A search (filter) operation on a collection resource SHOULD be defined as safe, idempotent and cacheable, therefore using the GET HTTP request method.
Every search parameter SHOULD be provided in the form of a query parameter. In the case of search parameters being mutually exclusive or require the presence of another parameter, the explanation MUST be part of operation's description.
A collection of orders can be filtered by either article id it includes or by article manufacturer id. The two parameters are mutually exclusive and cannot be used together. The API description for such a design should look as follows:
paths:
/orders:
x-summary: Collection of Orders
get:
summary: Retrieve or Search in the Collection of Orders
description: |
This operation allows to retrieve a filtered list of orders based on multiple criteria:
1. **Filter Orders by Article Id**
2. **Filter Orders by Manufacturer Id**
parameters:
- name: article_id
in: query
description: |
Article Id. Denotes the id of an article that must be in the order.
**Mutually exclusive** with `manufacturer_id`.
required: false
type: string
x-example: article_id_1
- name: manufacturer_id
in: query
description: |
Manufacturer Id. Denotes an id of a manufacturer of an article that must be in the order.
**Mutually exclusive** with `article_id`.
required: false
type: string
x-example: manufacturer_id_1
When it would be beneficial (e.g. one of the filter queries is more common than another one) a separate resource for the particular query SHOULD be provided. In such a case, the pivotal search parameter MAY be in the form of a path variable.
Building on top of the example mentioned above, we will provide the filtering of orders by article id as a separate resource.
paths:
/articles/{article_id}/orders:
x-summary: Collection of Orders for given Article
get:
summary: Retrieve the collection of Orders that contain given article.