Patent Publication Number: US-8543713-B2

Title: Computing environment arranged to support predetermined URL patterns

Description:
BACKGROUND OF THE INVENTION 
     Users navigate to and within websites using a network browser or other application. However, when displaying webpages, the network browser or other application typically displays a Universal Resource Locators (URL) of the network location of the webpage. With complex websites, such as online stores, the URLs tend to be long and not user understandable due to internal factors such as website design and web applications in use. Conventionally, the URLs can be produced by application framework control, such as provided by WebObjects from Apple Inc., but such URLs are complex, long and not user understandable. An example of one such URL is:
         http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/ 9044001 /wo/kv2t9HQgZXbD2QPKGZ12Mnf9UiC/2.?p=0
 
Another conventional approach is to manually produce and parse URLs. However, once the code is in place it is very difficult to make alterations. Another conventional approach is to directly map URLs to a programming object. The programming environments of JSP, JSF, WebObjects and Apache can provide direct mappings but such have limited ability to change and URLs are not generated in a consistent manner. Still another conventional approach uses pattern mapping to describe a URL format (i.e., using regex and “groups”), but such also has limited ability to change and its URLs are not consistent. Consequently, there remains a need for improved approaches to produce, utilize and manage URLs.
       

     Today, data centers (e.g., Internet data centers) are often used to store content associated with websites. These data centers must be capable of handing requests from large numbers of users without significant delay. Data centers conventionally load balance across duplicative hardware and software resources. Typically, load balancers can be configured to route traffic to different servers. However, load balancing is conventionally a static configuration that only operates on data in an incoming request and is not able to utilize rule sets that are customized to website or data center design. 
     SUMMARY OF THE INVENTION 
     The invention relates a computing environment for hosting web services and applications. The computing resources of the computing environment can be managed, controlled or utilized to facilitate improved hosting of web services, such as hosting of websites. 
     One aspect of the invention pertains to customized load balancing in a multi-computer system in view of configuration information. In one embodiment, the configuration information can pertain to particular configurations of applications, partitions and/or resources utilized within the multi-computer system. As a result, load balancing can be customized to computing environments and/or business objectives. 
     Another aspect of the invention pertains to Universal Resource Locators (URLs) that can be programmatically defined and utilized to centralize URL descriptions which can be utilized by applications provided by the multi-computer system. The URLs can thus be centrally controlled or managed such that application or processes can be provided in a manner that is independent of the particular URLs. As one example, the programmatically defined URLs are able to be intelligently parsed and/or written. This permits control over the URLs as well as the ability to render the URLs descriptive or at least meaningful to recipients of the URLs or applications that display the URLs. 
     The invention can be implemented in numerous ways, including as a method, system, device, or apparatus (including computer readable medium). Several embodiments of the invention are discussed below. 
     As a method for processing a request at a computing system coupled to a network, where the computing system supports a plurality of applications, one embodiment of the invention includes at least: receiving an incoming request; parsing the incoming request to determine one or more segments of the incoming request; determining an appropriate one of the applications to receive the incoming request based on at least one of the determined segments; directing the incoming request to the determined application; processing the incoming request at the determined application; and responding to the incoming request with a response provided by the determined application. 
     As a computing system having a plurality of server computers for supporting a website, one embodiment of the invention includes at least: a plurality of applications configured to interface with a plurality of processes operable on a set of the server computers, and a load balancer operatively connected to direct an incoming request to one of the applications. The load balancer compares the incoming request against a set of predetermined patterns to provide comparison data, and the load balancer operates to determine one of the applications to receive the incoming request based on the comparison data. 
     As a computer readable medium including at least executable computer program code tangibly embodied therein for processing a request to a computing system coupled to a network, where the computing system supports a plurality of applications, one embodiment of the invention includes at least: computer program code for receiving an incoming request; computer program code for parsing the incoming request to determine one or more segments of the incoming request; computer program code for determining whether one or more of the determined segments of the incoming request match any of a plurality of predetermined patterns; computer program code for determining an appropriate one of the applications to receive the incoming request based on the matching of one or more of the determined segments to one of the predetermined patterns; and computer program code for directing the incoming request to the determined application. 
