In the first post of this series I mentioned some popular modules in the community, such as underscore, async, etc.. I also listed a module named “Wind (zh-CN)”, which is created by one of my friend, Jeff Zhao (zh-CN). Now I would like to use a separated post to introduce this module since I feel it brings a new async programming style in not only Node.js but JavaScript world. If you know or heard about the new feature in C# 5.0 called “async and await”, or you learnt F#, you will find the “Wind” ......
In my previous post I demonstrated how to install, configure and run Node.js application on Windows. In this post I will cover a specific and short topic, which is how to use SQL Server in Node.js. Install SQL Service Module In NPM there are many SQL Server modules. From the command windows we can use “npm find” to find the modules for specified terms. For example, below is the result when I found “sqlserver”. In this post I will describe one of them, the “node-sqlserver” module. This module was ......
Two weeks ago I had had a talk with Wang Tao, a C# MVP in China who is currently running his startup company and product named worktile. He asked me to figure out a synchronization solution which helps his product in the future. And he preferred me implementing the service in Node.js, since his worktile is written in Node.js. Even though I have some experience in ASP.NET MVC, HTML, CSS and JavaScript, I don’t think I’m an expert of JavaScript. In fact I’m very new to it. So it scared me a bit when ......
In the previous post I discussed about the basic usage of WCF Discovery in 4.0. I implemented a managed discovery service by inheriting from System.ServiceModel.Discove... I utilized a concurrent dictionary as the endpoint repository. I created a WCF service which have the ServiceDiscoveryBehavior attached. It can send the online and offline message to the discovery service announcement endpoint. I also created a client which invoke the discovery service’s probe endpoint to retrieve ......
When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, ......
This morning I received an email from the Microsoft said that, a meaningful company, Microsoft Open Technologies Inc., had just release their first pre-production, the Redis on Windows. Redis If you had been working in the Linux world or interested in NoSQL field you should have probably known or heard about the Redis. Redis is an open source, advanced key-value store. Someone categorized Redis to the distributed cache since it’s an in-memory key-value store. Someone categorized it to the NoSQL, ......
We are almost done everything about the WCF transport extension over the message bus, which makes our services can be scaled out by introducing more instances over machines and servers. We had finished the structure of our transport extension and implemented the request reply mode in the 2nd post, the datagram and duplex mode in the 4th and 5th post. As I have said at the end of the 5th post, currently we can use our transport extension. But there still something left. Although are not that major ......
In our last post I demonstrated how to implement the datagram channel shape, and in the second and third post I described the request reply shape. In this post I will explain the last MEP in WCF, duplex, which is the most complex one. Basis of the Duplex Channel Shape (MEP) In the MSDN document it said that “The duplex MEP allows an arbitrary number of messages to be sent by a client and received in any order. The duplex MEP is like a phone conversation, where each word being spoken is a message. ......
In the previous posts we talked about the transport extension that scaling-out our WCF services over a message bus transportation. What we have done is to use request reply MEP as a example, and implement the asynchronous methods that makes our transport support the normal WCF usage – ServiceHost and ChannelFactory on service hosting and client invoking. Request reply MEP is the most common mode when we are using WCF, but there are two MEPs available in WCF as well: datagram and duplex. In this post ......
In the previous post I demonstrated how to implement a very basic transport extension over an in memory message bus that supports request reply MEP. At the end of that post I created a console application and establish the service and client directly through the channel listener (on the server side) and the channel factory (on the client side). But this is not the WCF usage that we are familiar with. If you have been using the WCF for a while the common pattern is to create a ServiceHost on the server ......
In my previous post I introduced the architecture of message bus based system, the dispatcher mode and the pulling mode. I also explained a bit about the channel mode and transport extensibility of WCF. And then, in order to make the following sample simple and easy to use I created an in process and in memory message bus. In this post, I will demonstrate how to create a WCF transport extension over this memory message bus, for the most common MEP – Request Reply mode. Before we go to the implementation, ......
Cloud computing gives us more flexibility on the computing resource, we can provision and deploy an application or service with multiple instances over multiple machines. With the increment of the service instances, how to balance the incoming message and workload would become a new challenge. Currently there are two approaches we can use to pass the incoming messages to the service instances, I would like call them dispatcher mode and pulling mode. Dispatcher Mode The dispatcher mode introduces ......