Merging other languages
This commit is contained in:
James Miranda
534
en/13.2.md
534
en/13.2.md
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# 13.2 自定义路由器设计
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## HTTP路由
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HTTP路由组件负责将HTTP请求交到对应的函数处理(或者是一个struct的方法)，如前面小节所描述的结构图，路由在框架中相当于一个事件处理器，而这个事件包括：
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- 用户请求的路径(path)(例如:/user/123,/article/123)，当然还有查询串信息(例如?id=11)
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- HTTP的请求方法(method)(GET、POST、PUT、DELETE、PATCH等)
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路由器就是根据用户请求的事件信息转发到相应的处理函数(控制层)。
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## 默认的路由实现
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在3.4小节有过介绍Go的http包的详解，里面介绍了Go的http包如何设计和实现路由，这里继续以一个例子来说明：
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func fooHandler(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
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}
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http.HandleFunc("/foo", fooHandler)
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http.HandleFunc("/bar", func(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
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})
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log.Fatal(http.ListenAndServe(":8080", nil))
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上面的例子调用了http默认的DefaultServeMux来添加路由，需要提供两个参数，第一个参数是希望用户访问此资源的URL路径(保存在r.URL.Path)，第二参数是即将要执行的函数，以提供用户访问的资源。路由的思路主要集中在两点：
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- 添加路由信息
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- 根据用户请求转发到要执行的函数
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Go默认的路由添加是通过函数`http.Handle`和`http.HandleFunc`等来添加，底层都是调用了`DefaultServeMux.Handle(pattern string, handler Handler)`,这个函数会把路由信息存储在一个map信息中`map[string]muxEntry`，这就解决了上面说的第一点。
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Go监听端口，然后接收到tcp连接会扔给Handler来处理，上面的例子默认nil即为`http.DefaultServeMux`，通过`DefaultServeMux.ServeHTTP`函数来进行调度，遍历之前存储的map路由信息，和用户访问的URL进行匹配，以查询对应注册的处理函数，这样就实现了上面所说的第二点。
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for k, v := range mux.m {
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if !pathMatch(k, path) {
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continue
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}
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if h == nil || len(k) > n {
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n = len(k)
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h = v.h
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}
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}
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## beego框架路由实现
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目前几乎所有的Web应用路由实现都是基于http默认的路由器，但是Go自带的路由器有几个限制：
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- 不支持参数设定，例如/user/:uid 这种泛类型匹配
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- 无法很好的支持REST模式，无法限制访问的方法，例如上面的例子中，用户访问/foo，可以用GET、POST、DELETE、HEAD等方式访问
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- 一般网站的路由规则太多了，编写繁琐。我前面自己开发了一个API应用，路由规则有三十几条，这种路由多了之后其实可以进一步简化，通过struct的方法进行一种简化
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beego框架的路由器基于上面的几点限制考虑设计了一种REST方式的路由实现，路由设计也是基于上面Go默认设计的两点来考虑：存储路由和转发路由
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### 存储路由
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针对前面所说的限制点，我们首先要解决参数支持就需要用到正则，第二和第三点我们通过一种变通的方法来解决，REST的方法对应到struct的方法中去，然后路由到struct而不是函数，这样在转发路由的时候就可以根据method来执行不同的方法。
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根据上面的思路，我们设计了两个数据类型controllerInfo(保存路径和对应的struct，这里是一个reflect.Type类型)和ControllerRegistor(routers是一个slice用来保存用户添加的路由信息，以及beego框架的应用信息)
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type controllerInfo struct {
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regex *regexp.Regexp
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params map[int]string
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controllerType reflect.Type
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}
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type ControllerRegistor struct {
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routers []*controllerInfo
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Application *App
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}
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ControllerRegistor对外的接口函数有
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func (p *ControllerRegistor) Add(pattern string, c ControllerInterface)
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详细的实现如下所示：
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func (p *ControllerRegistor) Add(pattern string, c ControllerInterface) {
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parts := strings.Split(pattern, "/")
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j := 0
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params := make(map[int]string)
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for i, part := range parts {
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if strings.HasPrefix(part, ":") {
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expr := "([^/]+)"
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//a user may choose to override the defult expression
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// similar to expressjs: ‘/user/:id([0-9]+)’
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if index := strings.Index(part, "("); index != -1 {
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expr = part[index:]
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part = part[:index]
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}
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params[j] = part
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parts[i] = expr
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j++
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}
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}
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//recreate the url pattern, with parameters replaced
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//by regular expressions. then compile the regex
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pattern = strings.Join(parts, "/")
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regex, regexErr := regexp.Compile(pattern)
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if regexErr != nil {
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//TODO add error handling here to avoid panic
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panic(regexErr)
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return
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}
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//now create the Route
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t := reflect.Indirect(reflect.ValueOf(c)).Type()
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route := &controllerInfo{}
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route.regex = regex
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route.params = params
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route.controllerType = t
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p.routers = append(p.routers, route)
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}
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### 静态路由实现
