Any online request causing delay on the main loop

[PawelSzymanski89]

I have one task with simple request to REST api and if i'll start in main esp loop is waiting for response...

class ApiRequest : public Task {
  public:
    void loop() {
      Serial.println("ApiRequest");
      if (WiFi.status() == WL_CONNECTED) {
        client.get("/basementData");
        int statusCode = client.responseStatusCode();
        String resBody = client.responseBody();
        //        Serial.println("-------------------------");
        //        Serial.println(resBody);
        if (statusCode = 200) {
          JsonObject root = doc.as<JsonObject>();
          auto error = deserializeJson(doc, resBody);
          if (!error) {
            //            double stoveTemp = root["stoveTemperature"];
            stoveTemperature = (int)root["stoveTemperature"];
            waterTemperature = (int)root["waterTemperature"];
            timeMills = root["timeStamp"];
          }
        }
      }
    }
} api_task;

[nrwiersma]

What is the issue exactly?

[dbuezas]

client.get will wait using the global Delay until the response is received and call the global yield, this blocks the tasks.

The only ways around this I can think of are:

• Implement the get request yourself so you can call the task-specific delay function instead code
• Expose Scheduler.current->delay globally and wrap the include"HTTPclient" around #define and #undefine to change the calls to global delay and yield to Scheduler.current->delay. (hacky but sounds fun) (didn't get it to work)

[dbuezas]

I found a way to make this work:

1. expose the yield function of the current Task (e.g SchedulerClass::yield())
2. Make a new class that inherits from HTTPSClient

class HTTPSClientScheduled : public HTTPSClient {
  int available() override {
    SchedulerClass::yield();
    return HTTPSClient::available();
  }
};

3. instantiate a client from HTTPSClientScheduled instead.

This works because GET makes extensive use of readStringUntil, which in term calls available, which just happens to be overridable. I'm using it with HTTPSRedirect

---

@nrwiersma would you consider a PR that exposes yield and delay in that way inside the Scheduler class?

[nrwiersma]

@dbuezas In light of #20 it seems unlikely.

[dbuezas]

I think it can be done (I first have to understand the run groups thing), I'll make a separate PR after #20 gave up on making it work with run groups.
For this functionality (w/o run groups), there's a fork

[xyzshantaram]

@dbuezas @nrwiersma So what's the verdict? Does the workaround in #16 (comment) still work? There's a new LeanTask now right? I have the same issue - I want to do MIDI playback in one task, delay() until the next note and then go back to polling. If it does work then this issue should probably be closed

[dbuezas]

I haven't used this in a long time, but the workaround should still work and be necessary

[xyzshantaram]

Thanks! Just to clarify, when you say HttpsClient do you mean WiFiClientSecure, HTTPClient, or something else entirely? I couldn't find a lib called HttpsClient.

[dbuezas]

Most likely WiFiClientSecure.