Content caching

1. A method performed by data processing apparatus, the method comprising:

routing, from a gateway within a network, a request by a client within the network, for a webpage;

routing, from the gateway to the client, a document associated with the webpage that identifies content to be embedded in the webpage;

receiving, at the gateway within the network, a message containing the content to be embedded in the webpage, the message conforming to a protocol that specifies a format of the content, the message having been sent from a server outside the network to the client within the network;

routing the message from the gateway to the client;

analyzing the message to determine whether the content is static by determining if the content has at least a threshold similarity to stored content previously returned from an address, wherein the content and the stored content share the address; and

depending on a result of the analyzing, selectively causing the content to be stored in the format specified by the protocol in a cache within the network.

2. The method of claim 1 wherein, when the result of the analysis comprises a determination that the content is static, said selectively causing the content to be stored comprises sending a message to the cache within the network instructing the cache to store the content in a format specified by the protocol.

3. The method of claim 1 wherein the message is a Hypertext Transfer Protocol (HTTP) message, the content is a single HTTP resource, and the cache indexes stored content by HTTP resource name.

4. The method of claim 1 wherein analyzing the message to determine that the content is static comprises analyzing a file extension of the content.

5. The method of claim 1 wherein analyzing the message to determine that the content is static comprises analyzing a header of the message.

6. The method of claim 1 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending the content to the cache.

7. The method of claim 1 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending a publicly available address of the contents to the cache.

8. The method of claim 7 the method further comprising requesting, by the cache, the content from the publicly available address.

9. The method of claim 8 the method further comprising storing, by the cache, the content in the format specified by the protocol and indexed according to the publicly available address.

10. A non-transitory computer storage media encoded with computer program instructions that, when executed by one or more processors, cause a computer device to perform operations comprising:

routing, from a gateway within a network, a request by a client within the network, for a webpage;

routing, from the gateway to the client, a document associated with the webpage that identifies content to be embedded in the webpage;

receiving, at the gateway within the network, a message containing the content to be embedded in the webpage, the message conforming to a protocol that specifies a format of the content, the message having been sent from a server outside the network to the client within the network;

routing the message from the gateway to the client;

analyzing the message to determine whether the content is static by determining if the content has at least a threshold similarity to stored content previously returned from an address, wherein the content and the stored content share the address; and

depending on a result of the analyzing, selectively causing the content to be stored in the format specified by the protocol in a cache within the network.

11. The computer storage media of claim 10 wherein, when the result of the analysis comprises a determination that the content is static, said selectively causing the content to be stored comprises sending a message to the cache within the network instructing the cache to store the content in a format specified by the protocol.

12. The computer storage media of claim 10 wherein the message is a Hypertext Transfer Protocol (HTTP) message, the content is a single HTTP resource, and the cache indexes stored content by HTTP resource name.

13. The computer storage media of claim 10 wherein analyzing the message to determine that the content is static comprises analyzing a file extension of the content.

14. The computer storage media of claim 10 wherein analyzing the message to determine that the content is static comprises analyzing a header of the message.

15. The computer storage media of claim 10 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending the content to the cache.

16. The computer storage media of claim 10 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending a publicly available address of the contents to the cache.

17. The computer storage media of claim 16 the operations further comprising requesting, by the cache, the content from the publicly available address.

18. The computer storage media of claim 17 the operations further comprising storing, by the cache, the content in the format specified by the protocol and indexed according to the publicly available address.

19. A system comprising:

one or more processors configured to execute computer program instructions;

and computer storage media encoded with computer program instructions that, when executed by one or more processors, cause a computer device to perform operations comprising:

routing, from a gateway within a network, a request by a client within the network, for a webpage;

routing, from the gateway to the client, a document associated with the webpage that identifies content to be embedded in the webpage;

receiving, at the gateway within the network, a message containing the content to be embedded in the webpage, the message conforming to a protocol that specifies a format of the content, the message having been sent from a server outside the network to the client within the network;

routing the message from the gateway to the client;

analyzing the message to determine whether the content is static by determining if the content has at least a threshold similarity to stored content previously returned from an address, wherein the content and the stored content share the address; and

depending on a result of the analyzing, selectively causing the content to be stored in the format specified by the protocol in a cache within the network.

20. The system of claim 19 wherein, when the result of the analysis comprises a determination that the content is static, said selectively causing the content to be stored comprises sending a message to the cache within the network instructing the cache to store the content in a format specified by the protocol.

21. The system of claim 19 wherein the message is a Hypertext Transfer Protocol (HTTP) message, the content is a single HTTP resource, and the cache indexes stored content by HTTP resource name.

22. The system of claim 19 wherein analyzing the message to determine that the content is static comprises analyzing a file extension of the content or analyzing a header of the message.

23. The system of claim 19 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending the content to the cache.

24. The system of claim 19 wherein sending a message to a cache on the network to store the content in the format specified by the protocol comprises sending a publicly available address of the contents to the cache.

25. The system of claim 24 the operations further comprising:

requesting, by the cache, the content from the publicly available address; and

storing, by the cache, the content in the format specified by the protocol and indexed according to the publicly available address.