CC3000 - Send GET request to an app, or sub-domain, on Heroku

Question

I am working with Arduino UNO + AdaFruit CC3000 Wi-Fi shield. I ran it with a lot of websites and webpages, but for now I am going to get sub-domain from Heroku, and it has no IP address. The sub-domain is myapp.herokuapp.com.

So, how can I send a GET request to such an application like that?

Here's the code :

 // Library headers section
 #include <Adafruit_CC3000.h>
 #include <ccspi.h>
 #include <SPI.h>
 #include <string.h>
 #include "utility/debug.h"
 // Constants area
 #define ADAFRUIT_CC3000_IRQ 3 // must be an interrupt pin (2 or 3)
 #define ADAFRUIT_CC3000_VBAT 5 // any pin
 #define ADAFRUIT_CC3000_CS 10 // any pin
 //use hardware SPI for remaining pins
 // Uno: SCK=13, MISO=12, MOSI=11
 Adafruit_CC3000 cc3000 = Adafruit_CC3000(ADAFRUIT_CC3000_CS, ADAFRUIT_CC3000_IRQ,
 ADAFRUIT_CC3000_VBAT, SPI_CLOCK_DIVIDER);
 #define WLAN_SSID "Ibtikar.AP2"
 #define WLAN_PASS "#ibtik@r#"
 // set security type
 // WLAN_SEC_UNSEC, WLAN_SEC_WEP, WLAN_SEC_WPA, WLAN_SEC_WPA2
 #define WLAN_SECURITY WLAN_SEC_WPA2
 #define IDLE_TIMEOUT_MS 3000 // amount of time to wait with no date recieved
 // before rejecting/closing the collection
 #define WEBSITE "myapp.herokuapp.com"
 uint32_t ip;
 void setup() {
 // put your setup code here, to run once:
 Serial.begin(115200);
 Serial.print("Free RAM: "); Serial.println(getFreeRam(), DEC);
/* Initialise the module */
 Serial.println(F("\nInitializing..."));
 delay(100);
 if (!cc3000.begin())
 {
 Serial.println(F("Couldn't begin()! Check your wiring?"));
 while(1);
 }
 Serial.print(F("\nAttempting to connect to ")); Serial.println(WLAN_SSID);
 if (!cc3000.connectToAP(WLAN_SSID, WLAN_PASS, WLAN_SECURITY)) {
 Serial.println(F("Failed!"));
 while(1);
 } 
 Serial.println(F("Connected!"));
 /* Wait for DHCP to complete */
 Serial.println(F("Request DHCP"));
 while (!cc3000.checkDHCP())
 {
 delay(100); // ToDo: Insert a DHCP timeout!
 } 
 /* Display the IP address DNS, Gateway, etc. */ 
 while (! displayConnectionDetails()) {
 delay(1000);
 }
 ip = 0;
 // Try looking up the website's IP address
 Serial.print(WEBSITE); Serial.print(F(" -> "));
 while (ip == 0) {
 if (! cc3000.getHostByName(WEBSITE, &ip)) {
 Serial.println(F("Couldn't resolve!"));
 }
 delay(500);
 }
 cc3000.printIPdotsRev(ip);
 // Optional: Do a ping test on the website
 Serial.print(F("\n\rPinging ")); cc3000.printIPdotsRev(ip); Serial.print("..."); 
 int replies = cc3000.ping(ip, 5);
 Serial.print(replies); Serial.println(F(" replies"));
 }
 void loop() {
 /* Try connecting to the website.
 Note: HTTP/1.1 protocol is used to keep the server from closing the connection before all data is read.
 */
 Adafruit_CC3000_Client www = cc3000.connectTCP(ip, 80);
 if (www.connected()) {
 www.fastrprint(F("GET "));
 www.fastrprint(F(" HTTP/1.1\r\n"));
 www.fastrprint(F("Host: myapp.herokuapp.com")); 
 //www.fastrprint(WEBSITE); 
 www.fastrprint(F("\r\n"));
 www.println();
 } else {
 Serial.println(F("Connection failed")); 
 return;
 }
 Serial.println(F("-------------------------------------"));
 unsigned long lastRead = millis();
 while (www.connected() && (millis() - lastRead < IDLE_TIMEOUT_MS)) {
 while (www.available()) {
 char c = www.read();
 Serial.print(c);
 lastRead = millis();
 }
 }
 www.close();
 Serial.println(F("-------------------------------------"));
 /* You need to make sure to clean up after yourself or the CC3000 can freak out */
 /* the next time your try to connect ... */
 Serial.println(F("\n\nDisconnecting"));
 cc3000.disconnect();
 delay(1000);
 }
 /**************************************************************************/
 /*!
 @brief Begins an SSID scan and prints out all the visible networks
 */
 /**************************************************************************/
 void listSSIDResults(void)
 { 
 uint32_t index;
 uint8_t valid, rssi, sec;
 char ssidname[33]; 
 if (!cc3000.startSSIDscan(&index)) {
 Serial.println(F("SSID scan failed!"));
 return;
 }
 Serial.print(F("Networks found: ")); Serial.println(index);
 Serial.println(F("================================================"));
 while (index) {
 index--;
 valid = cc3000.getNextSSID(&rssi, &sec, ssidname);
 Serial.print(F("SSID Name : ")); Serial.print(ssidname);
 Serial.println();
 Serial.print(F("RSSI : "));
 Serial.println(rssi);
 Serial.print(F("Security Mode: "));
 Serial.println(sec);
 Serial.println();
 }
 Serial.println(F("================================================"));
 cc3000.stopSSIDscan();
 }
 /**************************************************************************/
 /*!
 @brief Tries to read the IP address and other connection details
 */
 /**************************************************************************/
 bool displayConnectionDetails(void)
 {
 uint32_t ipAddress, netmask, gateway, dhcpserv, dnsserv;
 if(!cc3000.getIPAddress(&ipAddress, &netmask, &gateway, &dhcpserv, &dnsserv))
 {
 Serial.println(F("Unable to retrieve the IP Address!\r\n"));
 return false;
 }
 else
 {
 Serial.print(F("\nIP Addr: ")); cc3000.printIPdotsRev(ipAddress);
 Serial.print(F("\nNetmask: ")); cc3000.printIPdotsRev(netmask);
 Serial.print(F("\nGateway: ")); cc3000.printIPdotsRev(gateway);
 Serial.print(F("\nDHCPsrv: ")); cc3000.printIPdotsRev(dhcpserv);
 Serial.print(F("\nDNSserv: ")); cc3000.printIPdotsRev(dnsserv);
 Serial.println();
 return true;
 }
 }

Answer 1

You don't need to know the IP address; the getHostByName() method takes care of resolving the website to an address. It seems 2 lines are missing from your code:

 #define WEBPAGE "/index.html" // change the string to the webpage you want

at the top, and:

 www.fastrprint(WEBPAGE);

right after www.fastrprint(F("GET "));. Without these lines, you've failed to indicate the specific webpage you wish to GET. Anyways, when i tried to open myapp.herokuapp.com, I got a message saying that its offline for maintenance, so you'll most likely fail to retrieve anything.