Merge 17cdc21 into b7ea3dd

composer.json

@@ -18,11 +18,13 @@
         ]
     },
     "require": {
-        "php": ">=7.1"
+        "php": ">=7.1",
+        "amphp/amp": "^2"
     },
     "require-dev": {
         "phpunit/phpunit": "^6.5",
-        "amphp/php-cs-fixer-config": "dev-master"
+        "amphp/php-cs-fixer-config": "dev-master",
+        "amphp/phpunit-util": "^1.1"
     },
     "config": {
         "platform": {

src/Trailers.php

@@ -0,0 +1,113 @@
+<?php
+
+namespace Amp\Http;
+
+use Amp\Deferred;
+use Amp\Promise;
+
+final class Trailers
+{
+    /** @see https://tools.ietf.org/html/rfc7230#section-4.1.2 */
+    public const DISALLOWED_TRAILERS = [
+        "authorization" => 1,
+        "content-encoding" => 1,
+        "content-length" => 1,
+        "content-range" => 1,
+        "content-type" => 1,
+        "cookie" => 1,
+        "expect" => 1,
+        "host" => 1,
+        "pragma" => 1,
+        "proxy-authenticate" => 1,
+        "proxy-authorization" => 1,
+        "range" => 1,
+        "te" => 1,
+        "trailer" => 1,
+        "transfer-encoding" => 1,
+        "www-authenticate" => 1,
+    ];
+
+    /** @var string[] */
+    private $fields = [];
+
+    /** @var Promise<Message> */
+    private $headers;
+
+    /**
+     * @param Promise<string[]|string[][]> $promise Resolved with the trailer values.
+     * @param string[]            $fields Expected header fields. May be empty, but if provided, the array of headers
+     *                                    used to resolve the given promise must contain exactly the fields given in
+     *                                    this array.
+     *
+     * @throws InvalidHeaderException If the fields list contains a disallowed field.
+     */
+    public function __construct(Promise $promise, array $fields = [])
+    {
+        if (!empty($fields)) {
+            $this->fields = $fields = \array_map('strtolower', $fields);
+
+            foreach ($this->fields as $field) {
+                if (isset(self::DISALLOWED_TRAILERS[$field])) {
+                    throw new InvalidHeaderException(\sprintf("Field '%s' is not allowed in trailers", $field));
+                }
+            }
+        }
+
+        $deferred = new Deferred;
+
+        $promise->onResolve(static function (?\Throwable $exception, ?array $headers) use ($fields, $deferred): void {
+            if ($exception) {
+                $deferred->fail($exception);
+                return;
+            }
+
+            try {
+                $deferred->resolve(new class($headers, $fields) extends Message {
+                    public function __construct(array $headers, array $fields)
+                    {
+                        $this->setHeaders($headers);
+
+                        $keys = \array_keys($this->getHeaders());
+
+                        if (!empty($fields)) {
+                            // Note that the Trailer header does not need to be set for the message to include trailers.
+                            // @see https://tools.ietf.org/html/rfc7230#section-4.4
+
+                            if (\array_diff($fields, $keys)) {
+                                throw new InvalidHeaderException("Trailers do not contain the expected fields");
+                            }
+
+                            return; // Check below unnecessary if fields list is set.
+                        }
+
+                        foreach ($keys as $field) {
+                            if (isset(Trailers::DISALLOWED_TRAILERS[$field])) {
+                                throw new InvalidHeaderException(\sprintf("Field '%s' is not allowed in trailers", $field));
+                            }
+                        }
+                    }
+                });
+            } catch (\Throwable $exception) {
+                $deferred->fail($exception);
+            }
+        });
+
+        $this->headers = $deferred->promise();
+    }
+
+    /**
+     * @return string[] List of expected trailer fields. May be empty, but still receive trailers.
+     */
+    public function getFields(): array
+    {
+        return $this->fields;
+    }
+
+    /**
+     * @return Promise<Message>
+     */
+    public function getTrailers(): Promise
+    {
+        return $this->headers;
+    }
+}

test/TrailersTest.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Amp\Http\Test;
+
+use Amp\Http\InvalidHeaderException;
+use Amp\Http\Trailers;
+use Amp\PHPUnit\AsyncTestCase;
+use Amp\Success;
+
+class TrailersTest extends AsyncTestCase
+{
+    public function testMessageHasHeader()
+    {
+        $promise = new Success(['fooHeader' => 'barValue']);
+
+        $trailers = new Trailers($promise, ['fooHeader']);
+        $trailers = yield $trailers->getTrailers();
+
+        $this->assertTrue($trailers->hasHeader('fooHeader'));
+        $this->assertSame('barValue', $trailers->getHeader('fooHeader'));
+    }
+
+    public function testHasHeaderReturnsFalseForEmptyArrayValue()
+    {
+        $promise = new Success(['fooHeader' => []]);
+
+        $this->expectException(InvalidHeaderException::class);
+        $this->expectExceptionMessage('Trailers do not contain the expected fields');
+
+        $trailers = new Trailers($promise, ['fooHeader']);
+        $this->assertFalse((yield $trailers->getTrailers())->hasHeader('fooHeader'));
+    }
+
+    public function testDisallowedFieldsInConstructor()
+    {
+        $this->expectException(InvalidHeaderException::class);
+        $this->expectExceptionMessage("Field 'content-length' is not allowed in trailers");
+
+        $trailers = new Trailers(new Success, ['content-length']);
+    }
+
+    public function testDisallowedFieldsInPromiseResolution()
+    {
+        $this->expectException(InvalidHeaderException::class);
+        $this->expectExceptionMessage("Field 'content-length' is not allowed in trailers");
+
+        $trailers = new Trailers(new Success(['content-length' => 0]));
+
+        yield $trailers->getTrailers();
+    }
+}