This is a creation in Article, where the information may have evolved or changed. Hello, today I would like to share, in the ' Go ' language in series HTTP processor. Before using go, I used Nodejs + [EXPRESSJS] (http://expressjs.com/en/4x/api.html) to write an HTTP server application. This framework provides a very simple way to use middleware and concatenate many routing nodes, so you do not have to specify a full routing path to add handlers for it. [Figure 1] (https://raw.githubusercontent.com/studygolang/gctt-images/master/chain-http-hanlders/1.png) The idea is to split your route and process each part, concatenation to the processor, and each handler is only responsible for a portion. It's very simple to understand and very easy to use and maintain, so first I try to do something similar in Go. Out of the box, Go provides a great [http] (HTTPS://GOLANG.ORG/PKG/NET/HTTP) package that contains many different tools and, of course, [' Listenandserve '] (https://golang.org /pkg/net/http/#ListenAndServe) method, which initiates an HTTP server on a given port and passes the [' Handler '] (https://golang.org/pkg/net/http/#Handler To deal with it, what is this [' Handler '] (https://golang.org/pkg/net/http/#Handler)? "' Gotype Handler Interface {servehttp (responsewriter,*request)} ' [' Handler '] (https://golang.org/pkg/net/http/# Handler) is an interface that has a method-servehttp to process incoming requests and output responses. But what if we want to define a handler for each root route, such as/api/,/home,/about, and so on? [' Servemux '] (https://golang.org/pkg/net/http/#ServeMux)-An HTTP request multiplexer that can help you deal with this point. Use [' Servemux '] (https://golang.org/pkg/net/http/#ServeMux), we can specify the processor method to service any given route, but the problem is that we cannot do any nested [' Servemux '] (https://golang.org/pkg/net/ http/#ServeMux). The example in the document: "' Gomux: = http. Newservemux () Mux. Handle ("/api/", apihandler{}) mux. Handlefunc ("/", Func (w http.) Responsewriter, req *http. Request) {//the '/' pattern matches everything, so we need-check//that we ' re at the root here.if req. Url. Path! = "/" {http. NotFound (W, req) return}fmt. fprintf (W, "Welcome to the Home page!")}) "We can see that in this example a processor was customized for the '/api/' route and a processing method was defined for the root route. Therefore any route that begins with '/api/* ' will use the Apihandler processor method. But if we need to concatenate a usershandler to Apihandler, without any brainstorming or coding, we can't do that. For this I wrote a small library-[Gosplitter] (Https://github.com/goncharovnikita/gosplitter), which only provides a common method of ' Match (URL string, Mux *http. Servemux, http. Handler|http. handlerfunc|interface{}) '-he matches the given route part and processor, processing method or any structure you given! Let's take a look at an example: "go/** * defines a processor type */type apiv1handler struct {mux *http. Servemux}type colorshandler struct {mux *http. servemux}/** * Start-bind parent to Child */func (a *apiv1handler) Start () {var ColorshandlER = colorshandler{mux:a.mux,}gosplitter. Match ("/ping", A.mux, A.handleping ()) Gosplitter. Match ("/colors", A.mux, Colorshandler) Colorshandler.start ()}func (c *colorshandler) Start () {gosplitter. Match ("/black", C.mux, C.handleblack ())}/** * Simple HTTP Processor Method */func (a *apiv1handler) handleping () func (w http). Responsewriter, R *http. Request) {return func (w http. Responsewriter, R *http. Request) {W.write ([]byte ("Pong"))}}func (c *colorshandler) Handleblack () func (w http. Responsewriter, R *http. Request) {return func (w http. Responsewriter, R *http. Request) {W.write ([]byte ("#000000"))}}func main () {var mux = http. Newservemux () var apiV1 = Apiv1handler{mux:mux,}/** * Binds the API processor to the root directory */Gosplitter. Match ("/api/v1", Mux, apiV1)/** * Start API Processing */Apiv1.start ()} "" For example: "go/** * defines processor type */type apiv1handler struct {mux *h Ttp. Servemux}type colorshandler struct {mux *http. Servemux} ' ' Here we define a processor, it is a struct ' go/** * Start-Bind API processor to root directory */func (a *apiv1handler) Start () {var colorshandler = C Olorshandler{Mux:a.mux,}gosplitter. Match ("/ping", A.mux, A.handleping ()) Gosplitter. Match ("/colors", A.mux, Colorshandler) Colorshandler.start ()}func (c *colorshandler) Start () {gosplitter. Match ("/black", C.mux, C.handleblack ())} ' Add a ' Start ' method to our processor program, go to activate processing method ' go/** * Simple HTTP Processor Method */func (A * Apiv1handler) handleping () func (w http. Responsewriter, R *http. Request) {return func (w http. Responsewriter, R *http. Request) {W.write ([]byte ("Pong"))}}func (c *colorshandler) Handleblack () func (w http. Responsewriter, R *http. Request) {return func (w http. Responsewriter, R *http. Request) {W.write ([]byte ("#000000")}} "" Adds ' handleping ' and ' handleblack ' to our ' apiv1handler ', which responds to ' Pong ' and ' #000000 ' Gofunc Main () {var mux = http. Newservemux () var apiV1 = apiv1handler{mux:mux,}/** * Binds the API processor to the root route */gosplitter. Match ("/api/v1", Mux, apiV1)/** * Start API Processor */apiv1.start ()} "" We created a new ' Servemux ' in the ' main ' method and then created an instance of ' Apiv1handler ' , bind it to the '/api/v1 ' route, and then start it. So after all these simple operations we have two routes in work: '/api/v1/ping ' and '/api/v1/cOlors/black ', will respond to ' pong ' and ' #000000 '. Isn't it easy to use? I think so, now use this library in my project for easy routing and concatenation of processors:) <!--Thanks for reading! Any suggestions and critiques is welcome! -Thank you for reading, and you are welcome to make any suggestions and criticisms!
via:https://medium.com/@cashalot/how-to-chain-http-handlers-in-go-33c96396b397
Author: Nikita Translator: Marlonfan proofreading: Rxcai
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