Fanbox Discord Bot

This bot is used to automate access control for my Fanbox Discord server.

The bot accesses the Fanbox API using your Fanbox session token. This is found in your browser cookies when accessing Fanbox.

Fanbox API Restriction

As of 2024-06-26, it seems that Fanbox has increased security for their API, possibly to stop scrapers (by using Cloudflare). You may find that you have had to pass a captcha on Fanbox recently, and if you were using the bot before, it's now broken. Changes to the cookies the API uses seem to be tied to your IP address, so using the bot from another IP address will cause Fanbox API to return "403 Forbidden".

If you want to run the bot on an always-online VM, you can get the correct tokens by using your VM as a proxy for your web browser like so:

• Create an SSH tunnel to your VM server from the command line: ssh -N -D 9090 myuser@my.server.ip.address (replace myuser with your VM user name and my.server.ip.address with your VM's IP address).
  • On Windows, SSH might be installed by default, but if not, you can install PuTTY to make it available.
• Go into your browser proxy settings, for example in Firefox: Settings -> Network Settings -> Manual Proxy configuration
• Fill out SOCKS Host with localhost and Port with 9090, and click Ok
• Open a private tab, go to Fanbox and login.
• Collect the cookies and headers needed by config.yml (see below under Install and configuration)
  • Important cookies: cf_clearance, FANBOXSESSID
  • Important headers: user-agent
    • If you update the browser that you retrieved the user-agent from, you'll likely have to update this again too!
• Close the private tab and revert your browser network settings (usually Use System Proxy Settings)
• You can stop the SSH tunnel by pressing ctrl + C

Access control

The Discord user sends the bot their Pixiv ID number, which will grant appropriate access. You can simply tell the users to message their Pixiv profile link to the bot, for example https://www.pixiv.net/users/11, which will extract 11 and check that ID.

When only_check_current_sub is False, the user's Pixiv ID is checked against their Fanbox transaction records. More details below in Auto Role Update.

When only_check_current_sub is True, then the user's current subscription status is checked instead of their transaction records.

When strict_access is True, the bot will disallow different Discord users from using the same Pixiv ID. When a user successfully authenticates, their Discord ID is "bound" to their Pixiv ID. Successfully authenticating again will update their Pixiv ID binding. The user can only be unbound by an admin command. Some users may have had to create new Discord accounts, therefore the you will have to manually resolve unbinding of their old account. See Admin commands below.

Other functionality

Auto Purge

The bot can be configured to periodically purge old users without roles. See cleanup in the config.

Auto Role Update

The bot can be configured to periodically update a user's role based on their Fanbox subscription. See auto_role_update in the config.

When only_check_current_sub is False, the subscription is checked whenever the bot thinks the subscription is going to change based on a user's previous transactions. The behavior of this is for "fair access", meaning that if a user pays for a month of time, then they get a month of access from that payment date, roughly.

When only_check_current_sub is True, a previously registered user will have their roll updated based on their current subscription status at the time of the check. Transactions are not considered in this case. The behavior of this is like "unfair access", meaning that a user that subscribes only at the end of a month may not retain access into the next month. This behavior is similar to how Fanbox works.

If the user wants their role to be updated immediately (such as to a higher role), then they can submit their Pixiv ID to the bot again to force a check.

Period of role assignment by transactions

The bot will make the best effort to assign the correct role based on the user's previous recent transactions, as well as ensure that they get to retain the role for the contiguous overflow days since making those transactions. For example: If a user had subscribed on 6/15, 7/1, and 8/1, then the last day of their subscription is approximately 9/15.

Determining role assignment by transactions

The highest role assigned is determined like so: A calendar month's transactions for a user are summed up and replaced by the last transaction in that month, so if they had two 500 yen transactions on 6/10 and 6/15, then this would be represented by one 1000 yen transaction on 6/15. Then, for contiguous months of transactions, the days in that period of time are filled starting with the highest roles first, for a month worth of time, in the positions each transaction starts, or the next available position that can be filled. This is easier to demonstrate with the following graphs:

Why transactions?

