Twitter Direct Messages and SMS Instant Messages are great ways to send yourself important notes that you want to keep track of... privately. Today, we'll show you how to harness the power of Twitter and SMS to announce every call on your Asterisk® server with the name and number of the caller as well as the DID of the incoming call. Reconfiguring your Asterisk server takes less than 10 minutes. We think you'll find this to be the perfect complement to our free Urang II desktop screenpop utility.
Prerequisites. You'll need one of the Asterisk aggregations to get all of this working quickly. At a minimum, you need Asterisk 1.4 or 1.6, FreePBX, Apache, PHP 5, PHP/AGI, and SendMail or an equivalent. You'll also need a service that provides CallerID name lookups such as CallerID Superfecta. We're assuming you already have all of these components working including outbound email which is necessary to deliver the SMS alerts.
Overview. The design strategy for TweedleD is pretty straight-forward. When a call comes into your server, FreePBX should catch the call in an inbound route that looks for incoming calls on a particular DID. A CallerID Lookup source will be used in the Inbound Route to look up the name of the caller based upon their CallerID number. Then we will use a Custom Destination to route the call to a special Asterisk context which will run the TweedleD AGI script. This script actually sends out the Twitter Direct Messages as well as the SMS messages to your cellphone. Once the script completes its work, the context will send the call along to its final destination, e.g. an extension, a ring group, a day/night control, or an IVR.
NOTE: There is a 100-150 API calls per hour per IP address limit with the Twitter API. If you also are using one or more Twitter clients at your site, this is something worth keeping in mind if you have a busy phone system.
1. FreePBX Custom Context. The trick with designing FreePBX dialplans is to build them in reverse. So we'll start with the custom context and work our way back to the inbound route. First, log into your server as root and edit extensions_custom.conf in /etc/asterisk. At the end of the file, we want to create a new context that looks like this. We've provided several sample destinations at s,5 to show you the syntax. The first routes a call to an extension or ring group number. The second routes the call to Day/Night Control #1. And the third routes the call to an IVR. To find the correct IVR number or day/night control for what you want to do, review the IVR and app-daynight contexts in extensions_additional.conf to find the one you need. Obviously, you only use one s,5 line. Comment out the remaining ones as shown below. For Asterisk 1.6, replace the vertical bars in line s,3 with commas.
2. Installing PHP/AGI Scripts. Next we need to install the script that actually generates the messages for Twitter and SMS. In addition, we'll install Justin Poliey's terrific twitter.lib.php which is a PHP implementation of the Twitter API that lets you do just about anything with Twitter that you could do with the Twitter API itself. For a good writeup on the capabilities of twitter.lib.php, see Antonio Lupetti's article. To install the necessary code, issue the following commands while still logged in as root:
tar zxvf TweedleD.tgz
3. Configuring TweedleD. Now we need to configure the PHP script with your Twitter and SMS credentials so that TweedleD knows where to send the messages. Edit nv-twitter.php in the /var/lib/asterisk/agi-bin directory on your server: nano -w nv-twitter.php. You'll see a section of code near the top of the application that looks like this:
//-------- DON'T CHANGE ANYTHING ABOVE THIS LINE ----------------
$tweet = 0;
$username = "your-twitter-name";
$password = "your-twitter-password";
$user4msg = "recipients-twitter-name";
$sms = 0;
// $smsaddress = "firstname.lastname@example.org" ; // AT&T
// $smsaddress = "email@example.com" ; // AllTel
// $smsaddress = "firstname.lastname@example.org" ; // Nextel
// $smsaddress = "email@example.com" ; // Sprint
// $smsaddress = "firstname.lastname@example.org" ; // T-Mobile
// $smsaddress = "email@example.com" ; // Verizon
$debug = 0;
$newlogeachdebug = 1;
$emaildebuglog = 0;
$email = "yourname@yourdomain" ;
//-------- DON'T CHANGE ANYTHING BELOW THIS LINE ----------------
There are four things you can enable and, depending upon what choices you make, you need to add your credentials for the various options. Let's go through them in the order they appear.
