Want to make 2 different requests, but how to say to the "void requestCB" function to which requests the result belongs ?

[Rollmops67]

Hello !

Rather a question than an issue :

I'm new to asyncHTTPrequest.
I generally use the standard HTTPClient, but I'm looking for an asynchronous solution.

I did try the code in the "Examples" section and it works fine to extract one value (in my case "Pedf")
But I would like to extract another value from another request at a different url.
So in my sketch I prepared 2 functions to call, "sendRequest_0()" and "sendRequest_1()"

But how to say to the "void requestCB(......" function which value to extract ?

I think there must be a very simple solution, but I'm not familiar with the syntax of this library.

Thanks in advance for any help !

Roland

Here my code for a better understanding (runs on an ESP32)

#include <WiFi.h>
#include <AsyncTCP.h>
#include <asyncHTTPrequest.h>

unsigned long top_lect;
int intervalle = 5000 ; 

const char* ssid     = "xxxxxxxxxx";
const char* password = "yyyyyyyyyyyyyyy";
const int TimeOut_connexion =40;
int timeOut_counter =0;

float Pedf;
float Psol;

asyncHTTPrequest request;

// First request
void sendRequest_0()   // to gather the responseText() for the "Pedf" value
{
    if(request.readyState() == 0 || request.readyState() == 4)
    {
        request.open("GET", "http://192.168.1.12/emeter/0");
        request.send();
    }
}

/*********** The second request I would like to make  ********************
*
*void sendRequest_1()   //    // to gather the responseText() for a second value
*{
*    if(request.readyState() == 0 || request.readyState() == 4)
*    {
*        request.open("GET", "http://192.168.1.12/emeter/1");
*        request.send();
*    }
*}
*
************ The second request I would like to make END *****************/

void requestCB(void* optparm, asyncHTTPrequest* request, int readyState)
{
    if(readyState == 4)
    {
 //       Serial.println(request->responseText());
        Pedf = atof(((request->responseText()).substring(9,18)).c_str());
        Serial.println(Pedf);
    }
}
    

void setup()
{
  setCpuFrequencyMhz(80);     // réglage de la fréquence de la CPU (80, 160 ou 240 Mhz, en dessous le WiFi ne marche pas)

  Serial.begin(115200);
  delay(2000);

  Serial.print("Connection au WiFi...");
  
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED)
    {
      delay(250);
      Serial.print(".");
      timeOut_counter++;
      if (timeOut_counter > TimeOut_connexion) ESP.restart();   // redémarrage de l'ESP si pas de connexion pendant 10 sec
    }

  Serial.println("\n");
  Serial.println("Adresse IP : "+(WiFi.localIP().toString()));

  request.onReadyStateChange(requestCB);

}

void loop() 
{
  if (top_lect+intervalle<millis())             // condition vraie toutes les "intervalle" secondes
    {top_lect=millis(); sendRequest_0(); }        // aller à la routine de lecture des données du ShellyEM
}

[boblemaire]

Just to be clear, an instance of this class can only handle one request at a time. That said:

One solution is to simply change the callback to a different appropriate function prior to each request.

Another solution is to use the callback parameter to point to something that can be used to differentiate between the various requests.

[Rollmops67]

Hello and thank you for the fast answer !

Not knowing very well AsyncHTTPrequest and it different syntaxes (there is not much information) your 2 propositions are not of big help...

Change the callback to a different appropriate function, why not, but there are not many examples I can look how to do, and what function to use...

I think that your second solution is maybe related to the "void* optparm" option in the "void requestCB" function ?
But I tried to figure out how it works but I can't find where this "optparm" is defined and how to redirect (??) the callback with it.
Do you maybe have an example ?

TIA !

