XML::LibXML::Error - Structured Errors
eval { ... }; if (ref($@)) { # handle a structured error (XML::LibXML::Error object) } elsif ($@) { # error, but not an XML::LibXML::Error object } else { # no error }
$XML::LibXML::Error::WARNINGS=1; $message = $@->as_string(); print $@->dump(); $error_domain = $@->domain(); $error_code = $@->code(); $error_message = $@->message(); $error_level = $@->level(); $filename = $@->file(); $line = $@->line(); $nodename = $@->nodename(); $error_str1 = $@->str1(); $error_str2 = $@->str2(); $error_str3 = $@->str3(); $error_num1 = $@->num1(); $error_num2 = $@->num2(); $string = $@->context(); $offset = $@->column(); $previous_error = $@->_prev();
The XML::LibXML::Error class is a tiny frontend to libxml2 >>>>>'s structured error support. If XML::LibXML is compied with structured error support, all errors reported by libxml2 are transformed to XML::LibXML:Error objects. These objects automatically serialize to the corresponding error messages when printed or used in a string operation, but as objects, can also be used to get a detailed and structured information about the error that occurred.
Unlike most other XML::LibXML objects, XML::LibXML::Error doesn't wrap an
underlying libxml2 >>>>> structure directly, but rather transforms it to a blessed Perl hash reference
containing the individual fields of the structured error information as hash
key-value pairs. Individual items (fields) of a structured error can either be
obtained directly as $@->{field}, or using autoloaded methods such as as
$@->field()
(where field is the field name). XML::LibXML::Error objects have
the following fields: domain, code, level, file, line, nodename, message, str1,
str2, str3, num1, num2, and _prev (some of them may be undefined).
$XML::LibXML::Error::WARNINGS=1;
Traditionally, XML::LibXML was supressing parser warnings by setting libxml2's
global variable xmlGetWarningsDefaultValue to 0. Since 1.70 we do not change
libxml2's global variables anymore; for backward compatibility, XML::LibXML
suppresses warnings. This variable can be set to 1 to enable reporting of these
warnings via Perl warn
and to 2 to report hem via die
.
$message = $@->as_string();
This functions takes serializes a XML::LibXML::Error object to a string containing the full error message close to the message produced by libxml2 >>>>> default error handlers and tools like xmllint. This method is also used to overload "" operator on XML::LibXML::Error, so it is automatically called whenever XML::LibXML::Error object is treated as a string (e.g. in print $@).
print $@->dump();
This function serializes a XML::LibXML::Error to a string displaying all fields of the error structure individually on separate lines of the form 'name' => 'value'.
$error_domain = $@->domain();
Returns string containing information about what part of the library raised the error. Can be one of: "parser", "tree", "namespace", "validity", "HTML parser", "memory", "output", "I/O", "ftp", "http", "XInclude", "XPath", "xpointer", "regexp", "Schemas datatype", "Schemas parser", "Schemas validity", "Relax-NG parser", "Relax-NG validity", "Catalog", "C14N", "XSLT", "validity".
$error_code = $@->code();
Returns the actual libxml2 error code. The XML::LibXML::ErrNo module defines constants for individual error codes. Currently libxml2 uses over 480 different error codes.
$error_message = $@->message();
Returns a human-readable informative error message.
$error_level = $@->level();
Returns an integer value describing how consequent is the error. XML::LibXML::Error defines the following constants:
XML_ERR_NONE = 0
XML_ERR_WARNING = 1 : A simple warning.
XML_ERR_ERROR = 2 : A recoverable error.
XML_ERR_FATAL = 3 : A fatal error.
$filename = $@->file();
Returns the filename of the file being processed while the error occurred.
$line = $@->line();
The line number, if available.
$nodename = $@->nodename();
Name of the node where error occurred, if available. When this field is non-empty, libxml2 actually returned a physical pointer to the specified node. Due to memory management issues, it is very difficult to implement a way to expose the pointer to the Perl level as a XML::LibXML::Node. For this reason, XML::LibXML::Error currently only exposes the name the node.
$error_str1 = $@->str1();
Error specific. Extra string information.
$error_str2 = $@->str2();
Error specific. Extra string information.
$error_str3 = $@->str3();
Error specific. Extra string information.
$error_num1 = $@->num1();
Error specific. Extra numeric information.
$error_num2 = $@->num2();
In recent libxml2 versions, this value contains a column number of the error or 0 if N/A.
$string = $@->context();
For parsing errors, this field contains about 80 characters of the XML near the
place where the error occurred. The field $@->column()
contains the corresponding offset. Where N/A, the field is undefined.
$offset = $@->column();
See $@->column()
above.
$previous_error = $@->_prev();
This field can possibly hold a reference to another XML::LibXML::Error object representing an error which occurred just before this error.
Matt Sergeant, Christian Glahn, Petr Pajas
1.70
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.