Content delivery network (CDN) content server request handling mechanism with metadata framework support

Abstract

To serve content through a content delivery network (CDN), the CDN must have some information about the identity, characteristics and state of its target objects. Such additional information is provided in the form of object metadata, which according to the invention can be located in the request string itself, in the response headers from the origin server, in a metadata configuration file distributed to CDN servers, or in a per-customer metadata configuration file. CDN content servers execute a request identification and parsing process to locate object metadata and to handle the request in accordance therewith. Where different types of metadata exist for a particular object, metadata in a configuration file is overridden by metadata in a response header or request string, with metadata in the request string taking precedence.

1 . A method operative in a content delivery network (CDN) wherein participating content providers identify content to be served from a set of CDN content servers in response to requests, wherein the CDN uses metadata to determine how a CDN content server will handle a request for a given object, comprising: 
 establishing a framework for delivery of metadata to a given CDN content server either in-band or out-of-band;    at a given CDN content server, parsing a request for the given object and identifying a set of metadata; and    applying at least one precedence rule to the set of metadata to identify given metadata to be applied to the given content prior to serving a response to the request from the given CDN content server.    
   
   
       2 . The method as described in  claim 1  wherein the metadata is delivered to the given CDN content server in-band within a request string.  
   
   
       3 . The method as described in  claim 1  wherein the metadata is delivered to the given content server in-band within a HTTP response header.  
   
   
       4 . The method as described in  claim 1  wherein the metadata is delivered to the given content server out-of-band within a configuration file.  
   
   
       5 . The method as described in  claim 4  wherein the configuration file is generated by a CDN service provider and delivered to the CDN content servers over the CDN.  
   
   
       6 . The method as described in  claim 4  wherein the configuration file is generated by a participating content provider.  
   
   
       7 . The method as described in  claim 1  wherein the precedence rule overrides out-of-band metadata with in-band metadata to identify the given metadata.  
   
   
       8 . A method operative in a content delivery network (CDN) wherein participating content providers identify content to be served from a set of CDN content servers in response to requests, wherein the CDN uses metadata to determine how a CDN content server will handle a request for a given object, comprising: 
 delivering metadata to a given CDN content server in a configuration file;    at the given CDN content server, parsing a request for the given object and identifying the configuration file; and    overriding the configuration file with any in-band metadata associated with the request.    
   
   
       9 . The method as described in  claim 8  wherein the in-band metadata is delivered to the given CDN content server in the request string.  
   
   
       10 . The method as described in  claim 8  wherein the in-band metadata is delivered to the given CDN content server in an HTTP response header from a participating content provider origin server.  
   
   
       11 . The method as described in  claim 8  wherein the configuration file is delivered to the CDN content server from a CDN service provider.  
   
   
       12 . The method as described in  claim 8  wherein the configuration file is generated by a participating content provider.  
   
   
       13 . In a content delivery network (CDN) wherein participating content providers identify content to be served from a set of CDN content servers in response to requests and the CDN uses metadata to determine how a CDN content server will handle the request, the improvement comprising: 
 a framework for locating metadata for a given object in one or more of a set of data structures selected from the set of: a request string, a response header, and a configuration file; and    a CDN surrogate origin server including code for parsing a request for an object, for identifying metadata associated with the object, and for applying the metadata to the object prior to serving the object in response to the request.    
   
   
       14 . In the content delivery network as described in  claim 13  wherein the CDN surrogate origin server code applies a given precedence rule to the metadata prior to applying the metadata to the object.  
   
   
       15 . In the content delivery network as described in  claim 14  wherein the given precedence rule overrides metadata in the configuration file with any metadata in a request string or a response header.  
   
   
       16 . In the content delivery network as described in  claim 14  wherein the given precedence rule overrides metadata in the configuration file first with metadata in the response header and second with metadata in the request string.