add readme for main configuration

1 files changed, 50 insertions, 0 deletions

diff --git a/readme.md b/readme.md
index b791c8d..4add926 100644
--- a/readme.md
+++ b/readme.md
@@ -844,3 +844,53 @@ object Server extends cask.MainRoutes{
   initialize()
 }
 ```
+
+Main Customization
+------------------
+
+Apart from the code used to configure and define your routes and endpoints, Cask
+also allows global configuration for things that apply to the entire web server.
+This can be done by overriding the following methods on `cask.Main` or
+`cask.MainRoutes`:
+
+### def debugMode: Boolean = true
+
+Makes the Cask report verbose error messages and stack traces if an endpoint
+fails; useful for debugging, should be disabled for production.
+
+### def main
+
+The cask program entrypoint. By default just spins up a webserver, but you can
+override it to do whatever you like before or after the webserver runs.
+
+### def defaultHandler
+
+Cask is built on top of the [Undertow](http://undertow.io/) web server. If you
+need some low-level functionality not exposed by the Cask API, you can override
+`defaultHandler` to make use of Undertow's own
+[handler API](http://undertow.io/undertow-docs/undertow-docs-2.0.0/index.html#built-in-handlers)
+for customizing your webserver. This allows for things that Cask itself doesn't
+internally support: asynchronous requests & response,
+[Websockets](http://undertow.io/undertow-docs/undertow-docs-2.0.0/index.html#websockets),
+etc.
+
+### def port: Int = 8080, def host: String = "localhost"
+
+The host & port to attach your webserver to.
+
+### def handleNotFound
+
+The response to serve when the incoming request does not match any of the routes
+or endpoints; defaults to a typical 404
+
+### def handleEndpointError
+
+The response to serve when the incoming request matches a route and endpoint,
+but then fails for other reasons. Defaults to 400 for mismatched or invalid
+endpoint arguments and 500 for exceptions in the endpoint body, and provides
+useful stack traces or metadata for debugging if `debugMode = true`.
+
+### def mainDecorators
+
+Any `cask.Decorator`s that you want to apply to all routes and all endpoints in
+the entire web application
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