How Node, Express and Postgres and help meet the challenges of building a scalable Web Service. Node is event-oriented and able to take high load. Express makes your code very simple and maintainable. Supports API-styled web service. Postgres supports your data needs with a very flexible data structure.

1. WEB SERVICES
Why Node, Express and Postgres?

2. ABOUT ME.
• Programming as a hobby.
• Final student, NTU (Biz IT).
• Mainly involved in tech-related
entrepreneurial projects.
• Latest project is
VogueVerve.com.

3. CONTENTS.
• Nodejs
• Expressjs
• Node modules
– Passport
– Sequelize
– Bluebird
• Postgres, Mongo, Couchbase

4. IT’S SIMPLE.
IT’S JS FRONT-TO-BACK.

5. WHAT IS NODEJS?
• It is a server side Javascript
runtime environment.
• Powered by Chrome V8.
• Main intention of real-time
communication.
• It can be a standalone server.

6. WHO USES IT?

7. MAIN ATTRIBUTES.
• Single threaded.
• Async, non-blocking I/O.
• Event-oriented.

8. IT DOESN’T WAIT FOR
ANYTHING.

9. USING JS FOR SERVER-SIDE
APPLICATION SOUNDED LIKE
A BAD IDEA.
Search “Node.js is cancer”

11. HOW TO NODE?
• Delegate computationally
intensive tasks to lower-level
languages like C++.
• Make clusters (to combat
single-threading).
• Node errors will crash the
server. Gotta catch ‘em all.

12. MODULAR CONCEPT.

13. NPM REPOSITORY.
• Modularity and versioning.
• Updates and releases.
• The best thing since beer.

14. WHAT IS EXPRESS?

15. EXPRESS.
• It is a Node Module.
• The most popular web
framework for Node.
• “Sinatra inspired”.
• Makes building web
application incredibly easy.

16. ROUTE HANDLING

17. `REQ` AND `RES`
OBJECTS.
• `req` comes for the user.
• `res` is sent back to the user.
• I use it extensively for “API-
styled” web platform.

18. REQ AND RES OBJECTS

19. API IN 3 SIMPLE STEPS

20. NODE MODULES

21. PASSPORTJS.
• Authentication API.
• Supports almost any kind of
authentication framework.
• FaceBook, Twitter, Google
OAuth modules already
available.

22. AN EXAMPLE

23. HOW TO USE IT?
• Documentation is abit skimpy
and untelling.
• Learn by example:
https://scotch.io/tutorials/easy-
node-authentication-setup-
and-local

24. SEQUELIZEJS.
• Object-Relational-Mapper
(ORM)
• Works with MySQL, Postgres
and others.
• Promise-styled. Very intuitive
and maintainable code.
• Support transactions.

26. ACTIVE RECORDS

27. RAW QUERIES?
• You get replacements for free.

28. BLUEBIRD.
• Very good performance.
• Prevents `callback hell` in
asynchronous coding.
• Makes code very readable.
• Parallelism.

29. WHY ARE PROMISES SO
GOOD?
Because it’s very intuitive and
readable.
Codes that solves a problem but
cannot be easily understood, is a
problem.

30. CALLBACK HELL

32. SOME ADVICES
• Don’t use modules that are not
well-maintained.
• Worry about performance, but
not too much.

33. POSTGRES, MONGO, COUCH.

34. Relational
data
Documents
?

35. Your data.Your storage.
vs

37. MONGO AND COUCH -
JSON
Denormalized into a single
document. Fast.

38. IN THE MIDDLE
Use MongoDB/Couchbase + a
lot of indexing
OR
SQL with many many joins
SQL with serialized/encoded
arrays

39. THE OLD WAYS
• Joins are slow.
• Serializing can be problematic.
• Atomic updates impossible.
• Values cannot be used as
selection criteria.

40. MONGO AND COUCHBASE
CAN HANDLE SOME
“RELATIONAL” NEEDS AND
STILL REMAIN FAST. BUT…

41. THE PROBLEM
• What if Joe
changes
name?
• What if a
new field is
added to
users?

42. YOU MAY REACH A POINT
WHERE THERE IS JUST TOO
MUCH TO REPLICATE.

43. YOU CAN DO THIS AND IT IS
STILL PROBABLY FAST
You find yourself trying to do “joining”.
Are there any ORMs for
Mongo/Couchbase?

44. CHANGE IS THE ROOT OF ALL
PROBLEMS.
Will your data become more relational
than it is now?
http://www.sarahmei.com/blog/2013/11
/11/why-you-should-never-use-
mongodb/

45. POSTGRES JSON AND
HSTORE
• A field that can contain “array-
structured” data.
• Atomic operations: Key/values
can be searched for and
indexed.
• Fast.
• Best thing since NPM, and
beer.

46. A VERY FLEXIBLE
STRUCTURE
id name data
1 Mary { “country”: “Singapore”, “dataMeta”: { “following”: “299”, “followers”:
“484” }}
2 Lucy { “country”: “France”}
3 Jane null
4 Tom {“dataMeta”: { “following”: “479” }}
5 Dick {“dataMeta”: { “following”: “12”, followers: “40”}}

47. WHAT ABOUT THE NEED FOR
SPEED?

48. PERFORMANCE
• Different sources will stake
different claims.
• Comparing apples with
oranges.
• They are all quite fast.

49. TEST USING YOUR DATA
STRUCTURE AND YOUR
TYPICAL ROUTINE.

50. IT IS NOT PERFECT
• Only HSTORE supports atomic
updates, JSON does not.
• HSTORE does not support
nested structure.
• Postgres JSON is very new.
Library support is adequate
but not mature.

51. Relational
data
Documents

52. CONCLUSION ON PG
• It is a RDB that is very capable
of handling schemaless data.
• Don’t over-normalize your
data.
• Use relations and constraints
for critical portions of your
data.

53. 1. SERVER-SIDE JAVASCRIPT
IS A GOOD IDEA.

54. 2. IF YOU ARE BUILDING A
WEB SERVICE, USE EXPRESS.

55. 3. ASK NOT WHAT A TECH
CAN DO FOR YOU. ASK WHAT
IT CANNOT DO.

56. KEEP IN TOUCH!
• Facebook: /calvintwr
• Email: calvin14@gmail.com