Patent Application
20140089468
The present invention generally relates to caching performed by an intermediate proxy node via which client devices request data resources from a data resource server, and particularly relates to caching data resources in a request-agnostic manner.
A proxy node serves as an intermediary between client devices and a data resource server. In this role, the proxy node intercepts requests from client devices for data resources, such as files, services, web pages, data objects, or the like. The proxy node services any given request from a client device by forwarding the request to the data resource server, receiving the response to that request from the data resource server, and then relaying the response to the requesting client device.
Configuring a proxy node to serve as an intermediary in this way proves advantageous when the proxy node caches server responses. In this regard, after the proxy node services a particular request, the proxy node stores the response to that request in a cache on a request-by-request basis (i.e., the cache maps requests to corresponding responses). If the proxy node thereafter receives that same request again, the proxy node quickly returns the response to that request as stored in the cache rather than redundantly forwarding the request to the data resource server. The proxy node thereby accelerates resource requests from the perspective of the client devices, reduces the bandwidth required to forward requests to the data resource server, and reduces processing requirements on the data resource server.
There still remains a need, however, for fully realizing these advantages of proxy node caching in all contexts.
Teachings herein advantageously provide efficient proxy node caching in contexts where data resources are organized into different data resource collections. Rather than naively caching data resource server responses on a request-by-request basis, a proxy node herein intelligently caches data resources in a request-agnostic manner. As one example, this enables the proxy node to efficiently respond to a request for a subset of a data resource collection using data resources cached in response to a different request for a different subset of that collection.
More specifically, some embodiments herein include a method performed by an intermediate proxy node via which client devices request data resources from a data resource server. The data resources in these embodiments are organized into different data resource collections. The method includes receiving a request (e.g., an HTTP request) for a subset of a data resource collection and, responsive to receiving such a request, determining that the collection is not stored in a request-agnostic cache maintained by the proxy node. Responsive to this determination, the method further entails retrieving the collection from the data resource server. The method then includes extracting the requested subset from the retrieved data resource collection and selectively returning that subset as a response to the request. Finally, the method entails storing the data resource collection in the request-agnostic cache for serving other requests for data resources in the data resource collection, including a request for a different subset of the data resource collection.
In at least some embodiments, the method also includes receiving a different request for a different subset of the data resource collection. In one embodiment, for example, the request and the different request are received from different types of client devices with at least one of different display, memory, and processing capabilities. Regardless, in this case, the method entails, responsive to receiving this different request, extracting the different subset from the data resource collection stored in the request-agnostic cache and selectively returning the different subset extracted from the data resource collection as a response to the different request.
In one or more embodiments, receiving a request for a subset comprises receiving a request for a data resource collection in conjunction with one or more constraining parameters that constrain a response to the request to the subset. In this case, retrieving the data resource collection from the data resource server comprises sending the request for the data resource collection without the one or more constraining parameters towards the data resource server.
In one such embodiment, selectively returning the subset of the data resource collection as a response to the request thus comprises processing the data resource collection received from the data resource server according to the one or more constraining parameters in order to extract the subset from the data resource collection. This extracted subset is then returned as the response to the request.
One or more alternative embodiments herein include a different method performed by the intermediate proxy node. According to this different method, processing at the proxy node includes receiving a request for a subset of a data resource collection. Processing also includes identifying a first part of the requested subset as being stored in a request-agnostic cache maintained by the intermediate proxy node and a second part of the requested subset as not being stored in the request-agnostic cache. Processing further entails retrieving the first part of the requested subset from the request-agnostic cache and the second part of the requested subset from the data resource server, and then returning the requested subset as formed from the first and second parts retrieved.
In at least some embodiments, before the request for the subset is received, the first part of the subset is retrieved from the data resource server and stored in the request-agnostic cache in response to one or more requests for one or more different subsets. Similarly, in one or more embodiments, the method further involves storing the second part of the requested subset in the request-agnostic cache for serving other requests for data resources in the data resource collection. This includes a request for a different subset of the data resource collection. In one embodiment, receiving the request for the subset comprises receiving a request for the data collection in conjunction with one or more constraining parameters that constrain a response to the request to the subset. In this case, retrieving the second part of the requested subset from the data resource server comprises selectively sending the request for the data resource collection towards the data resource server with those of the constraining parameters that are to constrain a response to the second part of the subset, but without any of the constraining parameters that are to constrain a response to the first part of the subset.
