When a network error is encountered, API clients should be able to retry a request without a risk of their request being processed twice.\nWP API Idempotence adds support for clients to include an idempotency key that uniquely identifies that request. If the server detects\nthat a request with the same key has already been processed or is currently being processed, the response for the initial request will\nbe returned.<\/p>\n\n
For Example:<\/p>\n\n
{\n \"title\": \"My Important Post\",\n \"content\": \"This will only go out once!\",\n \"status\": \"draft\",\n \"idempotency_key\": \"1ced64e9-9537-4b7b-9919-444d9e15e201\"\n}\n<\/code><\/pre>\n\nConfiguration<\/h4>\n\n\n- Idempotency key can either be passed in the request header or the request body.<\/li>\n
- The idempotency key name can be customized.<\/li>\n
- Change the HTTP methods the idempotency key is supported for. Defaults to
POST<\/code>, PUT<\/code>, PATCH<\/code>.<\/li>\n<\/ul>\n\nA sample request interface is included to demonstrate the selected configuration.<\/p>\n\n
Developers<\/h4>\n\n
The plugin includes two actions to modify the dependency injection container (DIC) and insert custom services.<\/p>\n\n
The wp_api_idempotence_initialize_container_builder<\/code> action allows you to modify the Dependency Injection builder itself and\nthe wp_api_idempotence_initialize_container<\/code> action allows you to override dependencies. For example:<\/p>\n\nadd_action( 'wp_api_idempotence_initialize_container', function( $container ) {\n $container->set( '_dataStore', DI\\object( 'YourName\\CustomDataStore' ) );\n} );\n<\/code><\/pre>\n\nUnder the hood, the plugin is made up of a DataStore<\/code>, RequestHasher<\/code>, ResponseSerializer<\/code> and RequestPoller<\/code>.<\/p>\n\nThe DataStore<\/code> is primarily responsible for retrieving or storing an idempotent request. By default, requests\nare stored in a custom database table. This could be substituted for a custom driver by implementing the DataStore<\/code>\ninterface. For example a Redis server.<\/p>\n\nThe RequestHasher<\/code> produces a unique hash for a WP_REST_Request<\/code> object. This hash is based off of the contents of\nthe request, not for the object via spl_object_hash<\/code> or similar. This can also be substituted by implementing the\n RequestHasher interface.<\/p>\n\nThe ResponseSerializer<\/code> converts a WP_REST_Response<\/code> or WP_Error<\/code> object back and forth from a string representation.\nThe default JSON serializer supports filtering the serialization process using the wp_api_idempotence_serialized_response_data<\/code>\nand wp_api_idempotence_attach_serialized_response_data<\/code> filters. See src\/ResponseSerializer\/Filtered.php<\/code>.\nThe entire serializer can be substituted by implementing the ResponseSerializer<\/code> interface.<\/p>\n\nFinally, the RequestPoller<\/code> class polls the data store for a response if it is determined that an idempotent request\nis currently being processed when another request with the same key arrives. By default, the data store is polled\nevery seconds a maximum of 15 times to try and retrieve a response object. If no response is found, an error with code\n rest_duplicate_idempotency_key will be returned. This can be adjusted by overwriting the poll.sleepSeconds<\/code> and\n poll.maxQueries in the DIC. The RequestPoller<\/code> can also be entirely subsituted by implementing the RequestPoller<\/code>\ninterface.<\/p>\n\nContributing<\/h4>\n\n