feat: add contentType option

README.md

@@ -202,6 +202,7 @@ $defaultOptions = [
     'urgency' => 'normal', // protocol defaults to "normal". (very-low, low, normal, or high)
     'topic' => 'newEvent', // not defined by default. Max. 32 characters from the URL or filename-safe Base64 characters sets
     'batchSize' => 200, // defaults to 1000
+    'contentType' => 'application/json', // defaults to "application/octet-stream"
 ];
 
 // for every notification
@@ -235,6 +236,11 @@ In order to fix this, WebPush sends notifications in batches. The default size i
 to decrease this number. Do this while instantiating WebPush or calling `setDefaultOptions`. Or, if you want to customize this for a specific flush, give
 it as a parameter : `$webPush->flush($batchSize)`.
 
+#### contentType
+
+Sets the "Content-Type" header for HTTP requests with a non-empty payload sent to the push service. 
+Especially newer [Declarative push messages](https://www.w3.org/TR/push-api/#declarative-push-message) require a specific JSON payload, so this should be set to "application/json" in such cases.
+
 ### Server errors
 
 You can see what the browser vendor's server sends back in case it encountered an error (push subscription expiration, wrong parameters...).

src/Notification.php

@@ -43,6 +43,7 @@ public function getOptions(array $defaultOptions = []): array
         $options['TTL'] = array_key_exists('TTL', $options) ? $options['TTL'] : $defaultOptions['TTL'];
         $options['urgency'] = array_key_exists('urgency', $options) ? $options['urgency'] : $defaultOptions['urgency'];
         $options['topic'] = array_key_exists('topic', $options) ? $options['topic'] : $defaultOptions['topic'];
+        $options['contentType'] = array_key_exists('contentType', $options) ? $options['contentType'] : $defaultOptions['contentType'];
 
         return $options;
     }

src/WebPush.php

@@ -263,7 +263,7 @@ protected function prepare(array $notifications): array
                 $localPublicKey = $encrypted['localPublicKey'];
 
                 $headers = [
-                    'Content-Type' => 'application/octet-stream',
+                    'Content-Type' => $options['contentType'],
                     'Content-Encoding' => $contentEncoding,
                 ];
 
@@ -384,6 +384,7 @@ public function setDefaultOptions(array $defaultOptions): WebPush
         $this->defaultOptions['topic'] = $defaultOptions['topic'] ?? null;
         $this->defaultOptions['batchSize'] = $defaultOptions['batchSize'] ?? 1000;
         $this->defaultOptions['requestConcurrency'] = $defaultOptions['requestConcurrency'] ?? 100;
+        $this->defaultOptions['contentType'] = $defaultOptions['contentType'] ?? 'application/octet-stream';
 
 
         return $this;