Exceptions¶

All pyuppsala exceptions inherit from Python’s built-in Exception.

exception XmlParseError¶

Raised when the XML input is syntactically malformed (e.g. unclosed tags, invalid characters, unexpected end of input). The error message includes line and column numbers.

from pyuppsala import parse, XmlParseError

try:
    parse("<unclosed")
except XmlParseError as e:
    print(e)  # "1:10: ..."

exception XmlWellFormednessError¶

Raised when the XML violates a well-formedness constraint defined by XML 1.0, such as duplicate attributes or mismatched tags.

from pyuppsala import parse, XmlWellFormednessError

try:
    parse('<root a="1" a="2"/>')
except XmlWellFormednessError as e:
    print(e)  # duplicate attribute error

try:
    parse("<open></close>")
except XmlWellFormednessError as e:
    print(e)  # mismatched end tag

exception XmlNamespaceError¶

Raised when namespace processing fails, such as using an undeclared prefix.

from pyuppsala import parse, XmlNamespaceError

try:
    parse("<ns:root/>")  # "ns" is not declared
except XmlNamespaceError as e:
    print(e)

exception XPathError¶

Raised when an XPath expression cannot be parsed or evaluated.

from pyuppsala import Document, XPathEvaluator, XPathError

doc = Document("<root/>")
doc.prepare_xpath()
xpath = XPathEvaluator()

try:
    xpath.evaluate(doc, "///invalid[")
except XPathError as e:
    print(e)

exception XsdValidationError¶

Raised when an XSD schema itself is invalid (not when an instance document fails validation – that returns ValidationError objects).

from pyuppsala import XsdValidator, XsdValidationError

try:
    # Element declaration missing required 'name' attribute
    XsdValidator("""\
    <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
      <xs:element type="xs:string"/>
    </xs:schema>
    """)
except XsdValidationError as e:
    print(e)

Note

Individual validation failures from XsdValidator.validate() and XsdValidator.validate_str() are returned as ValidationError objects in a list, not raised as exceptions.

Exception hierarchy¶

Exception
├── XmlParseError
├── XmlWellFormednessError
├── XmlNamespaceError
├── XPathError
└── XsdValidationError