Add function for headers.

sources/fetch.php

@@ -54,6 +54,12 @@ class fetch {
      */
     private string $url;
 
+    /**
+     * This store headers of the request.
+     * @var array
+     */
+    private array $headers;
+
     /**
      * This create new fetch request. It is alias of constructor.
      * 
@@ -77,6 +83,7 @@ class fetch {
         $this->content = null;
         $this->content_type = null;
         $this->method = 'GET';
+        $this->headers = array();
         $this->url = $url;
     }
 
@@ -118,6 +125,55 @@ class fetch {
         return $this;
     }
 
+    /**
+     * That add new header to the request. Name of the header must be full 
+     * featured header name, like 'Cache-Control'. It also had been validated
+     * and when name had been blacklisted, it raise RuntimeException. It also
+     * raise RuntimeException when name has any white chars. Content had been 
+     * validating, and it could not have new lines. Name and content would be
+     * trimed before processing.
+     * 
+     * Blacklisted headers:
+     * Content-Type, Content-Length
+     * 
+     * @param string $name Name of the header.
+     * @param string $content Content of the header.
+     * @return fetch Self to chain processing.
+     */
+    public function add_header(string $name, string $content): object {
+        $name = trim($name);
+        $content = trim($content);
+
+        if (strpos($name, ' ') !== false) {
+            throw new RuntimeException(
+                'Header "'.$name.'" contains white char.'
+            );
+        }
+
+        $check_content = strpos($content, ' ') !== false;
+        $check_content = $check_content || strpos($content, "\r") !== false;
+        $check_content = $check_content || strpos($content, "\n") !== false;
+
+        if ($check_content) {
+            throw new RuntimeException(
+                'Header content "'.$content.'" contains invalid white char.'
+            );
+        }
+
+        if ($name === 'Content-Type') {
+            throw new RuntimeException('Content-Type header is automatic.');
+        }
+
+        if ($name === 'Content-Lenght') {
+            throw new RuntimeException('Content-Lenght header is automatic.');
+        }
+
+        $header = $name.': '.$content;
+        array_push($this->headers, $header);
+        
+        return $this;
+    }
+
     /**
      * This function set method of the request. Be careful, because it check 
      * that any content is not set, and when content is not null, but trying
@@ -148,21 +204,22 @@ class fetch {
      *
      * @return response Response from the server.
      */
-    public function request(): response { 
+    public function request(): response {
+        $headers = $this->headers;
         $request = curl_init($this->url);
+
         curl_setopt($request, CURLOPT_RETURNTRANSFER, true);
         curl_setopt($request, CURLOPT_FAILONERROR, true);
         curl_setopt($request, CURLOPT_HEADER, true);
         curl_setopt($request,CURLOPT_CUSTOMREQUEST, $this->method);
 
         if ($this->content !== null) {
-            $type = 'Content-Type: '.$this->content_type;
-            $headers = [ $type ];
-
-            curl_setopt($request, CURLOPT_HTTPHEADER, $headers);
+            array_push($headers, 'Content-Type: '.$this->content_type);
             curl_setopt($request, CURLOPT_POSTFIELDS, $this->content);
         }
 
+        curl_setopt($request, CURLOPT_HTTPHEADER, $headers);
+        
         $result = curl_exec($request);
         $error = curl_error($request);
         $error_number = curl_errno($request);
@@ -179,5 +236,5 @@ class fetch {
             .': "'.$error.'".'
         );
     }
-    
+
 }