Roland

[boblemaire]

Maybe something like this:

// First request
void sendRequest_0()   // to gather the responseText() for the "Pedf" value
{
    if(request.readyState() == 0 || request.readyState() == 4)
    {
        request.onReadyStateChange(request1CB);
        request.open("GET", "http://192.168.1.12/emeter/0");
        request.send();
    }
}



void sendRequest_1()   //    // to gather the responseText() for a second value
{
    if(request.readyState() == 0 || request.readyState() == 4)
    {
        request.onReadyStateChange(request2CB);
        request.open("GET", "http://192.168.1.12/emeter/1");
        request.send();
    }
}

void request1CB(void* optparm, asyncHTTPrequest* request, int readyState)
{
    if(readyState == 4)
    {
 //       Serial.println(request->responseText());
        Pedf = atof(((request->responseText()).substring(9,18)).c_str());
        Serial.println(Pedf);
    }
}

void request2CB(void* optparm, asyncHTTPrequest* request, int readyState)
{
    if(readyState == 4)
    {
 //       Serial.println(request->responseText());
        Pedf = atof(((request->responseText()).substring(9,18)).c_str());
        Serial.println(Pedf);
    }
}

[Rollmops67]

Ohhh thanks.

Ah, its the "request.onReadyStateChange(requestxxx);" wich does the magic !

i will try it.

Roland

[Rollmops67]

I just tried it, with the result that the ESP32 crashes each time the 2 requests are launched at the same time.
I changed my code so the first request starts every 5 seconds, and the second request 2,5 seconds after, and now it works !

Many many thanks !

Roland

[Rollmops67]

Edit :

Oooops,
After about 10 minutes it crashed, with a guru meditation error :

23:24:01.076 -> Guru Meditation Error: Core  1 panic'ed (InstrFetchProhibited). Exception was unhandled.
23:24:01.076 -> 
23:24:01.076 -> Core  1 register dump:
23:24:01.076 -> PC      : 0x00440022  PS      : 0x00060930  A0      : 0x820044f1  A1      : 0x3fca6b50  
23:24:01.076 -> A2      : 0x3fca2b78  A3      : 0x40010000  A4      : 0x3fca2b70  A5      : 0x0000000c  
23:24:01.076 -> A6      : 0x02c95354  A7      : 0x00ffffff  A8      : 0x820043f5  A9      : 0x3fca6b40  
23:24:01.076 -> A10     : 0x3fca2b78  A11     : 0x3fca6b5c  A12     : 0x3fca6b58  A13     : 0x00000000  
23:24:01.076 -> A14     : 0x00000001  A15     : 0x3fca2d40  SAR     : 0x0000000a  EXCCAUSE: 0x00000014  
23:24:01.076 -> EXCVADDR: 0x00440020  LBEG    : 0x400570e8  LEND    : 0x400570f3  LCOUNT  : 0xffffffff  
23:24:01.076 -> 
23:24:01.076 -> 
23:24:01.076 -> Backtrace: 0x0044001f:0x3fca6b50 0x420044ee:0x3fca6b80 0x42004504:0x3fca6ba0 0x4200481e:0x3fca6bc0
23:24:01.076 -> 
23:24:01.076 -> 
23:24:01.076 -> 
23:24:01.076 -> 
23:24:01.076 -> ELF file SHA256: a65d66640a0063d8
23:24:01.076 -> 
23:24:01.076 -> Rebooting...
23:24:01.076 -> ESP-ROM:esp32s3-20210327
23:24:01.076 -> Build:Mar 27 2021
23:24:01.076 -> rst:0xc (RTC_SW_CPU_RST),boot:0x8 (SPI_FAST_FLASH_BOOT)
23:24:01.076 -> Saved PC:0x420195f5
23:24:01.076 -> SPIWP:0xee
23:24:01.076 -> mode:DIO, clock div:1
23:24:01.076 -> load:0x3fce3808,len:0x44c
23:24:01.076 -> load:0x403c9700,len:0xbe4
23:24:01.076 -> load:0x403cc700,len:0x2a38
23:24:01.076 -> entry 0x403c98d4

Roland

[boblemaire]

Simultaneous requests work with the ESP8266. The ESP32 is a different animal. I don't use this with ESP32 because there is really no need to provide the asynchronous HTTP functionality with ESP32. You can just create a FREERTOS task to do the transaction with either HTTPclient or the underlying esp_http_client and blocking will only affect that task while your other tasks continue to execute. You get the added benefit of being able to use both processors.

[Rollmops67]

OK, I will try this way.

Thanks for the time spend.

Roland