#translation #gettext #data-format

polib

Read, manipulate and store translation data in GNU gettext PO format

3 releases (breaking)

0.3.0 Dec 13, 2025
0.2.0 Mar 11, 2023
0.1.0 Jan 20, 2022
0.0.1 Jan 15, 2022

#1 in #translation

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52,039 downloads per month
Used in 11 crates (10 directly)

MIT license

70KB
1.5K SLoC

polib

crates.io License: MIT GitHub Actions

A Rust library to read, manipulate and write GNU gettext translation data in .po format.

Basic Concepts

A Message represents a translation of a text entry from the source language to a target language.

A Catalog holds a collection of Messages, and is stored in a .po file.

Example

Iterate over messages in a .po file

use polib::po_file;
use std::error::Error;
use std::path::Path;

fn main() -> Result<(), Box<dyn Error>> {
    let catalog = po_file::parse(Path::new("foo.po"))?;
    for message in catalog.messages() {
        if message.is_translated() {
            if message.is_singular() {
                println!("{} => {}", message.msgid(), message.msgstr()?);
            } else { // message.is_plural()
                println!("{} => {}", message.msgid(), message.msgstr_plural()?.join(", "));
            }
        } else {
            println!("{} is untranslated", message.msgid());
        }
    }
    Ok(())
}

Remove untranslated or fuzzy entries and save to another .po file

let mut catalog = po_file::parse(Path::new(&input_file))?;
let mut filtered: usize = 0;
for mut message in catalog.messages_mut() {
    if !message.is_translated() || message.is_fuzzy() {
        message.delete();
        filtered += 1;
    }
}
po_file::write_to_file(&catalog, Path::new(&output_file))?;
println!("{} untranslated or fuzzy translations removed.", filtered);

Fill in missing translations from some other translation service

let mut catalog = po_file::parse(Path::new(&input_file))?;
for mut message in catalog.messages_mut() {
    if !message.is_translated() {
        if message.is_singular() {
            message.set_msgstr(/* some 3rdparty provided */translate(message.msgid()))?;
        }
    }
}
po_file::write_to_file(&catalog, Path::new(&output_file))?;

Compile a .po file to .mo format

mo_file::compile_from_po(Path::new(&input), Path::new(&output))?;

Documentation

Refer to docs.rs.

Dependencies

~225KB