Automating Bluesky to Twitter Cross-posting

This repository contains a Google Apps Script (GAS) that automates the process of retrieving posts from a Bluesky feed and cross-posting them to Twitter. It utilizes a Google Spreadsheet for tracking posts and OAuth2 authentication for Twitter.

Setup Instructions

1. Required Modifications

• Twitter and Bluesky API credentials: The script must be modified to dynamically obtain the following:
  • Bluesky ID
  • Twitter ID
  • Google Spreadsheet ID
  • Twitter API Key and Secret
• Note: This script is not currently compatible with Bluesky's OAuth2.0, and may become unusable in the future if Bluesky updates its authentication system.

2. Google Apps Script (GAS)

• Create a new Google Apps Script project by opening the script editor in a Google Spreadsheet.
• Copy and paste the code from this repository into the script editor.

3. Google Spreadsheet Setup

• Create a Google Spreadsheet with a sheet named "List".
• The sheet should have the following columns, starting from row 1:
  • Column 1: Post ID
  • Column 2: Text
  • Column 3: Is Reply (true/false)
  • Column 4: Includes Embed (true/false)
  • Column 5: Is Repost (true/false)
  • Column 6: Is Bluesky Limited (true/false)
  • Column 7: Posted to Twitter (true/false)
  • Column 8: Reply To Post ID
  • Column 9: Twitter Tweet ID

4. OAuth2 Authentication for Twitter

• Replace the placeholders for CLIENT_ID and CLIENT_SECRET in the code with your Twitter Developer App credentials.
• Run the doAuthorization() function to initiate the OAuth2 authentication process.
• Follow the authorization URL displayed in the logs to grant access to Twitter.

5. Scheduling the Script

• In the Apps Script editor, use GAS Triggers to schedule the Main() function to run once every minute.
• This ensures the script continuously checks for new posts on Bluesky and cross-posts them to Twitter when applicable.

6. Posting Rules

• Cross-posting of replies: This script will only cross-post replies to your own posts.
• Opt-out Mechanism: If you want to prevent a Bluesky post from being cross-posted to Twitter, include the Unicode Character “◌͏” (U+034F) in the post text. The script will detect this and skip cross-posting.

Functions Overview

• Main(): The main entry point of the script. It determines when to retrieve Bluesky posts and when to post them to Twitter.
• ListUpBlueskyPosts(): Fetches recent Bluesky posts and records them in the Google Spreadsheet.
• SendPostsToTwitter(): Posts the listed Bluesky posts to Twitter.
• getPosts(): Retrieves posts from the Bluesky API.
• getAccessJwt(): Manages the access token for Bluesky API requests.
• sendTweet(): Sends a tweet to Twitter using the Twitter API.
• doAuthorization(): Initiates OAuth2 authorization for Twitter.

Important Notes

• This script is not compatible with Bluesky's OAuth2.0, so future changes to Bluesky’s authentication method may render it unusable.
• The script should be triggered to run every minute to keep the posting process running smoothly.

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Acknowledgement

• This script is a modification of the script in the article "Blueskyに投稿したPostを自動でTwitterにも転載したい" by henteko (https://github.com/henteko).