A simple reverse proxy for San Francisco's public transportation powered by NextBus's XML feed.
To run locally:
# run reverseProxy server
$> ./run.sh
# test for common things
$> ./test.sh- Install docker-compose
- docker-compose up
- curl localhost:8080/api/v1/agencyList
- **Used Python Flask, the micro web framework as the reverse proxy broker because it is lightweight and easy to implement
- Redis for caching the responses of NextBus XML feed and storing the api metrics
- Python 2.7
- redis
- requests
- flask
- flask_caching
Design Choices
- Redis was the choice for caching, it supports
key:valuemappings- Redis gives one a scalable cache infrastructure as well as rich representations to cache objects.The metrics are also stored in the Redis database so that all the continers are using the same backend storage and advertising the same statistics.
- Flask as it is a light micro web framework, which is easy to impliment.
- Flask implements the most commonly-used core components of a web application framework, like URL routing, request and response objects, and templates which encompasses all that is required.
Configuration Settings
You can configure reverseProxy in config.ini
- "redis_host" & "redis_port" for caching and storing metrics
- "slow_requests_threshold"
- "cache_timeout"
The application address is, by default, 127.0.0.1:8080/. A brief description of all the end points are given below.
The api/v1/stats endpoint is particular to the state of reverse proxy
| api/v1/stats | Exposes Reverseproxy statistics |
|---|---|
| slow_requests | Lists the endpoints which had response time higher a certain threshold along with the time taken. |
| queries | List all the endpoints queried by the user along with the number of requests for each. |
To reset all the metrics and stats in the redisdb :
| /api/v1/stats/reset | Reset metrics and stats |
|---|
| End points | Description |
|---|---|
| api/v1/agencyList | Lists all agencies. |
| api/v1/routeList/{agency} | Lists all the routes for the agency tag supplied. |
| api/v1/routeConfig/{agency}/{route} | Lists all the stops for the route tag supplied. |
| api/v1/predictByStopId/{agency}/{stopId} | Lists arrival/departure predictions for a stop. |
| api/v1/predictByStop/{agency}/{route}/{stop} | Same as predictByStopId but using the {stop} tag instead {route} tag is required because {stop} tag is associated with a route. |
| api/v1/predictionsForMultiStops/{agency}/{stops} | Lists arrival/departure predictions for multi-stops. The format of the {stops} tag is route or stop . Append more stops using "&" for more stops . |
| api/v1/schedule/{agency}/{route} | Obtain the schedule information for a given {agency} and {route} tags |
| api/v1/messages/{agency}/{route} | List the active messages for the selected route. Append *{/route}*for more routes. |
| api/v1/vehicleLocations/{agency}/{route}/{time} | Lists vehicle locations for the selected {route}. {time} tag is in msec since the 1970 epoch time. If you specify a time of 0, then data for the last 15 minutes is provided. |
Get {agency} tags using `agencyList`
Get {route} tags using `routeList`,
Get {stop} and {stopId} tags using `routeConfig`.
A /{route} tag can be appended if predictions for only one route
are desired.
Append `&useShortTitles=true` to return short titles intended for display
devices with small screens.
api/v1/agencyListapi/v1/routeList/sf-muniapi/v1/routeConfig/sf-muni/Eapi/v1/predictByStopId/sf-muni/15184api/v1/predictByStop/sf-muni/E/5184&useShortTitles=Trueapi/v1/predictionsForMultiStops/sf-muni/N|6997&N|3909&useShortTitles=Trueapi/v1/schedule/sf-muni/Eapi/v1/vehicleLocations/sf-muni/E/0api/v1/stats