Fixed Link header behavior.

Author: roquie

.gitignore

@@ -3,3 +3,4 @@ configuration/local/
 vendor/
 example/vue-app/dist
 .phpunit.result.cache
+.DS_Store

src/Header.php

@@ -53,6 +53,8 @@ public function __construct(ConfigurationInterface $conf)
     /**
      * Prepare headers before handling requests.
      *
+     * https://tools.ietf.org/html/rfc5988#section-5.5
+     *
      * @return void
      */
     private function prepareBeforeRequest(): void
@@ -66,18 +68,21 @@ private function prepareBeforeRequest(): void
 
             // Backward compatibility.
             if (!isset($values[0]['value'])) {
-                $this->prepared[$item][] = join('; ', (array) $values);
+                $this->prepared[$item] = join('; ', (array) $values);
             }
 
             // Checks new extended format for sent headers from yaml values.
             if (is_array($values) && count($values) > 0 && isset($values[0]['value'])) {
+                $array = [];
                 foreach ($values as $value) {
                     if (!isset($value['value'])) {
                         throw new InvalidArgumentException('Invalid header format, see docs & examples.');
                     }
 
-                    $this->prepared[$item][] = join('; ', (array) $value['value']);
+                    $array[] = join('; ', (array) $value['value']);
                 }
+
+                $this->prepared[$item] = join(', ', $array);
             }
         }
     }
@@ -94,10 +99,8 @@ public function sent(Response $response): void
         $response->header('software-server', '');
         $response->header('server', '');
 
-        foreach ($this->prepared as $header => $values) {
-            foreach ($values as $value) {
-                $response->header($header, $value);
-            }
+        foreach ($this->prepared as $header => $value) {
+            $response->header($header, $value);
         }
     }
 }

tests/HeaderTest.php

@@ -16,7 +16,7 @@ public function testSendingHeaders()
 
         $response = $this->createMock(Response::class);
         $response
-            ->expects($this->exactly(count($conf->get('server.headers')) + 3)) // +3 because 2 hardcoded and 1 header have 2 values.
+            ->expects($this->exactly(count($conf->get('server.headers')) + 2)) // +2 because 2 hardcoded.
             ->method('header')
             ->willReturn(null);