How to read dynamically generated XML with Javascript and ActiveX XMLHTTP object?

[mikeyjudkins]

Ive been banging my head on the wall for hours with this one, hopefully
someone will know what Im doing wrong here :\

The Goal:
I have an xml file that is generated on the fly via JSP which I want to
load into a Microsoft.XMLHTTP ActiveX object and manipulate via
javascript on the client side. Data is retreived from the server at the
request of the javascript without having to reload the page.

The Problem:
For the JSP to dynamically output xml, the file must have the extension
JSP, which is set to the mime type of dynamo-internal/html on the
server side (as we are using ATG Dynamo). But the javascript on the
client side will not retrieve anything unless the file extension is
..xml (or the mime type is recognized as text/xml). So the only way I
can get it to work is to change the extension to .xml, which then of
course amkes it so that the server will not process any of the JSP
code.

Ive tried to override the mime type within the javascript, using the
setRequestHeader method after opening the file, but no luck. A call to
alert the value of req.responseXML.xml after the send() turns up empty.
Ive only gotten it to work if I use a static xml file in palce of the
jsp. Sample of the javascript code is below:

if (window.XMLHttpRequest) {
// branch for native XMLHttpRequest object - THIS WORKS
req = new XMLHttpRequest();
req.overrideMimeType("text/xml");
req.onreadystatechange = processReqChange;
req.open("GET", "models.jsp?cId=300006&mId=TAC24", true);
req.send(null);
} else if (window.ActiveXObject) {
// branch for IE/Windows ActiveX version - NOT WORKING
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req) {
req.onreadystatechange = processReqChange;
req.open("GET", "models.jsp?cId=300006&mId=TAC24", true);
req.setRequestHeader("Content-Type","text/xml");
req.send();
}
}

In looking at the following example the Microsoft gives (bottom of
page):

http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q290591&ID=KB;EN-US;Q290591

I just dont see what could be going wrong here.


I should note that I successfully got the script to work using the
XMLHttpRequest object and the overrideMimeType() method. This works
with FireFox adn I think some Mozilla clients, but not with the all
important IE5, which instead uses the XMLHTTP ActiveX control.

Thanks for any help,

Mike

 

[Stanimir Stamenkov]

/[email protected]/:

The Problem:
For the JSP to dynamically output xml, the file must have the extension
JSP, which is set to the mime type of dynamo-internal/html on the
server side (as we are using ATG Dynamo). But the javascript on the
client side will not retrieve anything unless the file extension is
.xml (or the mime type is recognized as text/xml). So the only way I
can get it to work is to change the extension to .xml, which then of
course amkes it so that the server will not process any of the JSP
code.

Probably not that XML specific, but you should set the
'Content-Type' response header in your JSP, always:

http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JSPIntro5.html#wp73360

If you further wish the request URL to end with ".xml", the
JavaServlet specification describes how conforming containers could
be configured (web.xml - mappings between request URLs and
servlets/JSPs). Consult with your Dynamo documentation to see how
it's done there.

Ive tried to override the mime type within the javascript, using the
setRequestHeader method after opening the file, but no luck. A call to
alert the value of req.responseXML.xml after the send() turns up empty.

I have no experience with the 'XMLHttpRequest' object but I don't
think setting a request header could change the response (generated
by the server) in any way.

 

[mikeyjudkins]

It worked after I changed the response header from within the JSP page.
Cant beleive I hadnt thought of that earlier!

 

[Diego Berge]

The Problem:
For the JSP to dynamically output xml, the file must have the extension
JSP, [....]
But the javascript on the
client side will not retrieve anything unless the file extension is
.xml (or the mime type is recognized as text/xml).

In addition to what's been suggested with regards to your specific
problem (set Content-Type response header), you may also want to have a
look at the classic "Cool URLs Don't Change"
<http://www.w3.org/Provider/Style/URI.html> on why file extensions in
URLs are a Bad Thing.

Regards,
Diego Berge.

 

[masantra]

It worked after I changed the response header from within the JSP page.
Cant beleive I hadnt thought of that earlier!

I have the same problem in reading the XML file in IE. I use exactly
the same code, but doesn't work. WHat you mean you change the response
header from within the JSP page? (is JSP refer to JavaScript, btw?)

Thanks,

 

[Martin Honnen]

I have the same problem in reading the XML file in IE. I use exactly
the same code, but doesn't work. WHat you mean you change the response
header from within the JSP page? (is JSP refer to JavaScript, btw?)

If you have a server side application (e.g. CGI, ASP, JSP, PHP)
dynamically generating XML then make sure you set the HTTP response
header to application/xml or some other XML MIME type so in PHP you would do
header('Content-Type: application/xml');
before sending the XML, in ASP
Response.ContentType = "application/xml"