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https://github.com/Intersection/gtfs-realtime-translators
A set of open source Python libraries for translating custom real-time transit data to the GTFS-rt format
https://github.com/Intersection/gtfs-realtime-translators
Last synced: about 2 months ago
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A set of open source Python libraries for translating custom real-time transit data to the GTFS-rt format
- Host: GitHub
- URL: https://github.com/Intersection/gtfs-realtime-translators
- Owner: Intersection
- License: apache-2.0
- Created: 2019-05-16T20:37:42.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2024-03-21T08:39:46.000Z (3 months ago)
- Last Synced: 2024-03-26T04:18:52.331Z (3 months ago)
- Language: Python
- Homepage: https://ixn.intersection.com/found-in-translation-announcing-a-library-of-gtfs-realtime-translators-1d196857dded
- Size: 260 KB
- Stars: 19
- Watchers: 9
- Forks: 2
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome-transit - gtfs-realtime-translators - A Python-based tool to translate custom arrival API formats to GTFS-realtime. As of July 2019 it supports LA Metro and SEPTA. (Uncategorized / Uncategorized)
- awesome-transit - gtfs-realtime-translators - A Python-based tool to translate custom arrival API formats to GTFS-realtime. As of July 2019 it supports LA Metro and SEPTA. (Uncategorized / Uncategorized)
README
# gtfs-realtime-translators
[](https://travis-ci.org/Intersection/gtfs-realtime-translators) [](https://lgtm.com/projects/g/Intersection/gtfs-realtime-translators/alerts/) [](https://lgtm.com/projects/g/Intersection/gtfs-realtime-translators/context:python)
`gtfs-realtime-translators` translates custom arrivals formats to GTFS-realtime. It uses the Google [`gtfs-realtime-bindings`](https://github.com/google/gtfs-realtime-bindings/tree/master/python) for Python, supplemented by Intersection extensions.
## Overview
Following the [GTFS-realtime spec](https://developers.google.com/transit/gtfs-realtime/), its three pillars are:
- `TripUpdate`
- `VehiclePosition`
- `Alert`
A `FeedMessage` is a list of _entities_, each of which is one of the types above. A `FeedMessage` may have entities of different types.
As of 2019-06-15, only `TripUpdate` is supported.
## Installation
```
pip install -e git+https://github.com/Intersection/gtfs-realtime-translators.git@#egg=gtfs-realtime-translators
```
## Usage
### Registry
The registry is used to return a translator for a given translator key. This is useful to decouple the translator lookup via external systems from its implementation.
```
from gtfs_realtime_translators.registry import TranslatorRegistry
translator_klass = TranslatorRegistry.get('la-metro')
translator = translator_klass(**kwargs)
```
### Translators
```
from gtfs_realtime_translators.translators import LaMetroGtfsRealtimeTranslator
translator = LaMetroGtfsRealtimeTranslator(stop_id='80122')
feed_message = translator(la_metro_rail_input_data)
```
At this point, `feed_message` is a standard protocol buffer object and adheres to the normal [Python Protocol Buffer interface](https://developers.google.com/protocol-buffers/docs/pythontutorial).
```
feed_bytes = feed_message.SerializeToString()
```
### Factories
New translators should be contributed back to this library.
```
from gtfs_realtime_translators.factories import TripUpdate, FeedMessage
trip_update = TripUpdate.create(entity_id=entity_id,
arrival_time=arrival_time,
departure_time=departure_time,
trip_id=trip_id,
stop_id=stop_id,
route_id=route_id)
entities = [ trip_update ]
feed_message = FeedMessage.create(entities=entities)
```
## GTFS-Realtime Bindings
### Source `gtfs-realtime.proto`
The GTFS-realtime spec is maintained in the [google/transit](https://github.com/google/transit.git) repository. Currently, since there is no versioned way to programmatically include this in our projects, we must clone it as a manual dependency.
```
git clone https://github.com/google/transit.git ../google-transit
cp ../google-transit/gtfs-realtime/proto/gtfs-realtime.proto gtfs_realtime_translators/bindings/
```
### Re-generate Bindings
For our Python libraries to understand the interface specified by the GTFS-realtime spec, we must generate language bindings.
```
virtualenv ~/.env/gtfs-realtime-bindings
source ~/.env/gtfs-realtime-bindings/bin/activate
pip install grpcio-tools
python3 -m grpc_tools.protoc -I gtfs_realtime_translators/bindings/ --python_out=gtfs_realtime_translators/bindings/ gtfs_realtime_translators/bindings/intersection.proto
```
Since we are using the published spec bindings, we must do one more step. Inside the generated file, `gtfs_realtime_translators/bindings/intersection_pb2.py`, change the following line
```
import gtfs_realtime_pb2 as gtfs__realtime__pb2
```
to
```
from google.transit import gtfs_realtime_pb2 as gtfs__realtime__pb2
```
## Run Tests Locally
```
pip install -r requirements.txt
pip install -e .
pytest
```