Enable writing response directly to file (#45)

* Switch the reading of response headers to a dedicated function

* Add example of saving request response directly to file

* Add test for the  function

* Update array initialization format to support PHP < 5.4

README.md

@@ -99,6 +99,22 @@ curl_set_opt($curl->curl, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MSIE 7.0;
 curl_close($curl->curl);
 ```
 
+```php
+// Example of downloading a file or any other content
+$curl = new Curl\Curl();
+// open the file where the request response should be written
+$file_handle = fopen($target_file, 'w+');
+// pass it to the curl resource
+$curl->setOpt(CURLOPT_FILE, $file_handle);
+// do any type of request
+$curl->get('https://github.com');
+// disable writing to file
+$curl->setOpt(CURLOPT_FILE, null);
+// close the file for writing
+fclose($file_handle);
+```
+
+
 ## Testing
 
 In order to test the library:

src/Curl/Curl.php

@@ -130,13 +130,18 @@ class Curl
     /**
      * @var string|array TBD (ensure type) Contains the response header informations
      */
-    public $response_headers = null;
+    public $response_headers = array();
 
     /**
      * @var string Contains the response from the curl request
      */
     public $response = null;
 
+    /**
+     * @var boolean Whether the current section of response headers is after 'HTTP/1.1 100 Continue'
+     */
+    protected $response_header_continue = false;
+
     /**
      * Constructor ensures the available curl extension is loaded.
      *
@@ -164,11 +169,35 @@ private function init()
         $this->curl = curl_init();
         $this->setUserAgent(self::USER_AGENT);
         $this->setOpt(CURLINFO_HEADER_OUT, true);
-        $this->setOpt(CURLOPT_HEADER, true);
+        $this->setOpt(CURLOPT_HEADER, false);
         $this->setOpt(CURLOPT_RETURNTRANSFER, true);
+        $this->setOpt(CURLOPT_HEADERFUNCTION, array($this, 'addResponseHeaderLine'));
         return $this;
     }
 
+    /**
+     * Handle writing the response headers
+     *
+     * @param resource $curl The current curl resource
+     * @param string $header_line A line from the list of response headers
+     *
+     * @return int Returns the length of the $header_line
+     */
+    public function addResponseHeaderLine($curl, $header_line)
+    {
+        $trimmed_header = trim($header_line, "\r\n");
+
+        if ($trimmed_header === "") {
+            $this->response_header_continue = false;
+        } else if (strtolower($trimmed_header) === 'http/1.1 100 continue') {
+            $this->response_header_continue = true;
+        } else if (!$this->response_header_continue) {
+            $this->response_headers[] = $trimmed_header;
+        }
+
+        return strlen($header_line);
+    }
+
     // protected methods
 
     /**
@@ -178,6 +207,7 @@ private function init()
      */
     protected function exec()
     {
+        $this->response_headers = array();
         $this->response = curl_exec($this->curl);
         $this->curl_error_code = curl_errno($this->curl);
         $this->curl_error_message = curl_error($this->curl);
@@ -186,17 +216,7 @@ protected function exec()
         $this->http_error = in_array(floor($this->http_status_code / 100), array(4, 5));
         $this->error = $this->curl_error || $this->http_error;
         $this->error_code = $this->error ? ($this->curl_error ? $this->curl_error_code : $this->http_status_code) : 0;
-
         $this->request_headers = preg_split('/\r\n/', curl_getinfo($this->curl, CURLINFO_HEADER_OUT), null, PREG_SPLIT_NO_EMPTY);
-        $this->response_headers = '';
-        if (!(strpos($this->response, "\r\n\r\n") === false)) {
-            list($response_header, $this->response) = explode("\r\n\r\n", $this->response, 2);
-            while (strtolower(trim($response_header)) === 'http/1.1 100 continue') {
-                list($response_header, $this->response) = explode("\r\n\r\n", $this->response, 2);
-            }
-            $this->response_headers = preg_split('/\r\n/', $response_header, null, PREG_SPLIT_NO_EMPTY);
-        }
-
         $this->http_error_message = $this->error ? (isset($this->response_headers['0']) ? $this->response_headers['0'] : '') : '';
         $this->error_message = $this->curl_error ? $this->curl_error_message : $this->http_error_message;
 
@@ -540,7 +560,7 @@ public function reset()
         $this->http_status_code = 0;
         $this->http_error_message = null;
         $this->request_headers = null;
-        $this->response_headers = null;
+        $this->response_headers = array();
         $this->response = null;
         $this->init();
         return $this;

tests/CurlTest.php

@@ -217,6 +217,19 @@ public function testHeaders() {
 				'key' => 'HTTP_ACCEPT',
 		)) === 'application/json');
 	}
+
+	public function testHeadersWithContinue() {
+		$headers = file(dirname(__FILE__) . '/data/response_headers_with_continue.txt');
+
+		$this->curl->response_headers = array();
+		foreach($headers as $header_line) {
+			$this->curl->addResponseHeaderLine(null, $header_line);
+		}
+
+		$expected_headers = array_values(array_filter(array_map(function($l) { return trim($l, "\r\n"); }, array_slice($headers, 1))));
+
+		$this->assertEquals($expected_headers, $this->curl->response_headers);
+	}
 
 	public function testReset()
 	{
@@ -236,7 +249,7 @@ public function testReset()
 		$this->assertSame(0, $curl->http_status_code);
 		$this->assertNull($curl->http_error_message);
 		$this->assertNull($curl->request_headers);
-		$this->assertNull($curl->response_headers);
+		$this->assertEmpty($curl->response_headers);
 		$this->assertNull($curl->response);
 	}
 

tests/data/response_headers_with_continue.txt

@@ -0,0 +1,13 @@
+HTTP/1.1 100 Continue
+
+HTTP/1.1 200 OK
+Server: nginx/1.1.19
+Date: Fri, 11 Aug 2017 13:22:00 GMT
+Content-Type: image/jpeg
+Content-Length: 62574
+Connection: close
+Cache-Control: max-age=7257600
+Expires: Fri, 03 Nov 2017 13:22:00 GMT
+Strict-Transport-Security: max-age=31536000; includeSubDomains
+X-Frame-Option: DENY
+