func ExampleServer_errorHandling() {
// Custom error handling:
//
// Every Router can have its own error handler. In this example
// a custom error handler is set on the API sub router to handler
// all errors occured on the /api route.
//
// Note: it is also possible to overwrite the default error handler of
// the server.
server := goserv.NewServer()
server.Get("/error", func(w http.ResponseWriter, r *http.Request) {
err := fmt.Errorf("a server error")
goserv.Context(r).Error(err, http.StatusInternalServerError)
})
api := server.SubRouter("/api")
api.Get("/error", func(w http.ResponseWriter, r *http.Request) {
err := fmt.Errorf("a API error")
goserv.Context(r).Error(err, http.StatusInternalServerError)
})
// Handle errors occured on the API router.
api.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err *goserv.ContextError) {
log.Printf("API Error: %s", err)
w.WriteHeader(err.Code)
goserv.WriteString(w, err.String())
}
log.Fatalln(server.Listen(":12345"))
}
func ExampleServer_parameters() {
// Use URL parameters:
//
// URL parameters can be specified by prefixing the name with a ":" in the handler path.
// The captured value can be retrieved from the RequestContext using the .Param method and
// the parameter's name.
//
// Servers and Routers both support parameter handlers which can be added using the
// .Param method, i.e. server.Param(...). The first argument is the name of the parameter
// (without the leading ":"). The parameter handlers are always invoked once before
// the request handlers get invoked.
//
server := goserv.NewServer()
// This route captures a single URL parameter named "resource_id".
server.Get("/resource/:resource_id", func(w http.ResponseWriter, r *http.Request) {
id := goserv.Context(r).Param("resource_id")
goserv.WriteStringf(w, "Requested resource: %s", id)
})
// Registers a parameter handler for the "resource_id" parameter.
server.Param("resource_id", func(w http.ResponseWriter, r *http.Request, id string) {
// Some sort of validation.
if len(id) < 12 {
goserv.Context(r).Error(fmt.Errorf("Invalid id"), http.StatusBadRequest)
return
}
log.Printf("Requesting resource: %s", id)
})
log.Fatalln(server.Listen(":12345"))
}
func ExampleServer_context() {
// Share data between handlers:
//
// The middleware stores a shared value in the RequestContext under the name "shared".
// The GET handler is the next handler in line and retrieves the value from the
// context. Since a RequestContext can store arbitrary types a type assertion
// is necessary to get the value in it's real type.
server := goserv.NewServer()
server.Use(func(w http.ResponseWriter, r *http.Request) {
goserv.Context(r).Set("shared", "something to share")
})
server.Get("/", func(w http.ResponseWriter, r *http.Request) {
shared := goserv.Context(r).Get("shared").(string)
goserv.WriteString(w, shared)
})
log.Fatalln(server.Listen(":12345"))
}
func ExampleServer_json() {
// Example server showing how to read and write JSON body:
//
// Since WriteJSON and ReadJSONBody are based on the encoding/json
// package of the standard library the usage is very similar.
// One thing to notice is that occuring errors are passed to
// the RequestContext which stops further processing and passes
// the error to the server's error handler.
server := goserv.NewServer()
// Send a simple JSON response.
server.Get("/", func(w http.ResponseWriter, r *http.Request) {
// JSON data to send.
data := &struct{ Title string }{"My First Todo"}
// Try to write the data.
// In case of an error pass it to the RequestContext
// so it gets forwarded to the next error handler.
if err := goserv.WriteJSON(w, data); err != nil {
goserv.Context(r).Error(err, http.StatusInternalServerError)
return
}
})
// Handle send JSON data.
server.Post("/", func(w http.ResponseWriter, r *http.Request) {
var data struct{ Title string }
// Read and decode the request's body.
// In case of an error pass it to the RequestContext
// so it gets forwarded to the next error handler.
if err := goserv.ReadJSONBody(r, &data); err != nil {
goserv.Context(r).Error(err, http.StatusBadRequest)
return
}
log.Println(data)
})
log.Fatalln(server.Listen(":12345"))
}