To enable Twitter Direct Messages, change $tweet=0 to $tweet=1. $username and $password are used to set your Twitter login credentials for your Twitter account. You must have one! $user4msg is the Twitter account name where the DMs should be delivered. They do not necessarily have to be delivered to your Twitter account although they can be. Be sure to preserve the quotes! And, remember, you can only send direct messages to people on Twitter that you are following, and they must be following you as well. If in doubt, attempt to send a direct message in Twitter to the desired recipient. Then you'll know for sure. TweedleD provides no error messages if things don't work.
To enable delivery of SMS messages to your cellphone, set $sms=1. TweedleD actually delivers SMS messages using email. Virtually all of the carriers provide an SMS-Email Gateway for this purpose. The trick is knowing the email domain for your desired carrier. The full list is available here. And here is an even newer Email to SMS Gateway list. In the script, we've provided samples for the major U.S. carriers so, if yours is in the list, just uncomment the appropriate line by removing the leading // on the line and replace 1234567890 with your 10-digit cellphone number.
If you want a debug log generated for each call, set $debug=1. The default is to overwrite the previous log (/var/log/asterisk/nv-twitter.txt) with each new call. If you'd prefer an ever-growing log, set $newlogeachdebug=0.
The debug log also can be emailed to you. Set $emaildebuglog=1 and enter your email address in $email.
When you've completed the configuration, save the file (Ctrl-X, Y, Enter) and reload the Asterisk dialplan: asterisk -rx "dialplan reload".
4. FreePBX Setup. Finally, we need to configure FreePBX to support TweedleD. We'll add a Custom Destination and then adjust our inbound route(s) to support the custom context we added in Step 1. Open FreePBX with a web browser and choose Admin, Tools, Custom Destinations, Add Custom Destination. For the Description, call it TweedleD. For the Custom Destination, enter the following: custom-twitter,s,1. Then click Submit. Now edit your Inbound Routes for the DIDs for which you wish to activate TweedleD. For each inbound route, make sure you have activated a CallerID lookup source and then set the destination to: Custom Destination: TweedleD. Save your changes and reload the dialplan.
Trying Out TweedleD. Now you're ready to place a test call. Just call into your system on one of the DIDs that has been configured for TweedleD. On the Asterisk CLI, you should see an entry that identifies the CallerID name and number of the caller. And, if you've activated delivery of notifications to Twitter and/or SMS, the messages will magically appear within seconds. Enjoy!
Tips of the Week. If you hurry, you can get 25GB of free, password-protected online storage with the new Micro$oft SkyDrive offering. Or, for a free incoming call number for your Skype account, check this service out. A new precompiled version of Asterisk 1.6 for Mac OS X Leopard has been released. You can download it here. Finally, Sprint is offering a Netbook for 99¢ with any 2-year EVDO contract at Best Buy stores this week. Regular price for the Compaq Mini is $389.99. Add your cell phone or Asterisk DID to the DO NOT CALL Registry. Just call 888-382-1222 using the CallerID of the number to wish to block.
Sign of the Times. Before you get too comfortable with all your free Google apps, you might want to read this article. Despite assurances to the contrary from Google's President of Enterprise, it seems that the free version of Google Apps has quietly disappeared.
VoIP Users Conference. Come join the fun. The VoIP Users Conference is held every Friday at noon, Eastern time. ISN: 8647*1061 (Hint: 8647 spells VOIP on your phone).
The World According to Twitter. Be on the lookout for David Pogue's new book, The World According to Twitter. It goes to press today! Incidentally, Pogue's books are just about the only reasonably priced tech books available for the Kindle, and they're all excellent.
Tomorrow's the Big Day. The last time this happened, it was a pretty quiet year. Just after noon tomorrow comes your once-in-a-lifetime moment when the time will officially be 12:34:56 7/8/9. The last time we had this much fun in our lifetime was... uh, about a year ago: 01:23:45 6/7/8. Can't wait for next year's thriller: 23:45:67 8/9/10. Ooops! That won't work on most clocks. Will it? Amazing what you can learn on Twitter. Isn't it? Thanks, @ejovi and @ev.
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