Prevent DTD download when parsing XML

Question

When using XmlDocument.Load , I am finding that if the document refers to a DTD, a connection is made to the provided URI. Is there any way to prevent this from happening?

Answer 1

This is actually a flaw in the XML specifications. The W3C is bemoaning that people all hit their servers like mad to load schemas billions of times. Unfortunately just about no standard XML library gets this right, they all hit the servers over and over again.

The problem with DTDs is particularly serious, because DTDs may include general entity declarations (for things like & -> &) which the XML file may actually rely upon. So if your parser chooses to forgo loading the DTD, and the XML makes use of general entity references, parsing may actually fail.

The only solution to this problem would be a transparent caching entity resolver, which would put the downloaded files into some archive in the library search path, so that this archive would be dynamically created and almost automatically bundled with any software distributions made. But even in the Java world there is not one decent such EntityResolver floating about, certainly not built-in to anything from apache foundation.