記Outlook插件與Web頁面交互的各種坑 (含c# HttpWebRequest 連接https 的完美解決方法)

1) 方案一,  使用Web Service  基礎功能沒問題, 只是在連接https (ssh) 網站時, 需要針對https進行開發 (即http 和https 生成兩套接口, 不太容易統一 ).   后來改為使用web頁面交互(實質是.ashx) 結果也遇到了不少問題.

 

2) 方案二, 使用  HttpWebRequest .      HttpWebRequest  這東西get數據很容易, POST卻很麻煩, 最終代碼如下:

 

public class WebApiClient
    {
        public string Url { get; set; }
        private CookieContainer Cookies = new CookieContainer();
         
          
        public static string Get( string url )
        {
            //this code can fix https after .net 4.6
            if (url.StartsWith("https", StringComparison.CurrentCultureIgnoreCase))
            {
                System.Net.ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
            }
            System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.ContentType = "application/x-www-form-urlencoded";
             
            System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
            System.IO.Stream s = response.GetResponseStream();
            using (StreamReader reader = new StreamReader(s))
            { 
                string strValue = reader.ReadToEnd();
                return strValue;
            }
        }
        private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            return true;  
        }
        public Result<DataTable> CallWebApi(string action, string json )
        {
            return CallWebApi(action, json, null, null);
        }
        public Result<DataTable> CallWebApi(string action, string json, string fileName, byte[] fileData)
        {
            string responseContent;
            var memStream = new MemoryStream();
            var webRequest = (HttpWebRequest)WebRequest.Create(Url); 
            var boundary = "---------------" + DateTime.Now.Ticks.ToString("x"); 
            var beginBoundary = Encoding.ASCII.GetBytes("--" + boundary + "\r\n");
            //var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read); 
            var endBoundary = Encoding.ASCII.GetBytes("--" + boundary + "--\r\n"); 
            webRequest.Method = "POST"; 
            //webRequest.Timeout = timeOut;
            webRequest.ContentType = "multipart/form-data; boundary=" + boundary;
            if (!string.IsNullOrEmpty(fileName))
            {
                const string filePartHeader =
               "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" +
                "Content-Type: application/octet-stream\r\n\r\n";
                var header = string.Format(filePartHeader, "file1", fileName);
                var headerbytes = Encoding.UTF8.GetBytes(header);
                memStream.Write(beginBoundary, 0, beginBoundary.Length);
                memStream.Write(headerbytes, 0, headerbytes.Length);
                memStream.Write(fileData, 0, fileData.Length);
            }
            
            
            var stringKeyHeader = "\r\n--" + boundary +
                                   "\r\nContent-Disposition: form-data; name=\"{0}\"" +
                                   "\r\n\r\n{1}\r\n";
            var bytes = Encoding.UTF8.GetBytes(string.Format(stringKeyHeader, "action", action));
            memStream.Write(bytes, 0, bytes.Length);
            bytes = Encoding.UTF8.GetBytes(string.Format(stringKeyHeader, "json", json));
            memStream.Write(bytes, 0, bytes.Length);
             
            memStream.Write(endBoundary, 0, endBoundary.Length);
            webRequest.ContentLength = memStream.Length;
            var requestStream = webRequest.GetRequestStream();
            memStream.Position = 0;
            var tempBuffer = new byte[memStream.Length];
            memStream.Read(tempBuffer, 0, tempBuffer.Length);
            memStream.Close();
            requestStream.Write(tempBuffer, 0, tempBuffer.Length);
            requestStream.Close();
            var httpWebResponse = (HttpWebResponse)webRequest.GetResponse();
            using (var httpStreamReader = new StreamReader(httpWebResponse.GetResponseStream(),
                                                            Encoding.GetEncoding("utf-8")))
            {
                responseContent = httpStreamReader.ReadToEnd();
            } 
            httpWebResponse.Close();
            webRequest.Abort();
            try
            {
                return JsonConvert.DeserializeObject<Result<DataTable>>(responseContent);
            }
            catch (Exception ex)
            {
                throw new ApplicationException("Parse server result error: " + responseContent, ex);
            } 
        }
         
