31:T474,md`# How to make a ~~Twitter~~ BlueSky Bot This notebook describes how to use [@endpointservices](https://observablehq.com/@endpointservices) [cron](https://observablehq.com/@endpointservices/cron)/[zapier](https://observablehq.com/@endpointservices/zapier)/[serverless-cells](https://observablehq.com/@endpointservices/serverless-cells) to build a Twitter bot that tweets the [top trending notebook](https://observablehq.com/trending) on Observable once a day (Twitter account [@trendingnotebo2](https://twitter.com/trendingnotebo2)). This shows how to execute custom notebook logic on a schedule, which can be useful for lots of different things. ### Update 2024-11-30 I have switched the bot over to BlueSky ([trendingnotebooks.bsky.social](https://bsky.app/profile/trendingnotebooks.bsky.social)). Instead of using Zapier, I post directly using the API (see [@tomlarkworthy/post-to-bluesky](https://observablehq.com/@tomlarkworthy/post-to-bluesky)). Everything is done within the browser, there are no tools to install! The video is less than 10 minutes, information dense and does not waste time. `32:[{"id":"957858205ae0648c60cb9f8511ee40f7074c36a48e8600e5a4531e4581690c888e86eb52b787c99eff67ef0a4c32c908ddf7d44d932c7fd8bf8fbb33300e96f5","href":"https://static.observableusercontent.com/files/957858205ae0648c60cb9f8511ee40f7074c36a48e8600e5a4531e4581690c888e86eb52b787c99eff67ef0a4c32c908ddf7d44d932c7fd8bf8fbb33300e96f5","name":"image.png","type":"image/png","lastModified":1615208272565.884,"size":130808}] 2f:{"title":"How to make a Twitter BlueSky Bot","cells":[{"id":0,"value":"$31","pinned":false,"hidden":false,"mode":"ojs"},{"id":163,"value":"html``","pinned":false,"hidden":false,"mode":"ojs"},{"id":263,"value":"md`#### Change log\n\n- 11/03/2021 Tweet deduplication logic added using HTTP cache and content hashing`","pinned":false,"hidden":false,"mode":"ojs"},{"id":7,"value":"md`## Cron job\n\nA \"cron\" job calls another URL on a regular schedule. We will use this to trigger a tweet once day, by setting the URL to a serverless-cell HTTP handler served from this Notebook.\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":5,"value":"import {createCron} from '@endpointservices/cron'","pinned":false,"hidden":false,"mode":"ojs"},{"id":125,"value":"viewof cronJob = createCron({\n name: \"tweetdaily\",\n schedule: \"15 12 * * *\", // Daily at 12:15 pm UTC\n url: topTrending.href\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":10,"value":"md`## URL handler\n\nThe URL handler receives the ping from the cron service on a regular schedule. \n\nWe create a custom handler using a serverless-cell. Calling \"deploy\" creates a public URL which will execute the code within the handler when called.\n\nIn our case we wish to send a Tweet about the top trending Notebook on [Observable](https://observablehq.com)\n\n\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":12,"value":"import { deploy } from \"@endpointservices/webcode\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":15,"value":"topTrending = deploy(\n \"tweetTopTrending\",\n async (req, res, context) => {\n const hasSent = (await db.child(contentHash).once(\"value\")).val() !== null;\n if (hasSent) return res.send(\"Already sent\");\n else {\n try {\n const response = await postWithImage(\n \"trendingnotebooks.bsky.social\",\n context.secrets[\"BLUESKY_TRENDING_APP_PASSWORD\"],\n imgBlob,\n text\n );\n await db.child(contentHash).set(true);\n return res.send(JSON.stringify(response));\n } catch (err) {\n return res.status(400).send(err.message);\n }\n }\n },\n {\n modifiers: [\"orchestrator\"],\n secrets: [\"endpointservices_BLUESKY_TRENDING_APP_PASSWORD\"]\n }\n)","pinned":true,"hidden":false,"mode":"ojs"},{"id":301,"value":"db = firebase.database().ref(`/@endpointservices/twitter-bot`)","pinned":false,"hidden":false,"mode":"ojs"},{"id":299,"value":"import {\n firebase,\n FKEY\n} with { FIREBASE_CONFIG as firebaseConfig } from \"@tomlarkworthy/firebase\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":296,"value":"FIREBASE_CONFIG = ({\n apiKey: \"AIzaSyBN4bxw6d0cM0CGPNzRrkRlBqwFQnPLdN4\",\n databaseURL:\n \"https://larkworthy-dfb11-default-rtdb.europe-west1.firebasedatabase.app\",\n projectId: \"larkworthy-dfb11\",\n appId: \"1:786910701676:web:8d7dd002acf3b78c74d049\"\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":18,"value":"md`## ~~Send Tweet~~\n\nCalling the Twitter API and authenticating is quite a lot of work. Instead of figuring out how to do that we use Zapier. Zapier has integrations for thousands of things including Twitter. Endpoint Services has an integration with [Zapier](https://observablehq.com/@endpointservices/zapier), so we can reach *a lot* of functionality just by using [@endpointservices/zapier](https://observablehq.com/@endpointservices/zapier).