Fix #20: Ensure required options are set

README.md

@@ -52,7 +52,6 @@ var_dump($curl->response_headers);
 
 ```php
 $curl = new Curl();
-$curl->setOpt(CURLOPT_RETURNTRANSFER, TRUE);
 $curl->setOpt(CURLOPT_SSL_VERIFYPEER, FALSE);
 $curl->get('https://encrypted.example.com/');
 ```

lib/Curl.class.php

@@ -140,6 +140,17 @@ class Curl {
 
     public function setOpt($option, $value, $_ch=null) {
         $ch = is_null($_ch) ? $this->curl : $_ch;
+
+        $required_options = array(
+            CURLINFO_HEADER_OUT    => 'CURLINFO_HEADER_OUT',
+            CURLOPT_HEADER         => 'CURLOPT_HEADER',
+            CURLOPT_RETURNTRANSFER => 'CURLOPT_RETURNTRANSFER',
+        );
+
+        if (in_array($option, array_keys($required_options), true) && !($value === true)) {
+            trigger_error($required_options[$option] . ' is a required option', E_USER_WARNING);
+        }
+
         $this->_options[$option] = $value;
         return curl_setopt($ch, $option, $value);
     }

tests/run.php

@@ -467,4 +467,28 @@ class CurlTest extends PHPUnit_Framework_TestCase {
         $curl->close();
         $this->assertFalse(is_resource($curl->curl));
     }
+
+    /**
+     * @expectedException PHPUnit_Framework_Error_Warning
+     */
+    public function testRequiredOptionCurlInfoHeaderOutEmitsWarning() {
+        $curl = new Curl();
+        $curl->setOpt(CURLINFO_HEADER_OUT, false);
+    }
+
+    /**
+     * @expectedException PHPUnit_Framework_Error_Warning
+     */
+    public function testRequiredOptionCurlOptHeaderEmitsWarning() {
+        $curl = new Curl();
+        $curl->setOpt(CURLOPT_HEADER, false);
+    }
+
+    /**
+     * @expectedException PHPUnit_Framework_Error_Warning
+     */
+    public function testRequiredOptionCurlOptReturnTransferEmitsWarning() {
+        $curl = new Curl();
+        $curl->setOpt(CURLOPT_RETURNTRANSFER, false);
+    }
 }