How to send Basic Authentication (BA) credentials in ruby on rails

HTTP Basic authentication is a simple authentication scheme in which user authentication is done by a username and password eliminating the needs of cookies, sessions and login pages. It is base64 encoded.

Rails provides a method for this type of authentication: authenticate_with_http_basic

This method can be used as follows:

authenticate_with_http_basic do |username, password|
  ——
end

Inside the block you can access the username and password.

But how to send a request with basic auth in rails ?

This is really tricky and I didn’t find any documentation for this. Here I am describing how to send a request with basic auth.

1. Use Faraday library (Faraday is an HTTP client lib)
https://github.com/lostisland/faraday

Create a connection:

connection = Faraday.new(:url => HOST) do |faraday|
      faraday.request  :url_encoded             # form-encode POST params
      faraday.response :logger                  # log requests to STDOUT
      faraday.adapter  Faraday.default_adapter  # make requests with Net::HTTP
      faraday.basic_auth(USERNAME, PASSWORD)
end

parameters = params[‘user’].permit!.to_h

response = connection.get do |req|
      req.url(params[:url])
      req.headers['Content-Type'] = 'application/json'
      req.params.merge!(parameters)
end

response = connection.post do |req|
        req.url(params[:url])
        req.headers['Content-Type'] = 'application/json'
        req.body = parameters
end

render json: response.body

Here,

HOST = 'http://lvh.me:3002'
USERNAME = 'EdcddzrbmET55016'
PASSWORD = 'UXBJnS309S49st3rHqmH5934'
params['url'] = '/users/profile'

We can use Faraday’s (‘faraday.basic_auth’) basic auth method to reach out our solution.

If you are getting any error like follows in post request

NoMethodError (undefined method `bytesize' for {}:ActiveSupport::HashWithIndifferentAccess):

Don’t forget to convert the ruby hash ‘parameters’ to json by calling ‘to_json’ upon it.

        req.body = parameters.to_json 

In Other way you can use something like this to generate the basic auth header

request.env['HTTP_AUTHORIZATION'] = ActionController::HttpAuthentication::Basic.encode_credentials(USERNAME, PASSWORD)

How to use Ruby Rest Client:

require 'rest_client'

headers = {
  :authorization => 'Basic FytxhZGKpbjpvcGVuIHNlc2FtHUHU'
}

response = RestClient.get 'https://yourdomain.com/api/users.json?activityId=02ddf868-6484-440f-8c39-c7d4fb4e7b33', headers
puts response
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Rbenv: Start with new ruby and rails versions

Check for the new ruby and rails versions
https://www.ruby-lang.org/en/downloads/
https://rubygems.org/gems/rails/versions

Suppose we are going to install Ruby – 2.4.1 & Rails – 5.1.3

Get rbenv into action

1. $ rbenv install --list # Gets the list of ruby versions available

$ rbenv install 2.4.1

ruby-build: definition not found: 2.4.1

The following versions contain `2.4.1' in the name:
  rbx-2.4.1

See all available versions with `rbenv install --list'.

If the version you need is missing, try upgrading ruby-build:

  brew update && brew upgrade ruby-build

Oops..!

rbenv cannot find the version: 2.4.1

Upgrade ruby-build

Mac:

$ brew upgrade ruby-build --HEAD

Now install ruby 2.4.1

$ rbenv install 2.4.1

Create a new gemset:

$ rbenv gemset create 2.4.1 demo-app
That set up a directory for you in ~/.rbenv/versions/2.4.1/gemsets/demo-app

Set the ruby version to the newest

$ rbenv local 2.4.1

$ rbenv version
=> 2.4.1

    Activate New Gemset


For activating a gemset we need to create a .rbenv-gemsets file in the current directory.