     As a method for managing universal resource locators, one embodiment of the invention includes at least: programmatically defining a URL pattern having a name and a URL path, the URL path structure including a plurality of path elements; defining at least one URL parameter provided as at least one of the path elements of the URL path structure; and subsequently processing a URL in accordance with the defined URL patterns and the at least one URL parameter. 
     As a computer readable medium including at least executable computer program code tangibly embodied therein for processing universal resource locators, one embodiment of the invention includes at least: computer program code, or a compiled data structure therefrom, that defines a plurality of predetermined URL patterns, each of the URL patterns including one or more parameters; computer program code for recognizing an incoming URL as matching one of the predetermined URL patterns; and computer program code for dispatching the incoming URL to an application for processing based on one of the predetermined URL patterns that matches the incoming URL. 
     Other aspects and embodiments of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  is a block diagram of a computing system according to one embodiment of the invention. 
         FIG. 2  is a block diagram of a computing system according to another embodiment of the invention. 
         FIG. 3  is a block diagram of a computing system according to still another embodiment of the invention. 
         FIG. 4  is a block diagram of a computing system according to yet still another embodiment of the invention. 
         FIG. 5  is a flow diagram of a response process according to one embodiment of the invention. 
         FIG. 6  is a flow diagram of an application determination process according to one embodiment of the invention. 
         FIG. 7  is a schematic illustration of an exemplary data structure according to one embodiment of the invention. 
         FIG. 8  is a flow diagram of a compare process according to one embodiment of the invention. 
         FIGS. 9A and 9B  are flow diagrams of a response process according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention relates a computing environment for hosting web services and applications. The computing resources of the computing environment can be managed, controlled or utilized to facilitate improved hosting of web services, such as hosting of websites. 
     One aspect of the invention pertains to customized load balancing in a multi-computer system in view of configuration information. In one embodiment, the configuration information can pertain to particular configurations of applications, partitions and/or resources utilized within the multi-computer system. As a result, load balancing can be customized to computing environments and/or business objectives. For example, load balancing can be customized to business logic, session data, and/or dynamic site data. 
     Another aspect of the invention pertains to Universal Resource Locators (URLs) that can be programmatically defined and utilized to centralize URL descriptions which can be utilized by applications provided by the multi-computer system. The URLs can thus be centrally controlled or managed such that application or processes can be provided in a manner that is independent of the particular URLs. As one example, the programmatically defined URLs are able to be intelligently parsed and/or written. This permits control over the URLs as well as the ability to render the URLs descriptive or at least meaningful to recipients of the URLs or applications that display the URLs. 
     Embodiments of various aspects of the invention are discussed below with reference to  FIGS. 1-9B . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. 
       FIG. 1  is a block diagram of a computing system  100  according to one embodiment of the invention. The computing system  100  typically utilizes a plurality of different computing devices that are interconnected to provide significant computing resources. In one embodiment, the computing system  100  can be utilized to support a web-based server system that can receive incoming requests for particular webpages, access and/or process data to form appropriate responses, and then supply appropriate responses back to the requesters in the form of the particular webpages. 
     The computing system  100  can utilize a load manager  102 . In general, the load manager  102  operates to distribute a processing “load” across the different computing resources. More particularly, the load manager  102  can receive an incoming request over a network link  104 , and evaluate the incoming request utilizing configuration data  106  to determine an appropriate application to process the incoming request. The configuration data  106  can, in one embodiment, be considered configuration data that serves to customize the load manager  102  for the computing environment in which the load manager  102  operates. In the embodiment illustrated in  FIG. 1 , the load manager  102  can direct the incoming request to either application A  108  or application B  110 . The configuration data  106  can be used to control or guide the manner in which the load manager  102  determines whether the incoming requests should be directed to the application A  108  or the application B  110 . As a result, the load manager  102  is able to intelligently distribute processing loads in accordance with the computing environment. Although  FIG. 1  illustrates the load manager  102  distributing processing loads to only a pair of applications, it should be understood that the load manager  102  can distribute processing load to a large number of computing resources, such as applications, partitions, processes or devices. 
