340 lines
10 KiB
Markdown
340 lines
10 KiB
Markdown
gorilla/mux
|
|
===
|
|
[](https://godoc.org/github.com/gorilla/mux)
|
|
[](https://travis-ci.org/gorilla/mux)
|
|
[](https://sourcegraph.com/github.com/gorilla/mux?badge)
|
|
|
|
|
|
|
|
http://www.gorillatoolkit.org/pkg/mux
|
|
|
|
Package `gorilla/mux` implements a request router and dispatcher for matching incoming requests to
|
|
their respective handler.
|
|
|
|
The name mux stands for "HTTP request multiplexer". Like the standard `http.ServeMux`, `mux.Router` matches incoming requests against a list of registered routes and calls a handler for the route that matches the URL or other conditions. The main features are:
|
|
|
|
* It implements the `http.Handler` interface so it is compatible with the standard `http.ServeMux`.
|
|
* Requests can be matched based on URL host, path, path prefix, schemes, header and query values, HTTP methods or using custom matchers.
|
|
* URL hosts and paths can have variables with an optional regular expression.
|
|
* Registered URLs can be built, or "reversed", which helps maintaining references to resources.
|
|
* Routes can be used as subrouters: nested routes are only tested if the parent route matches. This is useful to define groups of routes that share common conditions like a host, a path prefix or other repeated attributes. As a bonus, this optimizes request matching.
|
|
|
|
---
|
|
|
|
* [Install](#install)
|
|
* [Examples](#examples)
|
|
* [Matching Routes](#matching-routes)
|
|
* [Listing Routes](#listing-routes)
|
|
* [Static Files](#static-files)
|
|
* [Registered URLs](#registered-urls)
|
|
* [Full Example](#full-example)
|
|
|
|
---
|
|
|
|
## Install
|
|
|
|
With a [correctly configured](https://golang.org/doc/install#testing) Go toolchain:
|
|
|
|
```sh
|
|
go get -u github.com/gorilla/mux
|
|
```
|
|
|
|
## Examples
|
|
|
|
Let's start registering a couple of URL paths and handlers:
|
|
|
|
```go
|
|
func main() {
|
|
r := mux.NewRouter()
|
|
r.HandleFunc("/", HomeHandler)
|
|
r.HandleFunc("/products", ProductsHandler)
|
|
r.HandleFunc("/articles", ArticlesHandler)
|
|
http.Handle("/", r)
|
|
}
|
|
```
|
|
|
|
Here we register three routes mapping URL paths to handlers. This is equivalent to how `http.HandleFunc()` works: if an incoming request URL matches one of the paths, the corresponding handler is called passing (`http.ResponseWriter`, `*http.Request`) as parameters.
|
|
|
|
Paths can have variables. They are defined using the format `{name}` or `{name:pattern}`. If a regular expression pattern is not defined, the matched variable will be anything until the next slash. For example:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
r.HandleFunc("/products/{key}", ProductHandler)
|
|
r.HandleFunc("/articles/{category}/", ArticlesCategoryHandler)
|
|
r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler)
|
|
```
|
|
|
|
The names are used to create a map of route variables which can be retrieved calling `mux.Vars()`:
|
|
|
|
```go
|
|
func ArticlesCategoryHandler(w http.ResponseWriter, r *http.Request) {
|
|
vars := mux.Vars(r)
|
|
w.WriteHeader(http.StatusOK)
|
|
fmt.Fprintf(w, "Category: %v\n", vars["category"])
|
|
}
|
|
```
|
|
|
|
And this is all you need to know about the basic usage. More advanced options are explained below.
|
|
|
|
### Matching Routes
|
|
|
|
Routes can also be restricted to a domain or subdomain. Just define a host pattern to be matched. They can also have variables:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
// Only matches if domain is "www.example.com".
|
|
r.Host("www.example.com")
|
|
// Matches a dynamic subdomain.
