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Diffstat (limited to 'vendor/github.com/gorilla/mux/README.md')
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1 files changed, 355 insertions, 97 deletions
diff --git a/vendor/github.com/gorilla/mux/README.md b/vendor/github.com/gorilla/mux/README.md index b096bf6..e424397 100644 --- a/vendor/github.com/gorilla/mux/README.md +++ b/vendor/github.com/gorilla/mux/README.md @@ -1,5 +1,5 @@ -gorilla/mux -=== +# gorilla/mux + [](https://godoc.org/github.com/gorilla/mux) [](https://travis-ci.org/gorilla/mux) [](https://sourcegraph.com/github.com/gorilla/mux?badge) @@ -27,6 +27,9 @@ The name mux stands for "HTTP request multiplexer". Like the standard `http.Serv * [Static Files](#static-files) * [Registered URLs](#registered-urls) * [Walking Routes](#walking-routes) +* [Graceful Shutdown](#graceful-shutdown) +* [Middleware](#middleware) +* [Testing Handlers](#testing-handlers) * [Full Example](#full-example) --- @@ -45,11 +48,11 @@ 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) + r := mux.NewRouter() + r.HandleFunc("/", HomeHandler) + r.HandleFunc("/products", ProductsHandler) + r.HandleFunc("/articles", ArticlesHandler) + http.Handle("/", r) } ``` @@ -68,9 +71,9 @@ The names are used to create a map of route variables which can be retrieved cal ```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"]) + vars := mux.Vars(r) + w.WriteHeader(http.StatusOK) + fmt.Fprintf(w, "Category: %v\n", vars["category"]) } ``` @@ -122,7 +125,7 @@ r.Queries("key", "value") ```go r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool { - return r.ProtoMajor == 0 + return r.ProtoMajor == 0 }) ``` @@ -176,79 +179,34 @@ 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" - "strings" - - "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).Methods("POST") - r.HandleFunc("/articles", handler).Methods("GET") - r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT") - r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error { - t, err := route.GetPathTemplate() - if err != nil { - return err - } - // p will contain regular expression is compatible with regular expression in Perl, Python, and other languages. - // for instance the regular expression for path '/articles/{id}' will be '^/articles/(?P<v0>[^/]+)$' - p, err := route.GetPathRegexp() - if err != nil { - return err - } - m, err := route.GetMethods() - if err != nil { - return err - } - fmt.Println(strings.Join(m, ","), t, p) - 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: +request that matches "/static/\*". This makes it easy to serve static files with mux: ```go func main() { - var dir string + var dir string - flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir") - flag.Parse() - r := mux.NewRouter() + 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)))) + // 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, - } + 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()) + log.Fatal(srv.ListenAndServe()) } ``` @@ -334,29 +292,329 @@ The `Walk` function on `mux.Router` can be used to visit all of the routes that the following prints all of the registered routes: ```go +package main + +import ( + "fmt" + "net/http" + "strings" + + "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).Methods("POST") + r.HandleFunc("/articles", handler).Methods("GET") + r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT") + r.HandleFunc("/authors", handler).Queries("surname", "{surname}") + err := r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error { + pathTemplate, err := route.GetPathTemplate() + if err == nil { + fmt.Println("ROUTE:", pathTemplate) + } + pathRegexp, err := route.GetPathRegexp() + if err == nil { + fmt.Println("Path regexp:", pathRegexp) + } + queriesTemplates, err := route.GetQueriesTemplates() + if err == nil { + fmt.Println("Queries templates:", strings.Join(queriesTemplates, ",")) + } + queriesRegexps, err := route.GetQueriesRegexp() + if err == nil { + fmt.Println("Queries regexps:", strings.Join(queriesRegexps, ",")) + } + methods, err := route.GetMethods() + if err == nil { + fmt.Println("Methods:", strings.Join(methods, ",")) + } + fmt.Println() + return nil + }) + + if err != nil { + fmt.Println(err) + } + + http.Handle("/", r) +} +``` + +### Graceful Shutdown + +Go 1.8 introduced the ability to [gracefully shutdown](https://golang.org/doc/go1.8#http_shutdown) a `*http.Server`. Here's how to do that alongside `mux`: + +```go +package main + +import ( + "context" + "flag" + "log" + "net/http" + "os" + "os/signal" + "time" + + "github.com/gorilla/mux" +) + +func main() { + var wait