Transactions are used to determine roles because this is the only historical information that the Fanbox API provides. Unfortunately Fanbox does not provide what specific plan was purchased with a given transaction, which makes determining which role to assign more complicated. This also means that plans should be uniquely determined by their price.

Adding or removing plans from Fanbox

Each time the bot starts, plans are retrieved from Fanbox and cached. If you removed a plan from your Fanbox, you should still keep the plan in your plan_roles setting so that a user can still be granted the last valid role that plan represented. When no more users have that role, you could then remove that plan from the plan_roles setting without impacting user experience.

When only_check_current_sub is True, a user who was subscribed to a removed plan might lose access. This is hard to test for.

Admin commands

Admin commands are prefixed with !, for example !reset

• add-user PIXIV_ID DISCORD_ID attempt to grant access for another user. DISCORD_ID is the numerical ID of a user, not their user name. This command ignores strict_access.
• unbind-user-by-discord-id DISCORD_ID remove a user's Pixiv ID binding and roles.
• unbind-user-by-pixiv-id PIXIV_ID unbind all users sharing the same Pixiv ID.
• get-by-discord-id DISCORD_ID get the Pixiv ID bound to the given user.
• get-by-pixiv-id PIXIV_ID get all users using the same Pixiv ID.
• reset removes all roles in your config from all users. Any other roles will be ignored. Unbinds all users.
• purge manually runs the user purge. Any user with no roles will be kicked from the server.
• test-id PIXIV_ID tests if a pixiv ID can obtain a role at this moment in time. I use this for debugging.
• export-csv generates and sends you a CSV file containing user Discord IDs, Pixiv IDs and join dates.

Install and configuration

• Create a Discord app and bot:
  • https://discordpy.readthedocs.io/en/stable/discord.html
  • Additional steps: Go to your bot application settings, under the Bot tab, scroll down and enable the following settings:
    • Server Members Intent
    • Message Content Intent
  • ⚠ It is easiest to invite your bot instance to your server with administrator permissions to prevent permission errors. You can try using more restrictive permissions, but you will probably run into issues.
    • The bot's role must be higher in the role settings than the roles of the users it is assigning new roles to, otherwise you may get a permission error when assigning roles.
  • ⚠ Only invite one instance of a running bot to one server. If you invite the bot instance to multiple servers, it will only work with the first server it can find, which might be randomly ordered.
    • If you need a bot to run in multiple servers, then run different instances of the bot out of different directories, with different bot tokens (you have to create a new Discord app).
• The bot must be running continually to service random requests and run periodic functions. If you do not have a continually running computer, then I recommend renting a lightweight VM on a cloud service (Google Cloud, AWS, DigitalOcean, etc.) to host your bot instance. When you get to updating the bot config, refer to Fanbox API Restriction above for how to retrieve the correct tokens for your VM.
• I recommend installing Docker to run the bot, to both mitigate build issues and have your bot start automatically if your computer or VM restarts.
  • For Windows: https://www.docker.com/products/docker-desktop/
  • If using a cloud VM, typically Debian or Ubuntu Linux: run sudo apt update && sudo apt install docker
• Download (or clone) and extract this repository to a new directory.
• Copy config-template.yml to config.yml
• In config.yml, update all of the places with angle brackets: <...>
  • For example: <ROLE_ID> becomes 12345, but not <12345> (remove the brackets).
  • If you are not using a particular feature, you can fill it in with a dummy value, like 0.
• You can change any other default fields in config.yml as well to turn on other functionality.
• To start the bot, run docker compose up -d in the bot directory.
• To stop, run docker compose down in the bot directory.
• Logs are written to log.txt, or you can view output with Docker docker compose logs --follow

Updating the bot

• Stop the bot docker compose down
• Download the latest version of the bot
• Run docker compose build to update dependencies
• Start the bot docker compose up -d