ESP8266 Community Forum

Posted: **Thu Mar 17, 2016 7:55 am**

hello everyone,
I am trying to GET a TalkBack Command on Thingspeak.com using Arduino IDE but i am not getting any response on Serial Monitor. I have tested the following GET request with the Poster. it works perfectly.

https://api.thingspeak.com/talkbacks/74 ... FUJBI6Z115

Code: Select all

#include <ESP8266WiFi.h>

const char* ssid     = "XXX";
const char* password = "YYYYY";

const char* host = "api.thingspeak.com";

// Use WiFiClient class to create TCP connections
WiFiClient client;

void setup() {
  Serial.begin(115200);
  delay(100);

  // We start by connecting to a WiFi network

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}


void loop() {

  Serial.print("connecting to ");
  Serial.println(host);

if (client.connect(host,80)) { // "184.106.153.149" or api.thingspeak.com

String postStr = "GET /talkbacks/7441/commands/1145081?api_key=WSMCMVFUJBI6Z115 HTTP/1.1\n";

client.print(postStr);
client.print("Host: api.thingspeak.com\n");
client.print("Connection: close\n");
}

  // Read all the lines of the reply from server and print them to Serial
  while(client.available()){
    
    char c = client.read();
    Serial.print(c);
  }

  client.stop();
  
  Serial.println();
  Serial.println("closing connection");
  delay(15000);

}

i think something is wrong with my GET request
What is the correct way to send Talkback GET request ?

Posted: **Thu Mar 17, 2016 12:16 pm**

After the connect, you are checking client.available() and if nothing received yet you do a client.stop().
Don't expect a remote server to answer within microseconds, you need to have a delay between request and answer.
Personally, I don't simply add a dummy delay, but I'm doing a timeout loop such as :

Code: Select all

    int timeout = millis() + 5000;
    client.print("GET /search?q=arduino HTTP/1.1\r\nHost: google.com\r\n\r\n");
    while (client.available() == 0) {
      if (timeout - millis() < 0) {
        Serial.println(">>> Client Timeout !");
        client.stop();
        return;
      }
    }
    int size;
    while ((size = client.available()) > 0) {
      uint8_t* msg = (uint8_t*)malloc(size);
      size = client.read(msg, size);
      Serial.write(msg, size);
      free(msg);
    }
    client.stop();
    return;

Posted: **Mon Aug 01, 2016 6:46 am**

I made a correct thingspeak get request using this code

Code: Select all

  client.print("GET /channels/"+my_channel_id+"/fields/"+field_no+"/last?key="+apiKey+  " HTTP/1.1\r\n" +
               "Host: api.thingspeak.com" + "\r\n" + 
               "Connection: close\r\n\r\n");

fill in channe_id, field_number and apikey, this will fetch the LAST entry in that field and Martin is right about remote server. You can use following function just after the above code to receive from thingspeak

Code: Select all


String Get_reply (void)
  {
    String reply="";
      while(!client.available())
     {
        Serial.print('.');
        delay(200);         //could be reduced
     }

     while (client.available())
    {
       char c = client.read();
       Serial.print(c);
        reply.concat(c);
    }
      return(reply);
  }

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