Arcgis api for javascript學習筆記 - 不改變默認端口(6080)情況下，外網訪問Arcgis Server 發佈的接口

Arcgis Server發佈的地圖服務地址默認端口號是6080，假設本機上只對80端口做了外網映射，在IIS中部署了一個網站綁定了80端口，那麼網站中某個頁面通過arcgis api for js 加載Arcgis Server發佈的地圖服務就無法加載出來了。

在此情況下，可以將Arcgis Server發佈的地圖服務地址Url設爲網站的特定地址，然後通過攔截器攔截特定地址，在攔截器中用HttpWebRequest訪問localhost:6080，將HttpWebResponse響應流寫入Response.OutputStream中。

（其實就是類似於反向代理，將地圖服務接口的請求轉發到Arcgis Server 的Web服務器）

例：

　　服務器局域網地址爲：192.168.1.100

　　服務器80端口映射外網地址爲：61.135.169.125

　　服務器在IIS中部署網站綁定的端口爲：80

　　服務器Arcgis Server發佈的地圖服務地址端口爲：6080

現在如果想通過arcgis js api 加載 服務接口 192.168.1.100:6080/arcgis/rest/services/test/service1/FeatureServer/0；

如果在內網中訪問，下面的代碼地圖加載出來沒問題。

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 });

但是如果在外網訪問因爲無法訪問6080端口，所以必須通過80端口的網站通過模擬HttpWebRequest模擬請求 192.168.1.100:6080/arcgis/rest/services/test/service1/FeatureServer/0 ，然後返回客戶端

html頁面代碼：

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攔截器代碼：

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

        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[1024];
                    int count = 0;
                    while ((count = hwStream.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        application.Context.Response.OutputStream.Write(buffer, 0, count);
                    }
                    application.Context.Response.ContentType = hwResponse.ContentType;
                    application.Context.Response.End();
                }
            }
        }

        public void Dispose() { }
    }

HttpModule需要在Web.config中的<system.webServer>節點配置相關節點才能起到攔截請求的作用，在次不做說明。

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