Fluent Runtime

0.4.0 · active · verified Sat Apr 11

Fluent Runtime is the Python implementation of Project Fluent's runtime component, providing localization capabilities for expressive translations. It handles parsing and formatting of Fluent Localization (FTL) files. The current version is 0.4.0, with new releases occurring infrequently, often in conjunction with updates to the `fluent.syntax` library.

Warnings

breaking Support for Python 2.7 and 3.5 was dropped in version 0.4.0. Users on older Python versions must remain on `fluent-runtime<0.4.0`.
Fix: Upgrade your Python environment to 3.6 or newer.
breaking Major API changes were introduced in version 0.3.0. `FluentBundle.add_messages` was removed in favor of `FluentBundle.add_resource`. Additionally, `bundle.format()` was replaced by `bundle.format_pattern(bundle.get_message().value)` for direct formatting.
Fix: Replace `bundle.add_messages(msgs)` with `bundle.add_resource(FluentResource(msgs))` and update direct `bundle.format()` calls with `bundle.format_pattern(bundle.get_message(message_id).value, args)` or use the higher-level `FluentLocalization.format_value` method.
gotcha `fluent-runtime` is tightly coupled with `fluent.syntax`. Ensure your `fluent.syntax` version is compatible with your `fluent-runtime` version. For `fluent-runtime 0.4.x`, `fluent.syntax 0.19.x` is required.
Fix: Installing `fluent-runtime` via pip will automatically pull in a compatible `fluent.syntax` version. If managing dependencies manually, ensure `fluent.syntax>=0.19,<0.20` is installed alongside `fluent-runtime 0.4.x`.
gotcha For applications requiring locale management, fallback mechanisms, or dynamic resource loading, `FluentLocalization` is the recommended high-level entry point over direct `FluentBundle` usage.
Fix: Migrate direct `FluentBundle` instantiation and usage to `FluentLocalization` for managing multiple bundles and locale resolution in complex applications.

Install

pip install fluent-runtime Install stable version

Imports

FluentResource

from fluent.runtime import FluentResource

FluentBundle
```
from fluent.runtime import FluentBundle
```

FluentLocalization

from fluent.runtime import FluentLocalization

Quickstart

Initializes `FluentResource` objects from FTL strings, then creates `FluentBundle` objects for specific locales. `FluentLocalization` acts as the high-level manager, providing an easy way to switch locales and format messages using `format_value`.

from fluent.runtime import FluentResource, FluentBundle, FluentLocalization
from datetime import datetime

# 1. Define your FTL resources
resource_en = FluentResource("""
hello = Hello, { $name }!
welcome = Welcome, today is {DATETIME($date)}
""")

resource_fr = FluentResource("""
hello = Bonjour, { $name }!
welcome = Bienvenue, aujourd'hui c'est le {DATETIME($date)}
""")

# 2. Create FluentBundles for each locale
bundle_en = FluentBundle(["en-US"], use_isolating=False)
bundle_en.add_resource(resource_en)

bundle_fr = FluentBundle(["fr"], use_isolating=False)
bundle_fr.add_resource(resource_fr)

# 3. Use FluentLocalization as the main entrypoint
loc = FluentLocalization(
    ["en-US", "fr"], 
    [
        lambda locales: bundle_en, # Provider function for 'en-US'
        lambda locales: bundle_fr  # Provider function for 'fr'
    ]
)

# 4. Format messages
message_en_hello, errors_en = loc.format_value("hello", {"name": "World"})
print(f"EN Hello: {message_en_hello}")

message_fr_welcome, errors_fr = loc.format_value("welcome", {"date": datetime.now()})
print(f"FR Welcome: {message_fr_welcome}")

# Example Output:
# EN Hello: Hello, World!
# FR Welcome: Bienvenue, aujourd'hui c'est le 2024-04-11 12:34:56

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