JS获取外网IP的代码片段

<script>

    const getIPs = (callback) => {
        var ip_dups = {};
        var RTCPeerConnection = window.RTCPeerConnection
            || window.mozRTCPeerConnection
            || window.webkitRTCPeerConnection;
        var useWebKit = !!window.webkitRTCPeerConnection;
        var mediaConstraints = {
            optional: [{ RtpDataChannels: true }]
        };
        // 这里就是需要的ICEServer了
        var servers = {
            iceServers: [
                { urls: "stun:stun.services.mozilla.com" },
                { urls: "stun:stun.l.google.com:19302" },
            ]
        };
        var pc = new RTCPeerConnection(servers, mediaConstraints);
        function handleCandidate(candidate) {
            var ip_regex = /([0-9]{1,3}(\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/
            var hasIp = ip_regex.exec(candidate)
            if (hasIp) {
                var ip_addr = ip_regex.exec(candidate)[1];
                if (ip_dups[ip_addr] === undefined)
                    callback(ip_addr);
                ip_dups[ip_addr] = true;
            }
        }
        // 网络协商的过程
        pc.onicecandidate = function (ice) {
            if (ice.candidate) {
                handleCandidate(ice.candidate.candidate);
            }
        };
        pc.createDataChannel("");
        //创建一个SDP(session description protocol)会话描述协议 是一个纯文本信息 包含了媒体和网络协商的信息
        pc.createOffer(function (result) {
            pc.setLocalDescription(result, function () { }, function () { });
        }, function () { });
        setTimeout(function () {
            var lines = pc.localDescription.sdp.split('\n');
            lines.forEach(function (line) {
                if (line.indexOf('a=candidate:') === 0)
                    handleCandidate(line);
            });
        }, 1000);
    }
    getIPs((ip) => {
        console.log('ip', ip)
    });
    
</script>