Command-line XML validator for Windows

Question

I've always found validation against a schema to be an invaluable ward against thinkos and would like to incorporate validation checks as part of a project where I frequently need to hand-write XML files a few hundred lines in length. My text editor has a fairly nice CLI integration feature, so I'm looking for a command-line validator.

When I didn't find any clear winners via Google, I poked around here and found a similar question, but none of the tools suggested there quite fit my needs:

• libxml (via cygwin) — does not report line numbers; I have no idea where my errors are!
• msxml — cannot be run from the command line?
• xerces-c — seems to require a copy of Visual C?
• xerces2-j — cannot be run from the command line?
• xmlstarlet — insufficient XSD support*

(*The schema I'm validating against uses substitution groups — inappropriately, but it's external to the project, so I can't change it — which causes xmlstarlet to choke even on valid files.)

Normally, this is the point in solving a problem at which I'd give up on looking for an existing solution and reach for the Python-hammer, but Python's XML support is notoriously… well… actually, let's just leave it at "notorious".

So I'm back to looking for a pre-existing tool. My requirements are pretty simple:

• runs on Win32 (Windows XP SP3, specifically)
• command-line; my editor can work with just about any combination of stdin/-out/-err, arguments, temp files, etc.
• reasonably complete XSD support (particularly namespaces and substitution groups)
• reports the line number where the error occurred!

Does such a tool exist? I'd prefer not to have to install Visual Studio and friends (too bloated, IMO), but I do already have both Cygwin and Python installed.

Answer 1

Your first option, xmllint (libxml2), does give line numbers for errors in the xml (and also in the xsd). You probably just need a later version. I just confirmed both using my copy, which is:

>  xmllint --version
xmllint: using libxml version 20627

Example output:

invalidXml.xml:4: element c: Schemas validity error : Element 'c': This element is not expected. Expected is ( b ).
invalidXml.xml fails to validate
<?xml version="1.0"?>
<invalidXmlEg>
  <a/>
<!--  <b></b> -->
  <c/>
</invalidXmlEg>

Where the xsd is:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="invalidXmlEg">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="a" type="xs:string" />
        <xs:element name="b" type="xs:string" />
        <xs:element name="c" type="xs:string" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

NOTE: I have noticed that xmllint will accept elements names that it shouldn't (e.g. "<invalidXml.xsd>"), but this doesn't seem to affect your task.

EDIT adding the "compiled with" part of the version:

 compiled with: Threads Tree Output Push Reader
 Patterns Writer SAXv1 FTP HTTP DTDValid HTML Legacy
 C14N Catalog XPath XPointer XInclude Iconv ISO8859X
 Unicode Regexps Automata Expr Schemas Schematron
 Modules Debug Zlib