DiscordDoorway

Accept discord interactions in azure with ease

This repo provides a generalized method to accept messages from a discord interaction. It can provide a response and/or pass the interaction to an Azure storage queue for ingestion from another function app (or even the storage REST API).

Using This Code

To use this code in your own project:

1. create a .net Azure Function app and deploy this code (I like using github actions as an auto-deployment CI/CD chain from a forked repo).
2. Add your Discord bot's application ID (e.g. 952387339597017129) and public key to an app setting called APP_PUBLICKEY_<application_id>. E.g. Name: APP_PUBLICKEY_952387339597017129 Value:
3. Set your bot's Interactions Endpoint URL to the function endpoint. E.g. https://myFunctionApp.azurewebsites.net/api/Doorway.
4. If the last step lets you save the field, then you did it all right! If it says something else, like "interactions_endpoint_url: The specified interactions endpoint url could not be verified," then you need to double check your app and app setting.

Adding Instant Responses

By default, this app will accept any messages that come in to your specified Discord bots (via the APP_PUBLICKEY_ app settings). To respond to specific commands instantly, create an app setting with the command name (and optional sub command group/name). Ex: APP_COMMAND_<Command>_<SubCommand>.

You can place a simple text field in the value to be a static response. You can also paste in a JSON embed object to the field to make the response be an embed. Ex: {"title":"My Site","url":"https://www.reddit.com"}. Title, url, color, description currently supported.

You can also place a simple message or embed JSON within a JSON content property and also optionally set the private or passthru true/false properties. Setting private to true sets the response to be only visible to the submitter. Setting passthru makes the function pass the original interaction to the queue (instead of skipping because of the canned command). Some examples:

{"private":true,"content":{"title":"My Site","url":"https://www.reddit.com"}}

{"passthru":true,"content":"Thanks for submitting your request! I'll check this out later."}

Adding Downstream Discord Bots

Once you have this function up and running, you may want to add actual discord bots that do more than just reply with static responses. You can do that by creating another Azure Function that will consume the data that comes into the bot's storage queue.

To do this, you need to add a appsetting in your new azure function that contains the storage credentials for your function to access this function's storage account. I like to create one called AzureWebJobs_Doorway and paste the doorway storage connection string into there.

Next, you should have your function set to trigger based on queue items and set the queue name to the same ID as your discord bot's application ID.

Finally, you should consider how often you want your new Azure Function to check the storage queue for new items. That's done in your host config. For PowerShell runtime, we use the binding storage extensions like this in our host.json:

"extensions": {
    "queues": {
      "maxPollingInterval": "00:00:05",
      "visibilityTimeout": "00:00:05",
      "maxDequeueCount": 3
    }
  }