Arcgis api for javascript学习笔记 - 不改变默认端口(6080)情况下，外网访问Arcgis Server 发布的接口

Arcgis Server发布的地图服务地址默认端口号是6080，假设本机上只对80端口做了外网映射，在IIS中部署了一个网站绑定了80端口，那么网站中某个页面通过arcgis api for js 加载Arcgis Server发布的地图服务就无法加载出来了。

在此情况下，可以将Arcgis Server发布的地图服务地址Url设为网站的特定地址，然后通过拦截器拦截特定地址，在拦截器中用HttpWebRequest访问localhost:6080，将HttpWebResponse响应流写入Response.OutputStream中。

（其实就是类似于反向代理，将地图服务接口的请求转发到Arcgis Server 的Web服务器）

例：

　　服务器局域网地址为：192.168.1.100

　　服务器80端口映射外网地址为：61.135.169.125

　　服务器在IIS中部署网站绑定的端口为：80

　　服务器Arcgis Server发布的地图服务地址端口为：6080

现在如果想通过arcgis js api 加载 服务接口 192.168.1.100:6080/arcgis/rest/services/test/service1/FeatureServer/0；

如果在内网中访问，下面的代码地图加载出来没问题。

var myFeatureLayer0 = new FeatureLayer("http://192.168.1.100:6080/arcgis/rest/services/test/service1/FeatureServer/0", { "id": "myFeatureLayer0", "opacity": 0.5, "outFields": ["*"], "mode": FeatureLayer.MODE_ONDEMAND });

但是如果在外网访问因为无法访问6080端口，所以必须通过80端口的网站通过模拟HttpWebRequest模拟请求 192.168.1.100:6080/arcgis/rest/services/test/service1/FeatureServer/0 ，然后返回客户端

html页面代码：

var myFeatureLayer0 = new FeatureLayer("http://61.135.169.125/arcgis/rest/services/test/service1/FeatureServer/0", { "id": "myFeatureLayer0", "opacity": 0.5, "outFields": ["*"], "mode": FeatureLayer.MODE_ONDEMAND });

HttpModule拦截器代码：

    public class ArcgsiServerUrlMappingModule : IHttpModule
    {
        public void Init(HttpApplication application)
        {
            application.BeginRequest += this.Application_BeginRequest; //注册事件
        }

        private void Application_BeginRequest(Object source, EventArgs e)
        {
            HttpApplication application = (HttpApplication)source;
            string url = application.Context.Request.RawUrl;
            if (url.StartsWith("/arcgis/rest/services"))
            {
                url = "http://192.168.1.100:6080" + url;
                HttpWebRequest hwRequest = (HttpWebRequest)WebRequest.Create(url);
                hwRequest.UserAgent = "User-Agent:Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705";
                hwRequest.Accept = "*/*";
                hwRequest.KeepAlive = true;
                hwRequest.Headers.Add("Accept-Language", "zh-cn,en-us;q=0.5");
                using (HttpWebResponse hwResponse = (HttpWebResponse)hwRequest.GetResponse())
                {
                    Stream hwStream = hwResponse.GetResponseStream();
                    byte[] buffer = new byte[];
                    int count = ;
                    while ((count = hwStream.Read(buffer, , buffer.Length)) > )
                    {
                        application.Context.Response.OutputStream.Write(buffer, , count);
                    }
                    application.Context.Response.ContentType = hwResponse.ContentType;
                    application.Context.Response.End();
                }
            }
        }

        public void Dispose() { }
    }

HttpModule需要在Web.config中的<system.webServer>节点配置相关节点才能起到拦截请求的作用，在次不做说明。

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