How To Send a Binary Stream by Using XMLHTTP

This example uses the ADODB.Stream object to hold the binary data that is to be sent back to the server. If a newer version of MSXML has been installed in Side-by-Side mode, then to run the sample code with that specific version, you must explicitly use the GUIDs or ProgIDs for that version. For example, MSXML version 4 only installs in side-by-side mode. Please refer to the following article in the Microsoft Knowledge Base to see what code changes required to run the sample code with the MSXML 4.0 parser: Q305019 INFO: MSXML 4.0 Specific GUIDs and ProgIds.


For example, in the code below, you would create objects with MSXML 4.0 with the following statements:

• var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP.4.0");
• xmldoc = new ActiveXObject("Msxml2.DOMDocument.4.0");
• var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP.4.0");

To use XMLHTTP to send a binary stream to a server, follow these steps:

1. Paste the following code into a file in your default Web folder and name the file Receiver.asp.

   <%
   dim Connection
   dim rs
   Connection = "Provider=SQLOLEDB.1;Data Source=servername;User Id=username;Password=password;Initial Catalog=Northwind;"
   sql =  "Select * from Customers"
   
   
   set rs = server.CreateObject("ADODB.Recordset")
   
   if Request.QueryString("getRecordset") = "YES" then
   rs.ActiveConnection = Connection
   rs.CursorLocation = 3 'Client Side
   rs.CursorType = 3 'Static Recordset
   rs.LockType = 4 'Batch Optimistic
   rs.Open sql
   rs.Save response, 1 'persist adPersistXML
   Response.End
   else
   rs.open Request '.BinaryRead(Request.TotalBytes)
   rs.activeconnection = Connection 'Reconnect
   rs.updatebatch 'Update adAffectAll
   rs.close
   Response.Write "Recordset Saved" 'Send back response
   Response.End
   end if
   
   %>

2. Paste the following code into a file in your default Web folder and name the file Sender.asp

   <SCRIPT ID=clientEventHandlersJS LANGUAGE=javascript>
   <!--
   
   var rs;
   var xmldoc; 
   var xmlstream;
   
   function SendRS_onclick() {
   xmlstream = new ActiveXObject("ADODB.Stream");
   xmlstream.Mode = 3; //read write
   xmlstream.Open();
   xmlstream.Type = 1; // adTypeBinary
   rs.Save(xmlstream,0); //adpersistadtg
      var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
      xmlhttp.Open("POST","http://localhost/Receiver.asp?getRecordset=NO",false);
   xmlhttp.setRequestHeader("Content-Length",xmlstream.Size); //set the length of the content
      xmlhttp.send(xmlstream.Read(xmlstream.Size)); //Send the stream
      alert(xmlhttp.responseText);
   }
   
   function getRS_onclick() {
   rs = new ActiveXObject("ADODB.Recordset");
   xmldoc = new ActiveXObject("Msxml2.DOMDocument");
      var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
      xmlhttp.Open("Get","http://localhost/Receiver.asp?getRecordset=YES",false);
      xmlhttp.send();
      xmldoc.loadXML(xmlhttp.responseText); //load the returned stream into the dom document
      rs.Open(xmldoc); //load the dom document into the recordset
      alert("Recordset Loaded");
   }
   
   function Update_onclick() {
   alert("before: " + rs.Fields(2).Value);
   rs.Fields(2).Value = rs.Fields(2).Value + "!";
   rs.Update();
   alert("after: " + rs.Fields(2).Value);
   }
   
   //-->
   </SCRIPT>
   <INPUT type="button" value="Get Recordset" id=getRS name=getRS LANGUAGE=javascript onclick="return getRS_onclick()">
   <INPUT type="button" value="Update" id=Update name=Update LANGUAGE=javascript onclick="return Update_onclick()">
   <INPUT type="button" value="Send Recordset" id=SendRS name=SendRS LANGUAGE=javascript onclick="return SendRS_onclick()">
   

3. Modify the Receiver.asp page so that the connection variable contains a Microsoft SQL Server name and a valid SQL userid and password.
4. Start Microsoft Internet Explorer and browse to http://localhost/sender.asp.
5. Click Get Recordset. A message box appears and tells you that the recordset was loaded successfully.
6. Click Update. A message box appears and shows you the value before the update. A second message box appears and shows you the value after the update.
7. Click Send Recordset. A message box appears and tells you that the recordset was updated.

Known Limitations and Recommendations

• Although this allows you to use the persist mechanism to pass the data back and forth to the client, it is recommended that you use UpdateGrams or OpenXML with SQL Server 2000 to pass and send recordset data in XML format.
• There are limitations in shaped recordsets. Edited shaped recordsets cannot be persisted in XML format. Also, parameterized shaped commands cannot be persisted at all. For additional information on persisting and limitations, see the following Microsoft Developer Network (MSDN) Web site:
  XML Persistence Format
  http://msdn.microsoft.com/en-us/library/ms676547.aspx