time.Duration + flag.DurationVar(&wait, "graceful-timeout", time.Second * 15, "the duration for which the server gracefully wait for existing connections to finish - e.g. 15s or 1m") + flag.Parse() + + r := mux.NewRouter() + // Add your routes as needed + + srv := &http.Server{ + Addr: "0.0.0.0:8080", + // Good practice to set timeouts to avoid Slowloris attacks. + WriteTimeout: time.Second * 15, + ReadTimeout: time.Second * 15, + IdleTimeout: time.Second * 60, + Handler: r, // Pass our instance of gorilla/mux in. + } + + // Run our server in a goroutine so that it doesn't block. + go func() { + if err := srv.ListenAndServe(); err != nil { + log.Println(err) + } + }() + + c := make(chan os.Signal, 1) + // We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C) + // SIGKILL, SIGQUIT or SIGTERM (Ctrl+/) will not be caught. + signal.Notify(c, os.Interrupt) + + // Block until we receive our signal. + <-c + + // Create a deadline to wait for. + ctx, cancel := context.WithTimeout(context.Background(), wait) + defer cancel() + // Doesn't block if no connections, but will otherwise wait + // until the timeout deadline. + srv.Shutdown(ctx) + // Optionally, you could run srv.Shutdown in a goroutine and block on + // <-ctx.Done() if your application should wait for other services + // to finalize based on context cancellation. + log.Println("shutting down") + os.Exit(0) +} +``` + +### Middleware + +Mux supports the addition of middlewares to a [Router](https://godoc.org/github.com/gorilla/mux#Router), which are executed in the order they are added if a match is found, including its subrouters. +Middlewares are (typically) small pieces of code which take one request, do something with it, and pass it down to another middleware or the final handler. Some common use cases for middleware are request logging, header manipulation, or `ResponseWriter` hijacking. + +Mux middlewares are defined using the de facto standard type: + +```go +type MiddlewareFunc func(http.Handler) http.Handler +``` + +Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed to it, and then calls the handler passed as parameter to the MiddlewareFunc. This takes advantage of closures being able access variables from the context where they are created, while retaining the signature enforced by the receivers. + +A very basic middleware which logs the URI of the request being handled could be written as: + +```go +func loggingMiddleware(next http.Handler) http.Handler { + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + // Do stuff here + log.Println(r.RequestURI) + // Call the next handler, which can be another middleware in the chain, or the final handler. + next.ServeHTTP(w, r) + }) +} +``` + +Middlewares can be added to a router using `Router.Use()`: + +```go +r := mux.NewRouter() +r.HandleFunc("/", handler) +r.Use(loggingMiddleware) +``` + +A more complex authentication middleware, which maps session token to users, could be written as: + +```go +// Define our struct +type authenticationMiddleware struct { + tokenUsers map[string]string +} + +// Initialize it somewhere +func (amw *authenticationMiddleware) Populate() { + amw.tokenUsers["00000000"] = "user0" + amw.tokenUsers["aaaaaaaa"] = "userA" + amw.tokenUsers["05f717e5"] = "randomUser" + amw.tokenUsers["deadbeef"] = "user0" +} + +// Middleware function, which will be called for each request +func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler { + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + token := r.Header.Get("X-Session-Token") + + if user, found := amw.tokenUsers[token]; found { + // We found the token in our map + log.Printf("Authenticated user %s\n", user) + // Pass down the request to the next middleware (or final handler) + next.ServeHTTP(w, r) + } else { + // Write an error and stop the handler chain + http.Error(w, "Forbidden", http.StatusForbidden) + } + }) +} +``` + +```go r := mux.NewRouter() r.HandleFunc("/", handler) -r.HandleFunc("/products", handler).Methods("POST") -r.HandleFunc("/articles", handler).Methods("GET") -r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT") -r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error { - t, err := route.GetPathTemplate() + +amw := authenticationMiddleware{} +amw.Populate() + +r.Use(amw.Middleware) +``` + +Note: The handler chain will be stopped if your middleware doesn't call `next.ServeHTTP()` with the corresponding parameters. This can be used to abort a request if the middleware writer wants to. Middlewares _should_ write to `ResponseWriter` if they _are_ going to terminate the request, and they _should not_ write to `ResponseWriter` if