Firefox OS应用开发：解决XMLHttpRequest跨域请求阻塞问题

var message = "content";
var request = new XMLHttpRequest({mozSystem: true}); // 关键更改：添加 {mozSystem: true}

request.open('POST', 'http://localhost:8080/msgs', true);

request.onload = function () {
    if (request.status >= 200 && request.status < 400) {
        // 请求成功处理
        var data = JSON.parse(request.responseText);
        console.log(data);
    } else {
        // 服务器返回错误
        console.log("服务器错误:", request.status);
    }
};

request.onerror = function () {
    // 连接错误
    console.log("连接错误");
};

request.send(message);

{
  "name": "My Firefox OS App",
  "description": "A sample Firefox OS application.",
  "launch_path": "/index.html",
  "developer": {
    "name": "Your Name",
    "url": "http://yourdomain.com"
  },
  "permissions": {
    "systemXHR": {}, // 声明使用系统级XMLHttpRequest的权限
    // 可以根据需要添加其他权限，例如：
    // "geolocation": {},
    // "alarms": {}
  },
  "type": "privileged" // 确保您的应用类型为特权应用
}

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "log"
    "net/http"

    "google.golang.org/appengine"
    "google.golang.org/appengine/datastore"
)

// Message 结构体示例
type Message struct {
    Content string
    Date    string // 假设日期为字符串格式
}

func handleMessageQueue(w http.ResponseWriter, r *http.Request) {
    // 关键：设置Access-Control-Allow-Origin头，允许所有来源访问
    w.Header().Set("Access-Control-Allow-Origin", "*")
    // 根据需要设置其他CORS头，例如允许的方法和头
    w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS")
    w.Header().Set("Access-Control-Allow-Headers", "Content-Type")

    // 处理预检请求（OPTIONS方法）
    if r.Method == "OPTIONS" {
        w.WriteHeader(http.StatusOK)
        return
    }

    if r.Method == "POST" {
        c := appengine.NewContext(r)

        body, err := ioutil.ReadAll(r.Body)
        if err != nil {
            c.Errorf("Error reading request body: %v", err)
            http.Error(w, "Failed to read request body", http.StatusInternalServerError)
            return
        }
        defer r.Body.Close()

        // 假设body是需要存储的内容
        auth := string(body) // 原始示例中body直接被转换为auth，这里仅作示意
        _ = auth // auth变量未使用，避免编译警告

        // 示例：查询数据存储
        q := datastore.NewQuery("Message").Order("-Date")

        var msg []Message
        _, err = q.GetAll(c, &msg) // GetAll返回key和err，此处仅检查err

        if err != nil {
            c.Errorf("fetching msg: %v", err)
            http.Error(w, "Failed to fetch messages", http.StatusInternalServerError)
            return
        }

        w.Header().Set("Content-Type", "application/json")
        jsonMsg, err := json.Marshal(msg)
        if err != nil {
            c.Errorf("Error marshalling JSON: %v", err)
            http.Error(w, "Failed to marshal JSON response", http.StatusInternalServerError)
            return
        }
        fmt.Fprint(w, string(jsonMsg))
        return
    }

    // 对于非POST请求，返回方法不允许
    http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
}

func main() {
    http.HandleFunc("/msgs", handleMessageQueue)
    log.Fatal(http.ListenAndServe(":8080", nil))
}