ABCpdf (AddImageUrl) not working in IIS 7.5 for localhost

Question

We have been using ABCpdf for years now. In fact we are on version 6.1 still. It has just always worked. But we have recently upgraded to Windows 2008 x64 / IIS 7.5.

Our code that converts HTML pages (Invoices) to PDF now does not work. The basics are that there is a QueryString based URL that renders the Invoice in HTML, this allows us to "preview" it, then to send it to the client we use ASP .NET to execute the ABCpdf code (calling that same URL from the server to the server). This time the output is PDF, and that's what is attached to an email and sent off to the client.

Pretty simple and straight forward stuff right?

This is what we noticed about ABCpdf:

1) PdfObj.AddImageUrl("http://localhost/..."); // Localhost does not work.
2) PdfObj.AddImageUrl("http://127.0.0.1/..."); // Local IP does not work.
3) PdfObj.AddImageUrl("http://41.XX.XX.XX/..."); // Live IP does not work.
Now this:
4) PdfObj.AddImageUrl("http://www.google.com/"); // Works perfectly!

So we know the code and everything about it technically can and does work.

But it seems that any time the AddImageUrl() function calls a location that points to itself, the page does not render and we get "Unable to render HTML. Page load timed out. Unable to load page."

I know it's not to do with the timeout because if I use Fiddler (on the server) to execute the exact same code, it works perfectly.

I suspect this is to do with permissions... what what permissions? I read this: "... this is because ABCpdf uses the Microsoft MSHTML component" but how do I set the permissions on this component. I have already turned off "IE ESC".

What am I missing?

Answer 1

So it turned out after fiddling with just about every setting, that it came down to the fact that IIS did not allow URL calls from w3wp.exe to the same "site" within the same IIS.

There is more on that here: http://support.microsoft.com/kb/316451

It wasn't the "MSXML2.ServerXMLHTTP.3.0" requests, these seems to work - and why it was so confusing. But in ABC PDF, there is obviously something similar, and so IIS was blocking it... in fact the entire "site" locked up while it was failing.

In the end all it took was to make a clone of the main site ("site2"), and changing the URL that was parsed to ABC pdf to use the clone site.