Revision as of 14:50, 1 March 2021

Syntax Check and Valid OSIS/TEI files

An OSIS or TEI test is an XML Document that must be:

1. Well formed, it means that its syntax must conforms to the XML specs. An XML file that is not well formed is not an XML file.
2. Valid. A valid XML document is well-formed and conforms to the formal definition provided in a schema (or DTD). A document cannot have elements, attributes, or entities not defined in the schema. A schema can also define how entities may be nested, the possible values of attributes, etc.

There are online facilities for XML validation, many programs capable of schema validation exist and most XML editors (XML Copy Editor, Oxygen, XMLSpy, Topologi, etc.) support some sort of XML schema validation.

Bible Technologies Group

The BTG that sponsored the OSIS committee and hosted the OSIS schema no longer exists. The schema location therefore now needs to be for a local copy on your computer or to a copy hosted by CrossWire or elsewhere.

For more up to date details, see OSIS 211 CR which includes CrossWire's own updated schema.

Schema

Before validating XML files, you first need to download a schema from Crosswire.

• For OSIS encoded source files: osisCore.2.1.1-cw-latest.xsd:

https://www.crosswire.org/~dmsmith/osis/osisCore.2.1.1-cw-latest.xsd

• For TEI encoded source files: teiP5osis.2.5.0.xsd:

http://www.crosswire.org/OSIS/teiP5osis.2.5.0.xsd

Online validators

The first and simpliest option for checking an XML file is to use online validators. They will check if your XML is both well-formed and valid.

Here are two websites, you'll find others on the Internet.

- Core Filing XML Schema Validator

 https://www.corefiling.com/opensource/schemaValidate/
 Accept huge files (tested with a 5.5MB file)

- FreeFormatter Validator

 https://www.freeformatter.com/xml-validator-xsd.html
 The maximum size limit for file upload is 2MB

With these validators, you have to upload the XML File and the schema (.xsd) file to the website before validating.

We no not recommend online validation, it may raises privacy concerns with copyright texts, and although it may be fine for a one shot validation task, it becomes quickly boring when you're creating and editing a text and want periodically validate your work.

CLI Validators

When you're editing a text, one of the fastest option for checking your XML is to use a CLI tool.

xmllint

The simplest way is to use the xmllint program included with libxml2. For Mac and Linux users, you likely already have xmllint installed. Windows users willing to try xmllint will find interesting instructions here: https://techrina.net/2019/01/25/using-xmllint-program-for-windows-7/

To validate an OSIS xml file enter:

   xmllint --noout --schema osisCore.2.1.1-cw-latest.xsd test.osis.xml

To validate a TEI xml file enter:

   xmllint --noout --schema teiP5osis.2.5.0.xsd test.tei.xml

xmlstarlet

XMLStarlet is an open source XML toolkit that you can use with Linux, Mac or Windows. XMLStarlet is linked statically to both libxml2 and libxslt, so generally all you need to process XML documents is one executable file, it may be a better option for Windows users.

On Linux, xmlstarlet is available as a regular package.

For Mac or Windows, the download page is at: http://xmlstar.sourceforge.net/download.php

To validate a TEI XML file enter:

   xmlstarlet val --xsd ../../schemas/teiP5osis.2.5.0.xsd test.tei.xml

Xerces

Xerces is Apache's collection of software libraries for parsing, validating, serializing and manipulating XML. The implementation is available in the Java, C++ and Perl programming languages, the Java version having the most features.

xerces-c

On Ubuntu/debian, you can install xerces-c tools:

   apt install libxerces-c-samples

To validate an OSIS XML file enter:

   StdInParse -v=always -n -s < test.osis.xml.

You'll find the full syntax here: https://xerces.apache.org/xerces-c/stdinparse-3.html

xsd-validator by Adrian Mouat

There isn’t a simple way to immediately run the Xerces validator in Java from the command line. For that reason, Adrian Mouat wrote a Java program to solve this issue.

It's called 'xsd-validator', for installing it:

Either clone the git repository at: https://github.com/amouat/xsd-validator.git or download xsd-validator zip from: https://github.com/amouat/xsd-validator/releases/download/v1.0/xsdv-1.0.zip

To validate an OSIS XML file enter:

   cd xsd-validator
   ./xsdv.sh osisCore.2.1.1-cw-latest.xsd test.osis.xml

There is also a cmd file that you can use to run xsdv from a windows Command Prompt.

For installing xsd-validator, run:

   sudo ant install

Editors Supporting Validation

The final choice is to use an editor with validation on the fly. If you’re doing a lot of XML editing and validation it may well be worth looking into one of the editors listed below.

NOTE: If for any reason they do not find a schema, many editor silently fallback to only checking if the file is well-formed, which may generate false-positive results. To be sure, run the Solomon test: Add tag <solomonTest /> in your text. This tag conforms to the XML specifications but is not part of our schemas, so the editor must show up an error.

