Introduce a global error variable for non-TLS connections and update corresponding error handling across the codebase. This enhances readability and maintainability of the error management logic.
Introduce a method to retrieve the TLS connection state of the client's current connection. This method checks if the connection uses TLS and is established, returning appropriate errors otherwise.
Correct the sequence of mutex unlocking in TLSConnectionState to ensure the mutex is always released properly. This prevents potential deadlocks and ensures the function behaves as expected in a concurrent context.
This commit revises locking mechanism usage around connection operations to avoid potential deadlocks and improve code clarity. Specifically, defer statements were removed and explicit unlocks were added to ensure that mutexes are properly released after critical sections. This change affects several methods, including `Close`, `cmd`, `TLSConnectionState`, `UpdateDeadline`, and newly introduced locking for concurrent data writes and reads in `dataCloser`.
This commit introduces a RWMutex to the Client struct in the smtp package to ensure thread-safe access to shared resources. Critical sections in methods like Close, StartTLS, and cmd are now protected with appropriate locking mechanisms. This change helps prevent potential race conditions, ensuring consistent and reliable behavior in concurrent environments.
Reordered and grouped fields in the Client struct for clarity. The reorganization separates logical groups of fields, making it easier to understand and maintain the code. This includes proper grouping of TLS parameters, DSN options, and debug settings.
Add mutex locking for client connections to ensure thread safety. Introduce `HasConnection` method to check active connections and `UpdateDeadline` method to handle timeout updates. Refactor connection handling in `checkConn` and `tls` methods accordingly.
The logging system in the smtp.go and log package has been refactored. A new custom log type `Log` was introduced, that includes the message direction, format and arguments. The `Logger` interface and the `Stdlog` implementation were modified to accept this new type. This change provides a clearer understanding of message direction inside logs, allowing for easier debugging and reduced complexity. This change does not affect features or disrupt user functionality. Additionally, it allows for custom implementations of the log.Logger interface to without being forced to use the C --> S/C <-- S direction logging.
Since we are Go <1.20 compatible, we can't easily combine errors here. The suggested golangci-lint fix will not work neither, since the %w verb can't be used twice. Therefore, for now we will ignore the linting error
Closes#119
As stated in https://github.com/wneessen/go-mail/pull/102#issuecomment-1411956040 it would be beneficial if, instead of forcing the Go stdlib logger on the user to provide a simple interface and use that for logging purposes.
This PR implements this simple log.Logger interface as well as a standard logger that satisfies this interface. If no custom logger is provided, the Stdlog will be used (which makes use of the Go stdlib again).
Accordingly, a `Client.WithLogger` and `Client.SetLogger` have been implemented. Same applies for the smtp counterparts.
This PR refactors the the DSN (RFC 1891) SMTP client handling, that was introduced in f4cdc61dd0.
While most of the Client options stay the same, the whole workaround logic for the SMTP client has been removed and added as part of the SMTP client instead.
This was we got rid of the Client's own `mail()`, `rcpt()`, `dsnRcpt()`, `dsnMail()` methods as well as the copies of the `cmd()` and `validateLine()` methods. The Client is now using the proper `Mail()` and `Rcpt()` methods of the SMTP client instead.
Resolves#101.
Since we now have full control over the SMTP client we can also access the message input and output.
This PR introduces a new debug logging feature. Via the `Client.WithDebugLog` the user can enable this feature. It will then make use of the new `smtp/Client.SetDebugLog` method. Once the flag is set to true, the SMTP client will start logging incoming and outgoing messages to os.Stderr.
Log directions will be output accordingly
- Also import the original BSD-3-Clause.txt license from the Go team into the LICENSES directory
- Further on, license headers should hold "The go-mail Authors" instead of my name. Did this already for the MIT license.
As part of #97 we are going to fork the official `net/smtp` package into go-mail to provide us with more flexibility.
This commit fulfills the first big step of importing the package into smtp/. Also go-mail's own LoginAuth has been moved from auth/ into smtp/ to be consistent with the stdlib.
There are still a couple of open issues (i. e. license adjustments and making golangci-lint happy) but so far all tests already work, which is a good start.