Rufen Sie den URL-Export programmgesteuert auf

Exportieren Sie Daten dynamisch aus einem Skript oder Webservice, indem Sie einen URL-Export aus einer beliebigen Programmiersprache aufrufen.

Vorbereitungen

Erforderliche Rolle: keine

Warum und wann dieser Vorgang ausgeführt wird

Das folgende Verfahren enthält Code-Muster, die den Aufruf eines URL-Exports in C# für einen .NET Framework-Aufruf veranschaulichen:

Prozedur

1. Fügen Sie die folgenden Importe hinzu:

   using System.Net;
   using System.IO;

2. Rufen Sie die Download-Methode auf:

   static void Main(string[] args)
   
        {
           // Call to DownloadFile method supplying the URL and location to save CSV file locally
           int read = DownloadFile("https://<instance>.service-now.com/incident_list.do?CSV&sysparm_query=priority=1&sysparm_orderby=assigned_to",
                        "c:\\test\\incident.csv");
       }

3. Erstellen Sie wie folgt eine Download-Methode:

   public static int DownloadFile(String url,
                                          String localFilename)
       {
           // Function will return the number of bytes processed
           // to the caller. Initialize to 0 here.
           int bytesProcessed = 0;
           // Assign values to these objects here so that they can
           // be referenced in the finally block
           Stream remoteStream = null;
           Stream localStream = null;
           WebResponse response = null;
           // Use a try/catch/finally block as both the WebRequest and Stream
           // classes throw exceptions upon error
           try
           {
               // Create a request for the specified remote file name
               WebRequest request = WebRequest.Create(url);
               // Create the credentials required for Basic Authentication
               System.Net.ICredentials cred = new System.Net.NetworkCredential("user_name", "password");
               // Add the credentials to the request
               request.Credentials = cred;
               if (request != null)
               {
                   // Send the request to the server and retrieve the
                   // WebResponse object 
                   response = request.GetResponse();
                   if (response != null)
                   {
                       // Once the WebResponse object has been retrieved,
                       // get the stream object associated with the response's data
                       remoteStream = response.GetResponseStream();
                       // Create the local file
                       localStream = File.Create(localFilename);
                       // Allocate a 1k buffer
                       byte[] buffer = new byte[1024];
                       int bytesRead;
                       // Simple do/while loop to read from stream until
                       // no bytes are returned
                       do
                       {
                           // Read data (up to 1k) from the stream
                           bytesRead = remoteStream.Read(buffer, 0, buffer.Length);
                           // Write the data to the local file
                           localStream.Write(buffer, 0, bytesRead);
                           // Increment total bytes processed
                           bytesProcessed += bytesRead;
                       } while (bytesRead > 0);
                   }
               }
           }
           catch (Exception e)
           {
               Console.WriteLine(e.Message);
           }
           finally
           {
               // Close the response and streams objects here 
               // to make sure they're closed even if an exception
               // is thrown at some point
               if (response != null) response.Close();
               if (remoteStream != null) remoteStream.Close();
               if (localStream != null) localStream.Close();
           }
           // Return total bytes processed to caller.
           return bytesProcessed;
       }