class HTTP::Server

• HTTP::Server
• Reference
• Object

Overview

A concurrent HTTP server implementation.

A server is initialized with a handler chain responsible for processing each incoming request.

NOTE To use Server, you must explicitly import it with require "http/server"

require "http/server"

server = HTTP::Server.new do |context|
  context.response.content_type = "text/plain"
  context.response.print "Hello world!"
end

address = server.bind_tcp 8080
puts "Listening on http://#{address}"
server.listen

Request processing

The handler chain receives an instance of HTTP::Server::Context that holds the HTTP::Request to process and a HTTP::Server::Response which it can configure and write to.

Each connection is processed concurrently in a separate Fiber and can handle multiple subsequent requests-response cycles with connection keep-alive.

Handler chain

The handler given to a server can simply be a block that receives an HTTP::Server::Context, or it can be an instance of HTTP::Handler. An HTTP::Handler has a #next method to forward processing to the next handler in the chain.

For example, an initial handler might handle exceptions raised from subsequent handlers and return a 500 Server Error status (see HTTP::ErrorHandler). The next handler might log all incoming requests (see HTTP::LogHandler). And the final handler deals with routing and application logic.

require "http/server"

server = HTTP::Server.new([
  HTTP::ErrorHandler.new,
  HTTP::LogHandler.new,
  HTTP::CompressHandler.new,
  HTTP::StaticFileHandler.new("."),
])

server.bind_tcp "127.0.0.1", 8080
server.listen

Response object

The HTTP::Server::Response object has status and headers properties that can be configured before writing the response body. Once any response output has been written, changing the status and headers properties has no effect.

The HTTP::Server::Response is a write-only IO, so all IO methods are available on it for sending the response body.

Binding to sockets

The server can be bound to one or more server sockets (see #bind)

Supported types:

• TCP socket: #bind_tcp, #bind_unused_port
• TCP socket with TLS/SSL: #bind_tls
• Unix socket #bind_unix

#bind(uri : URI) and #bind(uri : String) parse socket configuration for one of these types from an URI. This can be useful for injecting plain text configuration values.

Each of these methods returns the Socket::Address that was added to this server.

require "http/server"

server = HTTP::Server.new do |context|
  context.response.content_type = "text/plain"
  context.response.print "Hello world!"
end

address = server.bind_tcp "0.0.0.0", 8080
puts "Listening on http://#{address}"
server.listen

It is also possible to bind a generic Socket::Server using #bind(socket : Socket::Server) which can be used for custom network protocol configurations.

Server loop

After defining all server sockets to listen to, the server can be started by calling #listen. This call blocks until the server is closed.

A server can be closed by calling #close. This closes the server sockets and stops processing any new requests, even on connections with keep-alive enabled. Currently processing requests are not interrupted but also not waited for. In order to give them some grace period for finishing, the calling context can add a timeout like sleep 10.seconds after #listen returns.

Reusing connections

The request processor supports reusing a connection for subsequent requests. This is used by default for HTTP/1.1 or when requested by the Connection: keep-alive header. This is signalled by this header being set on the HTTP::Server::Response when it's passed into the handler chain.

If in the handler chain this header is overridden to Connection: close, then the connection will not be reused after the request has been processed.

Reusing the connection also requires that the request body (if present) is entirely consumed in the handler chain. Otherwise the connection will be closed.

Defined in:

Instance Method Summary

• #bind_tcp(host : String, port : Int32, write_timeout : Int32 | Nil = nil, read_timeout : Int32 | Nil = nil, reuse_port : Bool = false) : Socket::IPAddress
• #bind_tls(host : String, port : Int32, context : OpenSSL::SSL::Context::Server, write_timeout : Int32 | Nil = nil, read_timeout : Int32 | Nil = nil, reuse_port : Bool = false) : Socket::IPAddress
• #bind_unix(path : String, write_timeout : Int32 | Nil = nil, read_timeout : Int32 | Nil = nil) : Socket::UNIXAddress

  Creates a UNIXServer bound to path and adds it as a socket.

• #listen

  Starts the server.

Instance Method Detail

require "http/server"

server = HTTP::Server.new { }
server.bind_unix "/tmp/my-socket.sock"