     In one embodiment, the configuration data  106  pertains to or includes predetermined network address patterns, namely, predetermined universal resource locator (URL) patterns. The load manager  102  can determine whether the incoming request  104 , which itself is or has a URL, matches any of the predetermined URL patterns. If it is determined that the incoming request  104  does match one of the predetermined URL patterns, the load manager  102  can cause the incoming request to be directed to the application that has previously been associated with the predetermined URL pattern. 
     In one embodiment, the configuration data  106  is provided as one or more files containing a compiled version of the predetermined URL patterns. The predetermined URL patterns can be programmatically defined and then compiled into a binary form (compiled version). In one implementation, to facilitate rapid matching with respect to the predetermined URL patterns, the configuration data  106  can be provided in a data structure suitable for efficient matching. For example, one data structure suitable for efficient matching is a Trie data structure. 
       FIG. 2  is a block diagram of a computing system  200  according to one embodiment of the invention. The computing system  200  is somewhat similar to the computing system  100  illustrated in  FIG. 1 . Like the computing system  100 , the computing system  200  typically utilizes a plurality of different computing devices that are interconnected to provide significant computing resources. In one embodiment, the computing system  200  can be utilized to support a web-based server system that can receive incoming requests for particular webpages, access and/or process data to form appropriate responses, and then supply the appropriate responses back to the requester in the form of the particular webpages. 
     The computing system  200  can utilize a load manager  202 . The load manager  202  can receive an incoming request over a network link  204 , and evaluate the incoming request utilizing configuration file  206  to determine an appropriate application to process the incoming request. The configuration file  206  can contain configuration data that serves to customize the load manager  202  for the computing environment in which the load manager  202  operates. The load manager  202  can also direct the incoming request to either application A  208  or application B  210 . More particularly, the load manager  202  can direct the incoming request to application A  208  or application B  210  based on configuration data provided in the configuration file  206 . As a result, the load manager  202  is able to intelligently distribute processing loads in accordance with the computing environment. 
     In one embodiment, the configuration file  206  can contain predetermined URL patterns that are associated with the applications  208  and  210 . If it is determined that the incoming request does match one of the predetermined URL patterns, the load manager  202  can cause the incoming request to be directed to the application that has previously been associated with the predetermined URL pattern. The application receiving the incoming request can then process the incoming request to produce an appropriate response, and then supply the appropriate response back to the requester in the form of the particular webpages. 
     On the other hand, if it is determined that the incoming request does not match any of the predetermined URL patterns, the load manager  202  can direct the incoming request to a web server  212  or a web server  214 . Here, the computing system  200  can further include one or more web servers, such as the web server  212  and the web server  214 , which are suitable to process or forward the incoming request. The web server  212 ,  214  may be able to satisfy the incoming request. Alternatively, the web server  212 ,  214  may direct the incoming request to any of a number of available applications. For example, as illustrated in  FIG. 2 , either of the web servers  212  and  214  can direct the incoming request to application A  216  or application B  218 . The manner by which the load manager  202  selects one of the web servers  212  and  214  may not use the configuration file  206 . Instead, the load manager  202  can merely distribute the incoming requests to a web server so as to balance the load across the web servers  212  and  214  without regard for the computing environment. Alternatively, the load manager  212  might use a simplified rule, such as a rule based on a file extension, to direct the incoming requests to one of the web servers  212  and  214 . For example, if the incoming request is a request for a specific image file (e.g., “.jpg” file extension), then the load manager  202  can direct the incoming request to one of the web servers  212  and  214  for processing, which merely involves retrieval of the image file. 
     Although  FIG. 2  illustrates the load manager  202  distributing processing loads to a pair of web servers or several applications, it should be understood that the load manager  102  can distribute processing loads to a large number of web servers or applications. 
