Catalog Resolver

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XML documents often rely on Document Type Definitions (DTD). While parsing a document with BaseX elements and entities can be checked for validity with respect to that particular DTD. Currently the DTD is used only for entity resolution.

XHTML for example defines its doctype via the following line:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" ""> 

Fetching the xhtml1-strict.dtd obviously involves network traffic. When dealing with single files this may seem tolerable, but importing large collections might benefit from caching these resources locally. Depending on your connection you will experience significant speed improvements.

XML Entity and URI Resolvers in BaseX

BaseX comes with a default URI resolver that is usable out of the box.

To enable entity resolving you have to provide a valid XML Catalog file. A simple working example for XHTML might look like this:

<?xml version="1.0"?>
<catalog prefer="system" xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
   <rewriteSystem systemIdStartString="" rewritePrefix="file:///path/to/dtds/" />

This rewrites all SystemIds starting with: to file:///path/to/dtds/.

The XHTML DTD xhtml1-strict.dtd and all its linked resources will now be loaded from the specified path.

GUI Mode

Location for the Catalog File

When running BaseX in GUI mode simply provide the path to your XML Catalog file in the Parsing-Tab of the Database Creation Dialog.

Console & Server Mode

To enable Entity Resolving in Console Mode specify the following options:

  • SET CATFILE [path]

Now entity resolving is active for the current session. All subsequent ADD commands will use the catalog file to resolve entities.

The path to your catalog file and the actual entities may be either absolute or are relative to the current working directory.

Please note that entity resolving only works with option: SET INTPARSE false. INTPARSE is set to false by default.

Using the internal parser let's you specify manually whether you want to parse DTDs and entities or not.

Using other Resolvers

There might be some cases when you do not want to use the built-in resolver that Java provides by default (via*).

BaseX offers support for the Apache maintained XML Commons Resolver available for download here. To use it add resolver.jar to the classpath when starting BaseX:

java -cp basex.jar:resolver.jar org.basex.BaseXServer

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