How to get data from web by NodeMCU - c++

Question

I'm using NodeMCU v3, and can already send some information on its server.
But how can I receive some information from other web pages, let say for beginning, a plain text?

Answer 1

You need a HttpClient to communicate with a web server.
Good way to start is to use the HttpClient sample -> ReuseConnection.
This will allow you to make more requests than one.
You can see in Serial Monitor in Arduino IDE to see the response from the request.
Sample code:
Note: replace " http://:/someroute " with the desired http page you want to get.
#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#include <ESP8266HTTPClient.h>
#define USE_SERIAL Serial
ESP8266WiFiMulti WiFiMulti;
HTTPClient http;
void setup() {
USE_SERIAL.begin(115200);
// USE_SERIAL.setDebugOutput(true);
USE_SERIAL.println();
USE_SERIAL.println();
USE_SERIAL.println();
for(uint8_t t = 4; t > 0; t--) {
USE_SERIAL.printf("[SETUP] WAIT %d...\n", t);
USE_SERIAL.flush();
delay(1000);
}
WiFiMulti.addAP("SSID", "PASSWORD");
// allow reuse (if server supports it)
http.setReuse(true);
}
void loop() {
// wait for WiFi connection
if((WiFiMulti.run() == WL_CONNECTED)) {
http.begin("http://<IP>:<Port>/someroute");
int httpCode = http.GET();
if(httpCode > 0) {
USE_SERIAL.printf("[HTTP] GET... code: %d\n", httpCode);
// file found at server
if(httpCode == HTTP_CODE_OK) {
String payload = http.getString();
USE_SERIAL.println(payload);
}
} else {
USE_SERIAL.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str());
}
http.end();
}
delay(3000);
}