       FIG. 3  is a block diagram of a computing system  300  according to one embodiment of the invention. The computing system  300  includes a basic load balancer  302 . The basic load balancer  302  can receive an incoming request over a network link  304 . The basic load balancer  302  can then determine whether the incoming request  304  should be directed to a custom load balancer  306 . The custom load balancer can, for example, pertain to the load manager  102  illustrated in  FIG. 1  or the load manager  202  illustrated in  FIG. 2 . The custom load balancer  306  can cause the incoming request to be directed to a particular application based on configuration data provided in a configuration file  308 . In particular, the custom load balancer  306  can compare the incoming request with predetermined URL patterns associated with the configuration data provided by the configuration file  308 , and then direct the incoming request to either application A  310  or application B  312  based upon the comparison results. The application A  310  or application B  312  receiving the incoming request can then itself (or with assistance of other processing resources) produce a response that can be returned to the requester. For example, when the incoming request is a request for a particular webpage, the application A  310  or application B  312  can render the requested webpage and provide the requested webpage to the requester. 
     The computing system  300  also includes web servers  314  and  316 . The basic load balancer  302  can direct a subset of the incoming requests to the web servers  314  and  316 . For example, if there is a basic rule or class of incoming request that cannot or need not be processed by the custom load balancer  306 , such incoming requests can be directed to one of the web servers  314  and  316 . The web servers  314  and  316  are able to access and utilize application a  318  and application b  320  if needed to satisfy an incoming request. The web servers  314  and  316  can thus satisfy the incoming request by returning a response to the requester. Additionally, the custom load balancer  306  can also be coupled to the web servers  314  and  316  so that the custom load balancer  306  can optionally direct an incoming request that does not match any of the predetermined URL patterns to one of the web servers  314  and  316  for processing. 
       FIG. 4  is a block diagram of a computing system  400  according to one embodiment of the invention. In one embodiment, the computing system  400  can be utilized to support a web-based server system that can receive incoming requests for particular webpages, access and/or process data to form appropriate responses, and then supply appropriate responses back to the requesters in the form of the particular webpages. 
     The computing system  400  can utilize a software load balancer  402 . In general, the software load balancer  102  operates to distribute a processing “load” across the different computing resources. As an example, the load manager  102  illustrated in  FIG. 1  can be implemented by the software load balancer  402 . The software load balancer  402  can receive an incoming request over a network link  404 , and evaluate the incoming request to determine an appropriate application to process the incoming request. The software load balancer  402  can be programmatically operated to balance the processing load from incoming requests to various resources of the computing system  400 . In particular, the software load balancer  402  can direct an incoming request to either application A  405  or application B  407 . The decision by the software load balancer  402  can be based configuration data (such as system configuration data). As noted herein, the configuration data can include or pertain to predetermined patterns. 
     The applications  405  and  407  manage processing of incoming requests as supplied by the software load balancer  402 . If the application A  405  receives the incoming request, an application policy A  406  within the application A  405  can then decide whether the incoming request should be directed to partition A 1   410  or partition A 2   412 . The decision by the application policy A  406  can be based configuration data (such as system configuration data). Similarly, if the application B  407  receives the incoming request, an application policy B  408  can then decide whether the incoming request should be directed to partition B 1   414  or partition B 2   414 . The decision by the application policy B  408  can also be based configuration data (such as system configuration data). In one embodiment, the application policy A  406  and the application policy B  408  pertain to modules or data structures that include a name and a policy and also use configuration data (e.g., the system configuration data). In one embodiment, the partitions  410 - 416  are also modules or data structures. 
     For a given incoming request, one of the partitions  410 - 416  can receive the incoming request and then in turn direct the incoming request to a destination resource  418 - 440 . In one embodiment, a destination resource can represent a process operating on a hardware device within the computing system  400 . For example, the computing system  400  can pertain to a data center and the destination resources  418 - 440  can be a physical host, applications (e.g., web applications), or ports of the data center. The computing system  400  typically utilizes a plurality of different computing devices that are interconnected to provide significant computing resources. The destination resource receiving the incoming request can process the incoming request to determine data for a response. One or more of the destination resource, the partition and the application policy can form a response to the incoming request, and the application can cause the response to be returned to the requester. As shown in  FIG. 4 , the destination resources  418 - 440  can be allocated to particular partitions  410 - 416 . For example, the partition A 1   410  has destination resources  418 ,  420  and  422  associated therewith. Alternatively, the resources could be shared by different partitions. 