|
|
r.Host("{subdomain:[a-z]+}.domain.com")
|
|
```
|
|
|
|
There are several other matchers that can be added. To match path prefixes:
|
|
|
|
```go
|
|
r.PathPrefix("/products/")
|
|
```
|
|
|
|
...or HTTP methods:
|
|
|
|
```go
|
|
r.Methods("GET", "POST")
|
|
```
|
|
|
|
...or URL schemes:
|
|
|
|
```go
|
|
r.Schemes("https")
|
|
```
|
|
|
|
...or header values:
|
|
|
|
```go
|
|
r.Headers("X-Requested-With", "XMLHttpRequest")
|
|
```
|
|
|
|
...or query values:
|
|
|
|
```go
|
|
r.Queries("key", "value")
|
|
```
|
|
|
|
...or to use a custom matcher function:
|
|
|
|
```go
|
|
r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool {
|
|
return r.ProtoMajor == 0
|
|
})
|
|
```
|
|
|
|
...and finally, it is possible to combine several matchers in a single route:
|
|
|
|
```go
|
|
r.HandleFunc("/products", ProductsHandler).
|
|
Host("www.example.com").
|
|
Methods("GET").
|
|
Schemes("http")
|
|
```
|
|
|
|
Setting the same matching conditions again and again can be boring, so we have a way to group several routes that share the same requirements. We call it "subrouting".
|
|
|
|
For example, let's say we have several URLs that should only match when the host is `www.example.com`. Create a route for that host and get a "subrouter" from it:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
s := r.Host("www.example.com").Subrouter()
|
|
```
|
|
|
|
Then register routes in the subrouter:
|
|
|
|
```go
|
|
s.HandleFunc("/products/", ProductsHandler)
|
|
s.HandleFunc("/products/{key}", ProductHandler)
|
|
s.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler)
|
|
```
|
|
|
|
The three URL paths we registered above will only be tested if the domain is `www.example.com`, because the subrouter is tested first. This is not only convenient, but also optimizes request matching. You can create subrouters combining any attribute matchers accepted by a route.
|
|
|
|
Subrouters can be used to create domain or path "namespaces": you define subrouters in a central place and then parts of the app can register its paths relatively to a given subrouter.
|
|
|
|
There's one more thing about subroutes. When a subrouter has a path prefix, the inner routes use it as base for their paths:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
s := r.PathPrefix("/products").Subrouter()
|
|
// "/products/"
|
|
s.HandleFunc("/", ProductsHandler)
|
|
// "/products/{key}/"
|
|
s.HandleFunc("/{key}/", ProductHandler)
|
|
// "/products/{key}/details"
|
|
s.HandleFunc("/{key}/details", ProductDetailsHandler)
|
|
```
|
|
|
|
### Listing Routes
|
|
|
|
Routes on a mux can be listed using the Router.Walk method—useful for generating documentation:
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"net/http"
|
|
|
|
"github.com/gorilla/mux"
|
|
)
|
|
|
|
func handler(w http.ResponseWriter, r *http.Request) {
|
|
return
|
|
}
|
|
|
|
func main() {
|
|
r := mux.NewRouter()
|
|
r.HandleFunc("/", handler)
|
|
r.HandleFunc("/products", handler)
|
|
r.HandleFunc("/articles", handler)
|
|
r.HandleFunc("/articles/{id}", handler)
|
|
r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
|
|
t, err := route.GetPathTemplate()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
fmt.Println(t)
|
|
return nil
|
|
})
|
|
http.Handle("/", r)
|
|
}
|
|
```
|
|
|
|
### Static Files
|
|
|
|
Note that the path provided to `PathPrefix()` represents a "wildcard": calling
|
|
`PathPrefix("/static/").Handler(...)` means that the handler will be passed any
|
|
request that matches "/static/*". This makes it easy to serve static files with mux:
|
|
|
|
```go
|
|
func main() {
|
|
var dir string
|
|
|
|
flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir")
|
|
flag.Parse()
|
|
r := mux.NewRouter()
|
|
|
|
// This will serve files under http://localhost:8000/static/<filename>
|
|
r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir))))
|
|
|
|
srv := &http.Server{
|
|
Handler: r,
|
|
Addr: "127.0.0.1:8000",
|
|
// Good practice: enforce timeouts for servers you create!
