generators+promises FTW

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

diff --git a/lib/API/Call.php b/lib/API/Call.php
new file mode 100644 (file)
index 0000000..56e15dc
--- /dev/null
+++ b/lib/API/Call.php
@@ -0,0 +1,123 @@
+<?php
+
+namespace seekat\API;
+
+use Exception;
+use http\Client;
+use http\Client\Request;
+use http\Client\Response;
+use React\Promise\Deferred;
+use seekat\API;
+use SplObserver;
+use SplSubject;
+
+class Call extends Deferred implements SplObserver
+{
+       /**
+        * The endpoint
+        * @var \seekat\API
+        */
+       private $api;
+
+       /**
+        * The HTTP client
+        * @var Client
+        */
+       private $client;
+
+       /**
+        * The executed request
+        * @var Request
+        */
+       private $request;
+
+       /**
+        * The promised response
+        * @var Response
+        */
+       private $response;
+
+       /**
+        * Create a deferred promise for the response of $request
+        *
+        * @var \seekat\API $api The endpoint of the request
+        * @var Client $client The HTTP client to send the request
+        * @var Request The request to execute
+        */
+       function __construct(API $api, Client $client, Request $request) {
+               $this->api = $api;
+               $this->client = $client;
+               $this->request = $request;
+
+               parent::__construct(function($resolve, $reject) {
+                       return $this->cancel($resolve, $reject);
+               });
+               
+               $client->attach($this);
+               $client->enqueue($request);
+               /* start off */
+               $client->once();
+       }
+
+       /**
+        * Progress observer
+        *
+        * Import the response's data on success and resolve the promise.
+        *
+        * @var SplSubject $client The observed HTTP client
+        * @var Request The request which generated the update
+        * @var object $progress The progress information
+        */
+       function update(SplSubject $client, Request $request = null, $progress = null) {
+               if ($request !== $this->request) {
+                       return;
+               }
+
+               $this->notify((object) compact("client", "request", "progress"));
+
+               if ($progress->info === "finished") {
+                       $this->response = $this->client->getResponse();
+                       $this->complete(
+                               [$this, "resolve"],
+                               [$this, "reject"]
+                       );
+               }
+       }
+
+       /**
+        * Completion callback
+        * @param callable $resolve
+        * @param callable $reject
+        */
+       private function complete(callable $resolve, callable $reject) {
+               $this->client->detach($this);
+
+               if ($this->response) {
+                       try {
+                               $resolve($this->api->import($this->response));
+                       } catch (Exception $e) {
+                               $reject($e);
+                       }
+               } else {
+                       $reject($this->client->getTransferInfo($this->request)["error"]);
+               }
+
+               $this->client->dequeue($this->request);
+       }
+
+       /**
+        * 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");
+               }
+       }
+}