     In one embodiment, the computing system  400  implements a software load balancer according to one embodiment of the invention. In such an embodiment, the software load balancer  402  represents a front-end interface to the software load balancer. Also, in this embodiment, the application policies  406  and  408  and the partitions  410 - 416  are all part (e.g., modules or data structures) of the software load balancer. Still father, in this embodiment, the destination resources  418 - 440  can be considered separate or part of the software load balancer. 
       FIG. 5  is a flow diagram of a response process  500  according to one embodiment of the invention. The response process  500  is processing that can be performed by any of the computing systems  100 ,  200 ,  300  or  400  discussed above. The response process  500  can begin with a decision  502  that determines whether a request has been received. For example, the request can be received by a computing system over a network and seek a response containing certain information. When the decision  502  determines that a request has not been received, then the response process  500  waits until a request has been received. In other words, the response process  500  can be deemed to be invoked once a request is received. 
     In any event, once the decision  502  determines that a request has been received, the incoming request can be parsed  504 . For example, the incoming request can be in the form of a network address (e.g., URL) for a webpage containing certain information. The network address can be parsed  504  by identifying the multiple segments of the URL. Next, an appropriate application to process the incoming request can be determined  506 . For example, based upon one or more segments that have been parsed  504  from the incoming request, it can be determined which of a plurality of available applications is appropriate to process the incoming request. The available applications can, in one embodiment, pertain to data structures used by the software load balancer. The incoming request can then be directed to an appropriate application where the incoming request can be parsed  518 . Although the incoming request was parsed  504  to determining  506  the appropriate application to process the incoming request, the appropriate application, upon receiving the incoming request, can itself parse  508  the incoming request. In this regard, the parsing  508  of the incoming request by the determined application can be different than the parsing  504 . For example, the application can parse the incoming request to a greater extent so as to further understand the incoming request. The parsing  508  may identify one or more segments that correspond to parameters which may be objects. Next, the application can process the incoming request to produce  510  a response. The application that processes the request can be provided locally (e.g., within the load balancer or remotely with an external application). Thereafter, the response can be provided  512  to the requester. Following the block  512 , the response process  500  can return to repeat the decision  502  and subsequent blocks so that the response process  500  can similarly process other incoming requests. 
       FIG. 6  is a flow diagram of an application determination process  600  according to one embodiment of the invention. The application determination process  600  can, for example, be utilized as processing performed by the block  506  of the response process  500  illustrated in  FIG. 5 . The application determination process  600  can compare  602  segments of the incoming request to predetermined patterns. The predetermined patterns can be provided in the form of a data structure that facilitates match processing by the application determination process  600 . After the segments of the incoming request have been compared  602  to the predetermined patterns, a decision  604  can determine whether the segments of the incoming request match any of the predetermined patterns. When the decision  604  determines that the segments match one of the predetermined patterns, an application associated with the matching predetermined pattern can be identified  606 . Then, the incoming request can be directed  608  to the identified application. Following the block  608 , the application determination process  600  is complete with the application to process the incoming request having been determined. Thereafter, the processing can return to the block  508  of the response process  500  illustrated in  FIG. 5 . 
     Alternatively, when the decision  604  determines that the segments of the incoming request do not match any of the predetermined patterns, the incoming request can be directed  610  to a web server. The web server can then operate to produce  612  a response to the incoming request. Following the block  612 , the processing can proceed to block  512  of the response process  500  so that the response can be provided  512  to the requester. 
     As noted above, a data structure can be provided to configure or influence request processing. As one example, assume that an exemplary data structure is to include the following set of predetermined patterns: 
                                            /&lt;Store&gt;           /&lt;Store&gt;/browse/&lt;Path&gt;           /&lt;Store&gt;/help/&lt;Path&gt;           /&lt;Store&gt;/product/&lt;Part&gt;                        
These predetermined patterns can respectively correspond to a website application having a home webpage, a browse webpage, a help webpage, and a product webpage. Each of the paths is made up of a combination of segments separated by delimiters (“/”). Each segment is either a parameter or a path. The parameter or path can be static or dynamic. In this example, “&lt;Store&gt;” and “&lt;Part&gt;” are dynamic parameters, and “&lt;Path&gt;” is a dynamic path. Also, “browse”, “help” and “product” are all static parameters.
 
