A Slack app that provides users in Switzerland with public transport information. The source for this information is the Opendata Transport API.
If you want to use this for your own Slack, you can either use the instance at slack-publictransport-api2.jmnw.me and add it by clicking the Slack button on that page. To host your own instance, proceed to the Installation section.
Slack does not allow the creation of app commands if there is no page listening for the command, so we will first deploy the application without much configuration and then register the Slack app, so that we can finish the configuration.
To allow the application to run, you have to copy src/main/resources/config.example.properties to src/main/resources/config.properties since this file is required when the application starts up.
You can then run a Maven install by running mvn install in the project root folder. This will generate a slack-publictransport.war file in the target folder. Deploy this WAR somewhere internet-accessible on your preferred container (tested only on Tomcat 8). Note that you must provide the application over a secured connection (https) because Slack enforces this. You can use e.g. Nginx to terminate the secured connection and proxy to the unsecured application. From now on, I will use $BASE whenever you need to enter the secure URL you deployed the WAR at for simplicity.
We can now register our application on Slack's Your Apps page by clicking Create New App. Enter a snarky app name and click on Create App.
The next step is to set up the OAuth URL. For this, click on OAuth & Permissions in the lefthand menu. In the generous Redirect URL(s) field there, enter $BASE/api/v1/oauth.
After you have Save Changesd, we will move on to Interactive Messages. On that page, all you need to do is click Enable Interactive Messages, enter $BASE/api/v1/interactive and click Enable Interactive Messages once again.
We will now create the actual command on the Slash Commands page. The Create New Command button is your friend which opens up quite a form. The only thing that is a given is the Request URL, which needs to be set to $BASE/api/v1/connections. You can customize the rest to your likings. The syntax for the parameters is "from" "to" (time[an|ab]) where the quotation marks are optional if the name of the station is only one word and time is in the format HH:mm.
For the final part, open the Basic Information page for your Slack app. You should be able to find Client ID, Client Secret and Verification Token on this page. Those correspond to slack.client.id, slack.client.secret and slack.server.token in the configuration file src/main/resources/config.properties which you can now set to the correct values.
After that you also have to update the Client ID in src/main/webapp/index.jsp:
<!-- ... -->
<a href="https://slack.com/oauth/authorize?scope=commands&client_id=<Your client id here>">
<!-- ... -->Run a Maven install and redeploy your app. By visiting $BASE and clicking on the Slack button, you should be able to add the application to your team's Slack. Congratulations! :smiley: