gettext-parser
==============
[](http://travis-ci.org/andris9/gettext-parser)
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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](https://github.com/andris9/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**
```javascript
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**
```javascript
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**
```javascript
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**
```javascript
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**
```javascript
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).
```javascript
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](https://github.com/ashtuchkin/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](https://github.com/bnoordhuis/node-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
```json
{
"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](https://github.com/mikeedwards/po2json).
## License
**MIT**