       FIG. 7  is a schematic illustration of an exemplary data structure  700  according to one embodiment of the invention. The exemplary data structure  700  can represent one implementation of the exemplary data structure that represents the set of predetermined patterns in the above example. The exemplary data structure  700  is a Trie data structure having branch nodes  702 - 710  and element nodes  712 - 716 . More particularly, the exemplary data structure  700  includes an initial branch node  702 , a home branch/element node  704 , a browse branch node  706 , a help branch node  708 , a product branch node  710 , a browse element node  712 , a help element node  714 , and a product element node  716 . In this example, the branch/element node  704  can serve as either a branch node or an element node. Use of a Trie data structure serves to facilitate rapid, simultaneous searching for predetermined patterns that match an incoming request. 
       FIG. 8  is a flow diagram of a compare process  800  according to one embodiment of the invention. The compare process  800  is, for example, processing suitable for implementing the block  602  of the application determination process  600  illustrated in  FIG. 6 . 
     The compare process  800  can identify  802  URL segments of the incoming request. Typically, the incoming request is a URL having a plurality of URL segments. One or more of the identified URL segments can pertain to parameters, and one of the identified URL segments can pertain to a path (which may include one or a series of segments). The parameters can be either static or dynamic. A dynamic parameter can also be referred to as an object (or programming object). 
     Next, a first URL segment is selected  804  from the URL segments that have been identified  802 . Then, it is determined  806  whether the selected URL segment matches a corresponding element of at least one predetermined pattern. Typically, the URL segment is simultaneously compared to a plurality of different elements associated with a plurality of predetermined patterns. By simultaneously comparing the URL segment to these various elements of the plurality of predetermined patterns, the compare process  800  can rapidly determine whether a matching pattern exists. After it has been determined  806  whether the selected URL segment matches a corresponding element of at least one predetermined pattern, a decision  808  can determine whether there has been an element match. When the decision  808  determines that there is no matching element for the selected URL element, the lack of a matching predetermined pattern can be indicated  810 . At this point, in the case in which there is no match for the selected URL element, the compare process  800  ends with no match being found. 
     On the other hand, when the decision  808  determines that there is a match for the selected URL element, a decision  812  can determine whether there are more URL segments to be processed. When the decision  812  determines that there are more URL segments to process, the compare process  800  returns to repeat the block  804  so that a next URL element can be selected and similarly processed. Alternatively, when the decision  812  determines that there are no more URL segments to process, the matching predetermined pattern can be identified  814 . In this case, the compare process  800  ends with the matching predetermined pattern being identified  814 . 
       FIGS. 9A and 9B  are flow diagrams of a response process  900  according to one embodiment of the invention. The response process  900  can, for example, pertain to processing performed utilizing the computing system  300  illustrated in  FIG. 3 . 
     The response process  900  can begin with a decision  902  that determines whether a request has been received. When the decision  902  determines that a request is not yet been received, the response process  900  can await receipt of a request. The response process  900  can thus be deemed invoked when a request is received. In any event, once the decision  902  determines that a request has been received, the incoming request can be examined  904  for basic load balancing. As an example, in  FIG. 3 , the basic load balancer  302  can perform the basic load balancing. In one embodiment, the basic load balancing can determine whether to perform custom load balancing with respect to the incoming request. Hence, after examining  904  the incoming request for basic load balancing, a decision  906  can determine whether custom load balancing is to be performed. 
     When the decision  906  determines that custom load balancing is to be performed, additional processing can be carried out. In one implementation, the additional processing can be associated with processing performed by the custom load balancer  306  and the associated one or more applications  310  and  312  illustrated in  FIG. 3 . In particular, the incoming request can be parsed  908  to identify segments as discussed above. Next, an appropriate application can be determined  910 . Here, the segments of the incoming request can be compared against a plurality of predetermined patterns, and when a match is found, the application corresponding to the matching predetermined pattern can be determined  910 . 
     Once the appropriate application has been determined  910 , the incoming request can be directed  912  to the determined application. The determined application can then parse  914  the incoming request to determine an appropriate partition. Although  FIG. 3  does not illustrate partitions,  FIG. 4  illustrates how partitions can be utilized below the appropriate application to further manage utilization of processing resources being provided by the computing system. After the appropriate partition is determined, the appropriate application can then direct  916  a processing request to the determined partition. In other words, the appropriate application can request certain processing be performed by the determined partition on its behalf. The partition can in turn determine  918  a resource (processing resource) to process the processing request. The processing request can then be directed  920  the determined resource. The determined resource can then return  922  the processing results to the determined application via the determined partition. A response to the incoming request can then be formed  924  at the determined application utilizing the processing results that have been provided by the determined partition. Thereafter, the response can be returned  926  to the requester. Following the block  926 , in the case in which custom load balancing is performed, the response process  900  can end. 
     On the other hand, when the decision  906  determines that custom load balancing is not to be performed, the incoming request can be directed  928  to a selected web server. Then, a response to the incoming request can be determined  930  at the selected web server. Following the determination  930  of the response to the incoming request, the response process  900  can proceeded to return  926  the response to the requester. In this case, custom load balancing is not performed, but a response can nevertheless be returned to the requester. 
     According to one aspect of certain embodiments of the invention, predetermined paths can be used to mange utilization of available processing resources (e.g., load balancing). These predetermined paths can be described in configuration data that can be used to customize operation of a load balancer. The configuration data can be provided as a data structure that facilitates match processing. One example of a data structure is a Trie tree having a tree structure with branch nodes and element nodes. 
     In one embodiment, predetermined patterns of a website that are to be supported by a computing system can be programmatically defined. Thereafter, applications or processes operating on requests for webpages of the website can utilize programmatically defined predetermined patterns that parse or write network addresses (e.g., URLs) for such webpages. Moreover, in one embodiment, the programmatically defined predetermined patterns can be compiled into configuration data (e.g., data structure, such as a Trie) which can be searched for matching of incoming requests to the predetermined patterns. 
     As noted herein, one aspect of the invention pertains to programmatically defining URLs. One embodiment of programmatically defining the predetermined patterns is as follows. The programmatic definitions are able to be used for not only generating URLs but also recognizing them. A syntax for illustration can describe a pattern as follows: 
                                            name = {             url = “/some/path”;           };                        
This gives the pattern a name so that the software can refer to it and defines the structure of the URL as “/some/path”. Many URLs need to define parameters to a web application. The definition can also include one or more parameters. As an example, a parameter in the path can be defined by:
 
