Grand Central connects Web services
Web services networks fill the gaps between incompatible technologies
Imagine a world with no Postal Service nor Federal Express. Whenever you wanted to send a document to someone, you’d have to find out how they accepted documents, find a trustworthy carrier to transport the document, and then negotiate delivery mechanisms, notification requirements, and security measures.
This is the current situation of Web services. Sure, transport is available and there are some basic standards about envelopes and how to look up an address, but there’s not much else. In fact, unanswered questions about security, reliability, trust, and coordination abound.
Even when all of these issues have been sorted out, there’s still the basic problem of how to manage multiple connections between multiple organizations, not to mention the difficulty of overcoming incompatibilities in partner and customer systems.
Fortunately, Web services networks such as the one provided by Grand Central Communications provide a solution to this problem. In much the same way that the Postal Service and Federal Express provide a trustworthy, auditable, and convenient way to deliver paper messages to other parties around the world, Web services networks can provide a trustworthy means of exchanging Web services messages. Grand Central’s network provides reliability, security, logging, and interoperability as part of every transaction.
Testing the waters
Grand Central provides two kinds of services: endpoint services and routing services. Using endpoint services, messages are routed implicitly from one endpoint to another in the Grand Central network, as long as you don’t need conditional routing or to send messages to multiple recipients.
A routing service, on the other hand, explicitly connects to endpoints and allows messages to be delivered to one or more of these endpoints based on user-defined routing rules. These rules can be made to depend on either sender or topic, which is the same as the service URI (uniform resource identifier).
Grand Central provides a developer site that has access to evaluation accounts and a significant collection of how-tos and other documentation. The place to begin is the QuickStart document, which walks you through creating a demonstration account and a basic Echo service as an endpoint on the network. This is a good way for developers to become familiar with the Web site, but anyone hoping to discover what the network can do will want to quickly move beyond this simple demonstration.
To explore the various features of the network, we created a simple temperature-conversion Web service using SOAP Lite on our server. When we were satisfied that it worked, using a direct connection from a SOAP client on our laptop, we set up a simple endpoint service on the Grand Central network to push out any SOAP message it received to the conversion service on the server.
With a few simple modifications to the client to direct calls to the Grand Central endpoint and to support authentication, we were able to access the conversion service via the Grand Central network and view the transactions in the logs. This mode of operation is known in Grand Central’s terminology as a “synchronous proxy.”