Ruby and Rails Work
app/controlelrs
contains controllers
app/helpers
contains programs with classes to help model, view, or controller classes
app/config/database.yml
database configuration file
how do you write an initialize method
def initialize(a, b, c) @a_variable = a @b_variable = b @c_variable = c
an intializing method example
def initialize(id) @cust_id = id end
get infinite arguments in a function
def something(*x)
how do you write a method
def test end
hashname.delete('key')
delete one has element
how do you imbed a module into a class
include Modulename
packets
information sent over the internet broken in smaller pieces
where do you define a local variable
inside a method
@variable is a/an
instance variable
what is a class
instructions to tell ruby to make a new type of thing
how do you define a global variable
$name
to print out a string as long as you like
%q {}
how to make a string that goes across multiple line with no quotes
%q{ }
and logic operator
&&
example of an each do loop
(0..5).each do |i| puts "Value of local variable is #{i}" end
how do you write a class variable
@@variablename
how do you write an instance variable
@variablename
how do you create an app in heroku
heroku create
what is a module
a way of groping together methods classes and constants
what does a controller handle
a web request from a user
how do you make an app in heroku
heroku create
app folder
holds application components like views, controllers and models
components
holds applications that bundle model, view, and controller
containers
A container image is a lightweight, stand-alone, executable package of a piece of software that includes everything needed to run it:
#merge two hashes
h1 ={ "a" => "A"} h2 = {"c" => "C"} h1.merge!(h2)
app/models
has classes that model the data stored in the application database
app/view
holds display templates to fill in with data from our applicaiton, convert to html, and return to the user's browser
how do you print out a hash table
hsh.each do | key , value| print key, "is", value, "\n" end
acts_as_commontable
ides a single Comment model that can be attached to any model(s) within your app.
see which parameterd you get from a controller method
render plain: params[:articles].inspect
what is the equivalent command of python's import in ruby
require
add resources to routes.rb
resources :articles
arrayname.pop
return the end of the array while shortening it by one
how to make a new line in a string
"\n"
class X: def initialize(J
"class X has-a initialize that takes a J parameter
range inclusive
..
range exclusive
...
what extension do ruby files have
.rb
turn string to a float
.to_f
how you enclose ruby code in an erb document
<% %>
How do you enclose code to be printed out in an erb document
<% = %>
link to another from within a view
<%= link_to 'link text' , path_to_find %>
how do you insert a link in html?
<a href = "url"> Something </a>
how do you italicize in html
<em> </em>
how do you insert an image in html?
<img src = "url">
how do you make something bold in html?
<strong> </strong>
long comment in Ruby
= begin = end
class variable naming
@@no_of_customers
what are the three components of rails
Action controller, action view, active record
main steps to Set up rails project with postgres
After making postgresql instance 1.) gem install pg 2.) rails new myapp --database=postgresql 3.)edit database.yml 4.) rake db:setup
the 4 components of the TCP/IP model
Application, Transport, Internetwork, Link
get the first commandline argument
Argv.first
what are the standard SQL commands
CREATE, SELECT, INSERT, UPDATE, DELETE, and DROP, GRANT, REVOKE
how to check if a file exists
File.exist?(nameoffileargument)
how to delete a file
File::delete("file")
#to open a file
File::open("filename", "mode") mode can be "w", "a", "r"
#how to read a file
File::read("file.txt")
how to rename a file
File::rename("oldname", "newname")
what does ERB let you do
It lets you put Ruby code inside of an HTML file
how to create an empty new file on the command line in windows
NUL > newfile
acts_as_paranoid
This gem can be used to hide records instead of deleting them, making them recoverable later
what is a Procfile
a text file that declares what command starts your app
escape key for strings
\
double quote
\"
single quote
\'
bell
\a
escape backspace
\b
formfeed
\f advance downward to the next page
Character with octal value ooo
\ooo
return key
\r
carriage return
\r go back to front of current line without moving down