    }

 

POST數據的麻煩, 封裝一下可以忍了, 但是連接HTTPS的網站時, 有的網站可以, 有的網站會出錯: System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host

   at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)

   at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)

   --- End of inner exception stack trace ---

   at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)

   at System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count)

   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)

   at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)

   at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)

   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)

   at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)

   at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)

   at System.Net.ConnectStream.WriteHeaders(Boolean async)

   --- End of inner exception stack trace ---

   at System.Net.HttpWebRequest.GetResponse()

 

如果是普通的桌面程序 , 在.net 4.6以上版本時, Create  HttpWebRequest 對象前添加

1. if(url.StartsWith("https",StringComparison.CurrentCultureIgnoreCase))
2. {
3. System.Net.ServicePointManager.ServerCertificateValidationCallback=newRemoteCertificateValidationCallback(CheckValidationResult);
4. }

1. privatestatic bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain,SslPolicyErrors errors)
2. {
3. returntrue;
4. }

 

有的web服務器要求較新的HTTPS的安裝協議, 這種情況下.net4.0以下的版本不支持, 因此要升級到.net4.6以上, 並且在創建HttpWebRequest對象前加入如下設置代碼:

1. ServicePointManager.SecurityProtocol=SecurityProtocolType.Tls|SecurityProtocolType.Tls11|SecurityProtocolType.Tls12|SecurityProtocolType.Ssl3;

這樣就可以最大程度的兼容各種安全協議了. 有的時候發現我們的程序挑.net framework的版本, 大都是由這個原因引起的.

解決了HttpWebRequest連接HTTPS的問題之后, 該方案成為了功能最強的方案(重要是能較好的支持文件的上傳)

 

方案三 使用WebBrowser控件 .

 

初步試了一下, get https的頁面沒有問題, post 的略有麻煩, 網上查到的方法是截獲post事件進行處理:

WebBrowser 其實是對 ActiveX 控件 SHDocVw 的封裝，而這個SHDocVw的很多底層調用WebBrowser控件並沒有提供實現，我們需要直接操作 SHDoceVw 控件來實現這些高級調用。操作方法如下：
1、在 windows/system32 目錄下找到 shdocvw.dll 這個動態庫，將其添加到引用中

2、在 Form1_Load 中添加如下語句

SHDocVw.WebBrowser wb = (SHDocVw.WebBrowser)webBrowser1.ActiveXInstance; 
wb.BeforeNavigate2 +=   new DWebBrowserEvents2_BeforeNavigate2EventHandler(WebBrowser_BeforeNavigate2);

3、添加如下成員函數

private void WebBrowser_BeforeNavigate2(object pDisp, ref object URL, ref object Flags, 
ref object TargetFrameName, ref object PostData, ref object Headers, ref bool Cancel) 
{ 
    string postDataText = System.Text.Encoding.ASCII.GetString(PostData as byte[]); 
}

完成上述3步后，你post 數據時， 就會響應 BeforeNavigate2 事件，postDataText 中就是你post的數據。你也可以修改PostData，對這些數據進行轉換或加密。

來源： http://www.cnblogs.com/swtseaman/archive/2011/10/17/2215717.html

感覺會比較麻煩, 其實還有一種方法,就是利用WebBrowser的DocumentText屬性注入腳本(執行腳本), 然后利用Ajax的方式和web服務器進行交互. 之后利用JS和C#互操作來完成相應的功能.

互操作的C#類上需要加上這個設置:

1. [System.Runtime.InteropServices.ComVisibleAttribute(true)]

並且運行此代碼:

1. webBrowser1.ObjectForScripting=this;

C#里調用JS方法:

1. webBrowser1.Document.InvokeScript("jsFunction",newstring[]{‘ssss’});

 

JS里調用C#方法:

1. window.external.CSharpFunction(‘呵呵’);

這個方法也有些麻煩的地方, 而且不支持文件的上傳.

 

來自為知筆記(Wiz)