Shulou(Shulou.com)06/02 Report--

I. Preface

In solving the WebApi cross-domain secondary request and the Vue single page problem, Nginx solves the secondary request caused by the cross-domain problem, but it also gives rise to a new problem, that is, if you need to obtain a user's IP, the IP address is always the local address.

Second, the reason

Because after the Nginx reverse proxy, the IP obtained in the application is the IP of the reverse proxy server, and the domain name obtained is also the domain name of the Url configured by the reverse proxy.

III. Solutions

To solve this problem, you need to add some configuration information to the Nginx reverse proxy configuration in order to pass the real IP and domain name of the client to the application. At the same time, you need to modify the method of obtaining the IP address.

It is important to note, however, that after a reverse proxy through Nginx, if you go through several layers of proxies to access IP, the IP address you may get is in this format: clientIP,proxy1,proxy2.

If you need to insert an IP address into the database, you need to do something to prevent injection. Therefore, it is necessary to intercept the format of the above IP address.

3.1 Nginx is configured as follows

Server {listen 9461; # listener port number server_name localhost 192.168.88.22; # access address location / {path to the root project; # for example: eGroupPublishUnix; index index.html; # this is used to deal with Vue, Angular, React rewriting problems if (!-e $request_filename) {rewrite ^ (. *) / index.html last; break when using H5's History }} # proxy server interface location / api {proxy_pass http://localhost:9460/api;# proxy interface address # Host configuration and domain name passing proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header REMOTE-HOST $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;}}

3.2 C # code to get the real IP method

# region Ip (client IP address) / client IP address / public static string Ip {get {var result = string.Empty; if (HttpContext.Current! = null) {result = GetWebClientIp ();} if (string.IsNullOrWhiteSpace (result)) {result = GetLanIp ();} return result;}} / obtain Web client IP/// private static string GetWebClientIp () {var ip = GetWebProxyRealIp ()? GetWebRemoteIp (); foreach (var hostAddress in Dns.GetHostAddresses (ip)) {if (hostAddress.AddressFamily = = AddressFamily.InterNetwork) {return hostAddress.ToString ();}} return string.Empty;} / obtain Web remote IP/// private static string GetWebRemoteIp () {try {return HttpContext.Current.Request.ServerVariables ["HTTP_X_FORWARDED_FOR"]? HttpContext.Current.Request.ServerVariables ["REMOTE_ADDR"]?? ";} catch (Exception e) {return string.Empty;} / get the real Web agent IP/// private static string GetWebProxyRealIp () {var request = HttpContext.Current.Request; string ip = request.Headers.Get (" x-forwarded-for ") If (string.IsNullOrEmpty (ip) | | string.Equals ("unknown", ip, StringComparison.OrdinalIgnoreCase) {ip = request.Headers.Get ("Proxy-Client-IP");} if (string.IsNullOrEmpty (ip) | | string.Equals ("unknown", ip, StringComparison.OrdinalIgnoreCase)) {ip = request.Headers.Get ("WL-Proxy-Client-IP");} if (string.IsNullOrEmpty (ip) | | string.Equals ("unknown", ip, StringComparison.OrdinalIgnoreCase)) {ip = request.UserHostAddress } if (string.IsNullOrEmpty (ip)) {return string.Empty } / / there may be the following format: X-Forwarded-For: client, proxy1, proxy2 if (ip.Contains (",")) {/ / if there are multiple reverse proxies, the obtained IP is a comma-separated IP set, taking the first / / X-Forwarded-For: client first string [] ips = ip.Split (new string [1] {","}, StringSplitOptions.RemoveEmptyEntries); var I = 0; for (I = 0) I < ips.Length; iTunes +) {if (ips [I]! = ") {/ / determine whether it is intranet IP if (false = = IsInnerIp (IPs [I])) {IPAddress realIp; if (IPAddress.TryParse (ips [I], out realIp) & & IPS [I] .split ('.'). Length = = 4) {/ legal IP return ips [I];} return" } ip = ips [0]; / / obtain the first IP address} return ip;} / determine whether the IP address is a private network IP address / IP address / private static bool IsInnerIp (string ip) {bool isInnerIp = false; ulong ipNum = Ip2Ulong (ip) / * Private IP * Class A: 10.0.0.0-10.255.255.255 * Class B: 172.16.0.0-172.31.255.255 * Class C: 192.168.0.0-192.168.255.255 * of course, there is also a loopback address * / ulong aBegin = Ip2Ulong ("10.0.0.0"); ulong aEnd = Ip2Ulong ("10.255.255.255") Ulong bBegin = Ip2Ulong ("172.16.0.0"); ulong bEnd = Ip2Ulong ("10.31.255.255"); ulong cBegin = Ip2Ulong ("192.168.0.0"); ulong cEnd = Ip2Ulong ("192.168.255.255"); isInnerIp = IsInner (ipNum, aBegin, aEnd) | | IsInner (ipNum, bBegin, bEnd) | | IsInner (ipNum, cBegin, cEnd) | ip.Equals ("127.0.0.1"); return isInnerIp } / IP address / private static ulong Ip2Ulong (string ip) {byte [] bytes = IPAddress.Parse (ip). GetAddressBytes (); ulong ret = 0; foreach (var b in bytes) {ret

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