Add web SAPI input/output stream getter functions (#61)

lib/functions.php

@@ -62,6 +62,43 @@ function buffer(InputStream $source): Promise
     });
 }
 
+/**
+ * The php://input input buffer stream for the process associated with the currently active event loop.
+ *
+ * @return ResourceInputStream
+ */
+function getInputBufferStream(): ResourceInputStream
+{
+    static $key = InputStream::class . '\\input';
+
+    $stream = Loop::getState($key);
+
+    if (!$stream) {
+        $stream = new ResourceInputStream(\fopen('php://input', 'r'));
+        Loop::setState($key, $stream);
+    }
+
+    return $stream;
+}
+
+/**
+ * The php://output output buffer stream for the process associated with the currently active event loop.
+ *
+ * @return ResourceOutputStream
+ */
+function getOutputBufferStream(): ResourceOutputStream
+{
+    static $key = OutputStream::class . '\\output';
+
+    $stream = Loop::getState($key);
+
+    if (!$stream) {
+        $stream = new ResourceOutputStream(\fopen('php://output', 'w'));
+        Loop::setState($key, $stream);
+    }
+
+    return $stream;
+}
 /**
  * The STDIN stream for the process associated with the currently active event loop.
  *

test/StdStreamTest.php

@@ -8,6 +8,22 @@ use Amp\PHPUnit\TestCase;
 
 class StdStreamTest extends TestCase
 {
+    public function testGetInputBufferStream()
+    {
+        Loop::run(function () {
+            $stream = ByteStream\getInputBufferStream();
+            $this->assertSame($stream, ByteStream\getInputBufferStream());
+        });
+    }
+
+    public function testGetOutputBufferStream()
+    {
+        Loop::run(function () {
+            $stream = ByteStream\getOutputBufferStream();
+            $this->assertSame($stream, ByteStream\getOutputBufferStream());
+        });
+    }
+
     public function testGetStdin()
     {
         Loop::run(function () {