httprouter pass in many middleware functions

Question

I'm coming from node express, and I was able to pass in as many middleware as possible, for example: routes.use('/*', ensureAuth, logImportant, ... n);

How can I do something similar when using r.GET("/", HomeIndex)?

Am I forced to do something like EnsureAuth(HomeIndex)? Because I can get that to work. Unfortunately, I'm not sure what would be a good way to add as many middlewares as I want without chaining functions together.

Is there a more elegant way so I could somehow use variadic type function to do r.GET("/", applyMiddleware(HomeIndex, m1, m2, m3, m4)? I'm trying that out right now, but I feel like there's a better way to do this.

I've looked at the httprouter issues page, can't find anything :(

Thanks!

i'm new to Go and I read some articles and read that for JSON api httprouter would be fast performance and easy to use. — a person
how about your middlewares, are they of this signature func(http.Handler) http.Handler? — stevenferrer
yes. Well, I'm returning httprouter.Handle, and passing in handle of type httprouter.Handle. — a person
see if this package could help you github.com/justinas/alice — stevenferrer

stevenferrer stevenferrer · Accepted Answer · 2017-11-07T07:20:18

Here is an example how I did it:

package main

import (
    "context"
    "fmt"
    "log"
    "net/http"

    "github.com/julienschmidt/httprouter"
    "github.com/justinas/alice"
)

// m1 is middleware 1
func m1(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        //do something with m1
        log.Println("m1 start here")
        next.ServeHTTP(w, r)
        log.Println("m1 end here")
    })
}

// m2 is middleware 2
func m2(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        //do something with m2
        log.Println("m2 start here")
        next.ServeHTTP(w, r)
        log.Println("m2 end here")
    })
}

func index(w http.ResponseWriter, r *http.Request) {
    // get httprouter.Params from request context
    ps := r.Context().Value("params").(httprouter.Params)
    fmt.Fprintf(w, "Hello, %s", ps.ByName("name"))
}

// wrapper wraps http.Handler and returns httprouter.Handle
func wrapper(next http.Handler) httprouter.Handle {
    return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        //pass httprouter.Params to request context
        ctx := context.WithValue(r.Context(), "params", ps)
        //call next middleware with new context
        next.ServeHTTP(w, r.WithContext(ctx))
    }
}

func main() {
    router := httprouter.New()

    chain := alice.New(m1, m2)

    //need to wrap http.Handler to be compatible with httprouter.Handle
    router.GET("/user/:name", wrapper(chain.ThenFunc(index)))

    log.Fatal(http.ListenAndServe(":9000", router))
}

Link to code (you can't run it from play.golang.org though): https://play.golang.org/p/BOCt97xcoY

httprouter pass in many middleware functions

1 Answers