Class: Async::HTTP::Client

Inherits:
Object
  • Object
show all
Includes:
Methods
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: 3, connection_limit: nil) ⇒ 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).



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# File 'lib/async/http/client.rb', line 36

def initialize(endpoint, protocol = endpoint.protocol, scheme = endpoint.scheme, authority = endpoint.authority, retries: 3, connection_limit: nil)
	@endpoint = endpoint
	@protocol = protocol
	
	@retries = retries
	@pool = make_pool(connection_limit)
	
	@scheme = scheme
	@authority = authority
end

Instance Attribute Details

#authority ⇒ Object (readonly)

Returns the value of attribute authority.



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# File 'lib/async/http/client.rb', line 54

def authority
  @authority
end

#endpoint ⇒ Object (readonly)

Returns the value of attribute endpoint.



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# File 'lib/async/http/client.rb', line 47

def endpoint
  @endpoint
end

#pool ⇒ Object (readonly)

Returns the value of attribute pool.



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# File 'lib/async/http/client.rb', line 51

def pool
  @pool
end

#protocol ⇒ Object (readonly)

Returns the value of attribute protocol.



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# File 'lib/async/http/client.rb', line 48

def protocol
  @protocol
end

#retries ⇒ Object (readonly)

Returns the value of attribute retries.



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

def retries
  @retries
end

#scheme ⇒ Object (readonly)

Returns the value of attribute scheme.



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# File 'lib/async/http/client.rb', line 53

def scheme
  @scheme
end

Class Method Details

.open(*args, &block) ⇒ Object 



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# File 'lib/async/http/client.rb', line 56

def self.open(*args, &block)
	client = self.new(*args)
	
	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 74

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 = connection.call(request)
		
		# The connection won't be released until the body is completely read/released.
		Body::Streamable.wrap(response) do
			@pool.release(connection)
		end
		
		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.
		@pool.release(connection) if connection
		
		if attempt < @retries
			retry
		else
			raise
		end
	rescue
		@pool.release(connection) if connection
		
		if request.idempotent? and attempt < @retries
			retry
		else
			raise
		end
	end
end

#close ⇒ Object 



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

def close
	@pool.close
end