github.com/bnkamalesh/webgo/v2

WebGo v2.5.1

WebGo is a minimalistic framework for Go to build web applications (server side). Unlike full-fledged frameworks out there, it tries to get out of the developers' way as soon as possible. It has always been and will always be Go standard library compliant. With the HTTP handlers having the same signature as http.HandlerFunc.

WebGo provides the following features/capabilities

1. Multiplexer
2. Handler chaining
3. Middleware
4. Helper functions
5. HTTPS ready
6. Graceful shutdown
7. Logging
8. Sample

Multiplexer

The multiplexer/router is one of the most important component of a web application. It helps identifying HTTP requests and pass them on to respective handlers. A handler is uniquely identified using a URI. WebGo supports defining URIs with the following patterns

1. /api/users
   • URI pattern with no variables
2. /api/users/:userID
   • URI pattern with variable userID (named URI parameter)
   • This will not match /api/users/johndoe/account. It only matches till /api/users/johndoe/
     • If TrailingSlash is set to true, refer to sample
3. /api/users/:misc*
   • Named URI variable misc
   • This matches everything after /api/users

If multiple patterns match the same URI, the first matching handler would be executed. Refer to the sample to see how routes are configured. A WebGo Route is defined as following:

webgo.Route{
	Name string
	Method string
	Pattern string
	TrailingSlash bool
	FallThroughPostResponse bool
	Handlers []http.HandlerFunc
}

You can access the URI named parameters using the Context function.

func helloWorld(w http.ResponseWriter, r *http.Request) {
	// WebGo context
	wctx := webgo.Context(r)
	// URI paramaters, map[string]string
	params := wctx.Params
	// route, the webgo.Route which is executing this request
	route := wctx.Route
	webgo.R200(
		w,
		fmt.Sprintf(
			"Route name: '%s', params: '%s'", 
			route.Name,
			params, 
			),
	)
}

Handler chaining

Handler chaining lets you execute multiple handlers for a given route. Execution of a chain can be configured to run even after a previous handler has written a response to the http response. This is made possible by setting FallThroughPostResponse to true (refer sample).

webgo.Route{
	Name: "chained",
	Method: http.MethodGet,
	Pattern: "/api",
	TrailingSlash: false,
	FallThroughPostResponse: true,
	Handlers []http.HandlerFunc{
		handler1,
		handler2,
		.
		.
		.
	}
}

Middleware

WebGo middleware lets you wrap all the routes with a middleware. Unlike handler chaining, applies to the whole router. All middlewares should be of type Middlware. The router exposes a method Use to add a Middleware the to the router. Following code shows how a middleware can be used in WebGo.

import (
	"github.com/bnkamalesh/webgo"
	"github.com/bnkamalesh/webgo/middleware"
)

func routes() []*webgo.Route {
	return []*webgo.Route{
		&webo.Route{
			Name: "home",
			Pattern: "/",
			Handlers: []http.HandlerFunc{
				func(w http.ResponseWriter, r *http.Request) {
					webgo.R200(w, "home")
				}
			},
		},
	}
}

func main() {
	router := webgo.NewRouter(*webgo.Config, routes())
	router.Use(middleware.AccessLog)
	router.Start()
}

Any number of middleware can be added to the router, the order of execution of middleware would be LIFO (Last In First Out). i.e. in case of the following code

func main() {
	router.Use(middleware.AccessLog)
	router.Use(middleware.CorsWrap())
}

CorsWrap would be executed first, followed by AccessLog.

Helper functions

WebGo provides a few helper functions.

1. SendHeader(w http.ResponseWriter, rCode int) - Send only an HTTP response header with the provided response code.
2. Send(w http.ResponseWriter, contentType string, data interface{}, rCode int) - Send any response as is, with the provided content type and response code
3. SendResponse(w http.ResponseWriter, data interface{}, rCode int) - Send a JSON response wrapped in WebGo's default response struct.
4. SendError(w http.ResponseWriter, data interface{}, rCode int) - Send a JSON response wrapped in WebGo's default error response struct
5. Render(w http.ResponseWriter, data interface{}, rCode int, tpl *template.Template) - Render renders a Go template, with the provided data & response code.

Few more helper functions are available, you can check them here.

When using Send or SendResponse, the response is wrapped in WebGo's response struct and is sent as JSON.