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上面我们实现的动态路由的实现，Go的http包默认支持静态文件处理FileServer，由于我们实现了自定义的路由器，那么静态文件也需要自己设定，beego的静态文件夹路径保存在全局变量StaticDir中，StaticDir是一个map类型，实现如下：
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func (app *App) SetStaticPath(url string, path string) *App {
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StaticDir[url] = path
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return app
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}
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应用中设置静态路径可以使用如下方式实现：
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beego.SetStaticPath("/img","/static/img")
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### 转发路由
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转发路由是基于ControllerRegistor里的路由信息来进行转发的，详细的实现如下代码所示：
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// AutoRoute
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func (p *ControllerRegistor) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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defer func() {
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if err := recover(); err != nil {
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if !RecoverPanic {
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// go back to panic
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panic(err)
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} else {
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Critical("Handler crashed with error", err)
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for i := 1; ; i += 1 {
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_, file, line, ok := runtime.Caller(i)
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if !ok {
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break
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}
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Critical(file, line)
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}
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}
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}
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}()
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var started bool
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for prefix, staticDir := range StaticDir {
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if strings.HasPrefix(r.URL.Path, prefix) {
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file := staticDir + r.URL.Path[len(prefix):]
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http.ServeFile(w, r, file)
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started = true
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return
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}
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}
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requestPath := r.URL.Path
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//find a matching Route
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for _, route := range p.routers {
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//check if Route pattern matches url
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if !route.regex.MatchString(requestPath) {
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continue
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}
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//get submatches (params)
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matches := route.regex.FindStringSubmatch(requestPath)
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//double check that the Route matches the URL pattern.
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if len(matches[0]) != len(requestPath) {
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continue
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}
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params := make(map[string]string)
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if len(route.params) > 0 {
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//add url parameters to the query param map
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values := r.URL.Query()
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for i, match := range matches[1:] {
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values.Add(route.params[i], match)
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params[route.params[i]] = match
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}
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//reassemble query params and add to RawQuery
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r.URL.RawQuery = url.Values(values).Encode() + "&" + r.URL.RawQuery
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//r.URL.RawQuery = url.Values(values).Encode()
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}
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//Invoke the request handler
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vc := reflect.New(route.controllerType)
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init := vc.MethodByName("Init")
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in := make([]reflect.Value, 2)
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ct := &Context{ResponseWriter: w, Request: r, Params: params}
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in[0] = reflect.ValueOf(ct)
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in[1] = reflect.ValueOf(route.controllerType.Name())
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init.Call(in)
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in = make([]reflect.Value, 0)
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method := vc.MethodByName("Prepare")
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method.Call(in)
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if r.Method == "GET" {
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method = vc.MethodByName("Get")
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method.Call(in)
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} else if r.Method == "POST" {
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method = vc.MethodByName("Post")
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method.Call(in)
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} else if r.Method == "HEAD" {
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method = vc.MethodByName("Head")
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method.Call(in)
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} else if r.Method == "DELETE" {
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method = vc.MethodByName("Delete")
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method.Call(in)
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} else if r.Method == "PUT" {
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method = vc.MethodByName("Put")
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method.Call(in)
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} else if r.Method == "PATCH" {
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method = vc.MethodByName("Patch")
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method.Call(in)
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} else if r.Method == "OPTIONS" {
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method = vc.MethodByName("Options")
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method.Call(in)
