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有條件地執行多個模板

王林

Feb 09, 2024 am 11:48 AM

有條件地執行多個模板

php小編魚仔為您介紹一種強大的技巧：有條件地執行多個範本。在開發網站時，我們常常需要根據不同的條件動態地載入不同的模板文件，這就是有條件地執行多個模板的應用程式場景。透過使用這種技術，我們可以根據使用者的登入狀態、權限等條件來動態地載入相應的模板文件，從而實現更靈活、個人化的網站介面。這種技術不僅提高了網站的可擴展性和可維護性，還能為使用者提供更好的使用體驗。在本文中，我們將詳細介紹如何使用php實作有條件地執行多個範本的方法，幫助您更好地應用於實際專案中。

問題內容

我有一個具有兩種視圖的網頁，一種用於匿名用戶，一種用於管理員用戶。我想僅為管理員用戶顯示導覽列。對於兩種使用者類型，其他一切都保持不變。

這是我迄今為止嘗試過的

main.go

package main

import (
    "log"
    "net/http"
    "text/template"

    "github.com/julienschmidt/httprouter"
)

func basicauth(h httprouter.handle, requireduser, requiredpassword string) httprouter.handle {
    return func(w http.responsewriter, r *http.request, ps httprouter.params) {
        // get the basic authentication credentials
        user, password, hasauth := r.basicauth()

        if hasauth && user == requireduser && password == requiredpassword {
            // delegate request to the given handle
            h(w, r, ps)
        } else {
            // request basic authentication otherwise
            w.header().set("www-authenticate", "basic realm=restricted")
            http.error(w, http.statustext(http.statusunauthorized), http.statusunauthorized)
        }
    }
}

func anonymous(w http.responsewriter, r *http.request, _ httprouter.params) {
    t, err := template.parsefiles("index.html")
    if err != nil {
        log.fatalln(err)
    }
    err = t.execute(w, map[string]string{"name": "anonymous"})
    if err != nil {
        log.fatalln(err)
    }
}

func admin(w http.responsewriter, r *http.request, _ httprouter.params) {
    t, err := template.parsefiles("index.html", "admin.html")
    if err != nil {
        log.fatalln(err)
    }
    err = t.execute(w, map[string]string{"name": "admin"})
    if err != nil {
        log.fatalln(err)
    }
}

func main() {
    user := "admin"
    pass := "1234"

    router := httprouter.new()
    router.get("/", anonymous)
    router.get("/admin/", basicauth(admin, user, pass))

    log.fatal(http.listenandserve(":8080", router))
}

index.html

<!doctype html>
<html lang="en">
    <head>
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>{{ .name }}</title>
        <link href="https://cdn.jsdelivr.net/npm/[email&#160;protected]/dist/css/bootstrap.min.css" rel="stylesheet">
        <script src="https://cdn.jsdelivr.net/npm/[email&#160;protected]/dist/js/bootstrap.bundle.min.js"></script>
        <script src="https://code.jquery.com/jquery-3.6.4.min.js"></script>
        <script>
            function counter() {
                document.getelementbyid("x").innerhtml = "x: " + document.queryselectorall('.x').length;
                document.getelementbyid("y").innerhtml = "y: " + document.queryselectorall('.y').length;
                document.getelementbyid("z").innerhtml = "z: " + document.queryselectorall('.z').length;
            }
        </script>
    </head>
    <body onload="counter()">
        {{ template "dashboard" }}
        <nav class="navbar fixed-bottom">
            <div class="container-fluid nav-justified">
                <span id="x" class="navbar-brand nav-item"></span>
                <span id="y" class="navbar-brand nav-item"></span>
                <span id="z" class="navbar-brand nav-item"></span>
            </div>
        </nav>
    </body>
</html>

admin.html

{{ define "dashboard" }}
<nav class="navbar">
    <div class="container-fluid nav-justified">
        <span class="nav-item">
            <a class="navbar-brand" href="/a">a</a>
        </span>
        <span class="nav-item">
            <a class="navbar-brand" href="/b">b</a>
        </span>
        <span class="nav-item">
            <a class="navbar-brand" href="/c">c</a>
        </span>
    </div>
</nav>
{{ end }}

我的假設是，因為我在為匿名使用者執行模板時沒有傳入 admin.html 模板，所以儀表板模板不會被解析。但是，我遇到了這個錯誤：

template: index.html:18:14: executing "index.html" at <{{template "dashboard"}}>: template "dashboard" not defined

如何解決這個問題，或是有更好的方法嗎？

解決方法

使用 if 操作有條件地渲染 dashboard 範本：

{{ if eq .name "admin" }} {{ template "dashboard" }} {{ end }}

實踐是只解析模板一次，而不是在每個請求時解析它：

package main

import (
    "log"
    "net/http"
    "sync"
    "text/template"

    "github.com/julienschmidt/httprouter"
)

func BasicAuth(h httprouter.Handle, requiredUser, requiredPassword string) httprouter.Handle {
    return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        user, password, hasAuth := r.BasicAuth()

        if hasAuth && user == requiredUser && password == requiredPassword {
            h(w, r, ps)
        } else {
            w.Header().Set("WWW-Authenticate", "Basic realm=Restricted")
            http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
        }
    }
}

func Anonymous(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
    err := tmpl.Execute(w, map[string]string{"Name": "Anonymous"})
    if err != nil {
        log.Fatalln(err)
    }
}

func Admin(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
    err := tmpl.Execute(w, map[string]string{"Name": "Admin"})
    if err != nil {
        log.Fatalln(err)
    }
}

var (
    tmpl     *template.Template
    tmplOnce sync.Once
)

func main() {
    user := "admin"
    pass := "1234"

    tmplOnce.Do(func() {
        tmpl = template.Must(template.ParseFiles("index.html", "admin.html"))
    })

    router := httprouter.New()
    router.GET("/", Anonymous)
    router.GET("/admin/", BasicAuth(Admin, user, pass))

    log.Fatal(http.ListenAndServe(":8080", router))
}

以上是有條件地執行多個模板的詳細內容。更多資訊請關注PHP中文網其他相關文章！

陳述

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