify get_serializer_class to consider this action\n",
    "            serializer = self.get_serializer(recipe, data=request.data)\n",
    "\n",
    "            if serializer.is_valid():\n",
    "                serializer.save()\n",
    "                return Response(serializer.data, status=status.HTTP_200_OK)\n",
    "            else:\n",
    "                return Response(serializer.errors,\n",
    "                                status=status.HTTP_400_BAD_REQUEST)\n",
    "        elif(request.method == 'DELETE'):\n",
    "            if recipe.image:\n",
    "                recipe.image.delete()\n",
    "                serializer = self.get_serializer(recipe)\n",
    "                return Response(serializer.data, status=status.HTTP_200_OK)\n",
    "            \n",
    "            \n",
    "      def get_serializer_class(self):\n",
    "        if self.action == 'retrieve':\n",
    "            return serializers.RecipeDetailSerializer\n",
    "        elif self.action == 'upload_image':\n",
    "            return serializers.RecipeImageSerializer\n",
    "```\n",
    "<div style=\"border:2px solid;margin:0 20px 0 20px\" ></div> \n"
   ]
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   "source": [
    "###  How to use this API (Tests)\n",
    "\n",
    "> **POST** with **file obejct** and set **format** as **multipart** to the following URL\n",
    "```python\n",
    "reverse('recipe:recipe-upload-image', args=[recipe_id])\n",
    "```"
   ]
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   "cell_type": "markdown",
   "metadata": {},
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    "<div style=\"border:2px solid;margin:0 20px 0 20px\" ></div> \n",
    "\n",
    "```python\n",
    "# for image upload tests\n",
    "import tempfile\n",
    "import os\n",
    "from PIL import Image\n",
    "\n",
    "# recipies API to POST image (custom action)\n",
    "# /api/recipe/recipes/1/upload-image\n",
    "def image_upload_url(recipe_id):\n",
    "    return reverse('recipe:recipe-upload-image', args=[recipe_id])\n",
    "\n",
    "\n",
    "class RecipeImageUploadTest(TestCase):\n",
    "\n",
    "    def setUp(self):\n",
    "        self.client = APIClient()\n",
    "        self.user = get_user_model().objects.create_user(\n",
    "            'test@test.com',\n",
    "            'testpass'\n",
    "        )\n",
    "        self.client.force_authenticate(self.user)\n",
    "        self.recipe = sample_recipe(user=self.user)\n",
    "\n",
    "    # destructor. Clean up after test is completed\n",
    "    def tearDown(self):\n",
    "        self.recipe.image.delete()\n",
    "\n",
    "    # test image upload\n",
    "    def test_upload_image_to_recipe(self):\n",
    "        # Create a image file object\n",
    "        with tempfile.NamedTemporaryFile(suffix='.jpg') as ntf:\n",
    "            # 10x10 black image\n",
    "            img = Image.new('RGB', (10, 10))\n",
    "            img.save(ntf, format='JPEG')\n",
    "            ntf.seek(0)\n",
    "\n",
    "            # ntf is the file objet which has to to passed to Image field\n",
    "            res = self.client.post(image_upload_url(self.recipe.id),\n",
    "                                   {'image': ntf},\n",
    "                                   format='multipart')\n",
    "\n",
    "        # at this point ntf is not available in file system\n",
    "        self.recipe.refresh_from_db()\n",
    "        self.assertEqual(res.status_code, status.HTTP_200_OK)\n",
    "        self.assertIn('image', res.data)\n",
    "        self.assertTrue(os.path.exists(self.recipe.image.path))\n",
    "\n",
    "    # test image upload bad request\n",
    "    def test_upload_image_bad_request(self):\n",
    "        res = self.client.post(image_upload_url(self.recipe.id),\n",
    "                               {'image': 'notimage'},\n",
    "                               format='multipart')\n",
    "        self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)\n",
    "```\n",
    "<div style=\"border:2px solid;margin:0 20px 0 20px\" ></div> \n"
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