Learn Web development and Google mashups with dynamic examples

Many Web sites invite mashups by providing application program interfaces (API) to their services.

The API for each service is different, and often poorly documented. They generally require only basic programming skills, but figuring them out can be time consuming.

Google has made it a lot easier to learn their APIs by creating the Ajax API Playground, a very cool site for people who want to create mashups with Google Maps, Search, Feeds, Calendar, Visualization, Language, Blogger, Libraries or Earth.

The API Playground has over 170 examples, but they are not static, they are dynamic. Here is one of the examples -- the code is shown in the top pane and the resultant map below.

If f you change the value of the variable address, and click Run, the map will shift to the new address. Try it yourself.

The W3schools Web site offers similar dynamic examples of HTML, JavaScript and other Web development tools. Here is a simple HTML example.

Do you find these dynamic examples useful? Do you know of other dynamic example sites?

Interview of Nicholas Carr

We have seen that the Internet has made application development faster, cheaper and easier.

Well known author Nicholas Carr elaborates upon this point in his book The Big Switch, in which he predicts a move from entreprise data centers to network computing. Carr recently outlined his thesis in an 8-minute interview on National Public Radio. If you are in a rush, you can listen to this one minute excerpt, where he talks about how easy it is to establish a complex Web site.

If you like what you hear, you might subscribe to Carr's blog.

What are some of the key advantages and disadvantages of moving applications from an organization's data center to the Internet?

Amazon adds .NET support for enterprise developers

We have discussed infrastructure services – services that are intended for developers, not end users.

Amazon jumped off to a lead in this space, and many Web sites now use their virtual machines and storage services. They appreciate not having to invest in servers and the easy scalability of these services. The cost is also low because Amazon enjoys economies of scale and expertise in building and reliably running huge data centers.

Amazon has recently cut prices for their infrastructure services, added a service level agreement, and support for Microsoft .NET and SQL server. (They initially focused on Linux). These moves are designed to appeal to enterprise developers.

In focusing on enterprise developers, Amazon is in direct competition with Microsoft. Microsoft will be announcing their entry in this market soon. Rackspace, a large hosting firm, offers similar support for both .NET and Linux. They call it “Mosso,” which means fast in Greek, and claim that you can get started in only 8 minutes.

Web and enterprise developers will need to be able to use these infrastructure services in the future. Would you like to learn to deploy applications in the "cloud?"

Infrastructure services -- for developers, not users

We have discussed many Internet services intended for applications like editing documents or developing simple applications like blogs or online databases. These are generally intended for users -- people who use the Internet in their work or play, not professional developers.

We can contrast these user services with infrastructure services, which are intended for professional developers building user services or custom applications. Amazon has been a leader in this field. They learned to operate vast, efficient, reliable server "farms" in support of their shopping site, and decided to allow others to use the same infrastructure. Amazon Web services include virtual servers, storage space for large amounts of data, and storage and retrieval of data from flat files.

3Tera's Applogic offers a graphical user interface for designing a virtual server farm and deploying applications. In this example, the drag and drop interface was used to create a site with four firewalls (gray), a load balancer (yellow), two Web servers (blue), a MySQL server (red) and servers storing configuration files and logs (orange).



Each of these is an independent virtual server running Linux. Developers can configure these machines and load software on them as if they were in sitting on their desks. They create "dashboards" to monitor them, and can increase or decrease capacity in seconds. (Check out this Applogic video demonstration).

These services allow one to develop applications without hardware or datacenter cost. They bill for resources used -- CPU time, storage, bandwidth. That means there is essentially no cost while an application is being developed and debugged since there is no traffic. When the application goes live, the capacity, and hence cost, grow and shrink dynamically depending upon utilization.

Storage and computation are not the only infrastructure services. For example, Amazon offers a service for handling monetary payments from computers or users to other computers or users and Lypp.com offers telephony services. For example, a developer can give the user the ability to initiate a call between their telephone and a company. Lypp servers establish the call, interface with the switched telephone network, and bill for minutes used. Again, there is no traffic, so no cost, until the application is put in use.

Infrastructure services are the latest step in server evolution. Would infrastructure services appeal more to large or to small and medium sized organizations? Why? We offer courses today on programming for vendor-specific platforms like ASP.NET. Will we one day offer a course in programming for Amazon Web Services? Would you like to take such a course?

Using Zoho's cool form-creation service

We illustrated a three-tier application using a simple class roster file. It took me a day to develop, debug and document that application using Active Server Pages (ASP). It consists of six ASP pages, and I needed some knowledge of ASP, Visual Basic, and SQL to develop it.

I implemented the class roster application using the form-creation service at Zoho.com. It took me less than an hour to learn to use the service and implement the application. I needed no knowledge of programming -- it was similar to building the application using a simple database management system like Microsoft Access. Note also that the service-based application has powerful features like data export, access control and report sorting that are missing in the bare-bones ASP version.

The advantages of using a service to create this application are abundantly clear, but there are still questions. Will it scale -- how would it perform if we had an application with thousands of records and dozens of forms and views? Will Zoho continue offering this service -- can I count on it as part of my course curriculum? What will they charge for large databases? Would they be better off implementing their service using a file service like Amazon S3?

Micropayment for storage service

I just received a bill for the very small amount of storage I had used on Amazon's Simple Storage Service (S3) during the month of July. The charge for my storage and data transfer was 4 cents!

We have talked about micropayments for years, but, until now, I had never made one.

This is a terrific example of Web services. S3 is the base service -- offering reliable, infinitely scalable storage in Amazon's data centers. But, I do not deal directly with Amazon. Jungledisk has virtual disk software that makes my S3 store look like a standard disk drive on my computer. They insulate me from S3, pay Amazon, and bill me. My payment is automatic through another service, Paypal.

Amazon Web Services, a case study

Podcasting pioneer Doug Kaye, Amazon's Jeff Barr and others discuss a complex application Kaye built using Amazon Web Services. Kaye describes both the system architecture (loosely coupled services buffered by queues) and the business reasons (zero startup cost and seamless scalability) for using Amazon's virtual servers and storage rather than his own. He also expresses concern about the lack of a service-level agreement and dependence upon Amazon. Barr talks about Amazon's plans and the important role of the developer community. The show notes contain other links for those interested in more detail and other applications Amazon-based applications.

Amazon Web services

We have talked about data centers and mashups or composite applications. Amazon has exposed application programming interfaces for its applications and will also store your data at their data centers. All you supply is the business idea. Amazon CEO Jeff Bezos describes their services in in a short video or you can read more in this Business Week article. Amazon Web services could be used for Internet, intranet or extranet applications.