Decoding Base64 Encoded Data and saving the image

pgtips · September 24th, 2004, 04:52 AM

Looks like the problem is in the client-side code, the image data is not being sent:

Code:

function CreateXml()
{
...
    senv+="<imgdata></imgdata>\n";
...

joefawcett · September 24th, 2004, 05:37 AM

Quote:

quote:Originally posted by pgtips
Looks like the problem is in the client-side code, the image data is not being sent:

Code:

function CreateXml()
{
...
    senv+="<imgdata></imgdata>\n";
...

This part is supposed to add the image data.

Code:

var oDoc=new ActiveXObject("Microsoft.XMLDOM");
            oDoc.loadXML(senv);
            var oNode=oDoc.selectSingleNode("//imgdata");
            oNode.dataType="bin.base64";
            oNode.nodeTypedValue=ostream.Read();
            Textarea1.value=oDoc.xml;

            xmlhttp.Send(senv);
            ostream.Close();

Trying to establish if the Textarea1 shows the binary data...
It won't work on a decent parser because the imagedata node is not selected properly, it's in a namespace. But in that case the code should error. It's such a messay post it's hard to know what's happening :)

--

Joe (Co-author Beginning XML, 3rd edition)

datllc · September 28th, 2004, 05:02 PM

thanks, I found my problem: I was send "senv" instead of "xmldoc.xml"

Quote:

quote:Originally posted by joefawcett

Quote:

quote:Originally posted by pgtips

Quote:

Looks like the problem is in the client-side code, the image data is not being sent:

Code:

function CreateXml()
{
...
    senv+="<imgdata></imgdata>\n";
...

This part is supposed to add the image data.

Code:

var oDoc=new ActiveXObject("Microsoft.XMLDOM");
            oDoc.loadXML(senv);
            var oNode=oDoc.selectSingleNode("//imgdata");
            oNode.dataType="bin.base64";
            oNode.nodeTypedValue=ostream.Read();
            Textarea1.value=oDoc.xml;

            xmlhttp.Send(senv);
            ostream.Close();

Trying to establish if the Textarea1 shows the binary data...
It won't work on a decent parser because the imagedata node is not selected properly, it's in a namespace. But in that case the code should error. It's such a messay post it's hard to know what's happening :)

--

Joe (Co-author Beginning XML, 3rd edition)

hi2all · August 3rd, 2006, 04:02 PM

Hi mookashi
I am facing the same problem with .NET here and the situation is same as yours.
Can you please tell me how you did solve the issue?
If possible can you post /or send me the snippet which takes care of reading the binarydata from XML and saving as tiff file
My code goes like this and i am not able to assign the datatype
        Dim node As MSXML2.IXMLDOMNode
        Dim odoc As New MSXML2.DOMDocument50
        Dim inputXML As String = "C:\SUPPORT\testcode\VBXML\Input\PublishDocImagesJ msReq.xml"
        Try

            odoc.load(inputXML)
            odoc.async = False
            Dim oStream As New ADODB.Stream
            oStream.Type = 1 '//Binary
            oStream.Open()
            node = odoc.documentElement.selectSingleNode("//ContentInByteArray")
            node.dataType = "bin.base64"
            oStream.Write(node.nodeTypedValue)
            oStream.SaveToFile(PUBLISH_REQUEST_DECODED_TIFFFIL E)
            oStream.Close()
        Catch ex As System.Exception
            System.Console.WriteLine("{0}", ex.Message)

Appreciate your early response

Quote:

quote:Originally posted by mookashi
hi,
im a new member to this forum. i am having a problem displaying the image passed over through an XML document.

my VB application receives an xml document in which one of the elements has base64encoded data of tiff image. Now i want to read this data and save the image in the local disk. i understand that we have to decode the data and then write into the disk in binary mode and all that. i have tried many options but nothing works. whenever i try to open the image that i have saved it says invalid data format. here's what im trying to do:

     Dim objFile as scripting.FileSystemObject
     Dim objImageFile as scripting.TextStream
     Dim btArr() as Byte

        strBody = oNode.Text
' This node contains the base64 encoded data
' I have even tried strBody=oNode.nodeTypedValue

        strBody = Replace(strBody, "\r\n", "")
        strBody = Replace(strBody, " ", "")
        strBody = Replace(strBody, vbCrLf, "")
        strBody = Replace(strBody, vbTab, "")

        strBody = CStr(Base64decode(strBody))
        btArr = strBody
' can i directly assign a string to a byte array as done above

     Set objImageFile = objFile.CreateTextFile("C:\test.tif", True)
     objImageFile.Write (btArr)
     objImageFile.Close

where im i going wrong?????

joefawcett · August 3rd, 2006, 05:52 PM

Can you show the structure of the XML? You must also set the async property before loading the doc. The load method returns true or false. If false your file is malformed. The element holding the data should already be of type base64, there's no need to set it. One final thing is that version 5.0 may not support xdr schemas. Try with version 4.0. Why not use .net XML rather than COM?

--

Joe (Microsoft MVP - XML)