How to use the command xml validate (with examples)

The xml validate command is used to validate XML documents against specified schemas. It can be used to check if XML documents are well-formed, validate against a Document Type Definition (DTD), XML Schema Definition (XSD), or Relax NG schema (RNG). The command provides a comprehensive tool for XML validation.

Use case 1: Validate XML documents for well-formedness

Code:

xml validate path/to/input1.xml|URI input2.xml ...

Motivation: This use case is useful when you want to quickly check if one or more XML documents are well-formed. Well-formedness means that the XML syntax is correct, with properly nested tags, closed elements, and valid attribute values.

Explanation: In this use case, you simply need to provide the path to the XML document(s) you want to validate. You can specify multiple documents, separated by spaces. The path/to/input.xml represents the path to the XML document file, or you can use a URI to directly validate an XML document available on the web.

Example output:

path/to/input.xml: valid
URI: valid

Use case 2: Validate XML documents against a Document Type Definition (DTD)

Code:

xml validate --dtd path/to/schema.dtd path/to/input1.xml|URI input2.xml ...

Motivation: When you have XML documents that should adhere to a specific structure defined by a DTD, this use case comes in handy. You can ensure that the XML documents conform to the rules and constraints specified in the DTD.

Explanation: In this use case, you specify the path to the DTD file using the --dtd flag, followed by the path to the XML document(s) you want to validate. Similar to the previous use case, you can provide multiple documents to validate.

Example output:

path/to/input.xml: valid
URI: valid

Use case 3: Validate XML documents against an XML Schema Definition (XSD)

Code:

xml validate --xsd path/to/schema.xsd path/to/input1.xml|URI input2.xml ...

Motivation: XML Schema Definitions (XSD) provide a flexible and powerful way to define the structure, datatypes, and constraints of XML documents. This use case allows you to check if XML documents conform to the rules defined in the XSD.

Explanation: To validate against an XSD, you use the --xsd flag followed by the path to the XSD file. Then, provide the path to the XML document(s) you want to validate. You can validate multiple documents by separating the paths/URIs with spaces.

Example output:

path/to/input.xml: valid
URI: valid

Use case 4: Validate XML documents against a Relax NG schema (RNG)

Code:

xml validate --relaxng path/to/schema.rng path/to/input1.xml|URI input2.xml ...

Motivation: Relax NG schemas (RNG) provide a simpler and more human-readable alternative to XML Schema Definitions. This use case allows you to validate XML documents against the specified RNG schema.

Explanation: With the --relaxng flag, you can specify the path to the RNG schema file. Then, provide the path to the XML document(s) you want to validate. Multiple documents can be validated by separating the paths/URIs with spaces.

Example output:

path/to/input.xml: valid
URI: valid

Use case 5: Display help for the validate subcommand

Code:

xml validate --help

Motivation: If you are unsure about the available options or usage of the validate subcommand, this use case allows you to display detailed help information.

Explanation: By providing the --help flag after the xml validate command, you can get information about the command itself, available options, and examples of usage. This is useful for understanding the capabilities and syntax of the command.

Example output:

Usage: xml validate [OPTIONS] [PATHS-or-URIs ...]
  -d, --dtd STRING          check validity against DTD
  -s, --xsd STRING          check validity against XML Schema
  -r, --relaxng STRING      check validity against Relax NG
  -h, --help                display this help and exit

Conclusion:

The xml validate command is a powerful tool for validating XML documents against various schemas. It provides different options to validate for well-formedness, against DTDs, XSDs, and RNG schemas. By understanding the use cases and syntax presented above, you can easily validate XML documents with confidence.