基于Go语言开发一个 IP 归属地查询接口工具

package main

import (
	"encoding/json"
	"log"
	"net"
	"net/http"

	"github.com/lionsoul2014/ip2region/binding/golang/xdb"
)

// 响应结构
type IPInfo struct {
	IP      string `json:"ip"`
	Region  string `json:"region"`
	Error   string `json:"error,omitempty"`
}

var searcher *xdb.Searcher

func main() {
	// 加载 ip2region 数据库
	var err error
	searcher, err = xdb.NewWithFileOnly("ip2region.xdb")
	if err != nil {
		log.Fatalf("❌ 加载 ip2region.xdb 失败: %v", err)
	}

	http.HandleFunc("/ip", queryIP)

	log.Println("✅ IP 归属地查询服务已启动: http://localhost:8080/ip?addr=1.1.1.1")
	http.ListenAndServe(":8080", nil)
}

func queryIP(w http.ResponseWriter, r *http.Request) {
	addr := r.URL.Query().Get("addr")
	if addr == "" {
		writeJSON(w, IPInfo{Error: "缺少参数 addr"})
		return
	}

	if net.ParseIP(addr) == nil {
		writeJSON(w, IPInfo{IP: addr, Error: "无效的 IP 地址"})
		return
	}

	region, err := searcher.SearchByStr(addr)
	if err != nil {
		writeJSON(w, IPInfo{IP: addr, Error: err.Error()})
		return
	}

	writeJSON(w, IPInfo{IP: addr, Region: region})
}

func writeJSON(w http.ResponseWriter, data IPInfo) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(data)
}

go mod init ip-lookup
go get github.com/lionsoul2014/ip2region/binding/golang/xdb

go run main.go

curl "http://localhost:8080/ip?addr=8.8.8.8"

{
  "ip": "8.8.8.8",
  "region": "美国|0|加利福尼亚|圣克拉拉|谷歌"
}