matrix-moderation-tool/docs/server_functions.md

Server Commands Guide

This guide provides detailed steps for server-side operations that use the database and SSH. The commands and scripts are essential for handling specific server operations related to Matrix's Synapse server.

Table of Contents

• 1. Delete and Block Specific Media
• 2. Purge Remote Media Repository
• 3. Prepare Database for Copying Events of Multiple Rooms

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1. Delete and Block Specific Media

This command allows an admin to delete a specific media on their Matrix Synapse server and block it to prevent future accesses.

Process Flow:

1. Take media_id and remote server URL from the user.
2. Use SSH to query the Synapse PostgreSQL database for the associated filesystem_id.
3. Locate the target media files and thumbnails on the server's file system.
4. Zero out (empty) each file and make them immutable, meaning they cannot be modified or deleted.

Example:

For a media with ID eDmjusOjnHyFPOYGxlrOsULJ, the process would involve:

$ ssh matrix.perthchat.org "... SQL query to get filesystem_id..."
$ ssh matrix.perthchat.org "... command to locate files ..."
$ ssh matrix.perthchat.org "true > ...path to file..."
$ ssh matrix.perthchat.org "chattr +i ...path to file..."

2. Purge Remote Media Repository

This command purges the remote media repository for a certain range of days. Process Flow:

Ask the user for the range of days to purge.
Calculate the epoch timestamp for each day in the range.
Send a request to the Synapse server to purge media for that day.
Repeat for each day in the range.

Example:

$ date --date '149 days ago' +%s
$ curl -X POST --header "Authorization: Bearer ACCESS_TOKEN" '... Matrix Synapse purge endpoint ...'

3. Prepare Database for Copying Events of Multiple Rooms

This command prepares the PostgreSQL database to export events from multiple Matrix rooms. Process Flow:

Prompt for a list of room IDs.
Create a RAM disk on the server to store the export.
For each room ID:
    Create a SQL query to extract room events.
    Write the query to a file on the RAM disk.
Provide instructions for running the queries in the PostgreSQL container.

Notes:

This function is compatible with Spantaleev's Matrix deploy script.
Ensure proper permissions and consider the impact on the server when copying a large amount of data.

Example:

# As the root user on the target server:
$ mkdir /matrix/postgres/data/ramdisk
$ ... commands to set up RAM disk ...
$ ... commands to generate SQL queries for each room ...
$ docker exec -it matrix-postgres /bin/bash
bash-5.0$ ... commands to execute SQL queries ...

After copying the data, ensure to clean up the RAM disk:

$ rm -r /matrix/postgres/data/ramdisk/*
$ umount /matrix/postgres/data/ramdisk