MIT D-Lab ICT4D Lab 1: SMS Services

Intro to Lab Sessions Goal: Give overview and examples to jump-start you Three Sessions SMS applications J2ME (on-the-phone apps) Advanced features (NFC, Location, MMS, etc.) But … we can’t teach everything in 3 sessions! you’re expected to study and follow-up on your own we’ll just give you simple educational examples – not necessarily the best or most scalable solutions you’re welcome to use other tools and techniques not taught in class These tools are works in progress -- You’re welcome to help!

Recap: Mobile Phone Capabilities, Apps SMS (Text Messaging) –based services send text commands, receive info receive alerts and subscriptions MMS (Multimedia Messaging) –based services send and receive multimedia to/from server J2ME (Java 2 Micro Edition) applications programs running on the phone e.g., games Internet/Web services via WAP (limited) and/or GPRS (dialup-speed connection) via 3G (broadband speed connection) Location-based services services that make use of location of users Micropayment applications ability to send/transfer cellphone credits via SMS leads to cash-less, credit-card less, electronic payment mechanisms

Example: SMS Job Finder Service Service On-Demand User texts FINDJOB <JOB> to 123 e.g., FINDJOB DRIVER Service responds (via SMS text message) with … Agency: JobsRUs. DRIVER needed as of 2/1/08, Call (987) 654-3210 Subscription Service User can subscribe to alerts e.g., FINDJOB SUBS DRIVER

Mobile “Value-Added Services (VAS)” Architecture 3rd party app providers (aka content providers, “CPs”) small 3rd party CPs Users direct connection MNO aggregator SMSC VAS gateway in-house apps private “service” via GSM modem or phone

Writing SMS Apps: Three Options direct to Mobile Network Operator via Aggregator using GSM modem or phone

Tools Open Source Kannel SMSLib Gnokii, etc. Commercial Aggregators e.g., Clickatell Libraries for Using Private Lines e.g., NowSMS, WinSMS, etc.

Programming Options Protocols Languages direct via language-specific API TCP/IP-based protocols e.g., CIMD, SMPP, etc. HTTP-based protocols GET, POST, XML-RPC Languages Java, PHP, anything … Note: probably also need backend database web front-end

Legal Disclaimer The information here is for educational purposes only We assume your programs will be used for private/personal use only If you want to do a commercial or high-volume application, you may have to contact a mobile operator or an aggregator in your target market

Lab Examples

Writing an App (Easy!) IMPLEMENT THIS public interface SMSApplication { public SMSMessage onSMSMessageReceived(SMSMessage incomingMsg); public void setSMSSender(SMSSender sender); } public interface SMSSender { public boolean sendSMSMessage(SMSMessage outgoingMsg); IMPLEMENT THIS

How to connect your app Via Java Alternative: PHP via GSM modem adapter via SMSLib via HTTP GET adapter connecting from Kannel or other gateways (via email adapter) Alternative: PHP

Other Issues Databases Web Interface

References See ict4dlab.org for more info and links This is under development, so visit often for up-to-date info

Application Design Tips and Tricks

Caveats Watch how you keep state if you are running app from command-line, state that is not written to disk or persistent database will get lost when you run the app again similar issues with web-based solutions

Caveats: Security Watch for “SQL Injection” attacks!

General User-Interface Tips Make inputs case-insensitive Also whitespace insensitive Avoid hard-to-type characters Try to use keywords in T9 dictionary (or compound words composed of such words) Reply-based interfaces keep per-user state of last transaction enables simpler “Reply with …” commands e.g., “Reply NEXT to continue to get more info”