SMTP extension to preserve per-message and per-recipient properties

• US 6,035,327 A
• Filed: 12/08/1997
• Issued: 03/07/2000
• Est. Priority Date: 12/08/1997
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Buckley, David, Cranston, Wayne Merl, Brown, Donald Gordon
• Primary Examiner(s): Rinehart, Mark H.
• Assistant Examiner(s): Thompson, Marc D.
• Application Number:
  US08/987,338
• Time in Patent Office: 820 Days
• Field of Search: 709/206, 709/227, 709/230, 709/236, 709/249, 709/203, 709/229, 370/466, 370/467, 370/469
• US Class Current: 709/206
• CPC Class Codes: H04L 51/00 User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail

Abstract

The SMTP protocol takes a message formatted according to a defined internet standard and wraps the message in an envelope. The message and envelope are sent to servers for transfer through the Internet to their intended destination. The SMTP protocol strictly defines the information that is transferred in the envelope and the format of the message. There is thus a real possibility that when messages are transferred from one network into an SMTP network that information will either be lost or not transferred correctly. The present invention provides systems and methods that take advantage of defined mechanisms to extend the SMTP protocol in order to create the novel extension that allows the transfer of virtually any information after the envelope is transferred but before the message is transferred. The invention allows information usually contained in the message portion to be transferred in the envelope portion. The invention also allows the preservation and transfer of information that would otherwise be lost.

Claims

1. In a network system where messages created by a plurality of clients are transferred using mail messages comprising an envelope and said message between a plurality of mail servers using a defined protocol, a method for transferring said mail message between said servers using said defined protocol and for transferring additional data using an extension to said defined protocol, said method comprising the steps of:

creating by a client a message in a first format to be sent via the networked system to a destination location;

sending said message to a first of said servers for transfer via the networked system to said destination location;

creating a mail message from said message by associating said message with an envelope created for said message;

extracting one or more properties from said message;

establishing by said first of said servers a connection between said first of said servers and a second of said servers using procedures defined as part of an established protocol normally used to transfer mail messages between said servers;

transferring said envelope of said mail message from said first server to said second server using said protocol;

transferring said extracted one or more properties from said first server to said second server using an extension to said protocol;

transferring said message of said mail message from said first server to said second server using said protocol; and

terminating by said first server said connection to said second server.

2. A method for transferring a mail message as recited in claim 1 wherein said message comprises a plurality of properties, including said one or more properties, said plurality of properties together defining said message and wherein the method further comprises the step of:

identifying said one or more properties that should be extracted prior to the step of extracting said one or more properties.

3. A method for transferring a mail message as recited in claim 1 wherein said established protocol is an SMTP protocol.

4. A method for transferring a mail message as recited in claim 1 further comprising the step of checking to see if said extension to said protocol is supported by said second of said servers.

5. A method for transferring a mail message as recited in claim 1 wherein said message is encoded from said first format into a format suitable for use with said established protocol.

6. A method for transferring a mail message as recited in claim 1 wherein said message comprises properties, including said one or more properties, which together define said message and wherein said step of extracting said one or more properties comprises encoding said one or more properties, including the steps of:

(a) emitting the number of said one or more properties to be extracted and encoded;

(b) obtaining the next property to be encoded;

(c) emitting a property tag comprising an id value which identifies said next property and an data type value which identifies the data type of said next property;

(d) if said next property is a multi-valued property comprised of a plurality of items, then emitting the number of items in said next property;

(e) if a next item of said next property is of a data type that is variable in length, then emitting the size of said next item;

(f) emitting the value of said next item;

(g) if additional items remain in said next property then returning to step (e); and

(h) if additional properties remain to be encoded, then returning to step (b).

7. A method for transferring a mail message as recited in claim 1, further comprising, prior to the step of extracting said one or more properties, the step of determining whether the transfer of said extracted one or more properties is likely to be either desired or supported by said second server.