{
	"data": "<any valid JSON payload>",
	"status": "<HTTP status code, of type integer>"
}

When using SendError, the response is wrapped in WebGo's error response struct and is sent as JSON.

{
	"errors": "<any valid JSON payload>",
	"status": "<HTTP status code, of type integer>"
}

HTTPS ready

HTTPS server can be started easily, by providing the key & cert file. You can also have both HTTP & HTTPS servers running side by side.

Start HTTPS server

cfg := &webgo.Config{
	Port: "80",
	HTTPSPort: "443",
	CertFile: "/path/to/certfile",
	KeyFile: "/path/to/keyfile",
}
router := webgo.NewRouter(cfg, routes())
router.StartHTTPS()

Starting both HTTP & HTTPS server

cfg := &webgo.Config{
	Port: "80",
	HTTPSPort: "443",
	CertFile: "/path/to/certfile",
	KeyFile: "/path/to/keyfile",
}

router := webgo.NewRouter(cfg, routes())
go router.StartHTTPS()
router.Start()

Graceful shutdown

Graceful shutdown lets you shutdown the server without affecting any live connections/clients connected to the server. It will complete executing all the active/live requests before shutting down.

Sample code to show how to use shutdown

func main() {
	osSig := make(chan os.Signal, 5)

	cfg := &webgo.Config{
		Host:            "",
		Port:            "8080",
		ReadTimeout:     15 * time.Second,
		WriteTimeout:    60 * time.Second,
		ShutdownTimeout: 15 * time.Second,
	}
	router := webgo.NewRouter(cfg, routes())

	go func() {
		<-osSig
		// Initiate HTTP server shutdown
		err := router.Shutdown()
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		} else {
			fmt.Println("shutdown complete")
			os.Exit(0)
		}

		// If you have HTTP server running, you can use the following code
		// err := router.ShutdownHTTPS()
		// if err != nil {
		// 	fmt.Println(err)
		// 	os.Exit(1)
		// } else {
		// 	fmt.Println("shutdown complete")
		// 	os.Exit(0)
		// }
	}()

	signal.Notify(osSig, os.Interrupt, syscall.SIGTERM)

	router.Start()

	for {
		// Prevent main thread from exiting, and wait for shutdown to complete
		time.Sleep(time.Second * 1)
	}
}

Logging

WebGo exposes a singleton+global logger variable LOGHANDLER with which you can plugin your custom logger. Any custom logger should implement WebGo's Logger interface.

type Logger interface {
    Debug(data ...interface{})
    Info(data ...interface{})
    Warn(data ...interface{})
    Error(data ...interface{})
    Fatal(data ...interface{})
}

Sample

A fully functional sample is provided here. You can try the following API calls with the sample app.

1. http://localhost:8080/
   • Route with no named parameters configured
2. http://localhost:8080/matchall/
   • Route with wildcard parameter configured
   • All URIs which begin with /matchall will be matched because it has a wildcard variable
   • e.g.
     • http://localhost:8080/matchall/hello
     • http://localhost:8080/matchall/hello/world
     • http://localhost:8080/matchall/hello/world/user
3. `http://localhost:8080/api/
   • Route with a named 'param' configured
   • It will match all requests which match /api/<single parameter>
   • e.g.
     • http://localhost:8080/api/hello
     • http://localhost:8080/api/world

How to run the sample

If you have Go installed on your system, open your terminal and:

$ cd $GOPATH/src
$ mkdir -p github.com/bnkamalesh
$ cd github.com/bnkamalesh
$ git clone https://github.com/bnkamalesh/webgo.git
$ cd webgo
$ go run cmd/main.go

Info 2019/07/09 18:35:54 HTTP server, listening on :8080

Or if you have Docker, open your terminal and:

$ git clone https://github.com/bnkamalesh/webgo.git
$ cd webgo
$ docker run \
-p 8080:8080 \
-v ${PWD}:/go/src/github.com/bnkamalesh/webgo/ \
-w /go/src/github.com/bnkamalesh/webgo/cmd \
--rm -ti golang:latest go run main.go

Info 2019/07/09 18:35:54 HTTP server, listening on :8080

The gopher

The gopher used here was created using Gopherize.me. WebGo stays out of developers' way, and they can sitback and enjoy a cup of coffee just like this gopher, while using WebGo.