As we explained in Chapter 6
, Working with Models, SQLAlchemy, and Hyperlinked APIs in Flask, our API is able to update a single field for an existing resource, and therefore, we provide an implementation for the PATCH method. For example, we can use the PATCH method to update an existing message and set the value for its printed_once and printed_times fields to true and 1. We don't want to use the PUT method because this method is meant to replace an entire message. The PATCH method is meant to apply a delta to an existing message, and therefore, it is the appropriate method to just change the value of those two fields.
Now, we will compose and send an HTTP request to update an existing message, specifically, to update the value of the printed_once and printed_times fields. Because we just want to update two fields, we will use the PATCH method instead of PUT. Make sure you replace 1 with the id or primary key of an existing message in...
