OpenAPI parameter with brackets and variable name

Question

I am working on an API which allows searching with URLs like:

GET https://example.com/api/data?search[field1]=value1
GET https://example.com/api/data?search[field2]=value2
GET https://example.com/api/data?search[field1]=value1&search[field2]=value2

Basically, you can search for one or more field values by putting a field name in brackets. The problem is, the field names are defined by the user in their settings. The field name will be a string, but otherwise is not known ahead of time at a global level.

This answer is almost what I am looking to do, I just can't find a way to define the value inside the brackets to be "any string" rather than a list of known names.

Answer 1

The search parameter can be defined as a free-form object with the deepObject serialization style and minProperties: 1 to enforce the presence of at least one field in the search query.

Make sure you use OpenAPI 3.0 (openapi: 3.0.x) and not OpenAPI 2.0 (swagger: "2.0"); the latter does not support objects in query strings.

openapi: 3.0.2
...

paths:
  /api/data:
    get:
      parameters:
        - in: query
          name: search
          required: true
          schema:
            type: object
            additionalProperties: true  # Default value, may be omitted
            minProperties: 1
            # Optional example to use as a starting value for "try it out" in Swagger UI
            example: >
              {
                "field1": "value1",
                "field2": "value2"
              }
          style: deepObject
          explode: true
      responses:
        200:
          description: OK