escape tab
\t
Character with 16-bit hex value xxxx (Unicode only)
\uxxxx
ASCII vertical tab (VT)
\v
Character with hex value hh
\xhh
the most basic definition of the internet
a bunch of connected router that are moving packets
what is bundled software
a bunch of software all together
what is a container
a class, data structure, or an abstract data type whose instances are collections of other objects
daemon
a computer program that runs in the background
what is a procfike
a file that declares the commands to start your ap
IP address
a number assigned to a computer such that message can be routed to it
what is a record
a row in a table
Proxy server
a server that sits between two servers and sort of relays messages for them
hop
a single physical network connection
Thread
a small sequence of programmed instructions
what three main things does a packet contain (in addition to its content)
a source address, a destination address, information about how it can be put back together
what is a staging server
a special server used for testing
what is a database object
a table
Docker
a techno company that offers containers
what is double :: used for
accessing constants
where can you use global variables
across different classes
how to add a comment to a model instance
add this to a model : class Post < ActiveRecord::Base acts_as_commentable end and this to the model's controller commentable = Post.create comment = commentable.comments.create comment.title = "First comment." comment.comment = "This is the first comment." comment.save and fetch them from the view: commentable = Post.find(1) comments = commentable.comments.recent.limit(10).all
what is scaling
adding more resources for a particular application
what is scaling?
adding more resources for a particular application
how to open up a new file for appending
afile = file.new("filename", "rt")
how to write a file called afile
afile.syswrite
what does a class variable belong to?
alll objects of the class
how to change windows with just keys
alt + tab
if you return multiple items what are you actually returning?
an array
to assign things to your object what do you need within your class
an initialization method
how to loop through an array and print each item
arrayname.each do |i| puts i end
how do you reverse an array
arrayname.reverse
how do you sort an array
arrayname.sort
How do you make a new array
ary = Array.new
to make a new array preset to size 20
ary = Array.new(20)
how to loop through an array
ary.each do put i end
how to return array size
ary.size
what does gets do
asks user for input but on a new line
what is gets.chomp
asks usr for input all on the same line
when are blocka arguments used
at the beginning of thr block
when is END ran?
at the end of the program
what might before_filter be good for
authenticating users
when is BEGIN ran
before program runs
make a user to check the terms of service before a controller is ran
before_action :check_terms_of_service
#make a user a log in before a controller is ran
before_filter :authenticate_user!
begin/end/while loop
begin code end while conditional
break
break out of loop or function
to call a method in ruby just
call its name
call backs
callbacks- a callbacki s any executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at a given time
all constant names must be
capitalized
constants are always
capitalized
module names must be
capitalized
how do we format cacses
case variable name when variable option command else command end
what might before_action be good for calling
checking terms of service
double indicated
clasd method
what type of @@variable is this
class variable
while modifier format
code while condition
how to make hash containers
colors= { "red" => 1, "blue" =>}
routers
computers devoted to moving packets
what is ERB
embedded ruby
!(true && true)
false
!true
false
false && false
false
false && true
false
false || false
false
nil is
false
not (false || true)
false
not (true || false)
false
not (true || true)
false
true && false
false
until loop execute while the conditional is
false
what are the entities within tables called?
fields
how to close a file in ruby
file.close
how to read the contents of a file
file.read
how to read just one line of the textfile in ruby
file.readline
move the read or write position to the beginning of the file
file.seek()
empty a file completely in ruby
file.truncate
write stuff into a file
file.write("stuff")
what are regular expressions used for?
