Winter CMS Request

This is a modern implementation of the Winter CMS Request library. The original is based on jQuery, which may not be preferable for some developers to use. This library is intended for use on your front end, in themes. Most of the functionality and features have been kept from the original implementation, however it is not meant to replace the framework used in the backend of Winter.

Breaking Changes

• The data-* attributes that relied on eval() have been removed. There are better ways to achieve this functionality.
• Asset injection isn't supported by default, but you can extend the plugin to accomplish this.
• Global AJAX events are removed.
• $.Deferred() promises are removed.
• Support for the global object $.wn.stripeLoadIndicator is removed.

Improvements

• For the data-request-update and data-request-data attributes, JSON5 is used to parse that JSON-like syntax used in those attributes.
• Axios is used to make requests to the server. It uses these handy defaults:
  • Detects the XSRF-TOKEN cookie automatically
  • Uses the X-XSRF-TOKEN header automatically (set to the value of the XSRF cookie).
  • Request/Response content type is application/json.

Examples

Call an AJAX handler with just data.

const response = Request.instance({
  handler: 'onHandler',
  data: { /* ... */ }
}).send();

How the Winter AJAX Framework is implemented

This section serves to document the intricacies of how the communication between frontend JavaScript and backend/component AJAX handlers work.

Headers

| Name | Purpose | Values | --------------------------- | ------- | ------- | X-Requested-With | Tells Winter/Laravel/Symfony that the request is an "AJAX Request". | XMLHttpRequest | X-WINTER-REQUEST-HANDLER | Tells Winter which AJAX handler method to use on the controller/component. modules/backend/classes/Controller.php#L435 | Component handler: component::onEvent; Generic handler: onEvent (Note: the onAjax handler name will always return null) | X-WINTER-REQUEST-PARTIALS | Tells Winter which partials to render and return in the response. | Names of partials, separated by the & character. E.g. partial1&partial2&partial3 | X-WINTER-REQUEST-FLASH | Tells Winter that it should clear existing flash messages respond with new flash messages. modules/cms/classes/Controller.php#L764 | true | false

Response Data

{
  "result" : {},
  "X_WINTER_REQUEST_PARTIALS": {
    "name": "<div>HTML</div>",
    // ...
  },
  "X_WINTER_REDIRECT": "https://example.com",
  "W_WINTER_ASSETS": {
    "css": [
      // ...
    ],
    "js": [
      // ...
    ],
    "img": [
      // ...
    ],
  },
  "X_WINTER_ERROR_FIELDS": {
    "field": [
      "Validation message.",
      // ...
    ],
    // ...
  },
  "X_WINTER_ERROR_MESSAGE": ""
}

| Name | Purpose | JSON Structure Example | --------------------------- | ------- | ---------------------- | result | If your AJAX handler function returned an array, the data will be present under this key. | N/A | X_WINTER_REQUEST_PARTIALS | Contains the contents of the partials to update on the page. modules/backend/classes/Controller.php#L460 | { "myPartial": "<div>...</div>", ... } | X_WINTER_REDIRECT | Contains the URL that the browser should redirect to. modules/backend/classes/Controller.php#L494 | "https://example.com" | W_WINTER_ASSETS | Contains the assets that should be injected into the page. modules/backend/classes/Controller.php#L508 | { "css": [ "style.css", ... ], "js": [ "script.js", ... ], "img": [ "image.png", ... ] } | X_WINTER_ERROR_FIELDS | Contains the results of backend field validation. modules/backend/classes/Controller.php#L535 | { "email": [ "The email field must be a valid email address.", ... ] } | X_WINTER_ERROR_MESSAGE | Used in the backend/cms, not relevant for frontend requests. modules/cms/classes/Controller.php#L790

Making a request to the server

When making an AJAX request to Winter, the X-Requested-With header must be set to XMLHttpRequest.

• Winter checks if the request is a POST request made using AJAX, and if the X-WINTER-REQUEST-HANDLER header is set.
  • Laravel checks that header with Request#ajax() (which is an alias of Symfony's Request#isXmlHttpRequest())

Winter CMS will look for a handler function name that matches the one supplied in the header. Once executed, the response is returned to the client.