feat(events): Emit a new headerLines event to gain access the raw headers (#364)

Author: katlimruiz

lib/mail-parser.js

@@ -797,6 +797,10 @@ class MailParser extends Transform {
                         }
                     });
                     this.emit('headers', node.headers);
+
+                    if (node.headerLines) {
+                        this.emit('headerLines', node.headerLines);
+                    }                    
                 }
 
                 if (data.contentType === 'message/rfc822' && data.messageNode) {

test/mail-parser-test.js

@@ -141,6 +141,33 @@ exports['General tests'] = {
         });
     },
 
+    'HeaderLines event': test => {
+        let encodedText = 'X-Test: =?UTF-8?Q?=C3=95=C3=84?= =?UTF-8?Q?=C3=96=C3=9C?=\r\n' + 'Subject: ABCDEF',
+            mail = Buffer.from(encodedText, 'utf-8');
+
+        test.expect(3);
+        let mailparser = new MailParser();
+
+        mailparser.on('headerLines', headerLines => {
+            test.equal(!!headerLines.find(({ line }) => line === 'X-Test: =?UTF-8?Q?=C3=95=C3=84?= =?UTF-8?Q?=C3=96=C3=9C?='), true);
+            test.equal(!!headerLines.find(({ line }) => line === 'Subject: ABCDEF'), true);
+        });
+
+        mailparser.end(mail);
+        mailparser.on('data', data => {
+            if (data && data.release) {
+                data.content.on('data', () => false);
+                data.content.on('end', () => false);
+                data.release();
+            }
+        });
+
+        mailparser.on('end', () => {
+            test.ok(1, 'Parsing ended');
+            test.done();
+        });
+    },    
+
     'No priority': test => {
         let encodedText = 'Content-type: text/plain; charset=utf-8\r\nSubject: ÕÄÖÜ\n\r\n1234',
             mail = Buffer.from(encodedText, 'utf-8');