Class: Async::HTTP::Client

Inherits:
Protocol::HTTP::Methods
  • Object
show all
Defined in:
lib/async/http/client.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(endpoint, protocol: endpoint.protocol, scheme: endpoint.scheme, authority: endpoint.authority, retries: DEFAULT_RETRIES, connection_limit: DEFAULT_CONNECTION_LIMIT) ⇒ Client

Provides a robust interface to a server.

  • If there are no connections, it will create one.

  • If there are already connections, it will reuse it.

  • If a request fails, it will retry it up to N times if it was idempotent.

The client object will never become unusable. It internally manages persistent connections (or non-persistent connections if that's required).

Parameters:

  • endpoint (Endpoint)

    the endpoint to connnect to.

  • protocol (Protocol::HTTP1 | Protocol::HTTP2 | Protocol::HTTPS) (defaults to: endpoint.protocol)

    the protocol to use.

  • scheme (String) (defaults to: endpoint.scheme)

    The default scheme to set to requests.

  • authority (String) (defaults to: endpoint.authority)

    The default authority to set to requests.


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# File 'lib/async/http/client.rb', line 50

def initialize(endpoint, protocol: endpoint.protocol, scheme: endpoint.scheme, authority: endpoint.authority, retries: DEFAULT_RETRIES, connection_limit: DEFAULT_CONNECTION_LIMIT)
	@endpoint = endpoint
	@protocol = protocol
	
	@retries = retries
	@pool = make_pool(connection_limit)
	
	@scheme = scheme
	@authority = authority
end

Instance Attribute Details

#authorityObject (readonly)

Returns the value of attribute authority.


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# File 'lib/async/http/client.rb', line 68

def authority
  @authority
end

#endpointObject (readonly)

Returns the value of attribute endpoint.


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# File 'lib/async/http/client.rb', line 61

def endpoint
  @endpoint
end

#poolObject (readonly)

Returns the value of attribute pool.


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# File 'lib/async/http/client.rb', line 65

def pool
  @pool
end

#protocolObject (readonly)

Returns the value of attribute protocol.


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# File 'lib/async/http/client.rb', line 62

def protocol
  @protocol
end

#retriesObject (readonly)

Returns the value of attribute retries.


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# File 'lib/async/http/client.rb', line 64

def retries
  @retries
end

#schemeObject (readonly)

Returns the value of attribute scheme.


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# File 'lib/async/http/client.rb', line 67

def scheme
  @scheme
end

Class Method Details

.open(*arguments, **options, &block) ⇒ Object


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# File 'lib/async/http/client.rb', line 74

def self.open(*arguments, **options, &block)
	client = self.new(*arguments, **options)
	
	return client unless block_given?
	
	begin
		yield client
	ensure
		client.close
	end
end

Instance Method Details

#call(request) ⇒ Object


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# File 'lib/async/http/client.rb', line 95

def call(request)
	request.scheme ||= self.scheme
	request.authority ||= self.authority
	
	attempt = 0
	
	# We may retry the request if it is possible to do so. https://tools.ietf.org/html/draft-nottingham-httpbis-retry-01 is a good guide for how retrying requests should work.
	begin
		attempt += 1
		
		# As we cache pool, it's possible these pool go bad (e.g. closed by remote host). In this case, we need to try again. It's up to the caller to impose a timeout on this. If this is the last attempt, we force a new connection.
		connection = @pool.acquire
		
		response = make_response(request, connection)
		
		# This signals that the ensure block below should not try to release the connection, because it's bound into the response which will be returned:
		connection = nil
		
		return response
	rescue Protocol::RequestFailed
		# This is a specific case where the entire request wasn't sent before a failure occurred. So, we can even resend non-idempotent requests.
		if connection
			@pool.release(connection)
			connection = nil
		end
		
		if attempt < @retries
			retry
		else
			raise
		end
	rescue SocketError, IOError, EOFError, Errno::ECONNRESET, Errno::EPIPE
		if connection
			@pool.release(connection)
			connection = nil
		end
		
		if request.idempotent? and attempt < @retries
			retry
		else
			raise
		end
	ensure
		@pool.release(connection) if connection
	end
end

#closeObject


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# File 'lib/async/http/client.rb', line 86

def close
	while @pool.busy?
		Console.logger.warn(self) {"Waiting for #{@protocol} pool to drain: #{@pool}"}
		@pool.wait
	end
	
	@pool.close
end

#inspectObject


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# File 'lib/async/http/client.rb', line 142

def inspect
	"#<#{self.class} authority=#{@authority.inspect}>"
end

#secure?Boolean

Returns:

  • (Boolean)

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# File 'lib/async/http/client.rb', line 70

def secure?
	@endpoint.secure?
end