RSS Newsfeed

[Dennis Allen]

Hi. I wrote a simple asp script to read various rss newsfeeds. I got
one newsfeed, however, that comes back with a runtime error ['null' is
null or not an object]. Here's the code, distilled to the point of
error:

//
function xml_load(src) {
try {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
}
catch (e) {
alert(e)
return null
}
return xmlDoc
}
//
function xml_start() {
var xmlDoc = xml_load("http://stardate.org/feeds/rss.xml")
if (typeof(xmlDoc) != "object") return ''
var root = xmlDoc.documentElement
if (typeof(root) != "object") return ''
if (typeof(root.childNodes) != "object") return '' // bombs here
}
I'm at a loss. How can you have a xmlDoc object having no childNodes?
Is there something wrong with the file http://stardate.org/feeds/rss.xml
? No encode statement? Any advice would be appreciated...Dennis

[VK]

Dennis Allen wrote:

Hi. I wrote a simple asp script to read various rss newsfeeds. I got
one newsfeed, however, that comes back with a runtime error ['null' is
null or not an object]. Here's the code, distilled to the point of
error:

//
function xml_load(src) {
try {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
}
catch (e) {
alert(e)
return null
}
return xmlDoc
}
//
function xml_start() {
var xmlDoc = xml_load("http://stardate.org/feeds/rss.xml")
if (typeof(xmlDoc) != "object") return ''
var root = xmlDoc.documentElement
if (typeof(root) != "object") return ''
if (typeof(root.childNodes) != "object") return '' // bombs here
}
I'm at a loss. How can you have a xmlDoc object having no childNodes?
Is there something wrong with the file http://stardate.org/feeds/rss.xml
? No encode statement? Any advice would be appreciated...Dennis

As the first guess the stargate.org's admin did not set MIME for XML
('text/xml'). As the result responseXML cannot be used by XMLDOM (but
naturally XMLDOM as object still exists).
As XML/XLT serving remains (still!) a rather new bist, it is more
secure do not count on server admins but use MSXML parser for
responseText, here you will not wail.
The all times winner link:
<http://support.microsoft.com/Default.aspx?id=893659>

[Martin Honnen]

Dennis Allen wrote:

Hi. I wrote a simple asp script to read various rss newsfeeds. I got
one newsfeed, however, that comes back with a runtime error ['null' is
null or not an object]. Here's the code, distilled to the point of
error:

//
function xml_load(src) {
try {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
These (e.g. Microsoft.XMLHTTP) are program ids that make sense on the
client where you don't know which MSXML version is installed but in an
ASP script on the server you should find out which MSXML version is
installed and use one. In particular there is a special server side
version of XMLHTTP, e.g. for MSXML 4 Msxml2.ServerXMLHTTP.4.0.
xmlhttp.open("GET",src,false)
xmlhttp.send()
To find out what is happening respectively what is going wrong you can
examine
xmlhttp.status
xmlhttp.statusText
xmlhttp.getAllResponseHeaders()
xmlDoc = xmlhttp.responseXML
and then here
xmlDoc.parseError.errorCode
xmlDoc.parseError.reason
}
catch (e) {
alert(e)

alert in an ASP script? That is not going to work.
--

Martin Honnen
http://JavaScript.FAQTs.com/

[Dennis Allen]

I saw that site. Very confusing. Is it possible to test
xmlhttp.responseXML? If xmlDoc doesn't have the proper properties,
could we create code that would populate xmlDoc?
"VK" <sc**********@yahoo.com> wrote in message
news:11*********************@g49g2000cwa.googlegro ups.com...

Dennis Allen wrote:

Hi. I wrote a simple asp script to read various rss newsfeeds. I
got
one newsfeed, however, that comes back with a runtime error ['null'
is
null or not an object]. Here's the code, distilled to the point of
error:

//
function xml_load(src) {
try {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
}
catch (e) {
alert(e)
return null
}
return xmlDoc
}
//
function xml_start() {
var xmlDoc = xml_load("http://stardate.org/feeds/rss.xml")
if (typeof(xmlDoc) != "object") return ''
var root = xmlDoc.documentElement
if (typeof(root) != "object") return ''
if (typeof(root.childNodes) != "object") return '' // bombs here
}
I'm at a loss. How can you have a xmlDoc object having no
childNodes?
Is there something wrong with the file
http://stardate.org/feeds/rss.xml
? No encode statement? Any advice would be appreciated...Dennis