$ touch .rbenv-gemsets
$ echo demo-app > .rbenv-gemsets

Check active gemset:

$ rbenv gemset active

Install Rails 5.1.3

$ gem install rails -v '5.1.3'
$ gem install --no-rdoc --no-ri rails -v '5.1.3' # skips the documentation

Later we can delete this .rbenv-gemsets file and add a new file named ‘.ruby-gemset’ in the rails project directory. I cannot see any other good way of doing this. If anybody know about some other good way of doing this please give a comment.

Create a New Rails app

$ rails new demo-app

$ rm .rbenv-gemsets

$ cd demo-app
$ touch .ruby-gemset
$ echo demo-app > .ruby-gemset
$ touch .ruby-version
$ echo 2.4.1 > .ruby-version
$ rails s
=> Booting Puma
=> Rails 5.1.3 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.9.1 (ruby 2.4.1-p111), codename: Private Caller
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop

Goto http://localhost:3000/

rails-5-new.png

Done! Lets go…

#Rails 4.2 #Ruby2.2 How to find association class and other info from an object and its association name

When I was doing something, I encountered one situation like: I need the association class of an object. I have the object and its association name as input. How can I find the association class?

Suppose we have Student class that belongs to a school

class School
  has_many students
end

class Student
  belongs_to :school
end

and so many other relations like this in my project.

So I have

s = Student.last
:school symbol 

in my hand

I can use

s.school.class and s.school.class.name

But what if the school is blank? The result is ‘NilClass’ From the above code.

Basically for has_many associations we gets the class name as

"ActiveRecord::Associations::CollectionProxy"

because recently in new versions rails changed the Array of objects as associations to its own ‘CollectionProxy’.

So we can use ‘ActiveRecord::Reflection::ClassMethods’ for finding all the association info.

This Rails module is so useful to find all the association related information.

In the above situation we can use ‘reflect_on_association’ method for finding association reflection info. And it returns ‘ActiveRecord::Reflection’ Object.

http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html#method-i-reflect_on_association

> s.class.reflect_on_association(:school)
=> ##<ActiveRecord::StatementCache:0x000000037a5c08 
@query_builder=#, @bind_map=#<ActiveRecord::StatementCache::BindMap:0x000000037a7238 
@indexes=[0], @bind_values=[[#
, #
]]>>}, @scope_lock=#
, @class_name="Topic", @foreign_key="school_id">

Namespaced classes in Ruby

We can write namspaced classes in ruby in two ways.

In the normal way we can wrap the class inside a module. Lets say the module name as ‘MyModule’.
And the constants we define inside this module are accessed as follows:


module MyModule
    CONST1 = 1
    class Myclass
       CONST2 = 2
       def name
          "This is my name"
       end

       def const_1
         CONST1
       end

       def const_2
          CONST2
       end
    end
end

p MyModule::Myclass.new.name
p MyModule::Myclass.new.const_1
p MyModule::Myclass.new.const_2

The other way of doing this is the short way of writing the class name with module name and two columns.
As you can see, the const_1 is accessed as prefixing the module name with two columns.

module MyModule
    CONST1 = 1
end

class MyModule::Myclass
    CONST2 = 2
    
    def name
       "This is my name"
    end
    
    def const_1
        MyModule::CONST1        
    end
    
    def const_2
        CONST2
    end
end

p MyModule::Myclass.new.name
p MyModule::Myclass.new.const_1
p MyModule::Myclass.new.const_2

There is an another way of doing this, that may looks strange to most of the people. Nested classes.

class Myclass
  def name
     "This is my name"
  end

  def my_class_2_name
     Myclass2.new.name
  end

  class Myclass2
    def name
       Myclass.new.name
    end
  end
end

> p Myclass.new.name
> "This is my name"
> p Myclass.new.my_class_2_name
> "This is my name"

The two printing works. So what is the use of these nested classes? Hmmm. It is just namespacing the second class and it tells, somehow it relates to first class even though there is no relation between these two classes.

