ppkarwasz commented on issue #3704: URL: https://github.com/apache/logging-log4j2/issues/3704#issuecomment-3080017458
Hi @sidhantmourya, Thanks for digging into this! I must admit that when I introduced the Jakarta version of the SMTP appender, I only added a minimal abstraction for `MailManager`. In hindsight, I could have refactored more shared logic into the abstract base class. One reason I held back was that `SmtpManager` exposes Java EE Mail types in its public and protected methods, which we can’t remove without breaking backward compatibility. That said, if you'd like to take on abstracting `MimeMessage`, feel free — it would be a useful improvement. Alternatively, you're also welcome to duplicate the logic across both `MailManager` implementations. The Java EE version will be removed in Log4j 3.x anyway, so code duplication is a short-term compromise. A few quick notes on the code you shared: ```java setHeader.invoke(message, header.getName(), substitutor.replace(header.getValue())); ``` When calling `MimeMessage.setHeader()`, make sure the value is correctly encoded and safe. Specifically: 1. The value **must be ASCII-only**, per [RFC 5322, section 2.2](https://datatracker.ietf.org/doc/html/rfc5322#section-2.2). 2. It **must not contain newlines**, to avoid **header injection** vulnerabilities. 3. It **must respect the 998-character line length limit**, per [RFC 5322, section 2.1.1](https://datatracker.ietf.org/doc/html/rfc5322#section-2.1.1). For example, I’ve seen overly long headers cause message rejection on a Debian server running Exim with default settings. To handle these constraints, you can use the `encode` and `fold` methods from [`MimeUtility`](https://jakarta.ee/specifications/platform/9/apidocs/jakarta/mail/internet/mimeutility). Finally, although `HttpAppender` only supports [property substitution](https://logging.apache.org/log4j/2.x/manual/configuration.html#property-substitution), I’d personally prefer we allow full `PatternLayout` expressions here — just like the "Subject" field is implemented in `SmtpManager`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@logging.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
