Support all HTTP methods for Webendpoint handlers

[lcf]

Currently only GET and POST are supported (for no apparent reason)
https://github.com/slackapi/java-slack-sdk/blob/main/bolt/src/main/java/com/slack/api/bolt/WebEndpoint.java#L17

Alternatively, allow adding custom servlet handlers into SlackAppServer.

[seratch]

Hi @lcf, thanks for writing in! As mentioned here, the custom endpoint is supposed to be used for serving relatively simple URLs such as system healthcheck ones. So, if you need complehensitve HTTP method support, please go ahead with usual custom servlet handlers.

[lcf]

thank you for your response @seratch . The only problem is that we will have to copy-paste entire SlackAppServer, in order to add custom handlers - or is there an easier way?

[seratch]

@lcf In this case, I'd suggest embedding your Slack app within a Spring Boot app and run the whole app with a servlet server like Jetty. You can find examples at https://github.com/slackapi/java-slack-sdk/tree/main/bolt-spring-boot-examples