refactor

[m6w6/seekat] / lib / API / Call / Deferred.php

diff --git a/lib/API/Call/Deferred.php b/lib/API/Call/Deferred.php
new file mode 100644 (file)
index 0000000..a01891f
--- /dev/null
+++ b/lib/API/Call/Deferred.php
@@ -0,0 +1,157 @@
+<?php
+
+namespace seekat\API\Call;
+
+use Exception;
+use http\{
+       Client, Client\Request, Client\Response
+};
+use React\Promise\ExtendedPromiseInterface;
+use seekat\API;
+use SplObserver;
+use SplSubject;
+
+class Deferred extends \React\Promise\Deferred implements SplObserver
+{
+       /**
+        * The response importer
+        *
+        * @var Result
+        */
+       private $result;
+
+       /**
+        * The HTTP client
+        *
+        * @var Client
+        */
+       private $client;
+
+       /**
+        * Request cache
+        *
+        * @var callable
+        */
+       private $cache;
+
+       /**
+        * The executed request
+        *
+        * @var Request
+        */
+       private $request;
+
+       /**
+        * The promised response
+        *
+        * @var Response
+        */
+       private $response;
+
+       /**
+        * Create a deferred promise for the response of $request
+        *
+        * @param API $api The endpoint of the request
+        * @param Request $request The request to execute
+        * @param Cache\Service $cache
+        */
+       function __construct(API $api, Request $request, Cache\Service $cache = null) {
+               parent::__construct(function ($resolve, $reject) {
+                       return $this->cancel($resolve, $reject);
+               });
+
+               $this->request = $request;
+               $this->client = $api->getClient();
+               $this->result = new Result($api);
+               $this->cache = new Cache($cache);
+
+               if ($this->cache->load($this->request, $cached)) {
+                       $api->getLogger()->info("deferred -> cached", [
+                               "method" => $request->getRequestMethod(),
+                               "url" => $request->getRequestUrl(),
+                       ]);
+
+                       $this->response = $cached;
+                       $this->complete(
+                               [$this, "resolve"],
+                               [$this, "reject"]
+                       );
+               } else {
+                       $this->client->attach($this);
+                       $this->client->enqueue($this->request, function(Response $response) use($cached) {
+                               if ($response->getResponseCode() == 304) {
+                                       $this->response = $cached;
+                               } else {
+                                       $this->response = $response;
+                               }
+                               $this->complete(
+                                       [$this, "resolve"],
+                                       [$this, "reject"]
+                               );
+                               return true;
+                       });
+                       $api->getLogger()->info("deferred -> enqueued", [
+                               "method" => $request->getRequestMethod(),
+                               "url" => $request->getRequestUrl(),
+                       ]);
+                       /* start off */
+                       $this->client->once();
+               }
+       }
+
+       /**
+        * Progress observer
+        *
+        * Import the response's data on success and resolve the promise.
+        *
+        * @param SplSubject $client The observed HTTP client
+        * @param Request $request The request which generated the update
+        * @param object $progress The progress information
+        */
+       function update(SplSubject $client, Request $request = null, $progress = null) {
+               if ($request !== $this->request) {
+                       return;
+               }
+
+               $this->notify((object) compact("client", "request", "progress"));
+       }
+
+       /**
+        * Completion callback
+        * @param callable $resolve
+        * @param callable $reject
+        */
+       private function complete(callable $resolve, callable $reject) {
+               $this->client->detach($this);
+
+               if ($this->response) {
+                       try {
+                               $api = ($this->result)($this->response);
+
+                               $this->cache->save($this->request, $this->response);
+
+                               $resolve($api);
+                       } catch (Exception $e) {
+                               $reject($e);
+                       }
+               } else {
+                       $reject($this->client->getTransferInfo($this->request)->error);
+               }
+       }
+
+       /**
+        * Cancellation callback
+        * @param callable $resolve
+        * @param callable $reject
+        */
+       private function cancel(callable $resolve, callable $reject) {
+               /* did we finish in the meantime? */
+               if ($this->response) {
+                       $this->complete($resolve, $reject);
+               } else {
+                       $this->client->detach($this);
+                       $this->client->dequeue($this->request);
+                       $reject("Cancelled");
+               }
+       }
+}