This is an interactive visualization of UK Parliament (House of Commons) votes since 1997; it can be viewed online here.

• A series of scripts in the bin/ directory handle retrieving various public data on UK MPs and how they voted, made available by TheyWorkForYou, and extracting the relevant parts of this data into a Postgres database. The bin/setup script demonstrates the order in which these should typically be run.

• A tiny Sinatra server, server/server.rb, serves up the needed data from this database.

• An Elm web app, with entry point client/src/Main.elm, handles most of the UI, including making requests as needed for the above data.

• This communicates with JavaScript, with entry point client/src/index.js, via ports to render the visualization itself; in particular client/src/BubbleChart.js renders a bubble chart using the D3 force layout, and appropriately updates this with any new data sent from the Elm app.

The web app itself can be developed without needing to run a local server by using the live version of the server, like this:

cd client
yarn install

export ELM_APP_API_URL=https://api.parliament.bobwhitelock.co.uk
yarn run start

To develop the server or data retrieval scripts, a new empty Postgres database must be created and a TheyWorkForYou API key created, and then:

export DATABASE_URL=# URL to access the database created above.
export TWFY_API_KEY=# API key created above.
bin/setup

ruby server/server.rb

To use a local server with a local client, the value of ELM_APP_API_URL used when starting the client will need to be changed to point to this local server, usually like this:

export ELM_APP_API_URL=http://localhost:4567