Embodiments herein also include apparatus configured to implement these methods.
Of course, the present invention is not limited to the above features and advantages. Indeed, those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
The client devices 12 more specifically request data resources 16 from the data resource server 18 via an intermediate proxy node 28.
By intelligently caching data resources 16 in this request-agnostic manner, rather than naively caching data resources as responses to requests, the proxy node 28 advantageously provides caching that is efficient even when client devices 12 request subsets of a data resource collection 20 rather than the entire collection 20. Indeed, in this case, the request-agnostic cache 30 stores any data resources 16 within the collection 20 independently of whether those resources 16 belong to different requested subsets of the collection 20. This enables the proxy node 28 to efficiently respond to a request for a subset of the collection 20 using data resources 16 cached in response to a different request for a different subset of that collection 20. In this sense, then, the cache's storage of data resources 16 in a request-agnostic manner intelligently exploits the resource server's organization of the data resources 16 into different collections 20.
In one or more embodiments of request-agnostic caching, for example, the proxy node 28 proactively caches a data resource collection 20 responsive to a request for a subset of that collection 20. The proxy node 28 does so in anticipation of receiving other requests for other data resources 16 that are not in the requested subset but that are nonetheless in the collection 20. This means that the request-agnostic cache 30 effectively stores data resources 16 on a collection basis rather than on a request basis.
As shown in
Regardless, responsive to determining that the collection 20 is not stored in the request-agnostic cache 30, processing at the proxy node 20 entails retrieving the collection 20 from the data resource server 18. That is, even though only a subset of the collection 20 was requested, the proxy node 20 proactively retrieves the complete collection 20. Having retrieved the collection 20 in this way, processing at the proxy node 28 includes extracting the requested subset from the retrieved collection 20 and selectively returning that subset as a response to the request (Block 130). Processing also entails storing the collection 20 in the request-agnostic cache 30 for serving other requests for data resources 16 in the collection 20, including a request for a different subset of the collection 20 (Block 140). In some embodiments, for example, the proxy node 20 caches the collection 20 in anticipation of receiving these other requests in the future, from either the same client device 12 or a different client device 12 than the one that requested the subset.
In at least some embodiments, the request-agnostic cache 30 stores collection C for a predetermined amount of time. Once this amount of time expires, collection C as stored in the cache 30 is considered “dirty” or “stale” and is therefore discarded from the cache 30. In one or more embodiments, though, a request for one or more data resources 16 in collection C resets the expiration time of collection C as stored in the cache 30.
Regardless, continuing the example of
Note that proactive collection caching as described in
Consider an example where the first and second client devices 12-1 and 12-2 are different types of devices, at least in the sense that they have different display, memory, and/or processing capabilities. In one embodiment, for instance, the first client device 12-1 (e.g., as a mobile terminal) has relatively limited display, memory, and/or processing capabilities, while the second client device 12-2 (e.g., as a set-top-box) has relatively expanded display, memory, and/or processing capabilities. Given the greater capabilities of the second client device 12-2, the device 12-2 is configured to request subsets that are larger in size than that of the subsets requested by the first client device 12-1.
In one practical example, the data resources 16 comprise splash images (i.e., “posters”) associated with different videos available for viewing in an IPTV system. The data resource server 18 organizes these images into different collections that correspond to genres of the associated videos. For instance, one collection of images includes those images associated with an “Action/Adventure” genre of videos, while another collection of images includes those images associated with a “Kids” genre of videos, etc. Given the more limited capabilities of the first device 12-1, the device 12-1 at any given time requests a smaller subset of images for presenting the videos available within a given genre, while the second device 12-2 requests a larger subset of images. This means that the first and second devices 12-1, 12-2 will generate different requests for different subsets of images while browsing any given genre of videos. Despite this difference, the proxy node 28 advantageously responds to the second client device's request for a larger subset using the collection of images cached in response to the first client device's request for a smaller subset.
In at least some of these IPTV embodiments, and embodiments applicable in other contexts as well, a client device 12 requests a subset of a data resource collection 20 by sending a request for the collection 20 in conjunction with one or more constraining parameters. These constraining parameters constrain a response to the request to the subset. When the collection 20 is not stored in the request-agnostic cache 30, the proxy node 28 retrieves the collection 20 from the data resource server 18 by sending the request for the collection 20 without the one or more constraining parameters towards the server 18. That is, the proxy node 28 intelligently modifies the request received from the client device 12 so that the request excludes the one or more constraining parameters and then sends that modified request towards the data resource server 18. This way, the proxy node 28 forces the server 18 to naively respond with the complete collection 20, even though unbeknownst to the server 18 the client device 12 only requested a subset of that collection 20.