> p Myclass2.new.name
> uninitialized constant Myclass2

We cannot access Myclass2 without specifying the namespace ( Myclass )

> p Myclass::Myclass2.new.name
> "This is my name"

Set up capistrano deployment for Ruby On Rails

STEP 1:
Install capistrano gem

group :test, :development do
  gem 'capistrano'
end

Install capistrano with rvm

gem 'rvm-capistrano'

STEP 2:
Prepare your Project for Capistrano
Capify your project. The following command initialise your project with Capistrano.

$ capify .

STEP 3:
Do proper modificatons in Capistrano Recipe (config/deploy.rb)
http://guides.beanstalkapp.com/deployments/deploy-with-capistrano.html

Lets do the deployment for staging environment.
Create a ruby file under config/deploy/ folder named staging.rb
Copy the following content

set :domain, "mydomain.in"
role :app, domain
role :web, domain
role :db, domain, :primary => true
role :resque_worker, domain   # if you are using workers in your project, set role for them if needed
role :resque_scheduler, domain # if you are using workers in your project

set :deploy_to, "/home/my_deploy_path/"  # the deployment directory
set :environment, "staging"
set :rails_env, "staging"
set :branch, "staging"
set :previous_environment, "develop"

STEP 4:
Setup capistrano in deployment server

$ cap staging deploy:setup

This will Create folder structure that capistrano uses in the process.

Make sure that everything is set up correctly on the server by the command

$ cap staging deploy:check

Now you can see a message like:
“You appear to have all necessary dependencies installed”

Create shared/config folder in your deploy_to path
and copy database.yml and other config files as you written in the symlink_shared task in cap recipie (if any)

STEP 5:
Deploy your project:

cap staging deploy

How to categorise a blog posts data by month in Ruby On Rails

Suppose we created a ‘BlogPost’ Model in Rails and we have the following fields in a blog post:

title – title of the blog post
posted_on – date posted
permalink – a permanent link of each blog post (act as a primary key)
publish – a boolean field which decides the post need to show or not

Lets write a method in ‘BlogPost’ Model to get a recent list of posts.
Pass a ‘months_old’ parameter to determine how much months old posts we wanted to list.
Just select the required columns to show the details of the post (by ‘:select => ‘). And Group each post by posted month.

  def self.get_recent_months_post(months_old)
    @blog_posts = where("publish = ? AND posted_on > ?", true, Date.today - months_old.months).all(:select => "title, posted_on, permalink", :order => "posted_on DESC")
    (@blog_posts.group_by { |t| t.posted_on.beginning_of_month }).sort.reverse
  end

We successfully written the method above. Now lets write a method to get the archives (old posts).

  def self.get_archives(old)
    @blog_posts = where("publish = ? AND posted_on  "title, posted_on, permalink", :order => "posted_on DESC")
    (@blog_posts.group_by { |t| t.posted_on.beginning_of_month }).sort.reverse
  end

How to create a migration file dynamically from a rake task or a lib file in rails 4.0

If you want to add a migration file from lib file or somewhere from your ruby file and execute it, use the dynamic method which can create a class or method dynamically. The following code snippet is not complete. But gives a better idea to create migration file dynamically. Use a bit of metaprogramming.

 def create_columns(tb_with_cols)
    .........
    .........
    columns.each { |column| add_columns << "\tadd_column(':#{tb_name}', :#{column})\n" }
    columns
 end

 def migration_file_content(tb_with_cols)
<<-RUBY
  class AddMissingColumnsToTable < ActiveRecord::Migration
     def change_table
    #{create_columns(tb_with_cols)}
   end
 end
  RUBY
 end


 def write_content_to_file(path, content)
    File.open(path, 'w+') do |f|
      f.write(content)
    end
 end

Just call the method ‘migration_file_content’ in your code. Pass the parameter tb_with_cols as a Hash whose key is the table_name and value is the columns that should be added to that table like:

tb_with_cols = {:users => {:name => :string, :age => :integer, :address => :text} }

After that just call the method ‘write_content_to_file’ with your new migration file path and the content from our ‘migration_file_content’ method. 🙂