About Routing

RESTFul Routes 

Custom Routes

Named Routes

How to Redirect

Root Route

Route Parameters - Part 1

Route Parameters Part 2

Route Parameters Part 3

About Rails Controllers

tweet=find(1) cluttering up show.html.erb

Notice the tweets... tweets...tweets

Keep model code such as tweet=Tweet.find(1) in controllers

Instance variables via @ allows views to see what is in the controller

How to use status.html.erb in Show method via render

Using param[:id] in find method for flexibility

xml ? json?

Basic Controller Actions

Authorisation

Notice for Layouts

DRY out...Use before_filter

About Rails Views

link_to helper

See also http://api.rubyonrails.org/
More RESTful Routes like

link_to "Profile", profile_path(@profile)
# => <a href="/profiles/1">Profile</a>

or the even pithier



link_to "Profile", @profile
# => <a href="/profiles/1">Profile</a>

REST stands for Representational State Transfer. (It is sometimes spelled "ReST".) It relies on a stateless, client-server, cacheable communications protocol -- and in virtually all cases, the HTTP protocol is used.

REST is an architecture style for designing networked applications. The idea is that, rather than using complex mechanisms such as CORBA, RPC or SOAP to connect between machines, simple HTTP is used to make calls between machines.

In many ways, the World Wide Web itself, based on HTTP, can be viewed as a REST-based architecture.


RESTful applications use HTTP requests to post data (create and/or update), read data (e.g., make queries), and delete data. Thus, REST uses HTTP for all four CRUD (Create/Read/Update/Delete) operation

More at http://rest.elkstein.org/




Index.html.erb - List







Tweet.all in Rails 5 can be written as @Tweet.each do |tweet|

Rails Model: Validations and Relationships

Q. What is a model ?

A. Model is how Rails communicate with a data store.

VALIDATIONS

Try Ruby Tutorial

A really cool thing about Ruby is that you can always convert between different types using Ruby's "to" methods.

• to_s converts values to strings.
• to_i converts values to integers (numbers.)
• to_a converts values to arrays.

Strings have .reverse property eg "Chee".reverse => "eejC"

ARRAYS

Arrays are basically list of stored information.

Create empty array
[]

[517, 66, 07].max => 517

Assign array to a variable

nric=>[517, 66, 07]

Sort an Array

nric.sort =>[07,66,517]
nric=>[517, 66, 07]

// ! permanently sort 

nric.sort! =>[07,66,517]

nric =>[07,66,517]

Query Array

nric.include? 67 =>false
nric.include? 07 =>true

Comple list of string methods

Hash

Hashes store related information by giving reusable labels to pieces of data.

Create Hash aka Dictionary.
books={}

or

ratings=Hash.new(0)

Stuffing an Array

books["Inferno"] = :splendid
books["Kublai Khan"] = :historical
books["Davinci Code"]=:exciting

books => {"Inferno"=>:splendid, "Kublai Khan=>:historical, "Davinci Code"=>:exciting}

Block

Basically, a block is a chuck of ruby code

RoR Zombies Tutorial : Notable point

1. Reading Value out of a Hash
This is a Hash

t={id:, status: "Delicious Brains", zombie:"Jim"}

Read Recipe
Variable[:key] => value
Example
t[:id]=3
t[:status]="Delicious Brains"
t[zombie]="Jim"

How to retrieve the tweet object with id=3

ANSWER: t=Tweet.find(3)
{id: 3, status: "Delicious Brains", zombie:"Jim"}

Nb. Use id: in Hash and :id when reading Hash value

Hash Syntax vs Dot Syntax

puts t[:status] same as puts t.status
puts t[:zombie] same as puts t.zombie

Nb. Dot Syntax more suitable to access Tables

Accessing Tables

CRUD



CREATE

READ

 UPDATE

DELETE