\n\n\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":96,"value":"import {createTrigger} from '@endpointservices/zapier'","pinned":false,"hidden":false,"mode":"ojs"},{"id":98,"value":"sendTweet = createTrigger({\n name: \"sendTweet\",\n authorized_public_keys: [\"cg24TseUZnvEiO3XtXCFD08E9bX83Sv4rBHe2cjvpmU=\"],\n // Serverside check, ensure only the current trending tweet is used\n checkPayload: (payload) => payload.text === text && payload.img.startsWith(\"https://static.observableusercontent.com/thumbnail/\"), \n sample: {\n text: text,\n img: imgURL\n }\n })","pinned":true,"hidden":false,"mode":"ojs"},{"id":353,"value":"## Post to BlueSky","pinned":false,"hidden":false,"mode":"md"},{"id":355,"value":"import { postWithImage } from \"@tomlarkworthy/post-to-bluesky\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":359,"value":"viewof password = Inputs.password({\n label: \"app password\"\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":367,"value":"imgBlob = (await fetchp(imgURL)).blob()","pinned":false,"hidden":false,"mode":"ojs"},{"id":369,"value":"postWithImage(\"trendingnotebooks.bsky.social\", password, imgBlob, text)","pinned":true,"hidden":false,"mode":"ojs"},{"id":87,"value":"md`## Fetching Top Trending Notebook\n\nTo figure out the top trending Tweet we call the Observable API.\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":90,"value":"md`\nObservable's trending URL (/documents/public/trending) does not support cross origin requests so we use [fetchp](https://observablehq.com/@tomlarkworthy/fetchp) to get the data instead.\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":28,"value":"import {fetchp} from '@tomlarkworthy/fetchp'","pinned":false,"hidden":false,"mode":"ojs"},{"id":149,"value":"md`Now we can call the Observable API`","pinned":false,"hidden":false,"mode":"ojs"},{"id":26,"value":"trendingResponse = await fetchp(\n \"https://api.observablehq.com/documents/public/trending?page=1\"\n)","pinned":false,"hidden":false,"mode":"ojs"},{"id":31,"value":"trending = trendingResponse.status == 200\n ? trendingResponse.json()\n : new Error(await trendingResponse.text())","pinned":false,"hidden":false,"mode":"ojs"},{"id":201,"value":"md`The top notebook is the first result`","pinned":false,"hidden":false,"mode":"ojs"},{"id":40,"value":"topNotebook = trending.results[0]","pinned":false,"hidden":false,"mode":"ojs"},{"id":61,"value":"md`#### Top notebook Tweet Text`","pinned":false,"hidden":false,"mode":"ojs"},{"id":345,"value":"suffix = topNotebook.slug == null\n ? `d/${topNotebook.id}`\n : `@${topNotebook.owner.login}/${topNotebook.slug}`","pinned":false,"hidden":false,"mode":"ojs"},{"id":64,"value":"text = `\"${topNotebook.title}\" by ${topNotebook.owner.name} https://observablehq.com/${suffix}`","pinned":false,"hidden":false,"mode":"ojs"},{"id":58,"value":"md`#### Top Notebook image`","pinned":false,"hidden":false,"mode":"ojs"},{"id":47,"value":"imgURL = `https://static.observableusercontent.com/thumbnail/${topNotebook.thumbnail}.jpg`","pinned":false,"hidden":false,"mode":"ojs"},{"id":52,"value":"img = html`

`","pinned":false,"hidden":false,"mode":"ojs"},{"id":246,"value":"md`### Content hash`","pinned":false,"hidden":false,"mode":"ojs"},{"id":234,"value":"hash = async (str) => {\n let strBuf = new TextEncoder('utf-8').encode(str);\n const buffer = await crypto.subtle.digest(\"SHA-256\", strBuf);\n const hashArray = Array.from(new Uint8Array(buffer)); \n const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');\n return hashHex;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":249,"value":"contentHash = hash(text)","pinned":true,"hidden":false,"mode":"ojs"},{"id":310,"value":"contentHash.length","pinned":true,"hidden":false,"mode":"ojs"},{"id":339,"value":"import { footer } from \"@endpointservices/footer-with-backups\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":341,"value":"footer","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W32","stdlib":"1","titling":"auto"}