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}
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if AutoRender {
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method = vc.MethodByName("Render")
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method.Call(in)
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}
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method = vc.MethodByName("Finish")
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method.Call(in)
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started = true
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break
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}
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//if no matches to url, throw a not found exception
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if started == false {
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http.NotFound(w, r)
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}
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}
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### 使用入门
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基于这样的路由设计之后就可以解决前面所说的三个限制点，使用的方式如下所示：
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基本的使用注册路由：
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beego.BeeApp.RegisterController("/", &controllers.MainController{})
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参数注册：
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beego.BeeApp.RegisterController("/:param", &controllers.UserController{})
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正则匹配：
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beego.BeeApp.RegisterController("/users/:uid([0-9]+)", &controllers.UserController{})
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## links
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* [目录](<preface.md>)
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* 上一章: [项目规划](<13.1.md>)
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* 下一节: [controller设计](<13.3.md>)
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# 13.2 Customized routers
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## HTTP routing
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HTTP HTTP request routing components corresponding function handed process( or a struct method ), as described in the previous section structure, in the frame corresponds to a routing event handler, and the event comprises:
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- User requests a path(path)( e.g.:/user/123,/article/123), of course, the query string information(e.g., ? Id = 11)
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- HTTP request method(method)(GET, POST, PUT, DELETE, PATCH, etc. )
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The router is based on the user's request is forwarded to the respective event information processing function( control layer ).
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## Default route to achieve
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Have been introduced in section 3.4 Go's http package Detailed, which introduced the Go's http package how to design and implement routing, here continue to be an example to illustrate:
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func fooHandler(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
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}
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http.Handle("/foo", fooHandler)
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http.HandleFunc("/bar", func(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
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})
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log.Fatal(http.ListenAndServe(":8080", nil))
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The above example calls the http default DefaultServeMux to add a route, you need to provide two parameters, the first parameter is the resource you want users to access the URL path( stored in r.URL.Path), the second argument is about to be executed function to provide the user access to resources. Routing focused mainly on two ideas:
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- Add routing information
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- According to the user request is forwarded to the function to be performed
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Go add default route is through a function `http.Handle` and `http.HandleFunc`, etc. to add, the bottom is called `DefaultServeMux.Handle(pattern string, handler Handler)`, this function will set the routing information is stored in a map information in `map [string] muxEntry`, which would address the above said first point.
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Go listening port, and then receives the tcp connection thrown Handler to process, the above example is the default nil `http.DefaultServeMux`, `DefaultServeMux.ServeHTTP` by the scheduling function, the previously stored map traverse route information, and the user URL accessed matching to check the corresponding registered handler, so to achieve the above mentioned second point.
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for k, v := range mux.m {
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if !pathMatch(k, path) {
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continue
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}
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if h == nil || len(k) > n {
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n = len(k)
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h = v.h
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}
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}
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## Beego routing framework to achieve
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Almost all Web applications are based routing to achieve http default router, but the router comes Go has several limitations:
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- Does not support parameter setting, such as/user/: uid This pan type matching
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- Not very good support for REST mode, you can not restrict access methods, such as the above example, user access/foo, you can use GET, POST, DELETE, HEAD, etc. Access
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- General site routing rules too much, write cumbersome. I'm in front of an API to develop their own applications, routing rules have thirty several, in fact, this route after more than can be further simplified by a simplified method of the struct
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beego framework routers based on the above few limitations to consider the design of a REST approach to achieve routing, routing design is based on two points above the default design Go to consider: store -and-forward routing routing
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### Storing a routing
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For the previously mentioned restriction point, we must first solve the arguments supporting the need to use regular, second and third point we passed a viable alternative to solve, REST method corresponds to a struct method to go, and then routed to the struct instead of a function, so that when the forward routing method can be performed according to different methods.
