Freshness-aware presentation of content in communication terminals
A method includes caching content items in a cache memory of a communication terminal connected to a communication network. A content item, which is cached in the cache memory, is presented to a user of the communication terminal. An extent of freshness of the cached content item presented to the user is assessed. Presentation of the cached content item is conditionally modified depending on the assessed extent of freshness.
1. A method, comprising:
caching content items in a cache memory of a communication terminal connected to a communication network;
receiving, in a processor, a request to present a content item to a user of the communication terminal; and
in response to the request:
initially presenting to the user a cached version of the content item, which is cached in the cache memory;
fetching an updated version of the content item over the communication network to the communication terminal;
assessing, in the communication terminal, an extent of freshness of the initially-presented cached version with respect to the updated version;
if the extent of freshness is below a threshold, presenting the updated version to the user in place of the initially-presented version; and
if the extent of freshness is above the threshold, continuing to present the initially-presented version and refraining from presenting the updated version, even though the updated version has already been fetched to the communication terminal.
2. The method according to claim 1 , wherein caching the content items comprises prefetching the content items over the communication network.
3. The method according to claim 1 , wherein initially presenting the cached version is performed regardless of the extent of freshness of the cached version.
4. The method according to claim 1 , wherein assessing the extent of freshness comprises determining a soft, non-binary freshness metric for a difference in content between the cached version and the updated version of the content item.
5. The method according to claim 1 , wherein assessing the extent of freshness comprises comparing a first signature, which is calculated over the cached version of the content item, with a second signature, which is calculated over the updated version of the content item.
6. The method according to claim 1 , wherein assessing the extent of freshness comprises disregarding a freshness-related field in a header of a HTTP response in which the cached version of the content item was provided to the communication terminal.
7. The method according to claim 6 , wherein disregarding the freshness-related field is performed when operating in a guaranteed-prefetching mode, and not when operating in a best-effort prefetching mode.
8. The method according to claim 1 , wherein assessing the extent of freshness comprises setting the extent of freshness also based on an expiry time reported for the content item.
9. The method according to claim 1 , wherein assessing the extent of freshness comprises setting the extent of freshness also based on an age metric or version number of the content item.
10. The method according to claim 1 , and comprising presenting to the user an indication indicative of the extent of freshness of the presented content item.
11. The method according to claim 10 , wherein presenting the indication comprises presenting a first visual indication when the content item is assessed to be fresh, and a second visual indication, different from the first visual indication, when the content item is assessed to be not fresh.
12. The method according to claim 10 , wherein presenting the indication comprises presenting the indication when the content item is assessed to be not fresh, and not presenting the indication when the content item is assessed to be fresh.
13. A communication terminal, comprising:
a cache memory; and
a processor, configured to:
cache content items in the cache memory;
receive a request to present a content item to a user of the communication terminal; and
in response to the request:
initially present to the user a cached version of the content item, which is cached in the cache memory;
fetch an updated version of the content item over the communication network to the communication terminal;
assess, in the communication terminal, an extent of freshness of the initially-presented cached version with respect to the updated version;
if the extent of freshness is below a threshold, present the updated version to the user in place of the initially-presented version; and
if the extent of freshness is above the threshold, continue to present the initially-presented version and refrain from presenting the updated version, even though the updated version has already been fetched to the communication terminal.
14. The terminal according to claim 13 , wherein the processor is configured to prefetch the content items over the communication network, and to cache the prefetched content items.
15. The terminal according to claim 13 , wherein the processor is configured to initially present the cached version regardless of the extent of freshness of the cached version.
16. The terminal according to claim 13 , wherein the processor is configured to assess the extent of freshness by determining a soft, non-binary freshness metric fore a difference in content between the cached version and the updated version.
17. The terminal according to claim 13 , wherein the processor is configured to assess the extent of freshness by comparing a first signature, which is calculated over the cached version of the content item, with a second signature, which is calculated over the updated version of the content item.
18. The terminal according to claim 13 , wherein the processor is configured to assess the extent of freshness while disregarding a freshness-related field in a header of a HTTP response in which the cached version was provided to the communication terminal.
19. The terminal according to claim 18 , wherein the processor is configured to disregard the freshness-related field when operating in a guaranteed-prefetching mode, and not when operating in a best-effort prefetching mode.
20. The terminal according to claim 13 , wherein the processor is configured to set the extent of freshness also based on an expiry time reported for the content item.
21. The terminal according to claim 13 , wherein the processor is configured to set the extent of freshness also based on an age metric or version number of the content item.
22. The terminal according to claim 13 , wherein the processor is configured to present to the user an indication indicative of the extent of freshness of the presented content item.
23. The terminal according to claim 22 , wherein the processor is configured to present a first visual indication when the content item is assessed to be fresh, and a second visual indication, different from the first visual indication, when the content item is assessed to be not fresh.
24. The terminal according to claim 22 , wherein the processor is configured to present the indication when the content item is assessed to be not fresh, and not present the indication when the content item is assessed to be fresh.
25. A computer software product, the product comprising a tangible non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by a processor in a communication terminal, cause the one or more processors to:
cache content items in the cache memory;
receive requests to present a content item to a user of the communication terminal; and
in response to a received request:
initially present to the user a cached version of the content item, which is cached in the cache memory;
fetch an updated version of the content item over the communication network to the communication terminal;
assess, in the communication terminal, an extent of freshness of the initially-presented cached version with respect to the updated version;
if the extent of freshness is below a threshold, present the updated version to the user in place of the initially-presented version; and
if the extent of freshness is above the threshold, continue to present the initially-presented version and refrain from presenting the updated version, even though the updated version has already been fetched to the communication terminal.
26. The method according to claim 1 , wherein assessing the extent of freshness comprises assessing depending on a difference in content between the cached version and the updated version of the content item.
27. The terminal according to claim 13 , wherein the processor is configured to assess the extent of freshness depending on a difference in content between the cached version and the updated version of the content item.
28. The method according to claim 1 , wherein assessing the extent of freshness of the presented cached version comprises determining whether the cached version is sufficiently similar to the updated version.