About xml2pong

xml2pong is a simple Python program which extracts translatable content from free-form XML documents and outputs gettext compatible POT files.

It can work it's magic with most "simple" tags, and for complicated tags one has to provide a list of all tags which are "final" (that will be put into one "message" in PO file), "ignored" (skipped over) and "space preserving".

I will try to provide sane defaults for DocBook documents and other common document types (like Gnome Summaries, XHTML). For other kinds of documents, it is possible to use -a (--automatic-tags) to choose suitable translatable pieces. It usually works very well.

Requirements

xml2po 0.20.10 — © 2004, Danilo Segan, forked 2017 by Thomas Schraitle

• Python
• libxml2 and libxml2-python
• xml2po.py (this program)
• GNU gettext (msgfmt, msgmerge tools)

Quick install

To install in the same prefix as intltool:

$ ./setup.py install

Preparing a POTemplate from XML file

$ ./xml2pong -o template.pot file.xml

By default, xml2po treats documents as DocBook. If that's not correct, you may choose another "document mode" by passing option -m MODE on the command line. If there's currently no special module developed for document type you're trying to translate, use option -a for automatic detection of tags, which will work well even for simple DocBook documents.

Get back a translation from a translator

Save a translation to xx.po, where xx is language code of a translation (i.e. "sr" for Serbian, "de" for German, ...).

Execute:

$ ./xml2pong -p xx.po -o file-xx.xml file.xml

Now you've got a nice and translated XML file in file-xx.xml.

Updating a translation

When base XML file changes, the real advantages of PO files come to surface. To merge the translation you need to first produce a new POT file:

$ ./xml2pong -o newfile.pot newfile.xml

And then you need to use gettext "msgmerge" program to merge the translation with the new POT file:

$ msgmerge -o new-xx.po xx.po newfile.pot && mv new-xx.po xx.po

Alternatively, xml2pong provides option -u which does exactly these two steps for you:

$ ./xml2po.py -u xx.po newfile.xml

(Note that there has been a change in suggested behaviour between xml2po versions 1.0.9 and 1.0.10 — previously, you used only "xx", without ".po", what emulated intltool-update behaviour; users [Ismael Olea actually :] found that confusing, so I'm suggesting a full filename now.)

Special handling of document types

If you want to handle some document types in a special way, you may need to write short Python module to do it. Currently, two special document types come with xml2po: "docbook" and "empty".

Look at files modes/docbook.py and modes/empty.py to see how can one write new document handling modules. DocBook module sets "lang" attribute on "article" element, and also adds translators to <articleinfo> element in form of <copyright>s.

The basic features every module must provide are following functions:

• getIgnoredTags: list of tags to be skipped over, unless they're also "final"

• getFinalTags: list of tags that will end up as separate PO messages

• getPreserveSpaceTags: tags for which spaces should not be compressed

• getStringForTranslators: string that will be added to PO file which translators can translate with their names

• getCommentForTranslators: comment that should document what format should translators use to credit themselves

• postProcessXmlTranslation(doc, lang, credits): function which receives current document tree (doc), current language (lang) and list of translators (credits); if applicable, it should set language and credit translators appropriately

If a element name is in both ignored tags and final tags, then it is treated in a somewhat special way. It "resets" the state of parser, but is not included as a separate translable message in PO files.

This is useful with cases like nested lists in other final tags. In DocBook, if we have inside , we'd preferably have it replaced in its entirety, instead of getting in message something like:

<itemizedlist><listitem><placeholder-1/></listitem></itemizedlist>

(where is a another nested , which is itself a final tag). xml2po will try to do best even in cases like this, but giving it a hand can't hurt.

If you don't want to worry about nesting of tags, option "-a" tries to detect what nodes are most suitable as final-tags. This won't work well if one can nest tags indefinitely (like with DocBook documents, where one may have <para>Blah... <orderedlist><listitem>...</para> which may become very long string, what defeats the advantages of PO files).

Caveats

There are several situations in which xml2po produces temporary files. If permissions in current directory are too restrictive, they may cause mysterious breakages, though I have tried to make it act as sanely as possible.

Normally, xml2po doesn't substitute external entities, because such files should be translated by themselves. Unfortunately, Python bindings for libxml2 are not complete, and there's no simple way to detect if entity is external or not. Still, there's a method debugDumpNode which can output relevant data to a filehandle (it doesn't work with StringIO), so I decided to create a temporary file .xml2po-checkingentities in the current working directory. If it is not writeable, instead of showing an error, xml2po will replace every entity.

Option -p file.po depends on program msgfmt being available and in the path. If that fails, you'll see an error.