How to call URL with Arduino Ethernet shield?

Question

I'm working on Arduino and Ethernet shield.

I need to call a URL. How can do it? (This URL is HTTP API to send an SMS to my phone).

1. url: http://api.clickatell.com/http/sendmsg?user=mohammed.atha&password=********&api_id=3539384&to=********&text=hello

Answer 1

You need to use the EthernetClient. link

The exemple using your API call is:

if (client.connect(server, 80)) {
 Serial.println("connected");
 // Make your API request:
 client.println("GET /sendmsg?user=mohammed.atha&password=********&api_id=3539384&to=********&text=hello HTTP/1.1");
 client.println("Host: api.clickatell.com/http/sendmsg");
 client.println("Connection: close");
 client.println();
} 

Full example from Arduino.cc docs:

#include <SPI.h>
#include <Ethernet.h>
// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
// 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(74,125,232,128); // numeric IP for Google (no DNS)
char server[] = "www.google.com"; // name address for Google (using DNS)
// Set the static IP address to use if the DHCP fails to assign
IPAddress ip(192,168,0,177);
// 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):
EthernetClient client;
void setup() {
 // Open serial communications and wait for port to open:
 Serial.begin(9600);
 while (!Serial) {
 ; // wait for serial port to connect. Needed for Leonardo only
 }
 // start the Ethernet connection:
 if (Ethernet.begin(mac) == 0) {
 Serial.println("Failed to configure Ethernet using DHCP");
 // no point in carrying on, so do nothing forevermore:
 // try to congifure using IP address instead of DHCP:
 Ethernet.begin(mac, ip);
 }
 // give the Ethernet shield a second to initialize:
 delay(1000);
 Serial.println("connecting...");
 // if you get a connection, report back via serial:
 if (client.connect(server, 80)) {
 Serial.println("connected");
 // Make your API request:
 client.println("GET /sendmsg?user=mohammed.atha&password=********&api_id=3539384&to=********&text=hello HTTP/1.1");
 client.println("Host: api.clickatell.com/http/sendmsg");
 client.println("Connection: close");
 client.println();
 } 
 else {
 // kf 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 print them:
 if (client.available()) {
 char c = client.read();
 Serial.print(c);
 }
 // if the server's disconnected, stop the client:
 if (!client.connected()) {
 Serial.println();
 Serial.println("disconnecting.");
 client.stop();
 // do nothing forevermore:
 while(true);
 }
}

• Mohammed Athamneh: how this can help me !!! plz help me
• Vitor Leal: Just look at client.connect(server, 80) in code in the example, i've changed to work with your API call.
• Mohammed Athamneh: thnx thnx thnx :D but why use google.com as server ? (char server[] = "www.google.com";)
• Mohammed Athamneh: Is there a need for subnet and default gateway ?
• Vitor Leal: @MohammedAthamneh please vote in the answer if it helped you ;)