Content conversion system and content conversion server

1. A computer-readable, non-transitory medium storing a content conversion program causing a conversion server to execute a procedure, the procedure comprising:

analyzing, when a send request for content is received from a client terminal, the send request and distinguishing between client information and content information, wherein the client information indicates a type of the client terminal, the type indicating a usable format of content for the client terminal, and the content information indicates a content that is requested to be sent to the client terminal;

acquiring, from a storing unit, server information and cache information that are associated with a combination of the distinguished client information and the distinguished content information, wherein the storing unit stores therein a combination of the client information, the content information, server information and cache information, wherein the server information indicates a conversion server responsible for converting a format of the content to a usable format for the client terminal and the cache information indicates an identifier of a cache storing the content in the usable format for the client terminal; and

notifying a conversion server indicated by the server information, when the conversion server is not the conversion server executing the procedure, of the distinguished client information, the distinguished content information, the cache information and connection information indicating a connection that is established with the client terminal, the connection information including IP addresses, port numbers, a sequence number, and a confirmation response number.

2. A computer-readable, non-transitory medium storing a content conversion program causing a computer to execute a procedure, the computer acting as a conversion server responsible for converting a format of a content to a format usable for a client terminal wherein the content is requested to be sent to the client terminal, in accordance with client information indicating a type of the client terminal, the type indicating a usable format of content for the client terminal, the procedure comprising:

determining, when the conversion server is notified by another conversion server of the client information, content information that indicates the content and cache information that indicates an identifier of a cache storing the content in the usable format for the client terminal and connection information including IP addresses, port numbers, a sequence number, and a confirmation response number, whether a converted content, the content in the usable format for the client terminal, is stored in a cache in the conversion server, by the cache information; and

sending, when it is determined that the converted content is stored in the cache in the conversion server, the converted content to the client terminal

acquiring, when it is determined that the converted content is not stored in the cache in the conversion server, the content indicated by the content information from a content server that stores therein the content indicated by the content information notified by the another conversion server;

converting a format of the acquired content to a usable format for the client terminal whose type is indicated by the client information notified by the another conversion server; and

sending the converted content to the client terminal and storing the converted content in the cache in the conversion server.

3. The computer-readable, non-transitory medium according to claim 2 , wherein the procedure further comprises:

establishing, when it is determined that the converted content is not stored in the cache in the conversion server, a connection with the content server;

notifying the another conversion server of connection information indicating the established connection; and

acquiring, by a computer that acts as the another conversion server, when the content indicated by the content information is requested from the content server using the notified connection information, the content requested by the another conversion server using the connection established with the content server.

4. A content conversion system comprising:

a first conversion server including,

a storing unit that stores therein, in an associated manner, a combination of client information indicating a type of a client terminal, the type indicating a usable format of content for the client terminal, content information indicating content that is data requested to be sent to the client terminal, server information indicating a conversion server responsible for converting a format of the content to a usable format for the client terminal, and cache information indicating an identifier of a cache storing the content in the usable format for the client terminal,

a distinguishing unit that analyzes, when a send request for content is received from a client terminal, the send request and that distinguishes between the client information and the content information,

an acquiring unit that acquires, from the storing unit, the server information and the cache information that are associated with the combination of the client information and the content information that are distinguished by the distinguishing unit, and

a notifying unit that notifies a conversion server that is indicated by the server information acquired by the acquiring unit, when the conversion server is not the first conversion server, of the distinguished client information, the distinguished content information, the cache information and connection information indicating a connection that is established with the client terminal, the connection information including IP addresses, port numbers, a sequence number, and a confirmation response number; and

a second conversion server including,

a determining unit that determines, when the second conversion server is notified by the first conversion server of the client information, the content information and the cache information, whether a converted content, the content in the usable format for the client terminal, is stored in a cache in the second conversion server, by the cache information, and

a sending unit that sends, when it is determined, by the determining unit, that the converted content is stored in the cache in the second conversion server, to the client terminal, the converted content.

5. A content conversion server comprising:

a storing unit that stores therein, in an associated manner, a combination of client information indicating a type of a client terminal, the type indicating a usable format of content for the client terminal, content information indicating content that is data requested to be sent to the client terminal, server information indicating a conversion server responsible for converting a format of the content to a usable format for the client terminal, and cache information indicating an identifier of a cache storing the content in the usable format for the client terminal;

a distinguishing unit that analyzes, when a send request for content is received from a client terminal, the send request and that distinguishes between the client information and the content information;

an acquiring unit that acquires, from the storing unit, the server information and the cache information that are associated with the combination of the client information and the content information that are distinguished by the distinguishing unit; and

a notifying unit that notifies a conversion server that is indicated by the server information acquired by the acquiring unit, when the indicated conversion server is not the content conversion server, of the distinguished client information, the distinguished content information, the cache information and connection information indicating a connection that is established with the client terminal, the connection information including IP addresses, port numbers, a sequence number, and a confirmation response number.

6. A content conversion method comprising:

analyzing, when a send request for content is received from a client terminal, the send request and distinguishing between client information and content information, wherein the client information indicates a type of the client terminal, the type indicating a usable format of content for the client terminal, and the content information indicates a content that is requested to be sent to the client terminal;

acquiring, from a storing unit, server information and cache information that are associated with a combination of the distinguished client information and the distinguished content information, wherein the storing unit stores therein a combination of the client information, the content information, server information and cache information, wherein the server information indicates a conversion server responsible for converting a format of the content to a usable format for the client terminal and the cache information indicates an identifier of a cache storing the content in the usable format for the client terminal; and

notifying the conversion server indicated by the server information, when the indicated conversion server is not the conversion server, of the distinguished client information and the distinguished content information, the cache information and connection information indicating a connection that is established with the client terminal, the connection information including IP addresses, port numbers, a sequence number, and a confirmation response number.

7. A content conversion method performed in a conversion server responsible for converting a format of a content to a format usable for a client terminal wherein the content is requested to be sent to the client terminal, in accordance with client information indicating a type of the client terminal, the type indicating a usable format of content for the client terminal, the content conversion method comprising:

determining, when the conversion server is notified by another conversion server of the client information, content information that indicates the content and cache information that indicates an identifier of a cache storing the content in the usable format for the client terminal and connection information including IP addresses, port numbers, a sequence number, and a confirmation response number, whether a converted content, the content in the usable format for the client terminal, is stored in a cache in the conversion server, by the cache information; and

sending, when it is determined that the converted content is stored in the cache in the conversion server, the converted content to the client terminal

acquiring, when it is determined that the converted content is not stored in the cache in the conversion server, the content indicated by the content information from a content server that stores therein the content indicated by the content information notified by the another conversion server;

converting a format of the acquired content to a usable format for the client terminal whose type is indicated by the client information notified by the another conversion server; and

sending the converted content to the client terminal and storing the converted content in the cache in the conversion server.