Method and system for communicating content to a client device by pulling content from a publisher from a content delivery network when first requested by the client device

A method of operating a content delivery network comprising:

• receiving a request for a first content from a first client device at a content delivery network edge server;
• communicating the request for the first content to a content delivery network origin server disposed in the content delivery network;
• when the request for the first content is a first request, communicating a pull signal from the content delivery network origin server to a publisher origin server;
• receiving the first content at the content delivery network origin server from the publisher origin server;
• storing the first content at the content delivery network origin server of the content delivery network after receiving the first content;
• communicating the content from the content delivery network origin server to the content delivery network edge server;
• communicating the first content to the first client from the content delivery network edge server;
• receiving a second request for the first content at the content delivery network edge server from a second client device;
• communicating a validation query signal from the content delivery network to the publisher origin server in response to receiving a second request;
• generating a validation response signal at the publisher origin server comprising an indication as to whether the first content exists at the publisher origin server by determining whether the first content is still stored in the publisher origin server, whether the first content has changed and whether the expiration of the first content has changed, said validation response signal different than and separate from the first content;
• receiving the validation response signal at the content delivery network from the publisher origin server in response to the validation query signal;
• in response to the validation response signal indicating that the first content does not exist by indicating the first content is not stored at the publisher origin server, deleting the first content from the content delivery network;
• in response to the validation response indicating the expiration has changed, updating an expiration time of the first content in the content delivery network when the expiration has been changed and communicating the first content to the second client device from the content delivery network edge server;
• and
• in response to the validation response signal indicating the content has changed, updating the first content with an updated first content file in the content delivery network when the first content has changed and the expiration time has not passed and communicating the first content to the second client device from the content delivery network edge server.