HTTP Handler/Func

Although it’s very convenient to use gRPC + gRPC-Gateway to serve RESTful APIs, you sometime want to use prebuilt HTTP Handler/HandlerFunc(s) or similar.

Mortar provides 2 fx.Group(s) for that: ExternalHTTPHandlers and ExternalHTTPHandlerFunctions, one for http.Handler and the other for http.HandlerFunc.

Registering http.Handler

To register a new http.Handler, you need to define how it’s going to be served == Pattern:

1. Create a HTTPHandlerPatternPair:

   var customHandler http.Handler ...
   
   func createHandlerPair() types.HTTPHandlerPatternPair {
    return types.HTTPHandlerPatternPair{
        Pattern:"/your/pattern",
        Handler: customHandler,
    }
   }
   

2. Add this pair to the ExternalHTTPHandlers group:

   var customHandlerOption = fx.Provide(
       fx.Annotated{
           Group: groups.ExternalHTTPHandlers,
           Target: createHandlerPair, // function pointer, will be called by Uber-FX
       }
   )
   

3. All that’s left is to register it into the Uber-FX graph:

   return fx.New(
    ...
    customHandlerOption,
    ...
   )
   

Registering http.HandlerFunc

Registering http.HandlerFunc is very much similar to registering http.Handler.

Actually, you need to follow the exact same guide and replace Handler with HandlerFunc:

var customHandler http.Handler ...

func createHandlerPair() types.HTTPHandlerPatternPair {
 return types.HTTPHandlerPatternPair{
     Pattern:"/your/pattern",
     Handler: customHandler,
 }
}

var customHandlerOption = fx.Provide(
    fx.Annotated{
        Group: groups.ExternalHTTPHandlers,
        Target: createHandlerPair, // function pointer, will be called by Uber-FX
    }
) 
return fx.New(
 ...
 customHandlerOption,
 ...
)

var customHandlerFunc http.HandlerFunc ...

func createHandlerFuncPair() types.HTTPHandlerFuncPatternPair {
 return types.HTTPHandlerFuncPatternPair{
     Pattern:"/your/pattern",
     Handler: customHandlerFunc,
 }
}

var customHandlerFuncOption = fx.Provide(
    fx.Annotated{
        Group: groups.ExternalHTTPHandlerFunctions,
        Target: createHandlerFuncPair, // function pointer, will be called by Uber-FX
    }
) 
return fx.New(
 ...
 customHandlerFuncOption,
 ...
)