Farcaster Devs

trains

What if we forked Twitter’s dearly departed “choochoobot?” 

https://twitter.com/choochoobot/status/1681385362352898073

Saturday afternoon choochoobot speedrun, let's go! 🚂 

Follow along with the docs here:

Saturday afternoon choochoobot speedrun, let's go! 🚂 

Follow along with the docs here:
https://docs.farcaster.xyz/developers/guides/basics/hello-world

(this will be a long thread)

To start, I’ll register a new account using Warpcast. (Log out, create a new account, and follow the sign up steps). This creates an fid, rents storage, and adds a Warpcast account key.

We could do this all from scratch, but it’s nice to be able to log in to the bot account.

I'm eth newbie..just learning
(working on @farcaster)

terminally.online

Now we can jump to step #3 in the docs to create an account key for the bot and register it onchain. 

Here's a fresh TS project.

Now we can jump to step #3 in the docs to create an account key for the bot and register it onchain. 

Here's a fresh TS project. 

https://docs.farcaster.xyz/developers/guides/basics/hello-world#_3-add-an-account-key

https://github.com/horsefacts/farcaster-choochoobot/tree/f91a10387a09a25db149dfed7b1cef330f27368b

The "account key" choochoobot will use to sign Farcaster messages is an ed25519 key. Here's how we can generate one. Keys are 32 bytes, just like Ethereum keys. Keep the private key secret.

I ran this script and saved a fresh key as CHOOCHOOBOT_ACCOUNT_PRIVATE_KEY in .env. (Don't use the one in the screenshot below!)

Code here: https://github.com/horsefacts/farcaster-choochoobot/blob/4fb839760adbfd43cfe03436930582508bbc99fd/lib/generateAccountKeypair.ts

Now we need to register the key we created onchain by calling the Farcaster KeyGateway contract on Optimism. 

To set up the transaction, we need @choochoobot's FID (grab it from the Warpcast profile page), and Warpcast wallet mnemonic (reveal it under "Settings > Advanced" in the mobile app and keep it secret).

To register an account key, you need to provide the public key bytes and a blob of signed metadata. This signature shows which apps requested which keys.

The metadata signature is the tricky part, but here's how to generate it. In this example, @choochoobot is signing its own account key (very legal & very cool):

We need to send some OP ETH (~$1-2) to the sender account, then we can run the script and send the tx.

We need to send some OP ETH (~$1-2) to the sender account, then we can run the script and send the tx.

https://www.onceupon.gg/0x5bdbdd0d2a7fd0a5211dd9687fcb2f0bc503c492134a1fa1d21e1bde995ed64d

https://github.com/horsefacts/farcaster-choochoobot/blob/00c23d76d90d1619044049cdc9fc760ba30e563e/lib/registerAccountKey.ts

All aboard!
🚂🚃🚋🚃🚋🚃🚋🚃🚋💨

Now that our bot's public account key is registered onchain, we can use it to sign messages and submit them to Hubs.

To cast into a channel, set the parentUrl.

Now that our bot's public account key is registered onchain, we can use it to sign messages and submit them to Hubs.

To cast into a channel, set the parentUrl.

https://warpcast.com/choochoobot/0x7299aac6

Here's the latest code. We still need to run this on a schedule and generate cool trains, but we have all the Farcaster fundamentals in place to make posts from our bot.

Here's the latest code. We still need to run this on a schedule and generate cool trains, but we have all the Farcaster fundamentals in place to make posts from our bot. 

https://github.com/horsefacts/farcaster-choochoobot/blob/5f79ec497cad28a2e1f2984af14755deec694fc8/lib/sendCast.ts

OK, wrapping up. A simple train generator (we'll enhance this later):

And a Dockerfile based on the bun default. I'll run this on Railway and set up a cronjob to post once a day.

⛳️🏴‍☠️
/goose /golf /tarheels /pins /pizza

hmm, right now the trains run once a day but that’s a good idea