silverstripe-framework/control/PjaxResponseNegotiator.php

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<?php
/**
* Handle the X-Pjax header that AJAX responses may provide, returning the
* fragment, or, in the case of non-AJAX form submissions, redirecting back to the submitter.
*
* X-Pjax ensures that users won't end up seeing the unstyled form HTML in their browser
* If a JS error prevents the Ajax overriding of form submissions from happening.
* It also provides better non-JS operation.
*
* Caution: This API is volatile, and might eventually be replaced by a generic
* action helper system for controllers.
*/
class PjaxResponseNegotiator {
/**
* @var Array See {@link respond()}
*/
protected $callbacks = array(
// TODO Using deprecated functionality, but don't want to duplicate Controller->redirectBack()
'default' => array('Director', 'redirectBack'),
);
/**
* @param RequestHandler $controller
* @param Array $callbacks
*/
function __construct($callbacks = array()) {
$this->callbacks = $callbacks;
}
/**
* Out of the box, the handler "CurrentForm" value, which will return the rendered form.
* Non-Ajax calls will redirect back.
*
* @param SS_HTTPRequest $request
* @param array $extraCallbacks List of anonymous functions or callables returning either a string
* or SS_HTTPResponse, keyed by their fragment identifier. The 'default' key can
* be used as a fallback for non-ajax responses.
* @return SS_HTTPResponse
*/
public function respond(SS_HTTPRequest $request, $extraCallbacks = array()) {
// Prepare the default options and combine with the others
$callbacks = array_merge($this->callbacks, $extraCallbacks);
$response = new SS_HTTPResponse();
$responseParts = array();
if($fragmentStr = $request->getHeader('X-Pjax')) {
$fragments = explode(',', $fragmentStr);
foreach($fragments as $fragment) {
if(isset($callbacks[$fragment])) {
$responseParts[$fragment] = call_user_func($callbacks[$fragment]);
} else {
throw new SS_HTTPResponse_Exception("X-Pjax = '$fragment' not supported for this URL.", 400);
}
}
$response->setBody(Convert::raw2json($responseParts));
$response->addHeader('Content-Type', 'text/json');
} else {
if($request->isAjax()) throw new SS_HTTPResponse_Exception("Ajax requests to this URL require an X-Pjax header.", 400);
$response->setBody(call_user_func($callbacks['default']));
}
return $response;
}
/**
* @param String $fragment
* @param Callable $callback
*/
public function setCallback($fragment, $callback) {
$this->callbacks[$fragment] = $callback;
}
}