Glossary

New to REST APIs? Get up to speed with phrases used throughout our documentation.

Controller

Model-View-Controller is a standard pattern in software development. If you aren’t already familiar it, you should do a bit of reading to get up to speed.

Within WP-API, we’ve adopted the controller concept to have a standard pattern for the classes representing our resource endpoints. All resource endpoints extend WP_REST_Controller to ensure they implement common methods.

HEAD, GET, POST, PUT, and DELETE Requests

These “HTTP verbs” represent the type of action a HTTP client might perform against a resource. For instance, GET requests are used to fetch a Post’s data, whereas DELETE requests are used to delete a Post. They’re collectively called “HTTP verbs” because they’re standardized across the web.

If you’re familiar with WordPress functions, a GET request is the equivalent of wp_remote_get(), and a POST request is the same as wp_remote_post().

HTTP Client

The phrase “HTTP Client” refers to the tool you use to interact with WP-API. You might use Postman (Chrome) or REST Easy (Firefox) to test requests in your browser, or httpie to test requests at the commandline.

WordPress itself provides a HTTP Client in the WP_HTTP class and related functions (e.g. wp_remote_get()). This can be used to access one WordPress site from another.

Resource

A “Resource” is a discrete entity within WordPress. You may know these resources already as Posts, Pages, Comments, Users, Terms, and so on. WP-API permits HTTP clients to perform CRUD operations against resources (CRUD stands for Create, Read, Update, and Delete).

Pragmatically, here’s how you’d typically interact with WP-API resources:

  • GET /wp-json/wp/v2/posts to get a collection of Posts. This is roughly equivalent to using WP_Query.
  • GET /wp-json/wp/v2/posts/123 to get a single Post with ID 123. This is roughly equivalent to using get_post().
  • POST /wp-json/wp/v2/posts to create a new Post. This is roughly equivalent to using wp_insert_post().
  • DELETE /wp-json/wp/v2/posts/123 to delete Post with ID 123. This is roughly equivalent to wp_delete_post().

Routes / Endpoints

Endpoints are functions available through the API. This can be things like retrieving the API index, updating a post, or deleting a comment. Endpoints perform a specific function, taking some number of parameters and return data to the client.

A route is the “name” you use to access endpoints, used in the URL. A route can have multiple endpoints associated with it, and which is used depends on the HTTP verb.

For example, with the URL http://example.com/wp-json/wp/v2/posts/123:

  • The “route” is wp/v2/posts/123 – The route doesn’t include wp-json because wp-json is the base path for the API itself.
  • This route has 3 endpoints:

    • GET triggers a get_item method, returning the post data to the client.
    • PUT triggers an update_item method, taking the data to update, and returning the updated post data.
    • DELETE triggers a delete_item method, returning the now-deleted post data to the client.

Note: On sites without pretty permalinks, the route is instead added to the URL as the rest_route parameter. For the above example, the full URL would then be http://example.com/?rest_route=wp/v2/posts/123

Schema

A “schema” is a representation of the format for WP-API’s response data. For instance, the Post schema communicates that a request to get a Post will return id, title, content, author, and other fields. Our schemas also indicate the type each field is, provide a human-readable description, and show which contexts the field will be returned in.