listen

Is there a way for Node.js to listen to a change in a particular data in a collection of MongoDB, and fire an event if a change happens? I believe you are looking for a database trigger . Unfortunately, MongoDB has no support for them yet, so I don't think you can listen for changes directly from the database. You'll need to setup some sort of notification system (e.g. pub/sub) that alerts interested parties when a collection has changed. Well, this is an old question, but I was struggling with the same thing. I found a number of tidbits that helped me put together a solution, and I've

I read the man 2 listen . I don't understand what is the backlog value, it says The backlog argument defines the maximum length to which the queue of pending connections for sockfd may grow Right, how can I define what is the best value? Thanks Basically, what the listen() backlog affects is how many incoming connections can queue up if your application isn't accept() ing connections as soon as they come in. It's not particularly important to most applications. The maximum value used by most systems is 128, and passing that is generally safe. It's a fight between clients trying to connect.

I am trying to make an application for iPhone that can listen for traffick on a specific network port. A server on my network is sending out messages (different status messages for devices the server handles) on a specific port. My problem is that when I make a thread and makePairWithSocket I block the port for others who want to send messages to the server, so I only want to listen to the traffic on a specifyed port and then check for specific heraders and then use those messages. I know how to make the connection and talk to the server using write and read streams, but then I

#user nobody; worker_processes 1; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; #log_format main '$remote_addr - $remote_user [$time_local] "$request" ' # '$status $body_bytes_sent "$http_referer" ' # '"$http_user_agent" "$http_x_forwarded_for"'; #access_log logs/access.log main; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; #gzip on; #www.abc.com server { listen 80; server_name www.bac.com; #charset

I've got an API mode Rails 5 app that won't let me run rake routes or rails s . The error I get is: $ rake routes rake aborted! LoadError: Could not load the 'listen' gem. Add `gem 'listen'` to the development group of your Gemfile .../config/environment.rb:5:in `<top (required)>' LoadError: cannot load such file -- listen .../config/environment.rb:5:in `<top (required)>' Tasks: TOP => routes => environment (See full trace by running task with --trace) I've verified that listen is in the development group in my Gemfile: group :development do gem 'listen', '~> 3.1.5' # Spring speeds up

Listen & Read服务（多线程模型响应请求）（转载） import threading import socket import time encoding = 'utf-8' BUFSIZE = 1024 # a read thread, read data from remote class Reader (threading.Thread) : def __init__ (self, client) : threading.Thread.__init__(self) self.client = client def run (self) : while True : data = self.client.recv(BUFSIZE) if (data): string = bytes.decode(data, encoding) print "from client::" ,string, "" self.client.send( "return frome server::" + string) else : break print "close:" , self.client.getpeername() def readline (self) : rec = self.inputs.readline() if rec: string = bytes.decode

As I understand, backlog determines the size of the connection queue . Any extra requests greater this size at that time will be dropped off( is this statment right?? ). Now I have very simple program server.c socket() bind() listen(..., 5) while(1) { accept() read() write() sleep(3) close() } Now, I start 8 clients at a time to connect to this server. Surprisingly, the server serves all the 8 clients but instead it should queue only 5 clients & remaining 3 clients requests should be refused. Another interesting point is even if I put this backlog value as 0, the result is still same. Then I