finding words or patterns in text
how do you pass values to an argument
first, second, third, fourth, = ARGV
example of a Ruby forloop
for i in 0..5 puts "value of local variable is #{i} end
foo.K = Q
from foo get the K attribute and set it to Q
foo.M(j)
from foo get the M function and call it with the parameter J
deploy your google cloud app without changing the prior version
gcloud app deploy --no-promote
add route the simple way
get 'static_pages/hello'
what does gets.chomp does
get usrr input and then removes newlines or things that are not a string
how to reverse user input
gets.user
how to commit changes to github
git add. git commit -m "message" git add. git commit -m "message"
how to clone a repository onto your local machine
git clone url
how to work from a repository
git clone url cd xxx git add. git status git commit -m "statement" git push origin master
how do you deploy code to heroku in the cli
git push heroku master
how to deploy heroku code
git push heroku master
check if things worked in git
git status
to substitute one item for another
gsub(Find_word, replacement)
unless
inverse of if
until
inverse of while, executes while false
defined?
is this class, function/etc defined already
what is a GEMfile
its a Rails program dependency manager (what programs does this app need to run)
what is a gem file
its rubys dependency manager
arrayname.join
join arrays together
what does an instance variable belong to?
just that one object
class X: def M(J)
lass X has a function named m that takes a J parameter
LAN
local area network
and
logical and but lower priority than &&
RESTful design
lookups use GET PUT, POST, DELETE are used for mutation, creation deletion
class X <y
make a class named X that is-a Y
naming rules for classes in ruby
must be capitalized
naming rules for method
must be lowercase
?/n means
newline
can you define a constant within a method
no
can you define a constant within a method?
no
how do you call a method that goes with an object
objectidentifier.methodname
where is a local variable available
only inside a method
Go through some submitted parameter and only return the permitted few
params.permit( :seller_id :units :group_buyer id )
make sure a parameter was given to the controller from a broswer
params.require(:amg_order)
yield
pause and transfer control to the code block
block arguments are surrounded by
pipes
methods outside of a class are
private
methods inside of a class are
public
how do you print
puts
how do you insert variables inside or strings
puts " A is #{a}"
redo
redo a code block exactly the same
undef
remove a function defined within a class
add a root
root 'controllername#methodname'
hoe to run a ruby file
ruby test.rb
rescue
run this code if an exception happens
ensure
run this code whether an exception happens or not
belongs_to
self.inheritance_column
foo = X.new
set foo to an instance of class X
next
skip to the next element of the iterator
regular expression are surrounded by
slashes
how to compare a string to another string
str <=> other_str (results: less than: -1, same: 0, greater than: 1)
To test if an object is a string
str == obj ..if false; it isn't a string
how to capitalize a string
str. capitalize
concatenate two strings together
str.concat(str2)
make as tring with no white spaces
string.strip
how to make a string capitalized
stringname.upcase
if it starts with : its a
symbol
app/view/layouts
template files for layouts
scalability
the capability of a system, network, or pocess to handle a growing amount of work
scalability
the capability of a system, network, or process, to handle a growing amount of work
self
the current object, class, or module
Port
the end point of communication; has an IP and a protocol
what is an object
the most basic type of thing, an instance of a class
super
the parent class
what do if an case statements returb
the valur of the last expression executed
what do MySQL , MS Access" Oracle, Syvase, Informix, Postgres and SQL have in common
they are all relational database management systems
TCP stands for
transfer protocol
!(false && false)
true
!(false && true)
true
!(true && false)
true
!false
true
false || true
true
not (false || false)
true
true && true
true
true || false
true
true || true
true
while loops execute while the condition is
true
open a file
txt = open(filename, "w" )
close file
txt.close
read file
txt.read
go to the first byte of a file
txt.rewind(0)
write file
txt.write()
until loop format
until condition code change condition end
gets the first argument
user_name = ARGV.first
anybplain lowercase word in ruby is a
variable
#how to find some id in a table
variablename = tablename.find_by_id(thing to search in table)
what do controllers handle
web requests from a user
what is the format of doing a while loop
while condition do code end
WAN
wide area network
END block
will be printed last
BEGIN block
will be ran first
how should you always write constant identifiers
with uppercase letters
how do you make a new object
x = Classname.new
how to get userinput
x= gets
what is the command to enter a block called test if you are in a method called test
yield
or logic operator
||