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Based on the above ideas, we designed two data types controllerInfo( save path and the corresponding struct, here is a reflect.Type type ) and ControllerRegistor(routers are used to save user to add a slice of routing information, and the application of the framework beego information )
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type controllerInfo struct {
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regex *regexp.Regexp
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params map[int]string
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controllerType reflect.Type
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}
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type ControllerRegistor struct {
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routers []*controllerInfo
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Application *App
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}
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ControllerRegistor external interface function has
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|
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func(p *ControllerRegistor) Add(pattern string, c ControllerInterface)
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Detailed implementation is as follows:
|
||||
|
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func (p *ControllerRegistor) Add(pattern string, c ControllerInterface) {
|
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parts := strings.Split(pattern, "/")
|
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|
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j := 0
|
||||
params := make(map[int]string)
|
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for i, part := range parts {
|
||||
if strings.HasPrefix(part, ":") {
|
||||
expr := "([^/]+)"
|
||||
|
||||
//a user may choose to override the defult expression
|
||||
// similar to expressjs: ‘/user/:id([0-9]+)’
|
||||
|
||||
if index := strings.Index(part, "("); index != -1 {
|
||||
expr = part[index:]
|
||||
part = part[:index]
|
||||
}
|
||||
params[j] = part
|
||||
parts[i] = expr
|
||||
j++
|
||||
}
|
||||
}
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||||
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//recreate the url pattern, with parameters replaced
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||||
//by regular expressions. then compile the regex
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||||
|
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pattern = strings.Join(parts, "/")
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regex, regexErr := regexp.Compile(pattern)
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if regexErr != nil {
|
||||
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||||
//TODO add error handling here to avoid panic
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||||
panic(regexErr)
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||||
return
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||||
}
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||||
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||||
//now create the Route
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t := reflect.Indirect(reflect.ValueOf(c)).Type()
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route := &controllerInfo{}
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route.regex = regex
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route.params = params
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route.controllerType = t
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p.routers = append(p.routers, route)
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}
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### Static routing
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Above we achieve the realization of dynamic routing, Go the http package supported by default static file handler FileServer, because we have implemented a custom router, then the static files also need to set their own, beego static folder path stored in the global variable StaticDir, StaticDir is a map type to achieve the following:
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func (app *App) SetStaticPath(url string, path string) *App {
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StaticDir[url] = path
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||||
return app
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||||
}
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||||
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||||
Applications can use the static route is set to achieve the following manner:
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||||
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||||
beego.SetStaticPath("/img", "/static/img")
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||||
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||||
### Forwarding route
|
||||
|
||||
Forwarding route in the routing is based ControllerRegistor forwarding information, detailed achieve the following code shows:
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||||
|
||||
// AutoRoute
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||||
func (p *ControllerRegistor) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
||||
defer func() {
|
||||
if err := recover(); err != nil {
|
||||
if !RecoverPanic {
|
||||
// go back to panic
|
||||
panic(err)
|
||||
} else {
|
||||
Critical("Handler crashed with error", err)
|
||||
for i := 1; ; i += 1 {
|
||||
_, file, line, ok := runtime.Caller(i)
|
||||
if !ok {
|
||||
break
|
||||
}
|
||||
Critical(file, line)
|
||||
}
|
||||
}
|
||||
}
|
||||
}()
|
||||
var started bool
|
||||
for prefix, staticDir := range StaticDir {
|
||||
if strings.HasPrefix(r.URL.Path, prefix) {
|
||||
file := staticDir + r.URL.Path[len(prefix):]
|
||||
http.ServeFile(w, r, file)
|
||||
started = true
|
||||
return
|
||||
}
|
||||
}
|
||||
requestPath := r.URL.Path
|
||||
|
||||
//find a matching Route
|
||||
for _, route := range p.routers {
|
||||
|
||||
//check if Route pattern matches url
|
||||
if !route.regex.MatchString(requestPath) {
|
||||
continue
|
||||
}
|
||||
|
||||
//get submatches (params)
|
||||
matches := route.regex.FindStringSubmatch(requestPath)
|
||||
|
||||
//double check that the Route matches the URL pattern.
