Twilio provides a relatively painless SMS
interface. But the PHP documentation is
fragmented and takes some effort to aggregate.
So, to make it easier for others, I threw together a quick outline of
how you go about implementing a Twilio interface in PHP. The send interface is
very simple:
const SMS_PREFIX = '+1';
const MAX_SEND_CHARS = 160;
const TWILIO_SMS_APP_ID = '15 digit appId';
const TWILIO_SMS_APP_SECRET = '32 character app Secret';
/**
*send an SMS message
*
* @param string $smsNum
* @param string $smsBody
*
* @return string
*/
public function sendSms($smsNum, $smsBody) {
$cliTwilio = new Services_Twilio(self::TWILIO_SMS_APP_ID,
self::TWILIO_SMS_APP_SECRET);
$smsNum = self::SMS_PREFIX . $smsNum;
$smsFrom = self::SMS_PREFIX . $this->twilioNumber;
if (strlen($smsBody) > self::MAX_SEND_CHARS) {
throw new Exception ('Error: attempting to send message
of length (' .
strlen($smsBody) . ') but max
allowed chars is (' .
self::MAX_SEND_CHARS . ') for SMS number: ' . $smsNum);
} else {
$smsResponse = $cliTwilio->account->sms_messages->create($smsFrom, $smsNum,
$smsBody);
if ($smsResponse->sid != null) {
return $smsResponse->sid;
} else {
throw new Exception ('Error: SMS send returned invalid
(NULL) sid for ' .
'sms number: '
. $smsNum);
}
}
}
The “Services_Twilio” class referenced here is
in the Twilio library provided by Twilio.
You need to download it from Twilio.
To be able to receive SMS messages, you need to
go the Twilio website, login, select “Numbers”, and click into the number you
have setup for your Twilio account. Go
to the SMS section, and set the “SMS Request URL” to point to your receiving
web page (https is recommended but not required to make it work which is handy
for testing). The receiving web page on
your site needs something similar to the following in it:
class SMSMessageParser
{
/**
* Parse the incoming SMS message
*/
public function parse() {
if(!isset($_SERVER['HTTPS']) && $this->config->twilio->useSSL !="NO") {
header("HTTP/1.1
301 Moved Permanently");
header("Location:
https://" . $_SERVER["SERVER_NAME"] .
$_SERVER["REQUEST_URI"]);
exit();
}
if (empty($_REQUEST)) {
die();
} else {
$smsNum = substr($_REQUEST['From'],-10);
$smsMsg = $_REQUEST['Body'];
try {
$smsService = new SmsService();
$response = $smsService->parseSms($smsNum, $smsMsg);
} catch (Exception $e) {
$response = "We are sorry, but we
experienced an unexpected error " .
"processing your request.";
}
header("content-type:
text/xml");
echo "<?xml version=\"1.0\"
encoding=\"UTF-8\"?>\n";
echo "<Response>";
echo "<Sms>" . $response . "</Sms>";
echo "</Response>";
exit;
}
}
}
$parser = new SMSMessageParser();
$parser->parse();
And finally, you need a class to process the
incoming text:
class SmsService {
private $smsReservedVerbs = array('stop','unsubscribe','cancel','quit',
'start','yes','help');
/**
* parse incoming SMS message
*
* @param string $smsNum
* @param string $smsMsg
*
* @return string
*/
public function parseSms($smsNum, $smsMsg) {
$smsNum = trim($smsNum);
$smsMsg = trim($smsMsg);
if(strlen($smsNum) != 10) {
return false;
}
if ($smsMsg == "Whatever you are looking
for") {
// Do something with
message
} else if (in_array(strtolower($smsMsg), $this->smsReservedVerbs)) {
switch(strtolower($smsMsg)) {
case "unsubscribe":
case "stop":
case "cancel":
case "quit":
// User
unsubscribed so take appropriate action
break;
case "start":
case "yes":
// User
resubscribed. Act appropriately.
break;
case "help":
// send some
sort of appropriate information.
break;
default:
throw new Exception ('Error: We should not be able to
reach ' .
'this statement. Message was: ' . $smsMsg);
}
} else {
$responseString = 'We are sorry. Your message "' . $smsMsg . '" ' .
'was not
understood.' ;
}
return $responseString;
}
}
And that’s all there is to it.
