USOO5961601A United States Patent (19) 11 Patent Number: 5,961,601 Iyengar (45) Date of Patent: Oct. 5, 1999 54 PRESERVING STATE INFORMATION INA Bertrand Ibrahim, “World-wide algorithm animation”, CONTINUING CONVERSATION BETWEEN Computer Networks and ISDN Systems, Elsevier Science A CLIENT AND SERVER NETWORKED WIA B.V., pp. 255–265, (1994). A STATELESS PROTOCOL Alan Falconer Slater, “Extending W3 clients”, Computer Networks and ISDN Systems, Elsevier Science B.V., pp. 75 Inventor: Arun K. Iyengar, Yorktown Heights, 61–68, (1995). 73 Assignee: International Business Machines (List continued on next page.) Corporation, Armonk, N.Y. Primary Examiner Mark H. Rinehart Attorney, Agent, or Firm Kevin M. Jordan 21 Appl. No.: 08/660,633 57 ABSTRACT 22 Filed: Jun. 7, 1996 A method and System for preserving State in computers 51 Int. Cl. ........................... G06F 13/38; G06F 15/17 communicating over networks, such as the World Wide Web 52 U.S. Cl. .......................... 709/229; 709/228; 709/218; (WWW) using stateless protocols, e.g., HTTP State is 709/203 preserved in a conversation between a client requesting 58 Field of Search ......................... 395/200.32, 200.48, Services from a Served by performing the Service and 395/200.53, 200.59, 182.02, 182.03, 182.05; identifying all continuations (hyperlinks) in an output from 709/202, 218, 223, 229, 228, 203; 714/4, the Service; recursively embedding the State information in 5, 7 all identified continuations in the output Sent to the client. The State information may be embedded and communicated 56) References Cited by the server to the client. Alternatively, dynamically down U.S. PATENT DOCUMENTS loadable program code may be used to embed the State information at the client. Additional features enable the 5,218,695 6/1993 Novecket al.. filtering and/or addition of hyperlinks and data output from 5,623,656 4/1997 Lyons ................................. 395/200.49 5,668,943 9/1997 Attanasio et al. ................. 395/182.05 the Services according to predetermined criteria. State infor 5,701,451 12/1997 Rogers et al. ..................... 395/200.32 mation may be embedded by modifying an identified con 5,708,780 1/1998 Levergood et al. ............... 395/200.12 tinuation which is a request for an HTML file, to invoke a 5,710,918 1/1998 Lagarde et al. ... ... 395/200.32 CGI converter program with the identified continuation and 5,774,670 6/1998 Montulli ............................ 395/200.57 the State information passed as arguments. State information may also be embedded by modifying an identified continu FOREIGN PATENT DOCUMENTS ation which is an invocation to a CGI program with the 0604010 10/1993 European Pat. Off.. identified continuation and the State information passed as 0625750 11/1994 European Pat. Off.. arguments, and the embedding Step is performed by the CGI program. Alternatively, an identified continuation which is OTHER PUBLICATIONS an invocation of a CGI program may be modified to invoke “Haht Software Premiers HahtSite at Demo 96', PR News a CGI converter program with the identified continuation, an wire, Jan. 29, 1996. argument counter which indicates a number of arguments “Proposed HTTP State Management Mechanism”, Montulli asSociated with the CGI program, and the State information et al., HTTP Working Group, Feb. 16, 1996. passed as arguments. Here, the embedding is performed by Louis Perrochon et al., “IDLE: Unified W3-access to inter the converter program. active information servers', Computer Networks and ISDN Systems, Elsevier Science B.V., pp. 927–938, (1995). 68 Claims, 10 Drawing Sheets CLENT WEB BROWSER 450 CONNECTION MANAGER DATABASE (OPTIONAL) HTML FIES CGI PROGRAMS 5,961,601 Page 2 OTHER PUBLICATIONS “Hypertext Transfer Protocol-HTTP/1.0” http://www.ic “Behind The Scenes of The Adventure Web”, http://tww S.uci.edu/pub/ietf/http/draft-ietf-http-v10-spec-03.html, w.stanford.edu/adventure/impl.html Feb. 23, 1996. by T. Berners-Lee, R. Fielding, and H. Frystyk, Sep. 4, “Aug. 1995 Web Watch”, http:www.netgen.com/corpinfo/ 1995. press/webwtchv6n8.html Feb. 2, 1996. “Zebrafish Database', http://zfish.uoregon.edu/Zf info/ “Network News Transfer Protocol: A Proposed Standard for dbase/arch.html Oct. 24, 1995. the Stream-Based Transmission of News”, RFC 977, B. “Porting Interactive Applications to the Web”, http://ksi.cp Kantor and P. Lapsley, UC San Diego and UC Berkeley, Feb. sc.ucalgary.ca/articles/WWW/PortWeb/PortWeb.html Dec. 1986, http://ds.internic.net/rfc/rfc977.txt. 7, 1995. “MBA/MBARI Live Link to The Technology Museum of “Simple Mail Transfer Protocol", RFC 821, J.B. Postel, Innovation in San Jose' http://rockfish.mbari.org/BayLink/ Information Sciences http://ds.internic.net/std/std 10.txt. http