they _are not_ going to terminate it. + +### Testing Handlers + +Testing handlers in a Go web application is straightforward, and _mux_ doesn't complicate this any further. Given two files: `endpoints.go` and `endpoints_test.go`, here's how we'd test an application using _mux_. + +First, our simple HTTP handler: + +```go +// endpoints.go +package main + +func HealthCheckHandler(w http.ResponseWriter, r *http.Request) { + // A very simple health check. + w.WriteHeader(http.StatusOK) + w.Header().Set("Content-Type", "application/json") + + // In the future we could report back on the status of our DB, or our cache + // (e.g. Redis) by performing a simple PING, and include them in the response. + io.WriteString(w, `{"alive": true}`) +} + +func main() { + r := mux.NewRouter() + r.HandleFunc("/health", HealthCheckHandler) + + log.Fatal(http.ListenAndServe("localhost:8080", r)) +} +``` + +Our test code: + +```go +// endpoints_test.go +package main + +import ( + "net/http" + "net/http/httptest" + "testing" +) + +func TestHealthCheckHandler(t *testing.T) { + // Create a request to pass to our handler. We don't have any query parameters for now, so we'll + // pass 'nil' as the third parameter. + req, err := http.NewRequest("GET", "/health", nil) if err != nil { - return err + t.Fatal(err) } - // p will contain a regular expression that is compatible with regular expressions in Perl, Python, and other languages. - // For example, the regular expression for path '/articles/{id}' will be '^/articles/(?P<v0>[^/]+)$'. - p, err := route.GetPathRegexp() - if err != nil { - return err + + // We create a ResponseRecorder (which satisfies http.ResponseWriter) to record the response. + rr := httptest.NewRecorder() + handler := http.HandlerFunc(HealthCheckHandler) + + // Our handlers satisfy http.Handler, so we can call their ServeHTTP method + // directly and pass in our Request and ResponseRecorder. + handler.ServeHTTP(rr, req) + + // Check the status code is what we expect. + if status := rr.Code; status != http.StatusOK { + t.Errorf("handler returned wrong status code: got %v want %v", + status, http.StatusOK) } - m, err := route.GetMethods() - if err != nil { - return err + + // Check the response body is what we expect. + expected := `{"alive": true}` + if rr.Body.String() != expected { + t.Errorf("handler returned unexpected body: got %v want %v", + rr.Body.String(), expected) } - fmt.Println(strings.Join(m, ","), t, p) - return nil -}) +} +``` + +In the case that our routes have [variables](#examples), we can pass those in the request. We could write +[table-driven tests](https://dave.cheney.net/2013/06/09/writing-table-driven-tests-in-go) to test multiple +possible route variables as needed. + +```go +// endpoints.go +func main() { + r := mux.NewRouter() + // A route with a route variable: + r.HandleFunc("/metrics/{type}", MetricsHandler) + + log.Fatal(http.ListenAndServe("localhost:8080", r)) +} +``` + +Our test file, with a table-driven test of `routeVariables`: + +```go +// endpoints_test.go +func TestMetricsHandler(t *testing.T) { + tt := []struct{ + routeVariable string + shouldPass bool + }{ + {"goroutines", true}, + {"heap", true}, + {"counters", true}, + {"queries", true}, + {"adhadaeqm3k", false}, + } + + for _, tc := range tt { + path := fmt.Sprintf("/metrics/%s", tc.routeVariable) + req, err := http.NewRequest("GET", path, nil) + if err != nil { + t.Fatal(err) + } + + rr := httptest.NewRecorder() + + // Need to create a router that we can pass the request through so that the vars will be added to the context + router := mux.NewRouter() + router.HandleFunc("/metrics/{type}", MetricsHandler) + router.ServeHTTP(rr, req) + + // In this case, our MetricsHandler returns a non-200 response + // for a route variable it doesn't know about. + if rr.Code == http.StatusOK && !tc.shouldPass { + t.Errorf("handler should have failed on routeVariable %s: got %v want %v", + tc.routeVariable, rr.Code, http.StatusOK) + } + } +} ``` ## Full Example @@ -367,22 +625,22 @@ Here's a complete, runnable example of a small `mux` based server: package main import ( - "net/http" - "log" - "github.com/gorilla/mux" + "net/http" + "log" + "github.com/gorilla/mux" ) func YourHandler(w http.ResponseWriter, r *http.Request) { - w.Write([]byte("Gorilla!\n")) + w.Write([]byte("Gorilla!\n")) } func main() { - r := mux.NewRouter() - // Routes consist of a path and a handler function. - r.HandleFunc("/", YourHandler) + 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)) + // Bind to a port and pass our router in + log.Fatal(http.ListenAndServe(":8000", r)) } ``` |