add auto contentType detection on receiving messages if contentType not set

src/rabbit.ts

@@ -134,15 +134,27 @@ export class Rabbit {
 
   private parseContent(content: Buffer, content_type?: string): RabbitContentType {
     let final_content: RabbitContentType = content;
-    if (content_type === 'application/json') {
-      final_content = JSON.parse(content.toString());
-    }
-    else if (content_type === 'text/string') {
-      final_content = content.toString();
+    if (content_type) {
+      if (content_type === 'application/json') {
+        final_content = JSON.parse(content.toString());
+      }
+      else if (content_type === 'text/string') {
+        final_content = content.toString();
+      }
+      else if (content_type === 'text/number') {
+        final_content = parseFloat(content.toString());
+      }
     }
-    else if (content_type === 'text/number') {
-      final_content = parseFloat(content.toString());
+    else {
+      try {
+        final_content = content.toString();
+        final_content = JSON.parse(<string>final_content);
+      }
+      catch (e) {
+        // pass
+      }
     }
+
     return final_content;
   }
 
@@ -188,7 +200,9 @@ export class Rabbit {
    */
   public async publishTopic(topic: string, content: RabbitContentType = Buffer.from(''), options: amqplib.Options.Publish = {}): Promise<boolean> {
     const encodedContent = this.encodeContent(content);
-    options.contentType = options.contentType || this.getContentType(content);
+    if (options.contentType === undefined) {
+      options.contentType = this.getContentType(content);
+    }
     const channel = await this.pch;
     await channel.checkExchange(this.exchange);
     return channel.publish(this.exchange, topic, encodedContent, options);

test/rabbit.spec.ts

@@ -89,3 +89,20 @@ test('rpc with replyTo', (done) => {
     expect(msg).toBeNull;
   });
 });
+
+test('no content-type set', (done) => {
+  const io = new Io({cogPath: rabbitCog});
+  expect(io.rabbit).toBeInstanceOf(Rabbit);
+  if (!io.rabbit) {
+    return expect(true).toBeFalsy;
+  }
+
+  const topicName = `test.topic.${uuidv4().replace('-', '')}`;
+  io.rabbit.onTopic(topicName, (msg) => {
+    expect(msg.properties.contentType).toBeNull;
+    expect(msg.content).toStrictEqual({hello: 'world'});
+    (<Rabbit>io.rabbit).close().then(done());
+  });
+
+  io.rabbit.publishTopic(topicName, {hello: 'world'}, {contentType: ''});
+});