|
|
WriteTimeout: 15 * time.Second,
|
|
ReadTimeout: 15 * time.Second,
|
|
}
|
|
|
|
log.Fatal(srv.ListenAndServe())
|
|
}
|
|
```
|
|
|
|
### Registered URLs
|
|
|
|
Now let's see how to build registered URLs.
|
|
|
|
Routes can be named. All routes that define a name can have their URLs built, or "reversed". We define a name calling `Name()` on a route. For example:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler).
|
|
Name("article")
|
|
```
|
|
|
|
To build a URL, get the route and call the `URL()` method, passing a sequence of key/value pairs for the route variables. For the previous route, we would do:
|
|
|
|
```go
|
|
url, err := r.Get("article").URL("category", "technology", "id", "42")
|
|
```
|
|
|
|
...and the result will be a `url.URL` with the following path:
|
|
|
|
```
|
|
"/articles/technology/42"
|
|
```
|
|
|
|
This also works for host variables:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
r.Host("{subdomain}.domain.com").
|
|
Path("/articles/{category}/{id:[0-9]+}").
|
|
HandlerFunc(ArticleHandler).
|
|
Name("article")
|
|
|
|
// url.String() will be "http://news.domain.com/articles/technology/42"
|
|
url, err := r.Get("article").URL("subdomain", "news",
|
|
"category", "technology",
|
|
"id", "42")
|
|
```
|
|
|
|
All variables defined in the route are required, and their values must conform to the corresponding patterns. These requirements guarantee that a generated URL will always match a registered route -- the only exception is for explicitly defined "build-only" routes which never match.
|
|
|
|
Regex support also exists for matching Headers within a route. For example, we could do:
|
|
|
|
```go
|
|
r.HeadersRegexp("Content-Type", "application/(text|json)")
|
|
```
|
|
|
|
...and the route will match both requests with a Content-Type of `application/json` as well as `application/text`
|
|
|
|
There's also a way to build only the URL host or path for a route: use the methods `URLHost()` or `URLPath()` instead. For the previous route, we would do:
|
|
|
|
```go
|
|
// "http://news.domain.com/"
|
|
host, err := r.Get("article").URLHost("subdomain", "news")
|
|
|
|
// "/articles/technology/42"
|
|
path, err := r.Get("article").URLPath("category", "technology", "id", "42")
|
|
```
|
|
|
|
And if you use subrouters, host and path defined separately can be built as well:
|
|
|
|
```go
|
|
r := mux.NewRouter()
|
|
s := r.Host("{subdomain}.domain.com").Subrouter()
|
|
s.Path("/articles/{category}/{id:[0-9]+}").
|
|
HandlerFunc(ArticleHandler).
|
|
Name("article")
|
|
|
|
// "http://news.domain.com/articles/technology/42"
|
|
url, err := r.Get("article").URL("subdomain", "news",
|
|
"category", "technology",
|
|
"id", "42")
|
|
```
|
|
|
|
## Full Example
|
|
|
|
Here's a complete, runnable example of a small `mux` based server:
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"net/http"
|
|
"log"
|
|
"github.com/gorilla/mux"
|
|
)
|
|
|
|
func YourHandler(w http.ResponseWriter, r *http.Request) {
|
|
w.Write([]byte("Gorilla!\n"))
|
|
}
|
|
|
|
func main() {
|
|
r := mux.NewRouter()
|
|
// Routes consist of a path and a handler function.
|
|
r.HandleFunc("/", YourHandler)
|
|
|
|
// Bind to a port and pass our router in
|
|
log.Fatal(http.ListenAndServe(":8000", r))
|
|
}
|
|
```
|
|
|
|
## License
|
|
|
|
BSD licensed. See the LICENSE file for details.
|