                                            STORE = {               name = store;               type = StoreParameter;           };           home = {             url = “&lt;STORE&gt;/home”;           };                        
The resulting pattern can describe the pattern for a homepage as something that indicates the store followed by “home”. For example, the resulting pattern can represent URLs such as “/us/home”, “/uk/home” or “us-edu/home” which can represent home pages for different stores (based on countries, market or classification). Similar constructs can be used to describe optional/required parameters, query string (e.g., “?sort=top-sellers”) parameters, and their types.
 
     A “refactoring” or “composition” technique can be used to add an additional feature. Consider the following example of refactoring: 
                                            pattern1 = {             url = “/AppleStore/WebObjects/Mercury.woa/some/path”;           };           pattern2 = {             url = “/AppleStore/WebObjects/Mercury.woa/different/path”;           };                        
might be written as:
 
                                            MERCURY = {             fragment = “/AppleStore/WebObjects/Mercury.woa”;           };           pattern1 = {             url = “&lt;MERCURY&gt;/some/path”;           };           pattern2 = {             url = “&lt;MERCURY&gt;/different/path”;           };                        
Hence, common path elements can be expressed by factoring them out and building the final representation through composition.
 
     Advantageously, software programs can now refer to these patterns in URL generation. For example, a software program that writes a URL can merely specify a pattern and a parameter, such as:
         &lt;a pattern=“home” store=“[store]”&gt; . . .
 
Here, the pattern to be emitted is named is “home” and the parameter is a “store” parameter. The actual representation of this URL is encapsulated by the URL system and the software code is referring to it symbolically. If the URL pattern subsequently changes, the call sites in software programs need not change (unless additional parameters are now required). For example, if the pattern is redefined as:
       

                                            home = {             url = “&lt;STORE&gt;”;           };                        
URLs would be emitted and recognized as: “/us”, “/uk” or “/us-edu”. However, if the pattern is subsequently changed to the pattern of:
 
                                            home = {             url = “home?store=&lt;STORE&gt;”;           };                        
then the URLs would be emitted and recognized as: “/home?store=us”, “/home?store=uk” or “/home?store=us-edu”. The dispatch mechanism also has access to these patterns and can recognize “/us/home” as referring to the “home” pattern with “us” providing the store parameter.
 
     The defined patterns can further describe how to dispatch the URL. For example, additional metadata can be attached to the URL definition. This might tell the software program how to dispatch the recognized URL (e.g., what class/page it represents) Moreover, documentation could also be attached to the definition. 
     The defined patterns can also be used with URL forwarding or URL translation. In one embodiment, legacy URLs can be described with some additional metadata: 
                                            old-pattern = {           url = “/1-800-MY-APPLE/WebObjects/AppleStore.woa”;           parameters = {           // AppleStore really means “us”           store = us;           };           rewrite = home;           };                        
and then provides the URL they now map to:
 
                                            home = {           url = “&lt;STORE&gt;/home”;           };                        
This approach can be used with URLs that get deprecated or change over time and leverages the URL pattern definitions for both recognizing old URLs and understanding the format of the new URLs.
 
