Archiving and displaying tweets with dat

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First, make a new directory for the project:

mkdir tweet-stream && cd $_

Install node.js (nodejs in Debian/Ubuntu, node in Homebrew), update npm if needed (npm install -g npm) and install dat:

npm install -g maxogden/dat

dat is essentially git for data, so the data repository needs to be initialised before it can be used:

dat init

Next, start the dat server to listen for incoming connections:

dat listen

Data can be piped into dat as line-delimited JSON (i.e. one object per line - the same idea as CSV but with optional nested data). Happily, this is the format in which Twitter’s streaming API provides information, so it's ideal for piping into dat.

I used a PHP client to connect to Twitter’s streaming API as I was interested in seeing how it handled the connection (the client needs to watch the connection and reconnect if no data is received in a certain time frame). There may be a command-line client that is even easier than this, but I haven’t found one yet…

Install Phirehose using Composer:

composer init && composer require fennb/phirehose:dev-master && composer install

The streaming API uses OAuth 1.0 for authentication, so you have to register a Twitter application to get an OAuth consumer key and secret, then generate another access token and secret for your account. Add these to this small PHP script that initialises Phirehose, starts listening for filtered tweets and outputs each tweet to STDOUT as it arrives:

Run the script to connect to the streaming API and start importing data:

php stream.php | dat import -json

The dat server that was started earlier with dat listen is listening on port 6461 for clients, and is able to emit each incoming tweet as a Server-Sent Event, which can then be consumed in JavaScript using the EventSource API.

I’m in the process of making a twitter-stream Polymer element, but in the meantime this is how to connect to dat’s SSE endpoint:

var server = new EventSource(‘http://your-dat-ip-address:6461/api/changes?data=true&style=sse&live=true&limit=1&tail=1’);

server.addEventListener('data', function(event) {
    var item = JSON.parse(event.data).value;
    // do something with the tweet
});