Notepad++

With XML Tools plugin for Notepad++, Notepad++ will allow you to clean up unformatted files, check XML syntax function if you want just to check your existing XML file for errors, or use Enable Auto Validation for automatic validation of code as it is being written among other features.

Go to the “Plugins” menu, then to “Plugin Manager”, then “Show Plugin Manager”. Look for XML Tools in the opened window, set the checkbox, and click the button “Install”.

You must restart Notepad ++ after installation.

Sublime Text

Validate XML files on the fly with this Sublime Text 3 plugin:
https://packagecontrol.io/packages/Exalt

Emacs

It's a little bit tricky, but you can configure Emacs to provide the following features:

• Easy navigation
• Validation on the fly
• Auto completion

Use nxml-mode for editing XML

The first thing to do is to force Emacs to use nxml mode instead of xml mode when editing XML files. nxml-mode uses the nXML extension to provide automatic validation and lots of other helpful functions for editing XML files.

Add the following lines to your ~/.emacs file:

    (setq auto-mode-alist (cons '("\\.xml$" . nxml-mode) auto-mode-alist))
    (setq auto-mode-alist (cons '("\\.xsl$" . nxml-mode) auto-mode-alist))
    (setq auto-mode-alist (cons '("\\.xhtml$" . nxml-mode) auto-mode-alist))
    (setq auto-mode-alist (cons '("\\.page$" . nxml-mode) auto-mode-alist))

    (autoload 'xml-mode "nxml" "XML editing mode" t)

    (eval-after-load 'rng-loc
       '(add-to-list 'rng-schema-locating-files "~/.schema/schemas.xml"))

If you are using Emacs 24 or higher, you will also need this line that will give you auto-completion:

   (global-set-key [C-return] 'completion-at-point)

Set-up Crosswire Schemas

nxml-mode validates XML files using schemas in relaxng compact format (.rnc). We have to convert our files from .xsd format to .rnc.

Converting XSD is a very hard task; the XSD specification is complex. It seems that available command line tools that convert from xsd (XML Schema) to rng (RelaxNG) have problems of some sort.

We use Sun RELAX NG Converter, nowadays bundled with the (Sun) 'Multi-Schema Validator' to convert .xsd to .rng, then we use trang to convert .rng to .rnc:

Install on Fedora:

    # sudo dnf install msv-rngconv trang

Convert from .xsd to .rng:

   rngconv osisCore.2.1.1-cw-latest.xsd > osisCore.2.1.1-cw-latest.rng

Convert from .rng to .rnc

    trang -I rng -O rnc osisCore.2.1.1-cw-latest.rng osisCore.2.1.1-cw-latest.rnc

Tell nxml where to find our schemas

We have already (see above) set the variable rng-schema-locating-files to "~/.schema/schemas.xml

Now, we have to copy our new .rnc schemas in the .schema dir

   mkdir -p ~/.schema
   cp osisCore.2.1.1-cw-latest.rnc teiP5osis.2.5.0.rnc ~/.schema

and create ~/.schema/schemas.xml:

<locatingRules xmlns="http://thaiopensource.com/ns/locating-rules/1.0">
  <namespace ns="http://www.crosswire.org/2013/TEIOSIS/namespace" uri="teiP5osis.2.5.0.rnc"/>
  <namespace ns="http://www.bibletechnologies.net/2003/OSIS/namespace" uri="osisCore.2.1.1-cw-latest.rnc"/>
</locatingRules>

Auto-completion

Type a < character and hit Ctrl+Enter for a list of valid tags. You can type a few letters and hit Tab to use auto-completion. Hit Enter to insert the given tag. This also works with attributes: simply add a space after the tag, and hit Ctrl+Enter for attribute auto-completion.

Links

https://fedoraproject.org/wiki/How_to_use_Emacs_for_XML_editing https://lgfang.github.io/mynotes/emacs/emacs-xml.html#sec-9 https://www.emacswiki.org/emacs/NxmlMode

Validating from Windows Explorer

Here is a simple application for validating XML files from within Windows Explorer.

https://www.codeproject.com/Articles/8431/A-Simple-XML-Validator

Python

It's relatively straighforward to validate a file with Python:

Let's create simplest validator.py

    from lxml import etree

    def validate(xml_path: str, xsd_path: str) -> bool:

        xmlschema_doc = etree.parse(xsd_path)
        xmlschema = etree.XMLSchema(xmlschema_doc)

        xml_doc = etree.parse(xml_path)
        result = xmlschema.validate(xml_doc)

        return result

then write and run main.py

    from validator import validate

    if validate("path/to/file.xml", "path/to/scheme.xsd"):
        print('Valid! :)')
    else:
        print('Not valid! :(')