Re: [xml] external DTD validation of large XML's

[Jon <jon forums gmail com>]

> I am new to the libxml2 api and am looking to use it to create a simple tool that can validate large xml 
> files via external DTDs, and eventually XSDs. I've successfully built libxml2 on win7 using a mingw 
> toolchain and plan to build the tool as a statically linked exe for windows.
>
> I've found http://mail.gnome.org/archives/xml/2004-July/msg00055.html and 
> http://mail.gnome.org/archives/xml/2009-November/msg00039.html and would appreciate pointers in the right 
> direction, either sections in xmllint.c to review or ideas on how to use the Reader api to do this.
>
> I'm more concerned about memory usage and speed and have no preference between using the SAX2 or Reader 
> apis.


After skimming xmllint.c I want to confirm that my understanding of the following is correct.

1) The only way to use xmllint to validate against an external DTD file is

   xmllint --dtdvalid luddite.dtd file1.xml file2.xml ...

and the following will not work as neither `testSAX()` nor `streamFile()` validate against an external DTD 
file:

   xmllint --sax --dtdvalid luddite.dtd file1.xml ...
   xmllint --stream --dtdvalid luddite.dtd file1.xml ...


2) Does the following mean that when using libxml2's SAX functionality a document representation of the 
entire input XML is created in memory?

   http://git.gnome.org/browse/libxml2/tree/xmllint.c#n1711


3) As of v2.7.8 and using the Reader API, there is no way to validate using an external DTD similar to

   http://git.gnome.org/browse/libxml2/tree/xmllint.c#n1881
   http://git.gnome.org/browse/libxml2/tree/xmllint.c#n1896


4) As of v2.7.8 and using the Reader API, there is no way to a posteriori validate using an external DTD 
similar the following. A posteriori DTD validation is only available after parsing a full DOM into memory.

   http://git.gnome.org/browse/libxml2/tree/xmllint.c#n2759


If the above are correct, what do you suggest to people who want to use libxml2 to validate large XMLs with 
external DTD files?  Re-write the input XML file?

Jon

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