As the first guess the stargate.org's admin did not set MIME for XML
('text/xml'). As the result responseXML cannot be used by XMLDOM (but
naturally XMLDOM as object still exists).
As XML/XLT serving remains (still!) a rather new bist, it is more
secure do not count on server admins but use MSXML parser for
responseText, here you will not wail.
The all times winner link:
<http://support.microsoft.com/Default.aspx?id=893659>

[VK]

Dennis Allen wrote:

I saw that site. Very confusing. Is it possible to test
xmlhttp.responseXML?

If you want to be academic, *after* readyState==4 you always should:

if (myRequest.getResponseHeader("Content-Type") != "text/xml") {
// I'm in troubles
}

If you want to be a simple guy, *after* readyState==4 you always
should:

if (!myRequest.responseXML) {
// Damn that admin!
}

Even if MIME is not set to "text/xml", the XML content is here
(presuming you have loaded a valid XML file). It's just not considered
to be an XML object. For browser it's a set of strings, nothing more.
You need to *parse* it into XML. It is very easy on IE, rather tricky
on FF and rather impossible on other wannabes.

Before going into details: check myRequest.getResponseHeader on IE from
the site of the question. If it appears that the admin indeed gets his
doughnuts for nothing, let's talk further.

[Dennis Allen]

I tweeked xml_load() :

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
// var szResponse = xmlhttp.responseText
// xmlDoc.loadXML(szResponse)
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}

Something interesting. On the stardate.org xml file, if I change the
code to:

// xmlDoc = xmlhttp.responseXML
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)

....it works. But using this code breaks other newsfeeds (DTD not
found). Is there a way to test for error and use one way, then the
other?

[Dennis Allen]

"VK" <sc**********@yahoo.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

Dennis Allen wrote:

I saw that site. Very confusing. Is it possible to test
xmlhttp.responseXML?

If you want to be academic, *after* readyState==4 you always should:

if (myRequest.getResponseHeader("Content-Type") != "text/xml") {
// I'm in troubles
}

If you want to be a simple guy, *after* readyState==4 you always
should:

if (!myRequest.responseXML) {
// Damn that admin!
}

Even if MIME is not set to "text/xml", the XML content is here
(presuming you have loaded a valid XML file). It's just not considered
to be an XML object. For browser it's a set of strings, nothing more.
You need to *parse* it into XML. It is very easy on IE, rather tricky
on FF and rather impossible on other wannabes.

Before going into details: check myRequest.getResponseHeader on IE
from
the site of the question. If it appears that the admin indeed gets his
doughnuts for nothing, let's talk further.

I tweeked xml_load() :

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
// var szResponse = xmlhttp.responseText
// xmlDoc.loadXML(szResponse)
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}

I hope this is the way it should be written. Something interesting. On
the stardate.org xml file, if I change the code to:

// xmlDoc = xmlhttp.responseXML
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)

....it works. But using this code breaks other newsfeeds (DTD not
found). Is there a way to test for error and use one way, then the
other?

[Dennis Allen]

Hi again. After much trial and error, I found a routine that makes all
the newsfeeds happy:

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
if (typeof(xmlDoc) != "object" ||
xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)
}
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}

[Dennis Allen]

Hi. After much trial and error, I found a routine that makes all the
newsfeeds happy:

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
if (typeof(xmlDoc) != "object" ||
xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)
}
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}

[VK]

Dennis Allen wrote:

Hi. After much trial and error, I found a routine that makes all the
newsfeeds happy:

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
if (typeof(xmlDoc) != "object" ||
xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)
}
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}
Dennis Allen wrote: Hi. After much trial and error, I found a routine that makes all the
newsfeeds happy:

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
if (typeof(xmlDoc) != "object" ||
xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)
}
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}
Dennis Allen wrote: Hi. After much trial and error, I found a routine that makes all the
newsfeeds happy:

//
function xml_load(src) {
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM")
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
xmlhttp.open("GET",src,false)
xmlhttp.send()
xmlDoc = xmlhttp.responseXML
if (typeof(xmlDoc) != "object" ||
xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {
var szResponse = xmlhttp.responseText
xmlDoc.loadXML(szResponse)
}
if (typeof(xmlDoc) != "object") return 'no object defined'
if (xmlDoc.parseError.errorCode != 0) {
var x = ''
x += 'Error in File: ' + xmlDoc.parseError.url + '<br>'
x += 'Error on Line: ' + xmlDoc.parseError.line + '<br>'
x += 'Error Code : ' + xmlDoc.parseError.errorCode + '<br>'
x += 'Error Reason : ' + xmlDoc.parseError.reason
return x
}
return xmlDoc
}

Could be simplier, but it does the trick.

