CODEWITHSUNDEEP
clibxml2
Priyanka Bhatia
Priyanka Bhatia

Reputation: 97

How to validate an xml file using a schema file in C programming language using libxml2

I have been trying to validate XML file using schema file in my C Code. The validation happens successfully stating whether the file is valid or invalid.

But my issue is it prints valid/invalid only. There should be a report/output as to what was missing in the xml file in case it was invalid. May be something like the line number in XML file.

Hope, i have made my self clear.

Here's my C code:-

 int validateXmlFile()
{
    int iError = 0;
    xmlDocPtr pDoc;
    xmlDocPtr pSchemaDoc;
    xmlSchemaParserCtxtPtr pSchemaCtxt;
    xmlSchemaPtr pSchema;
    xmlSchemaValidCtxtPtr pValidCtxt;
    char * xmlFilename = "C:\\Documents and Settings\\pbhatia\\Desktop\\Schema\\ipt_config.xml";
    char * schemaFilename = "C:\\Documents and Settings\\pbhatia\\Desktop\\Schema\\ipt_config.xsd";

    PRNT(printf("Schema file : %s \n", schemaFilename));
    PRNT(printf("XML file : %s \n", xmlFilename));

    pDoc = xmlReadFile(xmlFilename, NULL, XML_PARSE_NONET);
    if (!pDoc)
        return -1;

    pSchemaDoc = xmlReadFile(schemaFilename, NULL, XML_PARSE_NONET);
    if (!pSchemaDoc)
        return -2;

    pSchemaCtxt = xmlSchemaNewDocParserCtxt(pSchemaDoc);
    if (!pSchemaCtxt)
        return -3;

    pSchema = xmlSchemaParse(pSchemaCtxt);
    if (!pSchema)
        return -4;

    pValidCtxt = xmlSchemaNewValidCtxt(pSchema);
    if(!pValidCtxt)
        return -5;

    // Attempting to validate xml with schema
    xmlSchemaFreeParserCtxt(pSchemaCtxt);
    xmlFreeDoc(pSchemaDoc);

    iError = xmlSchemaValidateDoc(pValidCtxt, pDoc);
        if (iError == 0)
        PRNT(printf("Document in %s is valid \n", xmlFilename));
    else
        PRNT(printf("Document in %s is NOT valid \n", xmlFilename));

    xmlSchemaFree(pSchema);
    xmlFreeDoc(pDoc);
    return 0;
}

Thanks, Priyanka

Upvotes: 3

Views: 3289

Answers (2)

Jarekczek
Jarekczek

Reputation: 7866

From reading xmllint.c source code it turns out that you may setup callbacks for errors and warnings in the context, using xmlSchemaSetValidErrors. In simplest case you forward fprintf and it would simply print errors.

xmlSchemaSetValidErrors(ctxt,
    (xmlSchemaValidityErrorFunc) fprintf,
    (xmlSchemaValidityWarningFunc) fprintf,
    stderr);

UTSL :)

Upvotes: 1

Peter Miehle
Peter Miehle

Reputation: 6070

not an answer to your schame part, but an answer to your "where to find" the error:

  FILE *f = fopen("/temp/xml_err.log", "a");

  xmlDocPtr doc;
  if (f) {
    xmlSetGenericErrorFunc(f, NULL);
  }
  doc = xmlParseMemory(xmlstr, XMLMAXSTRSIZE);
  if (f) {
    fclose(f);
  }

Upvotes: 0

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