[Cartoweb-users] Confused about .po files

Chris Duncan, GISmatters duncan at gismatters.com
Fri Oct 17 00:56:45 EDT 2008

Hi Oliver,

Thanks so much for your patient and clarifying response. Using what 
you wrote and going through the Cartoweb documentation and the web 
again, I now realize something which was not obvious to me before: 
that the whole text translation scheme is a widely-used method, not 
limited just to Cartoweb... Since I have never developed with these 
tools or with internationalization before, I did not know about Gnu 
gettext and the po/mo files; I thought it was something special to 
Cartoweb. Now I can read the gettext documentation to understand much 

One thing is still not quite clear to me: do I need to worry about 
gettext, po/mo files, and all of that if I just want to change some 
pieces of text *without translation* (the example I used last night is 
changing the zoomin tool hover text from "Zoom In" to "Choose this 
tool and click on the map to zoom in")?  I think the answer is "yes" 
-- even though I am not trying to internationalize or translate or 
localize the text, I think I must create po files and add my new text 
as the "translation" for the "zoomin" msgid. Is that correct?

One reason I am still confused on this point is that every reference 
to text and messages in the Cartoweb documentation talks about 
*translation*. There are lots of places that say, more or less, "If 
you need to translate this, you will need gettext... etc". I am not 
translating anything, so at first I thought none of those discussions 
applied to my situation, but now I think that changing the default 
text is basically the same process as translating. Is this correct?

I will continue my reading and then try to make sense of your examples 
and suggestions. Thanks again for starting to point me in the right 
direction. And thanks to you and Bruno for pointing out that gettext 
is apparently needed but not working or not available on my live web 
server... I will look into that problem after I get my development 
system correctly changing the text I'm working on.