If you add in

if xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {}

block an option for DOMParser:

....
var parser = new DOMParser();
var doc =
parser.parseFromString(xmlhttp.responseText,"appli cation/xml");
....

it will also fix the situation for Firefox and Opera 8
But actually what *really* should be done:
Go to <http://www.vwh.net/services/contactus_form.cfm> (by tracert this
is the host provider of stardate.org), choose "Webmaster" as addressee,
and write him to bring his MIME's headers in the decent state if he
wants to get one more free breakfast doughtnut in his sorry life.

[Dennis Allen]

"VK" <sc**********@yahoo.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...

Could be simplier, but it does the trick.

If you add in

if xmlhttp.GetResponseHeader("Content-Type") != "text/xml") {}

block an option for DOMParser:

...
var parser = new DOMParser();
var doc =
parser.parseFromString(xmlhttp.responseText,"appli cation/xml");
...

it will also fix the situation for Firefox and Opera 8

A block of DOMParser code for Firefox and Opera? How?

[VK]

Dennis Allen wrote:

A block of DOMParser code for Firefox and Opera? How?

So far your code is too Microsoft-oriented. Take something more
universal for the starting point. Maybe the discovery prototype itself
(that started all this biz)? That would be the best:
<http://jibbering.com/2002/4/httprequest.html>

<pseudo-code>
if IE
create XMLHttpRequest using
if IIS server : proper version of MSXML
if client : Microsoft.XMLHTTP
create MicrosoftXMLParser using
if IIS server : proper version of MSXML
if client : Microsoft.XMLDOM

else if XMLHttpRequest supported {
create XMLHttpRequest using
new XMLHttpRequest()
if window.DOMParser available
create MozillaXMLParser using
parser = new DOMParser();

else
XMLHTTP FUBAR

getXMLData

if Content-Type is not "text/xml"
if MicrosoftXMLParser
MicrosoftXMLParser.loadXML(xmlhttp.responseText)
else if MozillaXMLParser

MozillaXMLParser.parseFromString(xmlhttp*.response Text,"application/xml*");

// BTW: why "application/xml*" ???
// But this is what Mozilla docs imply
else
XMLHTTP FUBAR
else
use xmlhttp*.responseXML
</pseudo-code>

[Dennis Allen]

Thanks for the reply. Tested the asp script with IE6, Foxfire, NS7,
Opera, even NS4. No problem with any of the newsfeeds. When I get
time, I'll look into it some more.

"VK" <sc**********@yahoo.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...
Dennis Allen wrote:

A block of DOMParser code for Firefox and Opera? How?

So far your code is too Microsoft-oriented. Take something more
universal for the starting point. Maybe the discovery prototype itself
(that started all this biz)? That would be the best:
<http://jibbering.com/2002/4/httprequest.html>

<pseudo-code>
if IE
create XMLHttpRequest using
if IIS server : proper version of MSXML
if client : Microsoft.XMLHTTP
create MicrosoftXMLParser using
if IIS server : proper version of MSXML
if client : Microsoft.XMLDOM

else if XMLHttpRequest supported {
create XMLHttpRequest using
new XMLHttpRequest()
if window.DOMParser available
create MozillaXMLParser using
parser = new DOMParser();

else
XMLHTTP FUBAR

getXMLData

if Content-Type is not "text/xml"
if MicrosoftXMLParser
MicrosoftXMLParser.loadXML(xmlhttp.responseText)
else if MozillaXMLParser

MozillaXMLParser.parseFromString(xmlhttp*.response Text,"application/xml*");

// BTW: why "application/xml*" ???
// But this is what Mozilla docs imply
else
XMLHTTP FUBAR
else
use xmlhttp*.responseXML
</pseudo-code>