gettext-parser

Parse and compile gettext po and mo files with node.js, nothing more, nothing less.

This module is slightly based on my other gettext related module node-gettext. The plan is to move all parsing and compiling logic from node-gettext to here and leave only translation related functions (domains, plural handling, lookups etc.).

Usage

Include the library:

var gettextParser = require("gettext-parser");

Parse PO files

Parse a PO file with

gettextParser.po.parse(input[, defaultCharset]) → Object

Where

• input is a po file as a Buffer or an unicode string. Charset is converted to unicode from other encodings only if the input is a Buffer, otherwise the charset information is discarded
• defaultCharset is the charset to use if charset is not defined or is the default "CHARSET" (applies only if input is a Buffer)

Method returns gettext-parser specific translation object (see below)

Example

var input = require('fs').readFileSync('en.po');
var po = gettextParser.po.parse(input);
console.log(po.translations['']); // output translations for the default context

Parse PO as a Stream

PO files can also be parsed from a stream source. After all input is processed the parser emits a single 'data' event which contains the parsed translation object.

gettextParser.po.createParseStream([defaultCharset][, streamOptions]) → Transform Stream

Where

• defaultCharset is the charset to use if charset is not defined or is the default "CHARSET"
• streamOptions are the standard stream options

Example

var input = require('fs').createReadStream('en.po');
var po = gettextParser.po.createParseStream();
input.pipe(po);
po.on('data', function(data){
    console.log(data.translations['']); // output translations for the default context
});

Compile PO from a translation object

If you have a translation object you can convert this to a valid PO file with

gettextParser.po.compile(data) → Buffer

Where

• data is a translation object either got from parsing a PO/MO file or composed by other means

Example

var data = {
    ...
};
var output = gettextParser.po.compile(data);
require('fs').writeFileSync(output);

Parse MO files

Parse a MO file with

gettextParser.mo.parse(input[, defaultCharset]) → Object

Where

• input is a mo file as a Buffer
• defaultCharset is the charset to use if charset is not defined or is the default "CHARSET"

Method returns gettext-parser specific translation object (see below)

Example

var input = require('fs').readFileSync('en.mo');
var mo = gettextParser.mo.parse(input);
console.log(mo.translations['']); // output translations for the default context

Compile MO from a translation object

If you have a translation object you can convert this to a valid MO file with

gettextParser.mo.compile(data) → Buffer

Where

• data is a translation object either got from parsing a PO/MO file or composed by other means

Example

var data = {
    ...
};
var output = gettextParser.mo.compile(data);
require('fs').writeFileSync(output);

Notes

Overriding charset

If you are compiling a previously parsed translation object, you can override the output charset with the charset property (applies both for compiling mo and po files).

var obj = gettextParser.po.parse(inputBuf);
obj.charset = "windows-1257";
outputBuf = gettextParser.po.compile(obj);

Headers for the output are modified to match the updated charset.

ICONV support

By default gettext-parser uses pure JS iconv-lite for encoding and decoding non UTF-8 charsets. If you need to support more complex encodings that are not supported by iconv-lite, you need to add iconv as an additional dependency for your project (gettext-parser will detect if it is available and tries to use it instead of iconv-lite).

Data structure of parsed mo/po files

Character set

Parsed data is always in unicode but the original charset of the file can be found from the charset property. This value is also used when compiling translations to a mo or po file.

Headers

Headers can be found from the headers object, all keys are lowercase and the value for a key is a string. This value will also be used when compiling.

Translations

Translations can be found from the translations object which in turn holds context objects for msgctx. Default context can be found from translations[""].

Context objects include all the translations, where msgid value is the key. The value is an object with the following possible properties:

• msgctx context for this translation, if not present the default context applies
• msgid string to be translated
• msgid_plural the plural form of the original string (might not be present)
• msgstr an array of translations
• comments an object with the following properties: translator, reference, extracted, flag, previous.

Example

{
  "charset": "iso-8859-1",

  "headers": {
    "content-type": "text/plain; charset=iso-8859-1",
    "plural-forms": "nplurals=2; plural=(n!=1);"
  },

  "translations": {
    "": {
      "": {
        "msgid": "",
        "msgstr": ["Content-Type: text/plain; charset=iso-8859-1\n..."]
      }
    }
  },

  "another context": {
    "%s example": {
      "msgctx": "another context",
      "msgid": "%s example",
      "msgid_plural": "%s examples",
      "msgstr": ["% näide", "%s näidet"],
      "comments": {
        "translator": "This is regular comment",
        "reference": "/path/to/file:123"
      }
    }
  }
}

Notice that the structure has both a headers object and a "" translation with the header string. When compiling the structure to a mo or a po file, the headers object is used to define the header. Header string in the "" translation is just for reference (includes the original unmodified data) but will not be used when compiling. So if you need to add or alter header values, use only the headers object.

If you need to convert gettext-parser formatted translation object to something else, eg. for jed, check out po2json.

License

MIT