Problem nesting gorilla/mux routers

[Lee Hambley]

First of all, I've seen the thread "Is it possible to nest Mux routers?", and unfortunately as the OP was so tied to Negroni no solution was posted, although I did take onboard some of the debugging tips.

I'm trying to do something like this, the contrived example is:

package main

import (

"fmt"

"net/http"

"github.com/gorilla/mux"

)

func NewUserRouter() *mux.Router {

userRouter := mux.NewRouter()

userRouter.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {

fmt.Fprintf(w, "Users Index\n")

})

userRouter.HandleFunc("/show/{uuid}", func(w http.ResponseWriter, req *http.Request) {

fmt.Fprintf(w, "Users Show\n")

})

return userRouter

}

func NewOtherRouter() *mux.Router {

otherRouter := mux.NewRouter()

otherRouter.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {

fmt.Fprintf(w, "Other Index\n")

})

return otherRouter

}

func main() {

// Compose Routers

r := mux.NewRouter()

r.Path("/users").Handler(NewUserRouter())

r.Path("/other").Handler(NewOtherRouter())

// Run

http.ListenAndServe(":3001", r)

}

(Also at http://play.golang.org/p/s3gFqovlmF, incase the formatting here is off, but it won't run due to depending on `gorilla/mux`).

This isn't the first thing I've tried, I've also played around unsuccessfully with `Path().Handler()` and `SubRouter()`, but to no avail, also with more liberal regular expressions, e.g. `r.Path("/users.*").Handler(NewUserRouter())`

I think it goes without saying, that the behaviour I'm expecting is to be able to do the following, with the following output:

$ curl localhost:3001/users

=> "Users Index"

$ curl localhost:3001/users/show/foo

=> "Users Show"

$ curl localhost:3001/other

=> "Other Index"

I made the following change to `gorilla/mux` to print some kind of debugging information, but it's not terribly helpful:

diff --git a/route.go b/route.go

index c310e66..8512b50 100644

--- a/route.go

+++ b/route.go

@@ -35,12 +35,16 @@ type Route struct {

 

 // Match matches the route against the request.

 func (r *Route) Match(req *http.Request, match *RouteMatch) bool {

+

+ fmt.Printf("gorilla/mux Route.Match():\n\tRequest URL: %s\n", req.URL)

+

  if r.buildOnly || r.err != nil {

  return false

  }

  // Match everything.

  for _, m := range r.matchers {

  if matched := m.Match(req, match); !matched {

+ fmt.Printf("\tNot matched: %s\n", m)

  return false

  }

  }

It prints something like the following:

gorilla/mux Route.Match():

        Request URL: /users

        Not matched: &{/users %!s(bool=false) %!s(bool=false) %!s(bool=false) %!s(*regexp.Regexp=&{^/users$ 0xc208038b10 0xc208038b70 /users [47 117 115 101 114 115] false 47 8 4 0 [] false {0 0} [0xc208062600]}) /users [] []}

gorilla/mux Route.Match():

        Request URL: /users

        Not matched: &{/other %!s(bool=false) %!s(bool=false) %!s(bool=false) %!s(*regexp.Regexp=&{^/other$ 0xc208038e40 0xc208038ea0 /other [47 111 116 104 101 114] false 47 8 4 0 [] false {0 0} [0xc208062700]}) /other [] []}

(For simple curl requests to `curl localhost:3001/users`). 

I wonder if someone can please bump me in the correct direction?

[Lee Hambley]

Having continued to play around, I stumbled upon this thread at Github, that helped. Having changed my main to:

func main() {

// Compose Routers

r := mux.NewRouter().StrictSlash(true)

AddUserRouter(r.PathPrefix("/users").Subrouter())

AddNewOtherRouter(r.PathPrefix("/other").Subrouter())

// Gracefully Run

http.ListenAndServe(":3001", r)

}

The code is working perfectly. I also removed the `return` from the functions which is unnecessary as we're passing a pointer around.