Response delay time determination to maintain long polling connection

An operating method of an image forming apparatus, the method comprising:

• requesting an external device for a response about whether a job to be performed by the image forming apparatus is present based on a response delay time for long polling the external device by the image forming apparatus;
• detecting an error between the image forming apparatus and the external device, the error corresponding to a value of the response received for the request;
• adjusting the response delay time based on the error;
• and
• determining a final response delay time for maintaining a connection of the long polling by re-adjusting the adjusted response delay time based on a result of performing the long polling based on the adjusted response delay time.

A non-transitory machine-readable recording medium having recorded thereon instructions executable by a processor, the non-transitory machine-readable recording medium comprising:

• instructions for requesting an external device for a response about whether a job to be performed by an image forming apparatus is present based on a response delay time for long polling the external device by the image forming apparatus;
• instructions for detecting an error between the image forming apparatus and the external device, the error corresponding to a value of the response received for the request;
• instructions for adjusting the response delay time based on the error;
• and
• instructions for determining a final response delay time for maintaining connection of the long polling by re-adjusting the adjusted response delay time based on a result of performing the long polling based on the adjusted response delay time.