Fix for empty response body when debugging unseekable streams (#537)

* fix for empty response body when debugging unseekable streams

* run cs fixer and add test

* run cs fixer

Author: JonPurvis

src/Http/Response.php

@@ -9,6 +9,7 @@
 use function implode;
 use SimpleXMLElement;
 use function is_array;
+use GuzzleHttp\Psr7\Utils;
 use function mb_strtolower;
 use Saloon\Traits\Macroable;
 use InvalidArgumentException;
@@ -171,6 +172,21 @@ public function stream(): StreamInterface
         return $stream;
     }
 
+    /**
+     * Return a new response with the body replaced by a seekable stream containing the given content.
+     * Use when the original body stream is not seekable (e.g. after debug has consumed it) so
+     * subsequent callers still receive the full body.
+     */
+    public function withBufferedBody(string $body): static
+    {
+        return new static(
+            $this->psrResponse->withBody(Utils::streamFor($body)),
+            $this->pendingRequest,
+            $this->psrRequest,
+            $this->senderException
+        );
+    }
+
     /**
      * Get the headers from the response.
      */

src/Traits/HasDebugging.php

@@ -64,12 +64,24 @@ public function debugResponse(?callable $onResponse = null, bool $die = false):
         // is shown before it is modified by the user's middleware.
 
         $this->middleware()->onResponse(
-            callable: static function (Response $response) use ($onResponse, $die): void {
-                $onResponse($response, $response->getPsrResponse());
-
+            callable: static function (Response $response) use ($onResponse, $die): Response {
+                $stream = $response->getPsrResponse()->getBody();
+                if ($stream->isSeekable()) {
+                    $onResponse($response, $response->getPsrResponse());
+                    if ($die) {
+                        Debugger::die();
+                    }
+
+                    return $response;
+                }
+                $body = $response->body();
+                $replaced = $response->withBufferedBody($body);
+                $onResponse($replaced, $replaced->getPsrResponse());
                 if ($die) {
                     Debugger::die();
                 }
+
+                return $replaced;
             },
             order: PipeOrder::FIRST
         );

tests/Feature/DebugTest.php

@@ -13,6 +13,7 @@
 use Saloon\Tests\Fixtures\Requests\UserRequest;
 use Saloon\Tests\Fixtures\Connectors\TestConnector;
 use Saloon\Tests\Fixtures\Requests\AlwaysThrowRequest;
+use Saloon\Tests\Fixtures\Mocking\UnseekableBodyMockResponse;
 
 test('a user can register a request and response debugger on the connector and request', function () {
     $mockClient = new MockClient([
@@ -267,3 +268,23 @@
 
     expect($killed)->toBeTrue();
 });
+
+test('the response debugger receives a response with full body when the stream is unseekable', function () {
+    $expectedBody = '{"name":"Jon"}';
+    $mockClient = new MockClient([
+        new UnseekableBodyMockResponse(['name' => 'Jon'], 200),
+    ]);
+
+    $connector = new TestConnector;
+    $connector->withMockClient($mockClient);
+
+    $debuggerReceivedBody = null;
+
+    $connector->debugResponse(function (Response $response) use (&$debuggerReceivedBody) {
+        $debuggerReceivedBody = $response->body();
+    });
+
+    $connector->send(new UserRequest);
+
+    expect($debuggerReceivedBody)->toEqual($expectedBody);
+});

tests/Fixtures/Mocking/UnseekableBodyMockResponse.php

@@ -0,0 +1,126 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Saloon\Tests\Fixtures\Mocking;
+
+use Saloon\Http\Faking\MockResponse;
+use Psr\Http\Message\StreamInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\StreamFactoryInterface;
+use Psr\Http\Message\ResponseFactoryInterface;
+
+/**
+ * A MockResponse that uses an unseekable body stream so we can test
+ * that the response debugger buffers the body and shows it correctly.
+ */
+class UnseekableBodyMockResponse extends MockResponse
+{
+    public function createPsrResponse(ResponseFactoryInterface $responseFactory, StreamFactoryInterface $streamFactory): ResponseInterface
+    {
+        $response = parent::createPsrResponse($responseFactory, $streamFactory);
+        $body = (string) $response->getBody();
+
+        return $response->withBody(new UnseekableStream($body));
+    }
+}
+
+/**
+ * Stream that reports isSeekable() === false (e.g. like a network stream).
+ */
+final class UnseekableStream implements StreamInterface
+{
+    private string $contents;
+
+    private int $position = 0;
+
+    private bool $closed = false;
+
+    public function __construct(string $contents)
+    {
+        $this->contents = $contents;
+    }
+
+    public function __toString(): string
+    {
+        return $this->contents;
+    }
+
+    public function close(): void
+    {
+        $this->closed = true;
+    }
+
+    public function detach()
+    {
+        $this->closed = true;
+
+        return null;
+    }
+
+    public function getSize(): ?int
+    {
+        return mb_strlen($this->contents);
+    }
+
+    public function tell(): int
+    {
+        return $this->position;
+    }
+
+    public function eof(): bool
+    {
+        return $this->position >= mb_strlen($this->contents);
+    }
+
+    public function isSeekable(): bool
+    {
+        return false;
+    }
+
+    public function seek(int $offset, int $whence = SEEK_SET): void
+    {
+        throw new \RuntimeException('Stream is not seekable');
+    }
+
+    public function rewind(): void
+    {
+        throw new \RuntimeException('Stream is not seekable');
+    }
+
+    public function isWritable(): bool
+    {
+        return false;
+    }
+
+    public function write(string $string): int
+    {
+        throw new \RuntimeException('Stream is not writable');
+    }
+
+    public function isReadable(): bool
+    {
+        return ! $this->closed;
+    }
+
+    public function read(int $length): string
+    {
+        $chunk = mb_substr($this->contents, $this->position, $length);
+        $this->position += mb_strlen($chunk);
+
+        return $chunk;
+    }
+
+    public function getContents(): string
+    {
+        $remaining = mb_substr($this->contents, $this->position);
+        $this->position = mb_strlen($this->contents);
+
+        return $remaining;
+    }
+
+    public function getMetadata(?string $key = null)
+    {
+        return $key === null ? [] : null;
+    }
+}