ESP WDT reset getting Wunderground weather forecast
Posted: Fri Sep 30, 2016 7:16 amESP software watchdog timer causes ESP to crash and reboot after getting high temperature value from a requested JSON weather forecast on Wunderground.
I've read that the JSON string can be too long for the ESP memory buffer. How would I modify my code to handle the required buffer size?
I've read that the JSON string can be too long for the ESP memory buffer. How would I modify my code to handle the required buffer size?
Code: Select all
#include <SPI.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
// if you don't want to use DNS (and reduce your sketch size)
// use the numeric IP instead of the name for the server:
//IPAddress server(23,216,168,120); // numeric IP for Weather Underground (no DNS)
const char server[] = "api.wunderground.com"; // name address for Weather Underground (using DNS)
const char* ssid = "";
const char* password = "";
const String myKey = ""; //See: http://www.wunderground.com/weather/api/d/docs (change here with your KEY)
const String myFeatures = "forecast"; //See: http://www.wunderground.com/weather/api/d/docs?d=data/index&MR=1
const String query = "autoip";
//const String myCountry = "UK"; //See: http://www.wunderground.com/weather/api/d/docs?d=resources/country-to-iso-matching
//const String myCity = "Sertaozinho"; //See: http://www.wunderground.com/weather/api/d/docs?d=data/index&MR=1
// Set the static IP address to use if the DHCP fails to assign
//IPAddress ip(192,168,1,177);
// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 80 is default for HTTP):
WiFiClient client;
//Response from Server
String responseString;
boolean startCapture;
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial){
}
//Connecting to WiFi network
Serial.print("Connecting to ");
Serial.println(ssid);
Serial.print("Trying connection to");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED){ // Try to establish WiFi connection and startup Web server.
delay(500);
Serial.print("."); // Keep printing 'dots' whilst WiFi channel is not connected to ESP. Give up and continue rest of program after 30 sec.
}
Serial.println("");
Serial.println("WiFi connected"); // Inform user that WiFi has successfully connected!
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
// if you get a connection, report back via serial:
if (client.connect(server, 80))
{
Serial.println("Connected!");
String html_cmd1 = "GET /api/" + myKey + "/" + myFeatures + "/q/" + query + ".json HTTP/1.1";
String html_cmd2 = "Host: " + (String)server;
String html_cmd3 = "Connection: close";
//Uncomment this is necessary
Serial.println("Sending commands:");
Serial.println(" " + html_cmd1);
Serial.println(" " + html_cmd2);
Serial.println(" " + html_cmd3);
Serial.println();
// Make a HTTP request:
client.println(html_cmd1);
client.println(html_cmd2);
client.println(html_cmd3);
client.println();
responseString = "";
startCapture = false;
}
else
{
// if you didn't get a connection to the server:
Serial.println("Connection failed!");
}
}
void loop()
{
// if there are incoming bytes available
// from the server, read them and buffer:
if (client.available())
{
char c = client.read();
if (c != '}'){
if(c == 'c')
startCapture=true;
if(startCapture)
responseString += c;
}
}
// if the server's disconnected, stop the client:
if (!client.connected()) {
Serial.println("Received " + (String)responseString.length() + " bytes");
Serial.println("Disconnecting.");
client.stop();
client.flush();
delay(5000);
Serial.println();
//Now, some examples of how to use it!
Serial.print("Today's High: ");
Serial.print(getValuesFromKey(responseString, "celsius"));
Serial.println(" oC\n");
//Serial.print("Current Temperature: ");
//Serial.print(getValuesFromKey(responseString, "temp_c"));
//Serial.println(" oC\n");
//Serial.print("Today's Low: ");
//Serial.println(getValuesFromKey(responseString, "low"));
//Serial.println();
//Serial.print("Wind: ");
//Serial.println(getValuesFromKey(responseString, "wind_string"));
//Serial.println();
//Serial.print("Feels like: ");
//Serial.print(getValuesFromKey(responseString, "feelslike_c"));
//Serial.println(" oC\n");
// do nothing forevermore:
while(true);
}
}
String getValuesFromKey(const String response, const String sKey)
{
String sKey_ = sKey;
sKey_ = "\"" + sKey + "\":";
char key[sKey_.length()];
sKey_.toCharArray(key, sizeof(key));
int keySize = sizeof(key)-1;
String result = "";
int n = response.length();
for(int i=0; i < (n-keySize-1); i++)
{
char c[keySize];
for(int k=0; k<keySize; k++)
{
c[k] = response.charAt(i+k);
}
boolean isEqual = true;
for(int k=0; k<keySize; k++)
{
if(!(c[k] == key[k]))
{
isEqual = false;
break;
}
}
if(isEqual)
{
int j= i + keySize + 1;
while(!(response.charAt(j) == ','))
{
result += response.charAt(j);
j++;
}
//Remove char '"'
result.replace("\"","");
break;
}
}
return result;
}