8. In a network system (a) comprising (i) a first network where messages are transferred internally using a first protocol, said first network comprising a first server, and (ii) a second network where messages are also transferred internally using said first protocol, said second network comprising a second server, and (b) wherein mail messages are transferred between said first server and said second server using a second protocol and (c) wherein said mail messages comprise a message and an envelope, a method for transferring said mail messages between said servers using said second protocol and for transferring extension data with said mail messages using an extension to said second protocol, said method comprising the steps of:

creating, by a client system, a message to be sent via the networked system to a destination location, said method including properties that together define said message;

sending said message to said first server of said first network;

encoding, by said first server, said message in a format suitable for transfer to said second server of said second network using said second protocol;

creating a mail message from said encoded message by associating said encoded message with an envelope created for said message;

selecting one or more of said properties included in said message, wherein said one or more properties are to be sent to said second server as extension data;

establishing by said first server a connection between said first server and said second server using said second protocol;

transferring said envelope of said mail message from said first server to said second server using said second protocol;

transferring said extension data from said first server to said second server using an extension to said second protocol; and

transferring said encoded message of said mail message from said first server to said second server using said second protocol.

9. A method for transferring a mail message as recited in claim 8 wherein said extension data is transferred to said second server only if said second server supports said extension to said second protocol.

10. A method for transferring a mail message as recited in claim 9 wherein during the step of establishing said connection between said first server and said second server data is sent to said second server that elicits information that allows said first server to determine if said second server supports said extension to said second protocol.

11. A method for transferring a mail message as recited in claim 10 wherein said second protocol is an SMTP protocol.

12. A method for transferring a mail message as recited in claim 11, further comprising the step of encoding said one or more properties, including the steps of:

(a) emitting the number of said one or more properties that are to be sent to said second server as said extension data;

(b) obtaining the next of said one or more properties to be encoded;

(c) emitting a property tag comprising an id value which identifies said next property and an data type value which identifies the data type of said next property;

(d) if said next property is a multi-valued property comprised of a plurality of items, then emitting the number of items in said next property;

(e) if a next item of said next property is of a data type that is variable in length, then emitting the size of said next item;

(f) emitting the value of said next item;

(g) if additional items remain in said next property then returning to step (e); and

(h) if additional properties of said one or more properties remain to be encoded then returning to step (b).

13. A method for transferring a mail message as recited in claim 12 wherein said extension data comprises at least a first portion comprising per-message data and a second portion comprising per-recipient data.

14. In a network system (a) comprising (i) a first network where messages are transferred internally using a non-SMTP protocol, said first network comprising a first server, and (ii) a second network where messages are also transferred internally using said non-SMTP protocol, said second network comprising a second server, and (b) wherein mail messages are transferred between said first server and said second server using an SMTP protocol and (c) wherein said mail messages comprise a message and an envelope, a method for transferring said mail messages between said servers using said SMTP protocol and for transferring extension data with said mail messages using an extension to said SMTP protocol, said method comprising the steps of:

receiving at a first server a mail message comprising an envelope and a message that is to be transferred from said first server to a second server using an SMTP protocol;

establishing an SMTP session between said first server and said second server by said first server sending to said second server an SMTP request designed to elicit a response from said second server that will return any SMTP extensions supported by said second server;

receiving, at said first server, a list comprising all SMTP extensions supported by said second server, said list having been sent by said second server in response to said SMTP request and including a designated extension;

transferring said envelope of said mail message using the SMTP protocol from said first server to said second server;

based on said designated extension having been included in said list, then sending by said first server to said second server an encoded data packet comprising extension data, said encoded data packet being sent in addition to said envelope and said message of said mail message using said designated extension, said extension data including one or more selected properties of said message;

transferring said message of said mail message using the SMTP protocol from said first server to said second server; and

terminating, by said first server, the SMTP session with said second server.