     In another embodiment, canonicalization rules can be used to consolidate multiple addresses for the same page. Sometimes a website has several different ways of addressing the same page. For example, the following URLs can all lead to the same page:
         http://store.apple.com/us/ipod   http://store.apple.com/us/browse/home/family/ipod   http://store.apple.com/1-800-MY-APPLE/WebObjects/   AppleStore.woa?family=ipod   http://store.apple.com/1-800-MY-APPLE/WebObjects/ AppleStore.woa/wa/RSLID?nnmm=browse&amp;node=home/family/ipod
 
The first URL is the most desirable because it is the shortest and clearest. The rewriting technique described above can be used to describe that the latter two legacy URLs as mapping to the first URL. However, another approach would be to describe that the “browse” pattern as having some canonical forms based on the “path” parameter:
       

                                            browse = {           url = “&lt;STORE&gt;/browse/&lt;PATH&gt;”;           canonical-form = {           path = {           “home/family/ipod” = {           pattern = ipod;           };           };           };           };           ipod = {           url = “&lt;STORE&gt;/ipod”;           };                        
Here the metadata attached to the “browse” rules says that if the path is equal to “home/family/ipod” then it should substitute the ipod pattern. Advantageously, a single URL definition can be use in this manner across various sites. The system can automatically substitute the canonical URL based on the parameters. If a usage lands on a URL that has a better canonical form, the application can automatically redirect them to the canonical URL. As an additional benefit, search engine optimization operates when a single URL is used for a single page.
 
     In one embodiment, the parameters within a defined pattern may be complex types that are serialized into and out of the URL. The encapsulation allows us to symbolically name our patterns and parameters on the program side and generate the appropriate URLs. For example, the parameter for the home page is called “store” to the program, but might be rendered in the URL path (e.g., “/us/home”) or as a query string parameter (e.g., “/home?s=us”). In both cases, the representation in the URL is encapsulated by the URL system and not of any concern to the calling software program. Hence, the parameters of a defined pattern can be complex values or objects (i.e., programming language objects) which can be passed in as parameters and extracted when recognized. For example, one representation of a store might be a Store object: 
                                            Store {           String name;           ...           }                        
The such case, the current Store object is passed in (as opposed to the string “us”). The type of the parameter:
 
                                            STORE = {             name = store;             type = StoreParameter;           };                        
can indicate that we want the name to be put in th URL and when recognized, lookup the store with that name.
 
     Additionally, in one embodiment, the system may provide some automatic features based on the machine description of the URL patterns. One automatic feature is source code documentation. Documentation for non-annotated source code can be automatically generated based on the patterns and their arguments. If the pattern definitions provide some annotations, such can also be included in the documentation. Another automatic feature is an interactive URL debugger that can assist in troubleshooting parsing and generation issues. 
     Advantageously, any URL can be described using the programmatic definitions. Once defined, the patterns can be used for both generation and recognition of URLs. Callers never need to worry about the exact format of the URLs because that is encapsulated. Additionally, the features like canonicalization and complex parameter types remove the need to manually write code that would do that for you. The same pattern can be used for both the generation and recognition of the URLs. These patterns can be compiled into state machines. In one implementation, any number of URL patterns can be recognized with constant cost (based only on the length of the URL rather than the number of patterns). 
     The various aspects, embodiments, implementations or features of the invention can be used separately or in any combination. 
     The invention can be implemented by software, hardware, or a combination of hardware and software. The invention can also be embodied as computer readable code on a computer readable medium. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium generally include read-only memory and random-access memory. More specific examples of computer readable medium are tangible and include Flash memory, EEPROM memory, memory card, CD-ROM, DVD, hard drive, magnetic tape, and optical data storage device. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The many features and advantages of the present invention are apparent from the written description. Further, since numerous modifications and changes will readily occur to those skilled in the art, the invention should not be limited to the exact construction and operation as illustrated and described. Hence, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention.