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July 13, 2016
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How to translate JavaScript strings in Rails

Rails I18n and elegant message passing to JavaScript

The process of “internationalization” usually means to abstract all strings and other locale specific bits (such as date or currency formats) out of your application. The process of “localization” means to provide translations and localized formats for these bits. How I18n in Ruby on Rails Works

❝The limits of my language are the limits of my world.❞ ‒Ludwig Wittgenstein. With over 6,909 distinct languages in the world and most of them differing in so many different ways (e.g. in pluralization rules), it is difficult to provide specific tools for internalization. However, for unrestricted barriers of languages, Rails I18n API focuses on:

providing support for English and similar languages out of the box
making it easy to customize and extend everything for other languages

As part of this solution, every static string in the Rails framework – e.g. Active Record validation messages, time and date formats – has been internationalized, so localization of a Rails application means “over-riding” these defaults.

1.1 The Overall Architecture of the Library

Thus, the Ruby I18n gem is split into two parts:

The public API of the i18n frameworka Ruby module with public methods that define how the library works
A default backend (which is intentionally named Simple backend) that implements these methods

As a user you should always only access the public methods on the I18n module, but it is useful to know about the capabilities of the backend.

Here, the simplest way to implement internationalization in JavaScript;

a) Use the Script

<script type=”text/javascript”>
window.I18n = <%= I18n.backend.send(:translations).to_json.html_safe %>
</script>

b) You can add the below code in JS file;

I18n[“en-US”][“alpha”][“welcome”];

c) Get help from the application helper by adding the below method;

def current_translations

@translations ||= I18n.backend.send(:translations)

@translations[I18n.locale].with_indifferent_access

end

d) The backend needs to be initialized if it hasn’t been already.

I18n.backend.send(:init_translations) unless I18n.backend.initialized?

# now you can safely dump the translations to json

e) Invoke the below in your application.html.erb ;

<script type=”text/javascript”>

window.I18n = <%= current_translations.to_json.html_safe %>

</script>

f) To avoid having to know the current locale in JavaScript.

I18n[“alpha”][“welcome”]; Or I18n.alpha.welcome;

g) Various libraries and plugins for Internationalization & localisation:

i18next – http://github.com/i18next/i18next

I18n gem – http://github.com/svenfuchs/i18n

requirejs-i18n – http://requirejs.org/docs/api.html#i18n

Read More :http://www.railscarma.com/blog/technical-articles/how-to-translate-javascript-strings-rails/

July 12, 2016
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Ruby on Rails vs PHP

With more and more applications being built every day, programming languages too are becoming generic and all-purpose. Every programming language comes with its own set of specialization, and comparison between one programming languages to others may seem like a comparison between apples and oranges. However, comparison between two programming languages may offer you insights that might be crucial in your decision to go for a specific programming languages, especially when it comes to Ruby on Rails vs PHP. Since at RailsCarma, we work with both the ecosystems, we are able to understand the advantages and disadvantages of both. Here are some very simple and easy to understand comparison between Ruby on Rails and PHP.

PHP: PHP is a scripting language, used for web development to make interactive pages. The most common frameworks used for PHP are CakePHP, CodeIgnitor, Laravel, etc.

Ruby on Rails: Ruby is a scripting language and Rails is a web application framework written in Ruby.

  1. To Learn

PHP is simpler to learn as compared to Ruby especially for fresher in development. PHP codes can be easily run on server and deployed. To maintain the code, some standard needs to be followed. When it comes to frameworks, the benefit of PHP is that, it has more number of frameworks compared to Ruby. You can find more PHP developers compared to Ruby on Rails, which is really helpful for the companies or developers who need to learn the language. Documents and solutions are easily and readily available for PHP than Ruby on Rails, as applications and websites developed in PHP are more in number as compared to RoR.

  1. Resources

PHP provides lots of resources, frameworks and applications, such as WordPress, Drupal, Joomla, Magento, whereas Ruby on Rails in this department.

  1. Performance

PHP (language) is faster as compared to Ruby on Rails (framework) as it was designed only for web, but PHP is almost same or slower when it’s with frameworks like Laravel, CodeIgnitor, etc.

  1. Frameworks

Rails – The more you work on this framework, the more you will gain. It helps in providing quality products in less time when compared to PHP. Rails is a stable framework so companies and developers can easily adjust to it by learning one single framework, whereas for PHP there are a lot of frameworks which may make learning confusion. There are also no surety whether all the PHP frameworks will be supported in future or not.

  1. Development

Rails is a well-engineered framework where most of the necessary things are automated so that developer can just focus on business related work.

The points where PHP lacks are:

ScaffoldingGenerating a code in an easy and straightforward way, helps in faster development, whereas PHP lacks in this regard. However, PHP community has started work on this with FuelPHP providing similar features.
GemsRails provides plugins as a gem. Just add in your application and it fastens your development. Also, it’s easy to maintain as you are not trying to load libraries. For ex:Devise” gem which is used for authentication can be just installed in an application to handle all the processes.
ORMActiveRecord in the Ruby on Rails is the best part where you can perform all the database related queries using Ruby. Although PHP frameworks too provide the same but not up to the level of Ruby on Rails.
  1. Testing

Rails has testing frameworks that can be used to test your code and provide bug free code and make the client happy, where PHP framework are still trying to get this feature. PHPUnit is one such example.

  1. Cost

Development in PHP is much cheaper as compared to development in Ruby on Rails. Since, PHP is easier to learn and implement, it has more developers and so because of resources vs demand scale, it is cheaper to get your website developed in PHP as compared to Ruby on Rails.

Conclusion PHP has very large developer pool, it is easy to learn, has too many framework to choose, can find easy solution with the availability of experienced developers and is affordable. Ruby on Rails has passionate community, is always introducing new changes, application will be quick to market and best suits for agile development.

July 12, 2016
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Step-By-Step Guide to Building Your First Ruby Gem

Nowadays all the functionalities in Rails are built as Ruby gems. For example we can use devise gem for the authentication part of the application. It’s like a package or library that is written in Ruby programming language. Moreover it can be imported and used by others in their programs.

Step 1 Bundler is like a dependency management tool for Ruby, which is also used by Rails. We will use Bundler for the basic gem structure. It helps us to install the correct versions of the gem and forces us to use the same in the application. So the command for that is, gem bundler install After bundling, we should specify the gem “name” that we are going to create i.e. Bundle gem “testgem” will create a repository shown below

So in this we can see the basic gem structure. Under the lib folder, version file will be used to mention the version of the Gem. We can edit the version as per our convenience and release it that will be the version in Rubygems.

Step 2 We will consider testgem.gemspec, with testgem as the name of the gem that we will create for sample. It will be used to set up the gem on rubgems, for e.g., name of the gem, summary, description, files that are required in this project, test files that are used to testing the files in the project etc.

Rake file: – This makes releasing the new versions of the gem, and also helps other developers to check the test cases if they are going to modify the particular gem. After the rake, we should create a test folder and test cases for each segments will be included here in the app directory.

Step 3 Planning to make a rubygem, then we need to analyse the requirements what to build up and what all functionalities should be included in that. While generating, we should create a sample.rb file inside lib folder and create own class with namespace because the other plugin has also the same classes then it will get conflict in the names. And require the sample.rb file in the testgem.rb file like reqiure “testgem/sample”.

Step 4 We have require “bundler/gem_tasks” in rake file so when we run rake release, it will release the gem to ruby gems and make it available. Push to git repository

June 8, 2016
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SOCKET LIBRARY IN RUBY ON RAILS

There are basically two levels of accessing network services in case of rails .

The socket and network libraries are such important parts of integrating Ruby applications with the Internet and other communications-based environments.

One is through socket libraries provide low level access to connection oriented and connection-less protocols. Where user can implement client and server connection. Ruby is also having Network libraries that provide users a high level access to specific network protocols like FTP,HTTP and Etc.

At a low level, you can access the basic socket support in the underlying operating system, which allows you to implement clients and servers for both connection-oriented and connectionless protocols. Ruby also has libraries that provide higher-level access to specific application-level network protocols, such as FTP, HTTP, and so on.

What are Sockets?

Sockets are basically a bidirectional communications channel. Sockets may communicate within a process, between processes on the same machine, or between processes on different continents. Sockets can be implemented on different channels : Unix domain sockets, TCP, UDP, and so on. The socket library mainly provides specific classes and interface for handling a transports.

A SimpleClient:

Hereis a very basic client program which will open up a connection to a given port and given host. Ruby class TCPSocket provides open function to open a socket. The TCPSocket.open(hosname, port ) opens a TCP connection to hostname & theport.

Once socket is open, you can actually read that particular thing like IO object. When it’s done, just remember to close it, as you close that file. The following code connects to a given host and port, reads any available data from the socket, and then exits:

require ‘socket’ # Socket in standard library

hostname = ‘localhost’

port = 8080

s = TCPSocket.open(hostname, port)

while line = s.gets # Gets and Read the lines from the socket

puts line.chop # And print with platform line terminator end

s.close # socket Closed

A Simple Server: To write Internet servers, we basically use this TCPServer class. A TCPServer object is a factory for TCPSocket objects. Now call TCPServer.open(hostname, port function to specify a port for your service and create a TCPServer object. Next, call the accept method of the returned TCPServer object. This particular method waits till client connects to the port you specified above, and then returns a TCPSocket object that basically represents the connection to that client.

require ‘socket’ # Get sockets from stdlib server = TCPServer.open(8080) # Socket to listen on port 8080 loop { # Servers run forever

client = server.accept       # Wait for a client to connect
client.puts(Time.now.ctime)  # Send the time to the client
client.puts "Closing the connection. Bye!"
client.close                 # Disconnect from the client

}

Now run this server in background and then run above client to see the result.

June 7, 2016
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foreign_key option

It is also possible to specify that add_foreign_key should be added to the schema:

add_reference(:products, :supplier, foreign_key: true)
May 25, 2016
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Active Record Import

With activerecord-import, you’d just add your records to an array and call import:

records_to_import = pricing_data.map do |location, price|
  Inventory.new(location: location, price: price) 
end

Inventory.import records_to_import 
May 25, 2016
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May 25, 2016 - (v1.0.0 - v3.1.0)
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May 19, 2016 - (>= v4.1.8)
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Careful with arel column

I use what @equivalent suggests a lot but be careful, you MUST state the direction otherwise methods like take/last/first will fail silently!

StatusChange.arel_table[‘created_at’]. asc

not:

StatusChange.arel_table[‘created_at’]

May 5, 2016
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more loops

fruits = [‘apple’,‘orange”]

fruits.each do |fruit|

puts "A fruit of type: #{fruit}"

end

May 4, 2016 - (v1_9_3_392)
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April 12, 2016
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`value` or `text` method with parameter.

If your value or text method requires a parameter, like to_s(:select) then you need to create a separate method that references that in your model, like:

def to_s_select
  to_s(:select)
end

You can’t pass it in as a string like 'to_s(:select)'.

You have to use :to_s_select or 'to_s_select'.

March 23, 2016
1 thank

RE: RE: FALSE: Creates record by given attributes only if table is empty

keredson is still a little off on the behavior.

>> Where in reality this would grab the “first” record (say w/ email “john@smith.com”), and change its email to “derek@somwhere.com”, a fairly surprising action that doesn’t obviously fail, leading to some pretty subtle bugs.

This isn’t right, as if you look at the source it calls: “first || create(attributes, &block)”

So in the example of:

User.first_or_create(email: 'derek@somwhere.com')

it would find the first user with any email, and return it. And thats it. The attributes passed in as params are only used in the event that first returns no matches, and create is called.

I’m using it in a way similar to:

Foo.where(bar: baz_params[:bar]).first_or_create(baz_params)

This will find the first Foo where bar is equal to the bar sent from baz_params. If none is found, it will create it. It’s useful for me when importing large amounts of data where I know there will be duplicate records.

March 21, 2016
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Should include information about optional block

If a block exists, will return true if any records in the relation is true for the given block. Otherwise, returns true is there are any records.

March 21, 2016
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Description

Selects the first record within a relation if it exists, otherwise creates a new record with the optional attributes.

March 17, 2016
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No grammatical error

rajivekjain:

“A, B, and C” is correct in English, and is preferred by most style manuals. “A, B and C” is also correct in English. See en.wikipedia.org/wiki/Serial_comma

March 17, 2016 - (>= v4.2.1)
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Default values

By default :on_update and :on_delete have :restrict value.

March 11, 2016 - (>= v4.0.2)
1 thank

Ordering on associations using merge

For ordering on the attribute of an associated model you can add joins to query and merge order scope:

Product.joins(:category).merge(Category.order(priority: :desc))
March 6, 2016
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RE: FALSE: Creates record by given attributes only if table is empty

Dino’s comment was almost certainly due to a misunderstanding of the API, a mistake I made myself the first time I used it, and one I’ve witnessed multiple others make as well.

The fact that this method takes an attributes parameter leads one to think the passed params are the criteria for the selection. At first glance it would appear it would be used like this:

User.first_or_create(email: 'derek@somwhere.com')

Where in reality this would grab the “first” record (say w/ email “john@smith.com”), and change its email to “derek@somwhere.com”, a fairly surprising action that doesn’t obviously fail, leading to some pretty subtle bugs.

In reality it should be used like this:

User.where(email: 'derek@somwhere.com').first_or_create

And the attributes param. isn’t used in 99% of use cases. (If at all - the provision for the block that executes only on create fully duplicates what the attributes parameter can do in a much more obvious way.)

IMHO this is simply a bad API that one just needs to be aware of. But it’s unfair to knock dino for what’s likely a highly common misreading.

March 4, 2016 - (>= v4.0.2)
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FALSE: Creates record by given attributes only if table is empty

I very much doubt that dino’s comment was ever correct, but it certainly isn’t correct now. The behavior liantics describes is correct.

February 14, 2016
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Text values for enum

There is way to have text values for enum. It is useful to have localized select options and latin values in database. 1) User model: enum kind: { ‘текст’=>‘text’, ‘изображение’=>‘picture’, ‘звук’=>‘audio’, ‘видео’=>‘video’ } 2) Edit view: <%= select_tag ‘user[kind]’, options_for_select(User.kinds, @user.kind) %>

February 12, 2016
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group on hash

def group_by_hash hash, value
  hash.group_by do |k,v| 
    v > value ? "Big" : "Small"
  end
end

marks = {"Chair" => 30, "Table" => 40, "Bed" => 60, "stool" => 20}
group_by_hash(marks, 30)
February 12, 2016 - (<= v4.2.1)
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Generate Token

For generate a token, make this:

def generate_token
  self.token = SecureRandom.uuid
end

SecureRandom return a number random and the uuid make this number be unique. This a good idea for use in shopping cart, for example

February 4, 2016
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Fetch with default value

You can specify default value as a fail-back if a hash doesn’t have a given key.

{a: false}.fetch(:b, true)
=> true
{a: false}.fetch(:a, true)
=> false

It is useful especially in the case where you want to set default value for a method.

def initialize(args)
  @foo = args.fetch(:foo, 1)
  @bar = args.fetch(:bar, 2)

  # This can take over the following way.
  # `@bar = args[:bar] || 2` 
  # => @bar is overwritten if caller specifies nil for :bar!
end
February 3, 2016 - (v4.0.2 - v4.2.1)
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Params of conditions

You can pass an proc for o callback with the conditions

before_action :initial_value, only: [:index, :show], unless: -> { @foo.nil? }

before_action :initial_value, only: [:index, :show], if: -> { @foo }
February 3, 2016 - (v4.0.2 - v4.2.1)
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Params of conditions

You can pass an proc for o callback with the conditions

after_action :initial_value, only: [:index, :show], unless: -> { @foo.nil? }

after_action :initial_value, only: [:index, :show], if: -> { @foo }
January 28, 2016
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the method to make 'day' disappear.

If you wanna show “year” and “month” only, you can use “order” to do it:

select_date(Date.current, order: [:year, :month])

That’s it.

January 22, 2016
3 thanks

Creates record by given attributes only if table is empty

This method first searches the table for ANY FIRST RECORD, not the one matching given attributes. If no record is found at all, it creates one using the specified attributes. This might be misunderstood in many cases.

January 22, 2016
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Errno::EEXIST

When Errno::EEXIST is raised, it indicates there are permission issues, rather than an existing item.