WebGo v4.1.3
WebGo is a minimalistic framework for Go to build web applications (server side) with zero 3rd party dependencies. Unlike full-fledged frameworks, it gets out of your way as soon as possible in the execution flow. WebGo has always been and will always be Go standard library compliant; with the HTTP handlers having the same signature as http.HandlerFunc.
Important
❗
-
Regression introduced in
v4.0.4, exists onv4.0.6as well. Requests panic when not using Webgo's response methods (e.g. R200, Send, SendResponse etc.) because the default HTTP status is set as 0 -
ContextPayload.URIParams(*http.Request)map[string]stringwas replaced despite being newly introduced in v3.5.4. The new function isContextPayload.Params()map[string]string, and has a slight performance advantage compared to URIParams
Index
Router
The router is one of the most important component of a web application. It helps identify the HTTP requests and pass them on to respective handlers. A handler is identified using a URI. WebGo supports defining URIs with the following patterns
/api/users- Static URI pattern with no variables
/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
- URI pattern with variable
/api/users/:misc*- Named URI variable
misc - This matches everything after
/api/users. e.g./api/users/a/b/c/d
- Named URI variable
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{
// A name for the API (preferrably unique)
Name string
// HTTP verb, i.e. GET, POST, PUT, PATCH, HEAD, DELETE
Method string
// The URI pattern
Pattern string
// If the URI ends with a '/', should it be considered valid or not? e.g. '/api/users' vs '/api/users/'
TrailingSlash bool
// In case of chained handlers, should the execution continue after one of the handlers have
// responded to the HTTP request
FallThroughPostResponse bool
// The list of HTTP handlers
Handlers []http.HandlerFunc
}
You can access named parameters of the URI 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 handler has written a response to the http request. 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, middleware applies to all the handlers. All middleware should be of type Middlware. The router exposes a method Use && UseOnSpecialHandlers to add a Middleware to the router. Following code shows how a middleware can be used in WebGo.
import (
"github.com/bnkamalesh/webgo/v4"
"github.com/bnkamalesh/webgo/v4/middleware"
)
func routes() []*webgo.Route {
return []*webgo.Route{
&webo.Route{
Name: "home",
Method: http.http.MethodGet,
Pattern: "/",
Handlers: []http.HandlerFunc{
func(w http.ResponseWriter, r *http.Request) {
webgo.R200(w, "home")
}
},
},
}
}
func main() {
router := webgo.NewRouter(*webgo.Config{
Host: "",
Port: "8080",
ReadTimeout: 15 * time.Second,
WriteTimeout: 60 * time.Second,
}, routes())
router.UseOnSpecialHandlers(middleware.AccessLog)
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.
- ResponseStatus(w http.ResponseWriter) get the HTTP status code from response writer
- SendHeader(w http.ResponseWriter, rCode int) - Send only an HTTP response header with the provided response code.
- Send(w http.ResponseWriter, contentType string, data interface{}, rCode int) - Send any response as is, with the provided content type and response code
- SendResponse(w http.ResponseWriter, data interface{}, rCode int) - Send a JSON response wrapped in WebGo's default response struct.
- SendError(w http.ResponseWriter, data interface{}, rCode int) - Send a JSON response wrapped in WebGo's default error response struct
- 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 serialized 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 serialzied 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 HTTPS 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 scoped 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{})
}
Configuring the default Logger
The default logger uses Go standard library's log.Logger with os.Stdout (for debug and info logs) & os.Stderr (for warning, error, fatal) as default io.Writers. You can set the io.Writer as well as disable specific types of logs using the GlobalLoggerConfig(stdout, stderr, cfgs...) function.
GlobalLoggerConfig(nil, nil, LogCfgDisableDebug, LogCfgDisableInfo...)
Usage is shown in cmd/main.go.
Usage
A fully functional sample is provided here. You can try the following API calls with the sample app.
http://localhost:8080/- Route with no named parameters configured
http://localhost:8080/matchall/- Route with wildcard parameter configured
- All URIs which begin with
/matchallwill be matched because it has a wildcard variable - e.g.
- `http://localhost:8080/api/
- Route with a named 'param' configured
- It will match all requests which match
/api/<single parameter> - e.g.
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 2020/06/03 12:55:26 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 2020/06/03 12:55:26 HTTP server, listening on :8080
Contributing
Refer here to find out details about making a contribution
Credits
Thanks to all the contributors
The gopher
The gopher used here was created using Gopherize.me. WebGo stays out of developers' way, so sitback and enjoy a cup of coffee like this gopher.