15. A network system comprising:

a first network wherein mail messages are transferred internally using a first protocol, said first network comprising a first server;

a second network wherein mail messages are also transferred internally using said first protocol, said second network comprising a second server;

means for encoding a message which exists in a format suitable for internal storage and transfer in said first network into a format suitable for transfer to said second network using a second protocol, said encoded message being associated with an envelope to produce a transfer-ready mail message;

means for extracting, from said message, one or more properties that are to be transferred to said second network along with said transfer-ready mail message; and

means for transferring said transfer-ready mail message and said extracted one or more properties from said first server to said second server, said means for transferring comprising;

means for establishing a connection between said first server and said second server using said second protocol;

means for transferring said envelope of said transfer-ready mail message from said first server to said second server using said second protocol;

means for transferring said extracted one or more properties from said first server to said second server using an extension to said second protocol; and

means for transferring said encoded message of said transfer-ready mail message from said first server to said second server using said second protocol.

16. A networking system as recited in claim 15 further comprising means for generating said envelope of said transfer-ready mail message.

17. A networking system as recited in claim 15 further comprising means for encoding said extracted one or more properties prior to transfer to said second server.

18. A networking system as recited in claim 17 wherein said message comprises a plurality of properties that include said one or more properties, said plurality of properties together defining said message, and wherein said means for encoding said extracted one or more properties operates using a method comprising the steps of:

(a) emitting the number of said one or more properties to be extracted and encoded;

(b) obtaining the next property to be encoded;

(c) emitting a property tag comprising an id value which identifies said next property and an data type value which identifies the data type of said next property;

(d) if said next property is a multi-valued property comprised of a plurality of items, then emitting the number of items in said next property;

(e) if a next item of said next property is of a data type that is variable in length, then emitting the size of said next item;

(f) emitting the value of said next item;

(g) if additional items remain in said next property then returning to step (e); and

(h) if additional properties remain to be encoded, then returning to step (b).

19. A networking system as recited in claim 17 further comprising means for decoding, at said second network, said extracted one or more properties.

20. A networking system as recited in claim 15 further comprising means for receiving information transferred by said means for transferring said transfer-ready mail message and said extracted one or more properties.

21. A networking system as recited in claim 15 further comprising means for examining said message in order to determine whether transfer of said extracted one or more properties is likely to be supported by said second server.

22. A networking system as recited in claim 15 wherein said second protocol is an SMTP protocol.

23. A networking system as recited in claim 22 wherein said means for establishing sends an EHLO command in accordance with said SMTP protocol when said connection is being established between said first server and said second server.

24. A computer-readable medium having a plurality of data fields stored thereon, said plurality of data fields representing an extension data packet that has been constructed by a sending server and is to be transferred from the sending server to a receiving server with a mail message that includes a message and an envelope, said plurality of data fields having encoded thereon one or more properties that have been extracted from said message by said sending server and comprising:

a first data field stored in a first region of a range of memory addresses in said medium containing data representing the number of said one or more properties contained in said extension data packet;

a first set of data fields stored in a second region of said range of memory addresses, said first set of data fields being associated with a per-message property that has been extracted from said message by said sending server, said first set of data fields comprising;

a second data field containing a per-message property tag representing a data type of the per-message property and a name of the per-message property; and

a third data field encoding said per-message property and containing data representing the value of said per-message property; and

a second set of data fields stored in a third region of said range of memory addresses said second set of data fields being associated with a per-recipient property that has been extracted from said message by said sending server, said second set of data fields comprising;

a fourth data field containing a per-recipient property tag representing a data type of the per-recipient property and a name of the per-recipient property; and

a fifth data field encoding said per-recipient property and containing data representing the value of said per-recipient property.

