Accept optional rejection callback for ConnectionManagerReject

Author: clue

README.md

@@ -96,12 +96,15 @@ $delayed = new ConnectionManagerDelayed($connector, 0.5, $loop);
 
 ### Reject
 
-The `ConnectionManagerReject(?string $reason)` simply rejects every single connection attempt.
+The `ConnectionManagerReject(null|string|callable $reason)` simply rejects every single connection attempt.
 This is particularly useful for the below [`ConnectionManagerSelective`](#selective) to reject connection attempts
 to only certain destinations (for example blocking advertisements or harmful sites).
 
-The constructor accepts an optional rejection reason which will be used for the
-`Exception` instance that is used to reject the resulting promise.
+The constructor accepts an optional rejection reason which will be used for
+rejecting the resulting promise.
+
+You can explicitly pass a `string` value which will be used as the message for
+the `Exception` instance:
 
 ```php
 $connector = new ConnectionManagerReject('Blocked');
@@ -111,6 +114,19 @@ $connector->connect('www.google.com:80')->then(null, function ($e) {
 });
 ```
 
+You can explicitly pass a `callable` value which will be used to either
+`throw` or `return` a custom `Exception` instance:
+
+```php
+$connector = new ConnectionManagerReject(function ($uri) {
+    throw new RuntimeException($uri . ' blocked');
+});
+$connector->connect('www.google.com:80')->then(null, function ($e) {
+    assert($e instanceof \RuntimeException);
+    assert($e->getMessage() === 'www.google.com:80 blocked');
+});
+```
+
 ### Swappable
 
 The `ConnectionManagerSwappable($connector)` is a simple decorator for other `ConnectionManager`s to

src/ConnectionManagerReject.php

@@ -12,8 +12,7 @@ class ConnectionManagerReject implements ConnectorInterface
     private $reason = 'Connection rejected';
 
     /**
-     *
-     * @param ?string $reason
+     * @param null|string|callable $reason
      */
     public function __construct($reason = null)
     {
@@ -22,8 +21,21 @@ public function __construct($reason = null)
         }
     }
 
-    public function connect($_)
+    public function connect($uri)
     {
-        return Promise\reject(new Exception($this->reason));
+        $reason = $this->reason;
+        if (!is_string($reason)) {
+            try {
+                $reason = $reason($uri);
+            } catch (\Exception $e) {
+                $reason = $e;
+            }
+        }
+
+        if (!$reason instanceof \Exception) {
+            $reason = new Exception($reason);
+        }
+
+        return Promise\reject($reason);
     }
 }

tests/ConnectionManagerRejectTest.php

@@ -26,4 +26,38 @@ public function testRejectWithCustomMessage()
 
         $this->assertEquals('Blocked', $text);
     }
+
+    public function testRejectThrowsCustomException()
+    {
+        $cm = new ConnectionManagerReject(function ($uri) {
+            throw new RuntimeException('Blocked ' . $uri);
+        });
+
+        $promise = $cm->connect('www.google.com:80');
+
+        $exception = null;
+        $promise->then($this->expectCallableNever(), function ($e) use (&$exception) {
+            $exception = $e;
+        });
+
+        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertEquals('Blocked www.google.com:80', $exception->getMessage());
+    }
+
+    public function testRejectReturnsCustomException()
+    {
+        $cm = new ConnectionManagerReject(function ($uri) {
+            return new RuntimeException('Blocked ' . $uri);
+        });
+
+        $promise = $cm->connect('www.google.com:80');
+
+        $exception = null;
+        $promise->then($this->expectCallableNever(), function ($e) use (&$exception) {
+            $exception = $e;
+        });
+
+        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertEquals('Blocked www.google.com:80', $exception->getMessage());
+    }
 }