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/*
Wifi Twitter Client with Strings
This sketch connects to Twitter using using an Arduino WiFi shield.
It parses the XML returned, and looks for <text>this is a tweet</text>
This example is written for a network using WPA encryption. For
WEP or WPA, change the Wifi.begin() call accordingly.
This example uses the String library, which is part of the Arduino core from
version 0019.
Circuit:
* WiFi shield attached to pins 10, 11, 12, 13
created 23 apr 2012
modified 31 May 2012
by Tom Igoe
This code is in the public domain.
*/
#include <SPI.h>
#include <WiFi.h>
char ssid[] = "yourNetwork"; // your network SSID (name)
char pass[] = "password"; // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0; // your network key Index number (needed only for WEP)
int status = WL_IDLE_STATUS; // status of the wifi connection
// initialize the library instance:
WiFiClient client;
const unsigned long requestInterval = 30*1000; // delay between requests; 30 seconds
// 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(199,59,149,200); // numeric IP for api.twitter.com
char server[] = "api.twitter.com"; // name address for twitter API
boolean requested; // whether you've made a request since connecting
unsigned long lastAttemptTime = 0; // last time you connected to the server, in milliseconds
String currentLine = ""; // string to hold the text from server
String tweet = ""; // string to hold the tweet
boolean readingTweet = false; // if you're currently reading the tweet
void setup() {
// reserve space for the strings:
currentLine.reserve(256);
tweet.reserve(150);
//Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
// don't continue:
while(true);
}
// attempt to connect to Wifi network:
while ( status != WL_CONNECTED) {
Serial.print("Attempting to connect to SSID: ");
Serial.println(ssid);
// Connect to WPA/WPA2 network. Change this line if using open or WEP network:
status = WiFi.begin(ssid, pass);
// wait 10 seconds for connection:
delay(10000);
}
// you're connected now, so print out the status:
printWifiStatus();
connectToServer();
}
void loop()
{
if (client.connected()) {
if (client.available()) {
// read incoming bytes:
char inChar = client.read();
// add incoming byte to end of line:
currentLine += inChar;
// if you get a newline, clear the line:
if (inChar == '\n') {
currentLine = "";
}
// if the current line ends with <text>, it will
// be followed by the tweet:
if ( currentLine.endsWith("<text>")) {
// tweet is beginning. Clear the tweet string:
readingTweet = true;
tweet = "";
// break out of the loop so this character isn't added to the tweet:
return;
}
// if you're currently reading the bytes of a tweet,
// add them to the tweet String:
if (readingTweet) {
if (inChar != '<') {
tweet += inChar;
}
else {
// if you got a "<" character,
// you've reached the end of the tweet:
readingTweet = false;
Serial.println(tweet);
// close the connection to the server:
client.stop();
}
}
}
}
else if (millis() - lastAttemptTime > requestInterval) {
// if you're not connected, and two minutes have passed since
// your last connection, then attempt to connect again:
connectToServer();
}
}
void connectToServer() {
// attempt to connect, and wait a millisecond:
Serial.println("connecting to server...");
if (client.connect(server, 80)) {
Serial.println("making HTTP request...");
// make HTTP GET request to twitter:
client.println("GET /1/statuses/user_timeline.xml?screen_name=arduino HTTP/1.1");
client.println("Host: api.twitter.com");
client.println("Connection: close");
client.println();
}
// note the time of this connect attempt:
lastAttemptTime = millis();
}
void printWifiStatus() {
// print the SSID of the network you're attached to:
Serial.print("SSID: ");
Serial.println(WiFi.SSID());
// print your WiFi shield's IP address:
IPAddress ip = WiFi.localIP();
Serial.print("IP Address: ");
Serial.println(ip);
// print the received signal strength:
long rssi = WiFi.RSSI();
Serial.print("signal strength (RSSI):");
Serial.print(rssi);
Serial.println(" dBm");
}
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