25. A computer-readable medium, as an article of manufacture, for use with a network system comprising (a) a first network comprising a first server, and (b) a second network comprising a second server, said computer-readable medium having computer-executable instructions encoded thereon, comprising:

means for encoding a message which exists in a format suitable for internal storage and transfer in said first network into a format suitable for transfer to said second network using a message transfer protocol, said encoded message being associated with an envelope to produce a transfer-ready mail message;

means for extracting, from said message, one or more properties that are to be transferred to said second network along with said transfer-ready mail message; and

means for transferring said transfer-ready mail message and said extracted one or more properties from said first server to said second server, said means for transferring comprising;

means for establishing a connection between said first server and said second server using said message transfer protocol;

means for transferring said envelope of said mail message from said first server to said second server using said message transfer protocol;

means for transferring said extracted one or more properties from said first server to said second server using an extension to said message transfer protocol; and

means for transferring said encoded message of said mail message from said first server to said second server using said message transfer protocol.

26. A computer-readable medium as recited in claim 25 further comprising means for generating said envelope of said transfer-ready mail message.

27. A computer-readable medium as recited in claim 25 further comprising means for encoding said extracted one or more properties prior to transfer to said second server.

28. A computer-readable medium as recited in claim 27 wherein said message comprises a plurality of properties that include said one or more properties, said plurality of properties together defining said message, and wherein said means for encoding said extracted one or more properties operates using a method comprising the steps of:

(a) emitting the number of said one or more properties to be extracted and encoded;

(b) obtaining the next property to be encoded;

(c) emitting a property tag comprising an id value which identifies said next property and an data type value which identifies the data type of said next property;

(d) if said next property is a multi-valued property comprised of a plurality of items, then emitting the number of items in said next property;

(e) if a next item of said next property is of a data type that is variable in length, then emitting the size of said next item;

(f) emitting the value of said next item;

(g) if additional items remain in said next property then returning to step (e); and

(h) if additional properties remain to be encoded, then returning to step (b).

29. A computer-readable medium as recited in claim 27 further comprising means for decoding, at said second network, said extracted one or more properties.

30. A computer-readable medium as recited in claim 25 further comprising means for receiving information transferred by said means for transferring said transfer-ready mail message and said extracted one or more properties.

31. A computer-readable medium as recited in claim 25 further comprising means for examining said message in order to determine whether transfer of said extracted one or more properties is likely to be supported by said second server.

32. A computer-readable medium as recited in claim 25 wherein said message transfer protocol is an SMTP protocol.

33. A computer-readable medium as recited in claim 32 wherein said means for establishing sends an EHLO command in accordance with said SMTP protocol when said connection is being established between said first server and said second server.

34. In a network system where messages created by a plurality of clients are transferred using mail messages comprising an envelope and said message between a plurality of mail servers using a defined protocol, a method for transferring said mail message between said servers using said defined protocol and for transferring additional data using an extension to said defined protocol, said method comprising the steps of:

creating by a client a message in a first format to be sent via the networked system to a destination location, the message including properties that together define the message;

sending said message to a first of said servers for transfer via the networked system to said destination location;

creating a mail message from said message by associating said message with an envelope created for said message;

obtaining additional data to be sent with said mail message, the additional data including at least one of said properties encoded using at least the steps of;

(a) emitting the number of said properties to be included in said additional data;

(b) obtaining the next property to be encoded;

(c) emitting a property tag comprising an id value which identifies said next property and an data type value which identifies the data type of said next property;

(d) if said next property is a multi-valued property comprised of a plurality of items, then emitting the number of items in said next property;

(e) if a next item of said next property is of a data type that is variable in length, then emitting the size of said next item;

(f) emitting the value of said next item;

(g) if additional items remain in said next property then returning to step (e); and

(h) if additional properties remain to be encoded then returning to step (b);

establishing by said first of said servers a connection between said first of said servers and a second of said servers using procedures defined as part of an established protocol normally used to transfer mail messages between said servers;

transferring said envelope of said mail message from said first server to said second server using said protocol;

transferring said additional data from said first server to said second server using an extension to said protocol;

transferring said message of said mail message from said first server to said second server using said protocol; and

terminating by said first server said connection to said second server.