chains: A Go repository from bserdar

This is a simple middleware chain for HTTP handlers:

Each handler can be a function or a struct:

func MyHandler(ctx context.Context,w http.ResponseWriter, r *http.Request, cx ChainCtx) error
    ...
    if err:=cx.Next(ctx,w,r); err!=nil {
        return err
    }
    ...
    return nil
}

type AnotherHandler struct {
    ...
}

func (h AnotherHandler) HandleRequest(ctx context.Context,w http.ResponseWriter,r *http.Request, cx ChainCtx) error {
    ...
    if err:=cx.Next(ctx,w,r); err!=nil {
        return err
    }
    ...
    return nil
 }

You can create a chain using Chain() and ChainFunc() functions:

  c:=Chain(StructHandler{...}).ChainFunc(HandlerFunc).Chain(AnotherStruct{})

The chain also contains an error handler:

  c=c.Err(func(w http.ResponseWriter,error) {
              // Write error to w
          })

Each chain is initialized with a basic error handler that returns HTTP 500 status with no body.

A chain is an HTTP Handler, so you can use a chain wherever an HTTP handler is required. Or, you can simply call

 c.ServeHTTP(writer,request)

bserdar/chains