#include <ESP8266WiFi.h>

#include <ESP8266HTTPClient.h>
#include <WiFiClientSecureBearSSL.h>

#define WIFI_SSID "ssid"
#define WIFI_PASSWORD "password"

void setup() {
  Serial.print("Connecting to Wi-Fi");
  while (WiFi.status() != WL_CONNECTED)
  Serial.print("Connected with IP: ");

  std::unique_ptr<BearSSL::WiFiClientSecure>client(new BearSSL::WiFiClientSecure);
  HTTPClient http;

  http.begin(*client, "https://jsonplaceholder.typicode.com/photos");
  http.addHeader("Accept", "*/*");

  int httpCode = http.GET();
  Serial.print("HTTP CODE: "); Serial.println(httpCode);

  //reading response with buffer
  static char buff[128] = { 0 };
  while (http.connected() ) {
    size_t size = client->available();
    if (size) {
      int c = client->readBytes(buff, ((size > sizeof(buff) ) ? sizeof(buff) : size));
      //if i uncomment this next line, everything is fine.
      //Serial.write(buff, c); Serial.println();

      //but if i dont use serial.write program never gets here
      if (char * pch = strstr (buff, "quis fuga")) {
        char str[20] = { 0 }; int g =   0 ;
        while (pch[g] != '\"') {
          str[g] = pch[ g];
        Serial.print("FOUND IT: "); Serial.println(str);

    else if (!size) {
      Serial.println( "reading done");


void loop() {



EDIT here i created a compilable runnable code. basically i am trying to find a word in a http response. my real examples response isnt json and it is as long as this examples response. one other problem is i cant read all of the repsponse. it unexpectedly finishes reading sometimes after a few lines sometimes after a few hundred. in this particular request my nodemcu cant read after id 258. or id 8. object in the json response: https://jsonplaceholder.typicode.com/photos

if i dont use serial.write print buffer content, it finishes reading immideatly and thats exactly where i have the problem.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – VE7JRO
    Commented Jan 26, 2020 at 14:49

1 Answer 1


The Serial printing creates a delay. That delay enables to collect more characters in the buffer. If you read the input in small pieces (3 to 10 bytes) then the buffer doesn't contain the searched substring because it splits into two subsequent buffers. Even if you could read full buffers, it still can happen that the search string will be split.

To search for a string in a stream of data you can use function find(string). The networking Client class inherits this function from Arduino Stream class. find will read the stream until it finds the searched string. Then the next read from the stream will read the data right after the searched string.

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