XMLWF(1) XMLWF(1)
NAME
xmlwf - Determines if an XML document is well-formed
SYNOPSIS
xmlwf [ -s] [ -n] [ -p] [ -x] [ -e encoding] [ -w] [ -d output-dir] [ -c] [ -m] [ -r] [ -t]
[ -v] [ file ...]
DESCRIPTION
xmlwf uses the Expat library to determine if an XML document is well-formed. It is non-validating.
If you do not specify any files on the command-line, and you have a recent version of xmlwf, the
input file will be read from standard input.
WELL-FORMED DOCUMENTS
A well-formed document must adhere to the following rules:
The file begins with an XML declaration. For instance, <?xml version="1.0" standalone="yes"?>.
NOTE: xmlwf does not currently check for a valid XML declaration.
Every start tag is either empty (<tag/>) or has a corresponding end tag.
There is exactly one root element. This element must contain all other elements in the document.
Only comments, white space, and processing instructions may come after the close of the root ele-ment. element.
ment.
All elements nest properly.
All attribute values are enclosed in quotes (either single or double).
If the document has a DTD, and it strictly complies with that DTD, then the document is also consid-ered considered
ered valid. xmlwf is a non-validating parser -- it does not check the DTD. However, it does support
external entities (see the -x option).
OPTIONS
When an option includes an argument, you may specify the argument either separately ("-d output") or
concatenated with the option ("-doutput"). xmlwf supports both.
-c If the input file is well-formed and xmlwf doesn't encounter any errors, the input file is
simply copied to the output directory unchanged. This implies no namespaces (turns off -n)
and requires -d to specify an output file.
-d output-dir
Specifies a directory to contain transformed representations of the input files. By default,
-d outputs a canonical representation (described below). You can select different output for-mats formats
mats using -c and -m.
The output filenames will be exactly the same as the input filenames or "STDIN" if the input
is coming from standard input. Therefore, you must be careful that the output file does not
go into the same directory as the input file. Otherwise, xmlwf will delete the input file
before it generates the output file (just like running cat < file > file in most shells).
Two structurally equivalent XML documents have a byte-for-byte identical canonical XML repre-sentation. representation.
sentation. Note that ignorable white space is considered significant and is treated equiva-lently equivalently
lently to data. More on canonical XML can be found at http://www.jclark.com/xml/canonxml.html
.
-e encoding
Specifies the character encoding for the document, overriding any document encoding declara-
tion. xmlwf supports four built-in encodings: US-ASCII, UTF-8, UTF-16, and ISO-8859-1. Also
see the -w option.
-m Outputs some strange sort of XML file that completely describes the the input file, including
character postitions. Requires -d to specify an output file.
-n Turns on namespace processing. (describe namespaces) -c disables namespaces.
-p Tells xmlwf to process external DTDs and parameter entities.
Normally xmlwf never parses parameter entities. -p tells it to always parse them. -p implies
-x.
-r Normally xmlwf memory-maps the XML file before parsing; this can result in faster parsing on
many platforms. -r turns off memory-mapping and uses normal file IO calls instead. Of
course, memory-mapping is automatically turned off when reading from standard input.
Use of memory-mapping can cause some platforms to report substantially higher memory usage for
xmlwf, but this appears to be a matter of the operating system reporting memory in a strange
way; there is not a leak in xmlwf.
-s Prints an error if the document is not standalone. A document is standalone if it has no
external subset and no references to parameter entities.
-t Turns on timings. This tells Expat to parse the entire file, but not perform any processing.
This gives a fairly accurate idea of the raw speed of Expat itself without client overhead.
-t turns off most of the output options (-d, -m, -c, ...).
-v Prints the version of the Expat library being used, including some information on the compile-
time configuration of the library, and then exits.
-w Enables support for Windows code pages. Normally, xmlwf will throw an error if it runs across
an encoding that it is not equipped to handle itself. With -w, xmlwf will try to use a Win-
dows code page. See also -e.
-x Turns on parsing external entities.
Non-validating parsers are not required to resolve external entities, or even expand entities
at all. Expat always expands internal entities (?), but external entity parsing must be
enabled explicitly.
External entities are simply entities that obtain their data from outside the XML file cur-
rently being parsed.
This is an example of an internal entity:
<!ENTITY vers '1.0.2'>
And here are some examples of external entities:
<!ENTITY header SYSTEM "header-&vers;.xml"> (parsed)
<!ENTITY logo SYSTEM "logo.png" PNG> (unparsed)
-- (Two hyphens.) Terminates the list of options. This is only needed if a filename starts with
a hyphen. For example:
xmlwf -- -myfile.xml
will run xmlwf on the file -myfile.xml.
Older versions of xmlwf do not support reading from standard input.
OUTPUT
If an input file is not well-formed, xmlwf prints a single line describing the problem to standard
output. If a file is well formed, xmlwf outputs nothing. Note that the result code is not set.
BUGS
According to the W3C standard, an XML file without a declaration at the beginning is not considered
well-formed. However, xmlwf allows this to pass.
xmlwf returns a 0 - noerr result, even if the file is not well-formed. There is no good way for a
program to use xmlwf to quickly check a file -- it must parse xmlwf's standard output.
The errors should go to standard error, not standard output.
There should be a way to get -d to send its output to standard output rather than forcing the user to
send it to a file.
I have no idea why anyone would want to use the -d, -c, and -m options. If someone could explain it
to me, I'd like to add this information to this manpage.
ALTERNATIVES
Here are some XML validators on the web:
http://www.hcrc.ed.ac.uk/~richard/xml-check.html
http://www.stg.brown.edu/service/xmlvalid/
http://www.scripting.com/frontier5/xml/code/xmlValidator.html
http://www.xml.com/pub/a/tools/ruwf/check.html
SEE ALSO
The Expat home page: http://www.libexpat.org/
The W3 XML specification: http://www.w3.org/TR/REC-xml
AUTHOR
This manual page was written by Scott Bronson <bronson@rinspin.com> for the Debian GNU/Linux system
(but may be used by others). Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1.
24 January 2003 XMLWF(1)
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