Oliver Christen wrote:
> hi
> po are only human readable container for the text<->translation strings
> when running the cw3setup script, the .po get compilated by gettext into 
> binary .mo, these files are located in 
> cartoweb3/locale/*langcode*/LC_MESSAGES/*projectid.projectid.projectid*.mo
> these are the files actualy used by gettext to do the string replacement 
> in real time.
> the .po contains the string you want to translate.
> For convenience, cartoweb include 2 scripts one can use to generate some 
> basic .mo for a given project: client2pot and server2pot.
> These script simply look inside all the files of your project for every 
> strings included into I18n::gt(...) call (in php file) or into 
> {t}...{/t} tag (in templates files). additionaly, the server2pot also 
> get all the layer's labels from either the layers.ini file or the mapfile.
> dynamicaly generated strings will not get "recovered" by those scripts 
> unless someone provided some fake/hidden {t}..{/t} or I18n::gt(...), for 
> example for the tools's labels.
> client.po, server.*projectid*.po, server.po contain the raw 
> (untranslated) list of strings for a given project.
> msgid "IdRecentering"
> msgstr ""
> client.en.po, server.*projectid*.en.po, server.en.po are COPIES!!! of 
> the raw .po but this time they ALSO contain the translated strings for 
> the corresponding language.
> msgid "IdRecentering"
> msgstr "Identifiers recentering"
> to quickly add translations to your projects, you can easily copy the 
> existing .po files provided in cartoweb by default and modify them. You 
> will have some extra translated/unwanted strings but nothing that cant 
> be easily modified/removed if needed.
> copy ALL the .po files into your project's po folder.
> look at an existing demo /po folder to see whats there.
> if you want "clean" po files, you need to run the client2pot and 
> server2pot scripts to generate the RAW po files for your project and 
> then COPY these files and rename them with the extra 2 letters lang tag 
> (.po > .en.po) and EDIT them to add the translations for all the strings 
> you want.
> I would suggest moving/deleting all .po existing in cartoweb3/po/ BEFORE 
> doing that, as if some .po already exist, the script will try to merge 
> their content with the newly extracted content, which may be problematic.
> so once you have emptied the /po folder, go to /cartoweb3/scripts/ and 
> run the command "php client2pot.php *yourprojectid*" and "php 
> server2pot.php *yourprojectid*"
> if you see  ("zoomin", "query_by_bbox") it means the strings are NOT 
> translated.
> check that gettext is installed and that it works correctly (see 
> documentation on how to test that 
> http://www.cartoweb.org/doc/cw3.5/xhtml/user.i18n.html#user.i18n.translations.debug) 
> restart Apache too.
> gettext is a bit buggy and sometimes you need to restart Apache to see 
> the modification you did in the .po files even after you have run the 
> cw3setup script to generate the .mo
> regards
> Oliver
> ----- Original Message ----- From: "Chris Duncan, GISmatters" 
> <duncan at gismatters.com>
> To: "Cartoweb Users" <cartoweb-users at lists.maptools.org>
> Sent: Wednesday, October 15, 2008 11:30 PM
> Subject: [Cartoweb-users] Confused about .po files
>> I am *not* trying to internationalize my application -- for our user 
>> base and local application, there's no need to support any other 
>> language than English.
>> I would like, however, to change some of the text that appears (for 
>> example, in the tips that pop up when you hover over a tool like the 
>> zoom-in tool).
>> I have tried to understand the system of .po files (defaults, 
>> project-specific, alternate languages, sources vs. generated, etc), 
>> but have become completely confused. I have not found enough info in 
>> the documentation or wiki to clear up my confusion.
>> Could someone please provide a simple, clear, concise discussion of 
>> the following (if you don't have lots of time to answer, then please 
>> just skip to item (c) which is my most urgent question):
>> (a) When, and in what order, do .po files get used? For one thing, I'm 
>> confused about what happens when I refresh the installation using 
>> cw3setup vs. what happens at runtime when someone is using the site. I 
>> see that there are *generated* .po files in the htdocs/po folder... I 
>> assume *those* are the ones that actually provide text to the 
>> application at runtime. But even there I find "default" and 
>> project-specific folders and files. Where do "source" files live, and 
>> what is the chain of processing that converts and/or merges them to 
>> create the ones I see in htdocs/po?
>> (b) When do language-specific files get used? If there is both a 
>> client.po and client.en.po file, which one gets used? What is the 
>> interaction of the "generic" vs. the "language-specific" .po files?
>> (c) Last, but most important to me at this time: Suppose I wanted to 
>> change the hover-text of the "zoom in" button to say "Choose this tool 
>> and click on the map to zoom in" (we have some very un-savvy users!). 
>> What specific steps do I follow to make that change in the recommended 
>> way? My project currently has *no* po folder or files... do I copy 
>> them from <cartowebhome>/po and then modify them? Do I need to run 
>> server2pot.php and client2pot.php to initialize them in some way? I'm 
>> totally lost on how to proceed...
>> One final detail that adds to my confusion: on my development machine 
>> (WinXP, Apache server) I get message text like "Zoom in" or "Query by 
>> rectangle" when I hover over the tools; when I upload my project to 
>> the live web server (Windows Server, IIS) the tips are the message IDs 
>> instead of the text ("zoomin", "query_by_bbox"). Why do they differ?
>> Thanks in advance to any of you who can help me understand this! Cheers,
>> Chris
>> -- 
>> Chris Duncan, Ph.D.
>> President
>> GISmatters
>> duncan at GISmatters.com
>> http://www.gismatters.com/
>> 1 Tuckerman Ln
>> Amherst, MA 01002
>> Tel: 413-549-2052
>> Fax: 508-637-2557
>> _______________________________________________
>> Cartoweb-users mailing list
>> Cartoweb-users at lists.maptools.org
>> http://lists.maptools.org/mailman/listinfo/cartoweb-users


Chris Duncan, Ph.D.

duncan at GISmatters.com

1 Tuckerman Ln
Amherst, MA 01002

Tel: 413-549-2052
Fax: 508-637-2557

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