Handling multiple AsyncClients

[peterz0310]

Hey, I need some advice on how to manage multiple AsyncClients. I might be wrong, but it seems as though I need an AsyncClient for each different operation for everything to work properly. In my project specifically, I need 4. One for async RTDB operations, sync, stream, and Firestore. This seems memory expensive an inefficient, considering I don't think it's possible to change the SSL buffer sizes on an ESP32. 16k for each is overkill in my case but from what I've found, BearSSL doesn't fully support the ESP32 including the setBufferSizes function.

In another part of the code, I'm making an HTTP get request to download a file to an SD card using the HTTPClient library. I'm getting weird errors which make me think it's running out of memory or something. This never happened before when using your other Firebase library, so I think it's something to do with my new setup.

Thanks for the help.

Peter

[mobizt]

If you need 4 async tasks which included stream, and you don't mind that all tasks need to run simultaneously, you can use only 2 async client, i.e. one async client for stream and another for other async tasks which run one by one from FIFO queue.

Note that only two TCP socket connections from two SSL client.

If you want to run concurrent async tasks using 4 async clients (4 SSL Clients, 4 socket connections), you can use ESP_SSLClient that comes with this library as wrote in Readme which it works in the same way as in ESP8266 WiFiClientSecure which the buffer size can be set.

This is the example for how to use it.

The ESP_SSLClient repo is here is here for your reference (do not install it).

[peterz0310]

So it sounds like I can replace WifiClientSecure with ESP_SSLClient and it should work the same, plus the ability to set buffer sizes. On the topic of multiple async clients, are you saying it's possible to use a single instance for different applications? As in, can I mix async RTDB calls with Firestore ones under a single client? I know streaming has to be separate, and with some testing I found that sync/async 'gets' for example, also need separate async clients. This is how I ended up with:

AsyncClient aClient(ssl_client, getNetwork(network)); // Async RTDB
AsyncClient sClient(ssl_client2, getNetwork(network)); // Sync RTDB
AsyncClient streamClient(ssl_client3, getNetwork(network)); // RTDB stream
AsyncClient firestoreClient(ssl_client4, getNetwork(network)); // Async Firestore

Are you saying that I can use the same aClient in this case for both async RTDB and Firestore calls? This would save me precious memory.

Thanks!

[mobizt]

Yes, and you should know that the hosts between Realtime database and Firestore database are different then the session will be closed before connecting to a new host and it uses more time to connect because of SSL/TLS handshake.