1. NBN:URN Generator and Resolver ERPANET Workshop on Persistent Identifiers Cork, 17-18 June, 2004. Ádám Horváth National Széchényi Library Hungary

2. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Contents PreparationProtocol Design principles NBN:URN generation NBN:URN resolution The web interface Technical background Intended users

3. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Preparation Studied the relevant standards Studied the relevant standards http://www.uri.net/ Studied the existing implementations –Finnish –Norwegian –German

4. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Protocol THTTP protocol (RFC 2169) THTTP protocol (RFC 2169) Implemented features Implemented features –N2L –N2LS –L2N

5. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Design principles Simplicity Simplicity –User friendly generation –Administration free Reliability Reliability –The uniqueness of URN is guaranteed –Only the owner of the document can request a URN

6. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth The owner of the document Who is the owner? Who is the owner? –Who has the right to write into the document Advantages Advantages –Simple –Can be automated –There is no problem with passwords

7. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Requesting URN - Step 1 HTTP request HTTP request – –http://nbn.oszk.hu/GetNBN?url=http://s olanum.oszk.hu/proba.html The server checks The server checks –Does the document exist? –Is it an HTML document? –Is there already a URN for this document? –Has anyone placed a transaction for it?

8. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Answer Answer –The server place the request – –OK:0:urn:nbn:hu-3006 tid:3291d4fcf5b5fce1d0 – –Error:-9: Error message Requesting URN - Step 1 (cont’d)

9. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Writing the URN into the document Writing the URN into the document –It is the requester’s task – –...... Requesting URN - Step 2

10. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Finalizing the request Finalizing the request – –http://nbn.oszk.hu/GetNBN?url=http://so lanum.oszk.hu/proba.html &urn=urn:nbn:hu-3006 &tid=3291d4fcf5b5fce1d0 Requesting URN - Step 3

11. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth The server checks The server checks –Has the request already been placed –Does the document exist –Is it an HTML document –Does it contain the URN Answer Answer –OK –Error message Requesting URN - Step 3 (cont’d)

12. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth N2L (URN to URL) N2L (URN to URL) –HTTP request http://nbn.oszk.hu/N2L?urn:nbn:hu-3006 –HTTP coded answer 303 (SEE OTHER): redirects to the appropriate URL. 404 (NOT FOUND): if the URN does not exist Resolving URN

13. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth L2N (URL to URN) L2N (URL to URN) –HTTP request http://nbn.oszk.hu/L2N?http://solanum.oszk.hu/proba.ht ml –HTTP coded answer Text (eg. urn:nbn:hu-3006). 404 ( FOUND): if it does not exist. Resolving URN (cont’d)

14. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth N2Ls (URN to URLs) N2Ls (URN to URLs) –HTTP request http://nbn.oszk.hu/N2Ls? urn:nbn:hu-3006 –HTTP coded answer HTML page with a list of URLs text/uri-list MIME type (if explicitly requested). 404 ( FOUND): if it does not exist. Resolving URN (cont’d)

15. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Changing the URN - URL assignment Changing the URN - URL assignment –This is also a three step process The document must exist in both the old and the new URLThe document must exist in both the old and the new URL Deleting the URN - URL assignment Deleting the URN - URL assignment –This is also a three step process The document itself can only be deleted after the deletion of the URN - URL assignmentThe document itself can only be deleted after the deletion of the URN - URL assignment Other functions

16. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Request and modification for dynamic pages Request and modification for dynamic pages – –http://nbn.oszk.hu/GetNBN ?url=http://solanum.oszk.hu/proba.h tml &nocheck=1 Server Server –Does not check the existence of the document Other functions (cont’d)

17. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Bulk generation of URN’s is also possible Bulk generation of URN’s is also possible –Sample scripts written in Python are provided for the users Other functions (cont’d)

18. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth The functions can be invoked from a web interface The functions can be invoked from a web interface –Test request is also possible –The interface is bilingual: Hungarian and English The web interface also contains background material: user guide, the source of the application, sample script etc. The web interface also contains background material: user guide, the source of the application, sample script etc. Web interface

19. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth PHP for the interface PHP for the interface Java servlets for the functions Java servlets for the functions PostgreSql is the database PostgreSql is the database It is an open source application It is an open source application Technical background

20. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Hungarians Hungarians –How can we ensure this Only the Hungarian interface works on the production databaseOnly the Hungarian interface works on the production database The English interface works on the development database. The purpose of the English interface is to make our results more widely available.The English interface works on the development database. The purpose of the English interface is to make our results more widely available. Intended users

21. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth Copies of the same object should have the same URN Copies of the same object should have the same URN Different versions of the same object, e.g. in MS Word and HTML shall have different URNs. Different versions of the same object, e.g. in MS Word and HTML shall have different URNs. If an object is changed, a new URN only needs to be assigned if the intellectual content of the object changes. Editorial changes (e.g. changes to fonts etc.) do not necessitate a change of URN. If an object is changed, a new URN only needs to be assigned if the intellectual content of the object changes. Editorial changes (e.g. changes to fonts etc.) do not necessitate a change of URN. Guidelines for the request

22. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth We build a database on the THTTP resolvers. We build a database on the THTTP resolvers. –The OPAC display program consults with this database and sends the URN to the appropriate resolver. Resolving URN in the OPAC

23. NBN:URN Generator and Resolver - ERPANET Workshop, Cork - Ádám Horváth adam@oszk.hu Thank you for your attention