Go语言中高效处理x-www-form-urlencoded表单数据

go get github.com/gorilla/schema

package main

import (
    "fmt"
    "log"
    "net/http"
    "github.com/gorilla/schema"
)

// Person 结构体用于接收表单数据
type Person struct {
    Name    string `schema:"name"`
    Age     int    `schema:"age"`
    City    string `schema:"city,omitempty"` // omitempty 标签表示如果字段为空则忽略
    IsActive bool   `schema:"active"`
}

var decoder = schema.NewDecoder()

func FormHandler(w http.ResponseWriter, r *http.Request) {
    // 1. 解析表单数据
    // r.ParseForm() 必须在访问 r.Form 或 r.PostForm 之前调用
    // 它会解析 URL 查询参数和请求体中的 x-www-form-urlencoded 数据
    err := r.ParseForm()
    if err != nil {
        http.Error(w, fmt.Sprintf("Failed to parse form: %v", err), http.StatusBadRequest)
        return
    }

    // 2. 创建一个结构体实例用于接收数据
    person := new(Person)

    // 3. 使用 decoder.Decode 将表单数据映射到结构体
    // r.Form 包含了所有解析后的表单值 (包括查询参数和请求体)
    err = decoder.Decode(person, r.Form)
    if err != nil {
        http.Error(w, fmt.Sprintf("Failed to decode form data: %v", err), http.StatusBadRequest)
        return
    }

    // 4. 打印解析后的数据以验证
    fmt.Fprintf(w, "Person Name: %s\n", person.Name)
    fmt.Fprintf(w, "Person Age: %d\n", person.Age)
    fmt.Fprintf(w, "Person City: %s\n", person.City)
    fmt.Fprintf(w, "Person IsActive: %t\n", person.IsActive)
    log.Printf("Received person data: %+v\n", person)
}

func main() {
    http.HandleFunc("/submit", FormHandler)
    log.Println("Server starting on :8080")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

curl -X POST -d "name=Alice&age=30&city=NewYork&active=true" http://localhost:8080/submit

<form action="http://localhost:8080/submit" method="POST">
    <label for="name">Name:</label><br>
    <input type="text" id="name" name="name" value="Bob"><br>
    <label for="age">Age:</label><br>
    <input type="number" id="age" name="age" value="25"><br>
    <label for="city">City:</label><br>
    <input type="text" id="city" name="city" value="London"><br>
    <label for="active">Active:</label><br>
    <input type="checkbox" id="active" name="active" checked><br><br>
    <input type="submit" value="Submit">
</form>

// 伪代码示例：结合验证库
import (
    "github.com/kat-co/vala" // 假设使用 vala 进行验证
)

// ... 在 FormHandler 中解码后 ...

    // 假设 Person 结构体中定义了验证规则
    // type Person struct {
    //     Name string `schema:"name" vala:"required,min=2,max=50"`
    //     Age  int    `schema:"age" vala:"min=1,max=150"`
    // }

    // 进行数据验证
    validationErrors := vala.Validate(person)
    if validationErrors != nil {
        // 处理验证错误
        http.Error(w, fmt.Sprintf("Validation failed: %v", validationErrors), http.StatusBadRequest)
        return
    }

    // 验证通过，继续业务逻辑处理
    // ...