深入理解Go HTTP服务器与Goroutine：避免常见陷阱与优化文件服务

func loadPage(w http.ResponseWriter, path string) {
   s := GetFileContent(path) // 获取文件内容
   w.Header().Add("Content-Type", getHeader(path))
   w.Header().Add("Content-Length", GetContentLength(path))
   fmt.Fprint(w, s) // 将内容写入响应
}

func GetFileContent(path string) string {
   cont, err := ioutil.ReadFile(path) // 一次性读取整个文件
   if err != nil {
      // 错误处理
      return ""
   }
   return string(cont)
}
// 其他辅助函数如getHeader, GetContentLength, ArrayContainsSuffix

http.HandleFunc("/mypage", func(w http.ResponseWriter, r *http.Request) {
    go loadPage(w, "path/to/my/page.html") // 错误的使用方式
})

import (
    "io"
    "net/http"
    "os"
    "path/filepath"
)

func serveFileOptimized(w http.ResponseWriter, r *http.Request, filePath string) {
    f, err := os.Open(filePath)
    if err != nil {
        http.Error(w, "文件未找到", http.StatusNotFound)
        return
    }
    defer f.Close() // 确保文件句柄关闭

    // 设置Content-Type，可以根据文件扩展名判断
    // 示例：这里简化处理，实际应用中应更完善
    contentType := "application/octet-stream"
    ext := filepath.Ext(filePath)
    switch ext {
    case ".html", ".htm":
        contentType = "text/html; charset=utf-8"
    case ".css":
        contentType = "text/css; charset=utf-8"
    case ".js":
        contentType = "application/javascript; charset=utf-8"
    case ".jpg", ".jpeg":
        contentType = "image/jpeg"
    case ".png":
        contentType = "image/png"
    case ".gif":
        contentType = "image/gif"
    }
    w.Header().Set("Content-Type", contentType)

    // io.Copy 会自动处理Content-Length或分块传输
    _, err = io.Copy(w, f)
    if err != nil {
        // 如果在写入过程中发生错误，通常无法向客户端报告，因为部分数据可能已发送
        // 记录日志是更好的选择
        // http.Error(w, "内部服务器错误", http.StatusInternalServerError) // 可能会在响应头已发送后失败
        return
    }
}

// 在HTTP处理器中调用
// http.HandleFunc("/optimized-page", func(w http.ResponseWriter, r *http.Request) {
//     serveFileOptimized(w, r, "path/to/my/page.html")
// })

import (
    "fmt"
    "net/http"
    "sync"
    "time"
)

func complexHandler(w http.ResponseWriter, r *http.Request) {
    var wg sync.WaitGroup
    results := make(chan string, 2) // 用于收集Goroutine的结果

    // 任务1：模拟耗时操作
    wg.Add(1)
    go func() {
        defer wg.Done()
        time.Sleep(100 * time.Millisecond)
        results <- "数据来自任务A"
    }()

    // 任务2：模拟另一个耗时操作
    wg.Add(1)
    go func() {
        defer wg.Done()
        time.Sleep(150 * time.Millisecond)
        results <- "数据来自任务B"
    }()

    // 启动一个Goroutine等待所有任务完成并关闭结果通道
    go func() {
        wg.Wait()
        close(results)
    }()

    // 主Goroutine从结果通道读取数据并构建响应
    var responseBuilder string
    for res := range results {
        responseBuilder += res + "\n"
    }

    fmt.Fprint(w, "所有并发任务完成:\n", responseBuilder)
}

// 注册处理器
// http.HandleFunc("/complex", complexHandler)