Socket programming in Ruby

Socket programming in Ruby

This article mainly introduces Socket programming in Ruby. It is a basic knowledge in Ruby network programming. For more information, see

Ruby provides two access-level network services. At a lower level, you can access the underlying operating system, which supports basic Sockets for clients and servers with connection-free protocols.

Ruby also has libraries that provide more advanced network protocols for accessing specific applications, such as FTP and HTTP.

This tutorial introduces the concept of Ruby Socket programming and explains a simple example.

What is Sockets?

A socket is the endpoint of a two-way communication channel. The socket can communicate with each other in a process, process on the same machine, or process on different machines.

Sockets can implement many different types of channels: Unix Main Control sockets, TCP, UDP, and so on. The socket Library provides processing, and the rest are used to process common transmission, as well as specific classes as a common interface.

Socket terminology:

A simple client:

Here, we will write a very simple client program, which will open a connection to a given port and host. Ruby's TCPSocket class provides open functions to open a socket.

TCPSocket. open (hosname, port) open a TCP link to hostname in port.

Once a socket is opened, it can be read as any IO object. Remember to close it, because it is like closing a file.

The following code is a very simple client that connects to a given host and port, reads any available data from the socket, and then exits:

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Require 'socket '# Sockets are in standard library   Hostname = 'localhost' Port = 2000   S = TCPSocket. open (host, port)   While line = s. gets # Read lines from the socket Puts line. chop # And print with platform line terminator End S. close # Close the socket when done

A simple server:

To write data to an internet server, we use the TCPServer class. The TCPServer object is a factory used to create a TCPSocket object.

Call the TCPServer. open (hostname, port function to specify a port to serve you, and create a TCPServer object.

Next, call the accept method to return the TCPServer object. This method will wait for the client to connect to the specified port, and then return a TCPSocket object indicating to connect to the client.

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Require 'socket '# Get sockets from stdlib   Server = TCPServer. open (2000) # Socket to listen on port 2000 Loop {# Servers run forever Client = server. accept # Wait for a client to connect Client. puts (Time. now. ctime) # Send the time to the client Client. puts "Closing the connection. Bye! " Client. close # Disconnect from the client }

Now it runs on the backend server and then runs the result displayed on the client above.

Multi-client TCP Server:

Most Internet servers are designed to process a large number of customer requests at any time.

The Ruby Thread class allows you to easily create multi-threaded servers. Accept the request, and immediately create a new execution thread to process the connection, and allow the main program to wait for more connections:

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Require 'socket '# Get sockets from stdlib   Server = TCPServer. open (2000) # Socket to listen on port 2000 Loop {# Servers run forever Thread. start (server. accept) do | client | Client. puts (Time. now. ctime) # Send the time to the client Client. puts "Closing the connection. Bye! " Client. close # Disconnect from the client End }

There is a fixed loop in this example. When server. accept responds and immediately creates and starts a new thread to process the connection, it uses the connection object to pass to the thread. The main program returns immediately after the loop and waits for a new connection.

This method means that the Ruby thread code can be transplanted and run in Linux, OS X, and Windows in the same way.

A tiny Web browser:

We can use the socket library to implement any Internet protocol. For example, the webpage that obtains content in the Code:

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Require 'socket'   Host = 'www .tutorialspoint.com '# The web server Port = 80 # Default HTTP port Path = "/index.htm" # The file we want   # This is the HTTP request we send to fetch a file Request = "GET # {path} HTTP/1.0 rnrn"   Socket = TCPSocket. open (host, port) # Connect to server Socket. print (request) # Send request Response = socket. read # Read complete response # Split response at first blank line into headers and body Headers, body = response. split ("rnrn", 2) Print body # And display it

To implement similar web clients, you can use a pre-built library, such as Net: HTTP and HTTP. The following is the code, which is equivalent to the previous Code:

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Require 'net/http' # The library we need Host = 'www .tutorialspoint.com '# The web server Path = '/index.htm' # The file we want   Http = Net: HTTP. new (host) # Create a connection Headers, body = http. get (path) # Request the file If headers. code = "200" # Check the status code Print body Else Puts "# {headers. code} # {headers. message }" End

Check Similar libraries, FTP, SMTP, POP, and IMAP protocols.