Added cURL formatter (#50)

Added cURL formatter inspired by namshi/cuzzle

Author: Nyholm

README.md

@@ -47,6 +47,9 @@ $ composer test
 
 Please see our [contributing guide](http://docs.php-http.org/en/latest/development/contributing.html).
 
+## Cretids
+
+Thanks to [Cuzzle](https://github.com/namshi/cuzzle) for inpiration for the `CurlCommandFormatter`.
 
 ## Security
 

spec/Formatter/CurlCommandFormatterSpec.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace spec\Http\Message\Formatter;
+
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\StreamInterface;
+use Psr\Http\Message\UriInterface;
+use PhpSpec\ObjectBehavior;
+
+class CurlCommandFormatterSpec extends ObjectBehavior
+{
+    function it_is_initializable()
+    {
+        $this->shouldHaveType('Http\Message\Formatter\CurlCommandFormatter');
+    }
+
+    function it_is_a_formatter()
+    {
+        $this->shouldImplement('Http\Message\Formatter');
+    }
+
+    function it_formats_the_request(RequestInterface $request, UriInterface $uri, StreamInterface $body)
+    {
+        $request->getUri()->willReturn($uri);
+        $request->getBody()->willReturn($body);
+
+        $uri->withFragment('')->shouldBeCalled()->willReturn('http://foo.com/bar');
+        $request->getMethod()->willReturn('GET');
+        $request->getProtocolVersion()->willReturn('1.1');
+
+        $request->getHeaders()->willReturn(['foo'=>['bar', 'baz']]);
+        $request->getHeaderLine('foo')->willReturn('bar, baz');
+
+        $this->formatRequest($request)->shouldReturn('curl \'http://foo.com/bar\' -H \'foo: bar, baz\'');
+    }
+
+    function it_formats_post_request(RequestInterface $request, UriInterface $uri, StreamInterface $body)
+    {
+        $request->getUri()->willReturn($uri);
+        $request->getBody()->willReturn($body);
+
+        $body->__toString()->willReturn('body " data'." test' bar");
+        $body->getSize()->willReturn(1);
+        $body->isSeekable()->willReturn(true);
+        $body->rewind()->willReturn(true);
+
+        $uri->withFragment('')->shouldBeCalled()->willReturn('http://foo.com/bar');
+        $request->getMethod()->willReturn('POST');
+        $request->getProtocolVersion()->willReturn('2.0');
+
+        $request->getHeaders()->willReturn([]);
+
+        $this->formatRequest($request)->shouldReturn("curl 'http://foo.com/bar' --http2 --request POST --data 'body \" data test'\'' bar'");
+    }
+
+    function it_does_nothing_for_response(ResponseInterface $response)
+    {
+        $this->formatResponse($response)->shouldReturn('');
+    }
+}

src/Formatter/CurlCommandFormatter.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace Http\Message\Formatter;
+
+use Http\Message\Formatter;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * A formatter that prints a cURL command for HTTP requests.
+ *
+ * @author Tobias Nyholm <[email protected]>
+ */
+class CurlCommandFormatter implements Formatter
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function formatRequest(RequestInterface $request)
+    {
+        $command = sprintf('curl %s', escapeshellarg((string) $request->getUri()->withFragment('')));
+        if ($request->getProtocolVersion() === '1.0') {
+            $command .= ' --http1.0';
+        } elseif ($request->getProtocolVersion() === '2.0') {
+            $command .= ' --http2';
+        }
+
+        $method = strtoupper($request->getMethod());
+        if ('HEAD' === $method) {
+            $command .= ' --head';
+        } elseif ('GET' !== $method) {
+            $command .= ' --request '.$method;
+        }
+
+        $command .= $this->getHeadersAsCommandOptions($request);
+
+        $body = $request->getBody();
+        if ($body->getSize() > 0) {
+            if (!$body->isSeekable()) {
+                return 'Cant format Request as cUrl command if body stream is not seekable.';
+            }
+            $command .= sprintf(' --data %s', escapeshellarg($body->__toString()));
+            $body->rewind();
+        }
+
+        return $command;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function formatResponse(ResponseInterface $response)
+    {
+        return '';
+    }
+
+    /**
+     * @param RequestInterface $request
+     *
+     * @return string
+     */
+    private function getHeadersAsCommandOptions(RequestInterface $request)
+    {
+        $command = '';
+        foreach ($request->getHeaders() as $name => $values) {
+            if ('host' === strtolower($name) && $values[0] === $request->getUri()->getHost()) {
+                continue;
+            }
+
+            if ('user-agent' === strtolower($name)) {
+                $command .= sprintf('-A %s', escapeshellarg($values[0]));
+                continue;
+            }
+
+            $command .= sprintf(' -H %s', escapeshellarg($name.': '.$request->getHeaderLine($name)));
+        }
+
+        return $command;
+    }
+}