Auto-detecting Content-Type of a request

- A Content-Type header will be added to a request automatically based
  on the path of the request if a Content-Type header was not
  specifically set. Pass `false` to the second parameter of
  EntityEnclosingRequest::setBody() to not auto-detect a value.
- Removing default return value of application/octet-stream from
  EntityBody::getContentType()

src/Guzzle/Http/EntityBody.php

@@ -142,11 +142,9 @@ class EntityBody extends Stream implements EntityBodyInterface
      */
     public function getContentType()
     {
-        if (!($this->isLocal() && $this->getWrapper() == 'plainfile' && file_exists($this->getUri()))) {
-            return 'application/octet-stream';
-        }
-
-        return Mimetypes::getInstance()->fromFilename($this->getUri()) ?: 'application/octet-stream';
+        return (!($this->isLocal() && $this->getWrapper() == 'plainfile' && file_exists($this->getUri())))
+            ? null
+            : Mimetypes::getInstance()->fromFilename($this->getUri());
     }
 
     /**

src/Guzzle/Http/EntityBodyInterface.php

@@ -47,9 +47,9 @@ interface EntityBodyInterface extends StreamInterface
     public function getContentLength();
 
     /**
-     * Guess the Content-Type or return the default application/octet-stream
+     * Guess the Content-Type of a local stream
      *
-     * @return string
+     * @return string|null
      * @see http://www.php.net/manual/en/function.finfo-open.php
      */
     public function getContentType();

src/Guzzle/Http/Message/EntityEnclosingRequest.php

@@ -7,6 +7,7 @@ use Guzzle\Http\EntityBodyInterface;
 use Guzzle\Http\QueryString;
 use Guzzle\Http\RedirectPlugin;
 use Guzzle\Http\Exception\RequestException;
+use Guzzle\Http\Mimetypes;
 
 /**
  * HTTP request that sends an entity-body in the request message (POST, PUT, PATCH, DELETE)
@@ -78,6 +79,11 @@ class EntityEnclosingRequest extends Request implements EntityEnclosingRequestIn
         $this->body = EntityBody::factory($body);
         $this->removeHeader('Content-Length');
 
+        // Auto detect the Content-Type from the path of the request if possible
+        if ($contentType === null && !$this->hasHeader('Content-Type')) {
+            $contentType = Mimetypes::getInstance()->fromFilename($this->getPath());
+        }
+
         if ($contentType) {
             $this->setHeader('Content-Type', (string) $contentType);
         }

tests/Guzzle/Tests/Http/EntityBodyTest.php

@@ -143,7 +143,7 @@ class EntityBodyTest extends \Guzzle\Tests\GuzzleTestCase
     {
         // Test using a string/temp stream
         $body = EntityBody::factory('testing 123...testing 123');
-        $this->assertEquals('application/octet-stream', $body->getContentType());
+        $this->assertNull($body->getContentType());
 
         // Use a local file
         $body = EntityBody::factory(fopen(__FILE__, 'r'));

tests/Guzzle/Tests/Http/Message/EntityEnclosingRequestTest.php

@@ -41,11 +41,9 @@ class EntityEnclosingRequestTest extends \Guzzle\Tests\GuzzleTestCase
      */
     public function testCanSetBodyWithoutOverridingContentType()
     {
-        $request = new EntityEnclosingRequest('PUT', 'http://test.com', array(
-            'Content-Type' => 'application/json'
-        ));
+        $request = new EntityEnclosingRequest('PUT', 'http://test.com', array('Content-Type' => 'foooooo'));
         $request->setBody('{"a":"b"}');
-        $this->assertEquals('application/json', $request->getHeader('Content-Type'));
+        $this->assertEquals('foooooo', $request->getHeader('Content-Type'));
     }
 
     /**
@@ -523,4 +521,14 @@ class EntityEnclosingRequestTest extends \Guzzle\Tests\GuzzleTestCase
         $request->configureRedirects(false, false);
         $this->assertTrue($request->getParams()->get(RedirectPlugin::DISABLE));
     }
+
+    /**
+     * @covers Guzzle\Http\Message\EntityEnclosingRequest::setBody
+     */
+    public function testSetsContentTypeWhenSettingBodyByGuessing()
+    {
+        $request = new EntityEnclosingRequest('PUT', 'http://test.com/foo.json');
+        $request->setBody('{"a":"b"}');
+        $this->assertEquals('application/json', $request->getHeader('Content-Type'));
+    }
 }