Schema validation
Tutorials |
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This article is one several tutorials, guides, and annotated examples available in this wiki. |
Multipage tutorials: • COLLADA DOM user guide Shorter how-tos: • Using accessors • Schema validation • Using URIs • Various annotated examples Instructions for adding a tutorial |
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The COLLADA format is defined by a W3C schema. If a document doesn't conform to the schema then it isn't valid COLLADA data. This tutorial explains a few different ways to validate a COLLADA document against the COLLADA schema.
Using xmllint
xmllint
is a command-line application that can be used to validate an XML document against a W3C schema. xmllint
is distributed as part of libxml
. You can find binaries for Windows here. Mac OS X and most Linux distributions come with libxml
already installed.
To validate the COLLADA document duck.dae
against the latest COLLADA 1.4 schema available from Khronos, run the following command:
xmllint --noout --schema http://www.khronos.org/files/collada_schema_1_4_1.xsd duck.dae
You could also copy the schema locally and use your local version:
xmllint --noout --schema colladaSchema.xsd duck.dae
The --noout
option prevents superfluous output. If the COLLADA document violates the schema, xmllint
outputs an error message.
Using libxml from a C/C++ Application
Using libxml
, you can validate a COLLADA document against the schema from a C/C++ application. The following code illustrates how it works.
#include "libxml/xmlschemas.h" // libxml error handler void schemaErrorCallback(void*, const char* message, ...) { va_list varArgs; va_start(varArgs, message); vfprintf(stdout, message, varArgs); va_end(varArgs); } // libxml warning handler void schemaWarningCallback(void* callbackData, const char* message, ...) { } // Returns true if file validated successfully, false otherwise bool validate(const string& uri) { bool result = false; if (xmlSchemaParserCtxt* schemaParser = xmlSchemaNewParserCtxt("http://www.khronos.org/files/collada_schema_1_4_1.xsd")) { if (xmlSchema* schema = xmlSchemaParse(schemaParser)) { if (xmlSchemaValidCtxt* validityContext = xmlSchemaNewValidCtxt(schema)) { xmlSchemaSetValidErrors(validityContext, schemaErrorCallback, schemaWarningCallback, /* callback data */ 0); // Returns 0 if validation succeeded result = xmlSchemaValidateFile(validityContext, uri.c_str(), 0) == 0; xmlSchemaFreeValidCtxt(validityContext); } xmlSchemaFree(schema); } xmlSchemaFreeParserCtxt(schemaParser); } return result; }