Fail to Retrieve channel description
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Serial.println("AT");
delay(1000);
Serial.print("AT+CIPSTART=3,\"TCP\",\"api.thingspeak.com\",80\r\n");
delay(3000);
Serial.print("AT+CIPSEND=3,");
Serial.print(68);
Serial.print("\r\n");
delay(2000);
Serial.print("GET /channels/");
Serial.print(channel_id);
Serial.print("/feeds.json?api_key=");
Serial.print(mystringchar);
Serial.print("&results=0 HTTP/1.1\r\n");
Serial.print("Host:");
Serial.print(DST_IP);
Serial.println(); //web link
delay(300);
unsigned long lastRead = millis();
while (millis() - lastRead < 5000) {
while (Serial.available())
{
if (Serial.find("description\":\""))
{
String message = Serial.readStringUntil('$');
Serial.flush();
Serial.println(message);
}
}
This code was working fine for our production since 3 years but presently we are unable to retrive description .please do suggest us .
we are using sim-800c and esp8266-12f
回答（2 个）
Vinod
2020-9-28
0 个投票
Have you checked your GSM module to see that it still has data capacity? Nothing has changed on ThingSpeak early August that can be linked to what you are seeing.
Are you able to connect to any other site using the SIM-800C?
4 个评论
Asha Rani
2020-10-2
I am unable to reproduce the issue. Try this in your browser. This is the same request as you are trying to make from your device:
https://thingspeak.com/channels/366768/feeds.json?api_key=DoesNotMatter&results=0
Can you confirm that if you make the REST call using your Browser, POSTMAN or cURL from a desktop, you get the correct result?
Asha Rani
2020-10-8
Vinod
2020-10-8
Since the response is correct from POSTMAN and cURL, I suspect the issue is on your device code. I have pasted the Arduino sketch in my answer below that you can modify and try on your device.
Here's a working Arduino Sketch I have tried on an ESP32. It can be modified as needed for your device.
#include <WiFi.h>
const char* ssid = "YourSSIDHere";
const char* password = "YourWifiPasswordHere";
WiFiClient client;
const char* host = "api.thingspeak.com";
void setup() {
Serial.begin(115200);
delay(100);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
}
void loop() {
delay(5000);
if (!client.connect(host, 80)) {
Serial.println("connection failed");
return;
}
String url = "/channels/366768/feeds.json?api_key=DoesNotMatter&results=0&headers=false";
Serial.print("Requesting URL: ");
Serial.println(url);
client.print(String("GET ") + url + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
delay(500);
while(client.available()){
String line = client.readStringUntil('{');
line = client.readStringUntil('}');
Serial.print(line);
while(client.available()){client.readStringUntil('\r');}
Serial.print("\r\n");
}
delay(10000);
}
2 个评论
Asha Rani
2020-10-11
If existing devices are working fine but new production devices are not, I would suggest looking at what might be different on the new devices. It could be that one of the libraries you use has changed, or something about the hardware (available memory, memory partitions, etc.?) has changed causing you to see different results.
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