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PATCH endpoint using DynamoDB

PATCH:​

PATCH requests are used to update parts of single resources, i.e. where only a specific subset of resource fields should be replaced. The semantic is best described as "please change the resource identified by the URL according to my change request". The semantic of the change request is not defined in the HTTP standard and must be described in the API specification by using suitable media types.

  • PATCH requests are usually applied to single resources as patching entire collection is challenging;

  • PATCH requests are usually not robust against non-existence of resource instances;

  • On successful PATCH requests, the server will update parts of the resource addressed by the URL as defined by the change request in the payload;

  • Successful PATCH requests will usually generate 200 or 204 (if resources have been updated with or without updated content returned);

Note (To Be Clarified): since implementing PATCH correctly is a bit tricky, we strongly suggest to choose one and only one of the following patterns per endpoint.

  1. Use PUT with complete objects to update a resource as long as feasible (i.e. do not use PATCH at all);

  2. Use PATCH with partial objects to only update parts of a resource, whenever possible. (This is basically JSON Merge Patch,a specialized media type application/merge-patch+json that is a partial resource representation.);

  3. Use PATCH with JSON Patch, a specialized media type application/json-patch+json that includes instructions on how to change the resource;

  4. Use POST (with a proper description of what is happening) instead of PATCH, if the request does not modify the resource in a way defined by the semantics of the media type;

In practice JSON Merge Patch quickly turns out to be too limited, especially when trying to update single objects in large collections (as part of the resource). In this cases JSON Patch can shown its full power while still showing readable patch requests (see also JSON patch vs. merge).

Here is an example PR to show how to build a PATCH endpoint using DynamoDB

We have created a video that gives developers a good understanding of how we build API Endpoints using DynaomDB from beginning to end, following best practices.

Video Tutorial:​

Note: To go back a forth between the videos please use the playlist button available