prb.html Aug. 2, 1995. “Persistent Client State HTTP Cookies”, Netscape Commu J. Postel and J.K. Reynolds, “File Transfer Protocol (FTP)”, nications Corporation, 1996 http://home.netscape.com/ RFC 959, Information Sciences Institute, USC, Oct. 1985 newsref/std/cookie Spec.html. http://ds.internic.net/std/std9.txt. U.S. Patent Oct. 5, 1999 Sheet 1 of 10 5,961,601 T.J. Watson Research Center. Yorktown (left) and Hawthorne. O Welcome O Local Education Outreach O Visitor info and local site directions O Local hotels O IBM home page -- IBM Research home page G Click on icon to send your comments. Or, contact webmaster(awatson.ibm.com IBM home page Order Search Contact IBM | Help (C) (TM) FG. PRIOR ART U.S. Patent Oct. 5, 1999 Sheet 2 of 10 5,961,601 FG.2 PRIOR ART SKYLINE SUPPLIERS REGISTRATION FORM USERID PASSWORD PASSWORD (FOR VERIFICATION) ACTUAL NAME COMPANY E-MAIL ADDRESS PHONE NUMBER (RESET FORM) U.S. Patent Oct. 5, 1999 Sheet 3 of 10 5,961,601 FG.3 PRIOR ART 450 CLENT SERVER COMPLETED GENERATED FORM FORM INTERNET HIDDEN HIDDEN STATE STATE WARIABLES WARIABLES SERVER A.10 U.S. Patent Oct. 5, 1999 Sheet 4 of 10 5,961,601 FG.4 CLIENT SERVER CLIENT REQUESTS A SERVICE FROM THE SERVER STATELESS PROTOCOL CALL TO 505 YES 500 CONVERT 2. NO TO STEP 510 530 PRESERVATION 525 515 p. EXECUTE SERVICE YES CENT RECEIVES STATELESS PROTOCOL SEND TO CENT 520 SERVICE OUTPUT WITH CONTINUATIONS YCONVERT LOGIC MODIFIES AL CONTINUATIONS STATELESS PRODUCED BY THE SERVICE TO PROTOCOL EMBED STATE AND EXPLCT 540 CALL TO CONVERT 2' YES CONTINUATION SELECTED 530 CONVERT 2. INVOKES SERVICE WITH ARGUMENTS NO AND STATE WARIABLES END CONVERSATION 535 PASS OUTPUT AND STATE WARIABLES TO CONVERT 1 U.S. Patent Oct. 5, 1999 Sheet 5 of 10 5,961,601 ROUTING AND CONTROL INFO SERVICE 1 SERVICE ARGUMENTS FG.5 601 650 605 610 685 670 ROUTING AND STATE CONTROL INFO CONVERT 2 SERVICE 1 SERVICE ARGUMENTS WARIABLES 680 F.G. 6 U.S. Patent Oct. 5, 1999 Sheet 6 of 10 5,961,601 FG.7d SERVER 410 CLIENT CONVERTER - INTERNET OTHER BROWSER CG 414 PROGRAMS 460 413 HTML/CG DBMS 470 CONNECTION 475 MANAGER DATABASE 427 (OPTIONAL) 429 CGI PROGRAMS U.S. Patent Oct. 5, 1999 Sheet 7 of 10 5,961,601 FIG.7b CLIENT ACCESSES HOME PAGE 700 (STATELESS) CLENT BEGINS BROWSNG PRODUCT CATALOG 710 (STATELESS) CLIENT BROWSES NEW 720 CATALOG PAGE (STATELESS) CLIENT DESIRES TO 730 PURCHASE AN TEM (STATELESS) 740 CLIENT ENTERS USER-ID, PASSWORD 745 STATE WARIABLES EMBEDDED; USER-ID, SESSION-ID CLIENT BROWSES ADDITIONAL CATALOG PAGES (CONTINUATION SELECTED). 750 STATE WARIABLES PRESERVED FOR REMAINDER OF CONVERSATION U.S. Patent Oct. 5, 1999 Sheet 8 of 10 5,961,601 FG.8 INTERNET CLENT SERVER CLENT SELECTS HYPERLINK CGI PROGRAM BEGINS 810 PRESERVING STATE By 740' CALLING CONVERT 1 811 CONVERT 1 MODIFIES 81 3 LINKS TO HTML FILES CLIENT RECEIVES MODIFIED HTML TEXT Y CONVERT 17 MODIFIES LINKS TO CGI PROGRAMS CLIENT SELECTS HYPERTEXT LINK CALL TO Y CONVERT 2. ' PROCESS REQUEST FILE OR PROGRAM PASSED TO CONVERT 2. ' FETCH FILE AND PASS WITH STATE ARGS TOY CONVERT 1 7 EXECUTE PROGRAM & PASS OUTPUT WITH STATE ARGS TO 818 Y CONVERT 11 5,961,601 1 2 PRESERVING STATE INFORMATION IN A to use, separated from the rest of the locator by a “:”. Next CONTINUING CONVERSATION BETWEEN is the hostname or IP address of the target host; this is A CLIENT AND SERVER NETWORKED WIA delimited by the “//” on the left and on the right by a "/" or A STATELESS PROTOCOL optionally a “:”. The port number is optional, and is delim ited on the left from the hostname by a “:” and on the right FIELD OF THE INVENTION by a "/". The fourth component is the actual file name or program name. In this example, the ".html” extension means This invention is related to computers and computer that this is an HTML file. networks. In particular, the invention is related to computers Hyperlink (or Hypertext Link) preserving State while communicating over networkS via A network address embedded in a word, phrase, icon or StateleSS protocols. Even more particularly, the invention is picture that is activated when you Select it. Information related to a method and System for preserving State in about that item is returned to the client and displayed using computers communicating over the Internet, Specifically the a Web browser. World Wide Web, using the HyperText Transfer Protocol HyperText Markup Language (HTML) (HTTP). 15 HTML is the language used by Web servers to create and connect documents that are viewed by Web clients. HTML CROSS-REFERENCE TO RELATED PATENTS uses Hypertext documents. Other uses of Hypertext docu The present invention is related to the following United ments are described in U.S. Pat. No. 5,204,947, granted Apr. States of America Patents: 20, 1993 to Bernstein et al.; U.S. Pat. No.