Images

Data

Information about images is returned as part of the Content API.

Format:

{
  "id": 1,
  "meta": {
      "type": "images.Image",
      "detailUrl": "<backend-url>/api/images/1/",
      "tags": []
  },
  "title": "...",
  "width": 1000,
  "height": 500,
  "caption": "",
  "slug": "<slug>.jpeg",
  "version": 1

}

Where:

1. title: used for alt text
2. width and height: size of the original image
3. caption: caption
4. slug: slug of the image. Can be used to compose the image path in a user-friendly way
5. version: integer incremented every time the image is saved. Can be used to invalidate the cache when composing the image path

Serving

The endpoint for serving images is:

/images/<signature>/<id>/<filter-spec>/<version>/<slug>

Where:

1. signature: is the HMAC of some data using a private key (see below)
2. id: id of the image
3. filter-spec: spec indicating the size of the image (see below)
4. version: integer, version of the image. Only used to invalidate the cache and not actually meaningful
5. slug: slug of the image

Example:

/images/Uo5gv5k9XXsTt6NRHWmGDR4yxC4=/13/width-400/1/chicken-pox.jpg

Signature

HMAC(K, m) where:

1. K: shared private key only used for image signatures. See settings.IMAGE_SIGNATURE_KEY
2. m: the string <image-id>/<filter-spec>/ e.g. 1/width-800

Filter Spec

Specifies the size of the image returned. Possible values (100 and 200 are example values):

1. width-100: width 100 and variable height
2. height-200: height 200 and variable width
3. min-100x200: variable width and height but trying to keep the values at least 100x200
4. max-100x200: variable width and height but trying to keep the values at most 100x200
5. fill-100x200: crops the image so that the final size is exactly 100x200
6. original: original size