Add Content-type plugin to set content-type header automatically

spec/Plugin/ContentTypePluginSpec.php

@@ -0,0 +1,59 @@
+<?php
+
+namespace spec\Http\Client\Common\Plugin;
+
+use PhpSpec\Exception\Example\SkippingException;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\StreamInterface;
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class ContentTypePluginSpec extends ObjectBehavior
+{
+    function it_is_initializable()
+    {
+        $this->shouldHaveType('Http\Client\Common\Plugin\ContentTypePlugin');
+    }
+
+    function it_is_a_plugin()
+    {
+        $this->shouldImplement('Http\Client\Common\Plugin');
+    }
+
+    function it_adds_json_content_type_header(RequestInterface $request)
+    {
+        $request->hasHeader('Content-Type')->shouldBeCalled()->willReturn(false);
+        $request->getBody()->shouldBeCalled()->willReturn(json_encode(['foo' => 'bar']));
+        $request->withHeader('Content-Type', 'application/json')->shouldBeCalled()->willReturn($request);
+
+        $this->handleRequest($request, function () {}, function () {});
+    }
+
+    function it_adds_xml_content_type_header(RequestInterface $request)
+    {
+        $request->hasHeader('Content-Type')->shouldBeCalled()->willReturn(false);
+        $request->getBody()->shouldBeCalled()->willReturn('<foo>bar</foo>');
+        $request->withHeader('Content-Type', 'application/xml')->shouldBeCalled()->willReturn($request);
+
+        $this->handleRequest($request, function () {}, function () {});
+    }
+
+    function it_does_not_set_content_type_header(RequestInterface $request)
+    {
+        $request->hasHeader('Content-Type')->shouldBeCalled()->willReturn(false);
+        $request->getBody()->shouldBeCalled()->willReturn('foo');
+        $request->withHeader('Content-Type', null)->shouldNotBeCalled();
+
+        $this->handleRequest($request, function () {}, function () {});
+    }
+
+    function it_does_not_set_content_type_header_if_already_one(RequestInterface $request)
+    {
+        $request->hasHeader('Content-Type')->shouldBeCalled()->willReturn(true);
+        $request->getBody()->shouldNotBeCalled()->willReturn('foo');
+        $request->withHeader('Content-Type', null)->shouldNotBeCalled();
+
+        $this->handleRequest($request, function () {}, function () {});
+    }
+
+}

src/Plugin/ContentTypePlugin.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Http\Client\Common\Plugin;
+
+use Http\Client\Common\Plugin;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * Allow to set the correct content type header on the request automatically only if it is not set .
+ *
+ * @author Karim Pinchon <[email protected]>
+ */
+final class ContentTypePlugin implements Plugin
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function handleRequest(RequestInterface $request, callable $next, callable $first)
+    {
+        if (!$request->hasHeader('Content-Type')) {
+            $stream = $request->getBody();
+
+            if ($this->isJson($stream)) {
+                $request = $request->withHeader('Content-Type', 'application/json');
+
+                return $next($request);
+            }
+
+            if ($this->isXml($stream)) {
+                $request = $request->withHeader('Content-Type', 'application/xml');
+
+                return $next($request);
+            }
+        }
+
+        return $next($request);
+    }
+
+    /**
+     * @param $stream
+     *
+     * @return bool
+     */
+    private function isJson($stream)
+    {
+        json_decode($stream);
+
+        return json_last_error() == JSON_ERROR_NONE;
+    }
+
+    /**
+     * @param $stream
+     *
+     * @return \SimpleXMLElement|false
+     */
+    private function isXml($stream)
+    {
+        libxml_use_internal_errors(true);
+
+        return simplexml_load_string($stream);
+    }
+}