Extended SMTP tests to include SCRAM-SHA-1-PLUS and SCRAM-SHA-256-PLUS authentication mechanisms. Adjusted the `startSMTPServer` function to accept a hashing function and modified the server logic to handle TLS channel binding.
Add checks to handle errors when reading client messages. This ensures that an appropriate error message is sent back to the client if reading fails, improving the robustness of the SMTP authentication process.
Introduce new unit tests to verify SCRAM-SHA-1 and SCRAM-SHA-256 authentication for the SMTP client. These tests cover both successful and failing authentication cases, and include a mock SMTP server to facilitate testing.
Introduced new test cases for SCRAM-SHA-1, SCRAM-SHA-256, and their PLUS variants in `smtp_test.go`. Updated the authTest structure to include a `hasNonce` flag and implemented logic to handle nonce validation and success message processing.
Enhanced the LoginAuth test coverage by adding new scenarios with different sequences and invalid cases. This ensures more robust validation and better handling of edge cases in authentication testing.
The format string for the Debugf method calls within the smtp_test.go file have been updated. Previously, the format string was empty, but it has now been changed to "%s" to align with the standard formatting expectations, improving the correctness of the tests.
The Go version has been updated to 1.22 in the .golangci.toml file for compatibility reasons. Additionally, unnecessary white space has been removed from the smtp/smtp_test.go file to maximize code efficiency and readability.
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.
Fixes#121. `defer` in for loops can possibly lead to leaks.
The whole handling including the defer are now moved into anonymous functions outside the for loop and are called form the loop instead. This way the defer is handle when the inline function finishes
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.
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.