|
||||
if len(matches[0]) != len(requestPath) {
|
||||
continue
|
||||
}
|
||||
|
||||
params := make(map[string]string)
|
||||
if len(route.params) > 0 {
|
||||
//add url parameters to the query param map
|
||||
values := r.URL.Query()
|
||||
for i, match := range matches[1:] {
|
||||
values.Add(route.params[i], match)
|
||||
params[route.params[i]] = match
|
||||
}
|
||||
|
||||
//reassemble query params and add to RawQuery
|
||||
r.URL.RawQuery = url.Values(values).Encode() + "&" + r.URL.RawQuery
|
||||
//r.URL.RawQuery = url.Values(values).Encode()
|
||||
}
|
||||
//Invoke the request handler
|
||||
vc := reflect.New(route.controllerType)
|
||||
init := vc.MethodByName("Init")
|
||||
in := make([]reflect.Value, 2)
|
||||
ct := &Context{ResponseWriter: w, Request: r, Params: params}
|
||||
in[0] = reflect.ValueOf(ct)
|
||||
in[1] = reflect.ValueOf(route.controllerType.Name())
|
||||
init.Call(in)
|
||||
in = make([]reflect.Value, 0)
|
||||
method := vc.MethodByName("Prepare")
|
||||
method.Call(in)
|
||||
if r.Method == "GET" {
|
||||
method = vc.MethodByName("Get")
|
||||
method.Call(in)
|
||||
} else if r.Method == "POST" {
|
||||
method = vc.MethodByName("Post")
|
||||
method.Call(in)
|
||||
} else if r.Method == "HEAD" {
|
||||
method = vc.MethodByName("Head")
|
||||
method.Call(in)
|
||||
} else if r.Method == "DELETE" {
|
||||
method = vc.MethodByName("Delete")
|
||||
method.Call(in)
|
||||
} else if r.Method == "PUT" {
|
||||
method = vc.MethodByName("Put")
|
||||
method.Call(in)
|
||||
} else if r.Method == "PATCH" {
|
||||
method = vc.MethodByName("Patch")
|
||||
method.Call(in)
|
||||
} else if r.Method == "OPTIONS" {
|
||||
method = vc.MethodByName("Options")
|
||||
method.Call(in)
|
||||
}
|
||||
if AutoRender {
|
||||
method = vc.MethodByName("Render")
|
||||
method.Call(in)
|
||||
}
|
||||
method = vc.MethodByName("Finish")
|
||||
method.Call(in)
|
||||
started = true
|
||||
break
|
||||
}
|
||||
|
||||
//if no matches to url, throw a not found exception
|
||||
if started == false {
|
||||
http.NotFound(w, r)
|
||||
}
|
||||
}
|
||||
|
||||
### Getting started
|
||||
|
||||
After the design is based on the routing can solve the previously mentioned three restriction point, using a method as follows:
|
||||
|
||||
The basic use of a registered route:
|
||||
|
||||
beego.BeeApp.RegisterController("/", &controllers.MainController{})
|
||||
|
||||
Parameter registration:
|
||||
|
||||
beego.BeeApp.RegisterController("/:param", &controllers.UserController{})
|
||||
|
||||
Are then matched:
|
||||
|
||||
beego.BeeApp.RegisterController("/users/:uid([0-9]+)", &controllers.UserController{})
|
||||
|
||||
## Links
|
||||
|
||||
- [Directory](preface.md)
|
||||
- Previous section: [Project program](13.1.md)
|
||||
- Next section: [Design controllers](13.3.md)
|
||||
|
||||
Reference in New Issue
Block a user