Custom session serializers

CatraProto ships with FileSerializer which allows you to serialize the session to a specific file. In case you don’t like this behaviour and want to store your session somewhere else (for example a database) CatraProto allows that by implementing the IAsyncSessionSerializer.

What does a session file contain?

Session files are not to be confused with the database.
The database stores all information required to keep a local cache of data (used for example to resolve access_hash(es)). The sessions stores the authentication keys used to interact with the server and to store the current logged in user as well as the current updates state.

How are they serialized?

Session files are nothing more than binary blobs serialized with TL.

How to implement the IAsyncSessionSerializer interface

The IAsyncSessionSerializer interface declares two methods

• Task<byte[]> ReadAsync(ILogger logger, CancellationToken cancellationToken) - This method is only used once at startup in order to retrieve the session from your storage and store in memory. If no session file is present, an empty array must be returned.
• Task SaveAsync(byte[] data, ILogger logger, CancellationToken token) - This method is used to save the session file to your storage and can be called multiple times during the lifetime of the TelegramClient object, even concurrently.

Even though SaveAsync can be called concurrently, you will always receive a fully constructed session, but you may need to lock to avoid two (or more) concurrent calls overwriting each other. If you need an example implementation, you can use the FileSerializer.