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JavaScript Topic Maps in server environments


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This paper is about the JavaScript-based Topic Maps Engine tmjs.

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JavaScript Topic Maps in server environments

  1. 1. W E B V E V E R I E T JavaScript Topic Maps in server environments Jan Schreiber <> Ravn Webveveriet AS, 2010-10-01 1
  2. 2. Outline • JavaScript • The tmjs Topic Maps engine • Use Case: A PSI Server • Outlook W E B V E V E R I E T 2
  3. 3. JavaScript • JavaScript is LISP with a C-like syntax • Virtually every personal computer in the world has at least one JavaScript interpreter installed on it and in active use. W E B V E V E R I E T 3
  4. 4. tmjs • A Topic Maps engine • Written in pure JavaScript • Full TMDM including Variants • TMAPI 2.0-based • In-memory backend, JTM import/ export, experimental XTM 2.0 import (requires DOM) W E B V E V E R I E T 4
  5. 5. tmjs • Platform independent: All(iPhone & browsers, mobile devices modern Android), server-side JavaScript • Unit tests, CXTM tests (partly) & JSLint validating • Small changes to TMAPI due to the lack of method overloading • Syntactic sugar: Supports chaining of TMAPI calls W E B V E V E R I E T 5
  6. 6. Chaining 1 tm.createTopic().addSubjectIdentifier(foo). 2 createName('bar').getParent(). 3 createOccurrence(type,'baz'). 4 addScopingTopic(quux); W E B V E V E R I E T 6
  7. 7. tmjs: Outlook • More import/export formats: XTM 2.0, CTM • Complete TMAPI, add more tests, full CXTM • Persistence: • Web SQL Database backend • Persistent backend for Node (couchdb?) • Later: Query language W E B V E V E R I E T 7
  8. 8. Use Case: A PSI Server • Idea: Start the server with a Topic Map and it will serve information about all Subject Identifiers for a given domain W E B V E V E R I E T 8
  9. 9. • Screenshot node-psi-server W E B V E V E R I E T 9
  10. 10. Server-side JavaScript • 1996: Netscape releases LiveWire as part of Netscape Enterprise Server 2.0 • 2009: Ryan Dahl writes Node W E B V E V E R I E T 10
  11. 11. Node • A framework for low-level network applications based on Google's V8 engine • TCP, DNS and HTTP are first-class protocols • Event-based, asynchronous programming • All I/O is non-blocking W E B V E V E R I E T 11
  12. 12. result = db_query(db, "SELECT * FROM topic"); W E B V E V E R I E T 12
  13. 13. db_query(db, "SELECT * FROM topic", callback); W E B V E V E R I E T 13
  14. 14. db_query(db, "SELECT * FROM topic", callback); callback = function (err, result) { // ... } W E B V E V E R I E T 14
  15. 15. 1 var tm, servername; 2 // assumes that the TopicMap object tm has been initialized and 3 // the topic map in question has been imported successfuly. 4 // servername is set from a command line parameter 5 http.createServer(function (req, res) { 6 var url = 'http://'+servername+req.url, loc, topic; 7 loc = tm.createLocator(url); 8 topic = tm.getTopicBySubjectIdentifier(loc); 9 if (topic) { 10 res.writeHead(200, {'Content-Type': 'text/html'}); 11 // create a page with information about the PSI 12 } else { 13 // Not found: create a 404 response 14 } 15 res.close(); 16 }).listen(80); W E B V E V E R I E T 15
  16. 16. Use Case: A PSI Server • More output formats: XHTML, JTM, XTM • Support for logging, caching, templates • Configurable list of information elements that are included on generated pages (e.g. dc:description, supertype-subtype) • PSI black-listing • integration W E B V E V E R I E T 16
  17. 17. PSI Server: Observations • Easy to implement • It’s really fast: 200+200ms to read the Opera topic map, 1ms to serve a PSI page • tmjs can be used on server and client side Reuse of application code W E B V E V E R I E T 17
  18. 18. Summary & Outlook • Server side Topic Maps with JavaScript: possible! • Asynchronous TMAPI? • In its current state maybe best suited for low-level applications W E B V E V E R I E T 18
  19. 19. What could it be good for? • TMRAP, TM REST API • SDshare • P2P applications • DNS servers W E B V E V E R I E T 19
  20. 20. Questions? Download tmjs now! Coming soon: W E B V E V E R I E T 20