How to fix "Guru Meditation Error" caused by http.GET();? - http-get

Question

I want to send data on my web server from esp32. ESP32 can not get to website and reboot.
I used exaples from Arduino IDE.
I've tried to post(htt.POST("X")) something and got same error.
I marked code to find which line cause the problem.
Googled.
...
msg="192.168.4.22/parametr";
if(WiFi.status() == WL_CONNECTED){
if(client.connect(host,httpPort)){
http.begin(msg);
Serial.print("0");
Serial.print("[HTTP] GET...\n");
int httpCode = http.GET();
Serial.print("1");
...
I expect to get to website, but now esp32 reboots when achived http.GET() and never prints "1".
Error message: Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.

Answer 1

The URL you are passing to http.begin() is incorrect. You need to include the http:// prefix (see here). Semantically, it makes more sense to name this variable url rather than msg.
Also ... Check the return value of http.begin() - in case it is still failing.
const char *url = "http://192.168.4.22/parametr";
// Check Wi-Fi connected, etc.
if (!http.begin(url)) {
Serial.println("HTTP client failed to connect ...");
}
else {
int httpCode = http.GET();
// etc.
}
The LoadProhibited fatal error indicates an attempt to read or write an invalid memory location. When the library failed to parse the URL you provided, some member of the HTTPClient object may have been left uninitialized.
Log output
To assist your debugging, try setting the 'Core debug level' in the Arduino IDE to 'Debug'.
Arduino IDE -> Tools -> Core Debug Level -> Debug
This will ensure that the ESP log messages - such as might be printed if initialization of the HTTP client fails - will be printed over the serial port.
For example, this is the log output I see if I fail to include the http:// protocol specifier in the URL (after changing the core debug level).