When the proxy node 28 modifies the request in order to remove the one or more constraining parameters, the proxy node 28 stores those parameters in memory as having been sent in conjunction with the request. Then, responsive to receiving the collection 20 to which the request concerned from the data resource server 18, the proxy node 28 stores the collection 20 in the cache 30 and filters or processes the collection 20 according to the stored constraining parameters in order to extract the requested subset from the collection 20. In some sense, then, the proxy node 28 herein is advantageously equipped with intelligence or logic similar to that at the data resource server 18 for examining, understanding, and processing the constraining parameters sent with a request. Equipped with this intelligence, the proxy node 28 can exploit the server's organization of data resources into collections in order to efficiently cache those resources 16. In any event, upon applying this logic in order to extract the requested subset from the retrieved collection 20, the proxy node 28 returns that extracted subset to the client device 12 as the response to the request. The proxy node 28 handles subsequent requests for different subsets of the collection 20 in an analogous manner; that is, by processing the collection 20 as stored in the cache 30 according to the respective constraining parameters sent in conjunction with those requests.
In one embodiment, for example, the request comprises an HTTP request. In this case, the request is represented by a Uniform Resource Identifier (URI) whose destination address indicates a data resource collection 20 associated with the request and whose HTTP query string indicates the one or more constraining parameters. Consider for instance a URI of http://a.com/example?fetch=C1,C2. The destination address “http://a.com/example” represents a request for a data resource collection “example.” The HTTP query string “fetch=C1,C2” indicates the one or more constraining parameters. These parameters constrain a response to the request to a subset that includes the resources indexed as “C1” and “C2” within the “example” collection.
When the proxy node 28 receives this URI from a client device 12 and the collection “example” is not stored in the cache 30, the proxy node 28 modifies the URI to simply be “http://a.com/example” without the constraining parameters indicated by the HTTP query string. Responsive to sending this modified URI towards the data resource server 18, the proxy node 28 receives and caches the complete “example” collection from the server 18, which may include for instance resources C1-C30. The proxy node 28 then processes the collection 20 according to the constraining parameters indicated by the HTTP query string in order to extract the “C1” and “C2” resources and selectively return those extracted resources to the client device 12.
Consider now an example where the proxy node 28 thereafter receives a different URI of http://a.com/example?fetch=C1,C2,C3,C4 from the same or a different client device 12. The proxy node 28 in this case recognizes the URI as concerning the “example” collection and determines that this collection 20 has been (and still is) stored in the request-agnostic cache 30. Thus, rather than requesting resources C1-C4 from the data resource server 18, the proxy node 28 extracts those resources from the “example” collection stored in the request-agnostic cache 30 and selectively returns those extracted resources.
Rather than proactively retrieving resources 16 before they have been requested in order to cache a complete collection 20, as described above, the proxy node 28 in alternative embodiments herein reactively builds such a cache over time based on retrieving resources 16 as they are requested. That is, the request-agnostic cache 30 still generally stores data resources 16 on a collection basis as described above, but any given collection 20 in the cache 30 is populated over time responsive to requests for multiple different subsets of the collection 20 rather than responsive to a single request for any subset of the collection 20. Thus, responsive to any given request, some of the requested data resources 16 may be stored in the request-agnostic cache 30 while other requested data resources 16 may be absent from the cache 30.
As shown in
In one or more embodiments, the first part of the requested subset was stored in the request-agnostic cache 30 because the proxy node 28 had previously retrieved those resources 16 from the data resource server 16 in response to one or more requests for one or more different subsets of the collection 20. And, when the proxy node 28 retrieved those resources 16, the node 28 stored them in the request-agnostic cache 30 in anticipation of receiving future requests concerning the collection 20.
In the same manner, therefore, processing at the proxy node 28 in one or more embodiments further entails storing the second part of the requested subset in the request-agnostic cache 30 (Step 240). The proxy node 28 does so in anticipation of serving other requests for data resources 16 in the collection 20, including a request for a different subset of the collection 20.
