eloiGarrido / enhanceNextBus

enhanceNextBus

NextBus is a feed service that provides information about trains and buses in the United States. The information they serve includes agencies, routes, schedules, stops, vehicle location and more in XML format.

This code implements a little NextBus service JSON converter in python Tornado. The web-server, once running, creates a tunnel which redirects all RESTful queries to NextBus service (http://webservices.nextbus.com). Upon reception, the code translates the resulting query information into JSON format and presents it to the user via web interface.

Web server deployment

In order to run the web-server, several libraries have to be present in the destination computer.

1. Clone repository.

   First, install git in order to clone repository files.

   sudo apt-get install git
   

   To clone the repository, execute the following command in the directory of your choice.

   git clone https://github.com/eloiGarrido/enhanceNextBus.git
   

   This will download the web-server within the directory enhanceNextBus.

2. Install python3, and git if not already present in your computer.

   Validate if python is already installed.

   sudo apt-get update
   sudo apt-get -y upgrade
   python3 -V
   

   Output should be similar to:

   Python 3.5.2
   

   To install python packages pip library or similar is required. Install pip

   sudo apt-get install -y python3-pip
   

   These few previous steps can be executed using the setup.sh script located in /setup/setup.sh. Which will first install the system requirements and then attempt to install all required python libraries.

3. Manually install python libraries (Optional)

   If you have not run the installation script or you have encountered a problem you could try to install the python packages manually. To that end, run the following command:

   sudo pip3 install appdirs==1.4.3 packaging==16.8 pyparsing==2.2.0 six==1.10.0 tornado==4.4.3 xmljson==0.1.7 xmltodict==0.10.2
   

   Validate the correct installation with the command:

   pip3 freeze
   

4. Use Docker image (Optional)

   Optionally, one can download the docker image with the system set from:

   docker pull jesther21/nextbus_ubuntu
   

Run web server

Once the system has been deployed one can run the unittests to validate that the installation has been successful.

1. Go to enhancedNextBus/handlers and run the run_unittests.sh script.

   cd enhancedNextBus/handlers
   ./run_unittests.sh
   

   (optional) If permissions have not been set for the script one can modify with:

   chmod 777 run_unittests.sh
   

   This script should return OK after running a few unittest. Those test check a few system functions, like information caching and proper performance of custom endpoints as well as a few comparisons between expected regular nextBus API use against this web-server tunnel.

2. Launch web-server

   To launch the web server go to the root folder and execute the run.sh script in the same fashion as the unittest script. The terminal will show the message: Starting server on port 8888 when the server is ready to receive requests.

Web server use cases

This web-server accepts the same commands as NextBus Public XML Feed. However, in order to differentiate ourselves the access end point has been modified and two more endpoints have been added.

1. General nextBus tunnel queries:

   NextBus service uses query commands with the format:

   http://webservices.nextbus.com/service/publicXMLFeed?command=commandName&a=agency_tag&additionParams...
   

   Our system uses the same general format except that changes the endpoint link. Instead of using http://webservices.nextbus.com/service/publicXMLFeed the web-server uses http://localhost:8888/publicJSONFeed

   Therefore, an example query would look like:

   http://localhost:8888/publicJSONFeed?command=agencyList
   

   All the queries allowed by NextBus can be found in: https://www.nextbus.com/xmlFeedDocs/NextBusXMLFeed.pdf​.

   Apart from the common endpoints, this web-server provides two more endpoints:

   http://localhost:8888/queryCounter
   http://localhost:8888/slowestQueries
   

   The first will return the number of times a certain query has been called to a specific web-server instance.

   The second query will return a list of the 5 slowest queries performed by a specific instance of the web-server.