Added a Print function on router that prints routing paths

[markbates]

Very similar to using rake routes in Ruby on Rails, an application can use this print out a listing of the routes in their application.

Example application:

package main

import (
    "net/http"
    "os"

    "github.com/labstack/echo"
)

func main() {
    e := echo.New()

    e.Get("/foo", func(res http.ResponseWriter, req *http.Request) {})
    e.Put("/foo", func(res http.ResponseWriter, req *http.Request) {})
    e.Get("/foo/:id", func(res http.ResponseWriter, req *http.Request) {})
    e.Get("/bar/baz/:id", func(res http.ResponseWriter, req *http.Request) {})
    e.Get("/:controller/:action/:id", func(res http.ResponseWriter, req *http.Request) {})

    g := e.Group("/api/v1")
    g.Get("/users/:id", func(res http.ResponseWriter, req *http.Request) {})
    g.Get("/users/:id/edit", func(res http.ResponseWriter, req *http.Request) {})
    g.Post("/users/:id", func(res http.ResponseWriter, req *http.Request) {})

    e.Router.Print(os.Stdout)
}

Example output*:

GET /foo
    /foo/:id
    /bar/baz/:id
    /:controller/:action/:id
    /api/v1/users/:id
    /api/v1/users/:id/edit
POST    /api/v1/users/:id
PUT /foo

*please excuse the formatting on GitHub, it apparently doesn't care much for tabs.

[coveralls]

Coverage increased (+0.43%) to 89.82% when pulling d9c47b6 on markbates:print into 1e11762 on labstack:master.

[vishr]

@markbates We already have a data structure which holds all the routes. It is used by Echo.URI API. I will leverage from your code and expose an API. Let me know your thoughts.

[markbates]

Ultimately it would be great to have access to a simple version of the route information, like I have above. An API to gain access to that would be great so people can build middleware, and other extensions around it.

For example, had there an API for routes I would've written a handler that would generate this type of print out.

Another example would be to build route helpers, like you'd find in frameworks such as Rails e.g. generate the final href string given the name of the route and parameter values.