A second client device 12-2 later sends a request to the intermediate proxy node 28 for subset B of collection C (Step 68). Subset B differs from subset A because subset B includes not only data resources C1 and C2, but also includes data resources C3 and C4. Even though the proxy node 28 has not heretofore received a request for subset B, the proxy node 28 intelligently identifies a first part of subset B (namely, C1 and C2) as being stored in the cache 30 and a second part of subset B (namely, C3 and C4) as not being stored in the cache 30. Accordingly, rather than sending a request to the data resource server 18 for the complete subset B (or the complete collection C), the proxy node 28 requests and receives just the second part of subset B from the data resource server 18 (Steps 72 and 78). And, after requesting and receiving the first part of subset B from the request-agnostic cache 30 (Steps 74 and 76), the proxy node 28 itself forms subset B from the first and second parts retrieved (Step 80). The proxy node 28 then returns subset B to client device 12-2 (Step 82) and stores the second part of subset B in the cache 30 (Step 84).
Note that, unlike proactive collection caching, reactive collection caching as just described proves advantageous for responding to the request for subset B only if subset B at least partially overlaps with the previously requested subset A (or any other previously requested subsets). But, reactive collection caching proves more efficient than proactive collection caching in circumstances where, in hindsight, not all data resources 16 within a given collection 20 actually needed to be retrieved.
Also note that the proxy node 28 processes a request differently in reactive collection caching embodiments than in proactive collection caching embodiments, particularly when the request for a subset comprises a request for a collection 20 in conjunction with one or more constraining parameters. In this regard, when the proxy node 28 identifies the second part of the requested subset as not being stored in the request-agnostic cache 30, the proxy node 28 retrieves that second part from the data resource server 18 by selectively sending the request for the collection 20 towards the data resource server 18 with those of the constraining parameters that are to constrain a response to the second part of the subset, but without any of the constraining parameters that are to constrain a response to the first part of the subset. That is, the proxy node 28 intelligently modifies the request received from the client device 12 so that the request excludes the one or more constraining parameters associated with the first part, but still includes the one or more constraining parameters associated with the second part. The proxy node 28, for example, would modify an HTTP request for subset B in
Although the above embodiments discussed the request-agnostic cache 30 as if it was the only cache in the system 10, those skilled in the art will appreciate that in other embodiments other caches also store data resources 16. In at least one embodiment, though, the request-agnostic cache 30 is the only cache that implements proactive or reactive collection caching as described above. In one such embodiment, the request-agnostic cache 30 is closest cache to the data resource server 18. In still other embodiments, though, multiple different ones of the caches implement collection caching, across multiple different networks (i.e., not just in the service provider network 22). In this case, different proxy nodes 28 at different communicative distances from a given client device 12 have different sizes of caches 30 and/or different data staleness times.
In at least some embodiments, the proxy node 28 herein comprises an IPTV proxy in an IPTV system 10, such as a multi-screen IPTV system. Of course, those skilled in the art will appreciate that embodiments herein prove advantageous in many other contexts as well.
Moreover, in one or more embodiments, data resources 16 as used herein comprise public data, rather than private data. Public data in this case is capable of being freely shared by end-users and network nodes without security risk. Private data by contrast belongs specifically to an end-user and is not so freely shared.
Still further, the term “subset” is used herein in its general sense to refer to a part or portion of a larger set. This contrasts with the mathematical or technical sense of the term in which a subset may be the same as the set. In mathematical terms, a “subset” as used herein is really a “proper subset.”
In view of the various modifications and alternatives discussed above, those skilled in the art will appreciate that
The one or more processing circuits 86 are configured to extract digital data from the one or more interfaces 88 for processing, and to generate digital data for transmission over the one or more interfaces 88. More particularly, the one or more processing circuits 86 comprise one or several microprocessors, digital signal processors, and the like, as well as other digital hardware (not shown). The one or more processing circuits 86 also include memory 90. Memory 90, which may comprise one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc., stores program code for executing one or more data communications protocols and for carrying out one or more of the techniques described herein. Memory 90 further stores program data for carrying out such techniques, and also stores various parameters and/or other program data for controlling the operation of the proxy node 28.
Of course, not all of the steps of the techniques described herein are necessarily performed in a single microprocessor or even in a single module. Thus,
Those skilled in the art will of course recognize that the present invention may be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are thus to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
