We also discuss implementation details for a chat client and server, and instructions to deploy a sample chat application into your AWS account. Background information Building a chat application requires a communication channel over which a client can send messages that are redistributed to other participants in the chat room.
In particular, large, possibly chunk-encoded, messages. The interface is careful to never buffer entire requests or responses — the user is able to stream data.
HTTP message headers are represented by an object like this: Values are not modified. It deals with stream handling and message parsing only. It parses a message into headers and body but it does not parse the actual headers or the body.
The raw headers as they were received are retained in the rawHeaders property, which is an array of [key, value, key2, value2, For example, the previous message header object might have a rawHeaders list like the following: It maintains a queue of pending requests for a given host and port, reusing a single socket connection for each until the queue is empty, at which time the socket is either destroyed or put into a pool where it is kept to be used again for requests to the same host and port.
Whether it is destroyed or pooled depends on the keepAlive option. Pooled connections have TCP Keep-Alive enabled for them, but servers may still close idle connections, in which case they will be removed from the pool and a new connection will be made when a new HTTP request is made for that host and port.
Servers may also refuse to allow multiple requests over the same connection, in which case the connection will have to be remade for every request and cannot be pooled. The Agent will still make the requests to that server, but each one will occur over a new connection. When a connection is closed by the client or the server, it is removed from the pool.
Any unused sockets in the pool will be unrefed so as not to keep the Node.
It is good practice, to destroy an Agent instance when it is no longer in use, because unused sockets consume OS resources. Sockets are removed from an agent when the socket emits either a 'close' event or an 'agentRemove' event. When intending to keep one HTTP request open for a long time without keeping it in the agent, something like the following may be done: Can have the following fields: Ignored when the keepAlive option is false or undefined.
Only relevant if keepAlive is set to true. This will set the timeout after the socket is connected.
Before we dive into learning about the WebSocket protocol and API I first want to spend a little time going through some of problems that face real-time web applications and how the WebSocket spec aims to solve them.
This kind of system can quickly grow unmaintainable; as we add new chat message types, for example, the list grows longer and longer.
Adding features such as alerting you if your name is mentioned adds even more complexity onto the system. WebSocket: Lightweight Client-Server Communications [Andrew Lombardi] on timberdesignmag.com *FREE* shipping on qualifying offers.
Until recently, creating desktop-like applications in the browser meant using inefficient Ajax or Comet technologies to communicate with the server. With this practical guide. I have always been a C++ fan for it’s speed, and perhaps because it’s the language that I’m most experienced with.
It was when I started learning timberdesignmag.com when I came across the fact that we can actually develop plugins for it in C++. Cleared for Takeoff With timberdesignmag.com on IBM i. November 21, OK, I’m done with flight-related puns for now, I promise! In my last blog entry, we showed you how to expose web services using the Integrated Web Services (IWS) server on IBM i.