TILs - Fueling Curiosity, One Insight at a Time

At Codemancers, we believe every day is an opportunity to grow. This section is where our team shares bite-sized discoveries, technical breakthroughs and fascinating nuggets of wisdom we've stumbled upon in our work.

Published
Author
user-image
Syed Sibtain
System Analyst
Handling Image Uploads with Active Storage in Rails

Active Storage simplifies file uploads in Rails by attaching files to models.

Setup: Install Active Storage and run rails active_storage:install and rails db:migrate to create necessary tables.

Model Configuration: Use has_many_attached :images to allow multiple image uploads in our model. Example:

Ruby

class SomeModel < ApplicationRecord
  has_many_attached :images
end


Form: Ensure the form includes multipart: true and allows multiple file uploads with form.file_field :images, multiple: true.

Controller: Permit images in the strong parameters with images: []. Example:

Code

def some_params
  params.require(:some_model).permit(:note, images: [])
end


Migration: Remove old image columns if switching from direct storage to Active Storage.
#CU6U0R822 #activestorage #fileupload
Published
Author
user-image
Adithya Hebbar
System Analyst
To logout from Keycloak using the signOut function in NextAuth, you need to override the default behavior to ensure that the user is properly logged out from Keycloak as well. Here's how you can update your signOut function:

JavaScript

async signOut({ token }) {
  if (token.provider === "keycloak") {
    const issuerUrl = authOptions.providers.find((p) => p.id === "keycloak")
      .options!.issuer!;
    const logOutUrl = new URL(
      `${issuerUrl}/protocol/openid-connect/logout`
    );
    logOutUrl.searchParams.set("id_token_hint", token.id_token!);
    await fetch(logOutUrl);
  }
}


#keycloak #nextauth #nextjs #js
Published
Author
user-image
Giritharan
System Analyst
Delegating Permissions in Pundit:

I encountered a scenario where I needed to retrieve the scope of one policy and use it within another policy. Specifically, I wanted to delegate permissions from one policy to another.

To address this issue, I learned to use Pundit's methods for manually retrieving policies and scopes:
• Retrieving a Policy

Ruby

Pundit.policy(user, record)  # Returns nil if the policy does not exist
Pundit.policy!(user, record) # Raises an exception if the policy does not exist


• Retrieving a Policy Scope:

Code

Pundit.policy_scope(user, ModelClass)  # Returns nil if the policy scope does not exist
Pundit.policy_scope!(user, ModelClass) # Raises an exception if the policy scope does not exist


These methods allowed me to delegate permissions effectively by retrieving and applying the appropriate scopes and policies

#rails #pundit #pundit-policy #authorization
Published
Author
user-image
Syed Sibtain
System Analyst
Quick Tip: How can we open a PR from one repository to another repository

1. Create the branch in the current repo

Code

git checkout -b new-branch


2. Add the destination repository as a remote.

Code

git remote add destination https://github.com/username/destination-repo.git


3. Push the new branch to the destination repository

Code

git push destination new-branch


4. To check all the remote repositories added, we can do:

Code

git remote -v


Then, we create a PR in the destination repository from the new branch. This process effectively copies the changes from the original PR into a new PR in a different repository.

#github #git
Published
Author
user-image
Sujay
Rails templates accept any locals as arguments. However, starting from Rails 7.1, we can restrict which locals a template must accept using "Strict Locals".


Code

// _search.html.erb

<# locals: (:url, :field_name, :placeholder) -%>


We can also set default values

Code

<# locals: (placeholder: "Search", :url, :field_name) -%>


#rails
Published
Author
user-image
Adithya Hebbar
System Analyst
Detecting a mobile browser using regex.

You can use regex which returns a true or false value depending on whether or not the user is browsing with a mobile. WOW!

JavaScript

window.mobilecheck = function () {
  var mobileCheck = false;
  (function (a) {
    if (
      /(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(
        a
      ) ||
      /1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(
        a.substr(0, 4)
      )
    )
      mobileCheck = true;
  })(navigator.userAgent || navigator.vendor || window.opera);
  return mobileCheck;
};


I wonder who in the world wrote this snippet!!! :)

#javascript #browser
Published
Author
user-image
Syed Sibtain
System Analyst
Ransack adds several class methods to ActiveRecord::Base for managing search and sort capabilities. These methods allow us to define which attributes, associations, and scopes are accessible through Ransack queries, thus enhancing security and control.

ransackable_attributes: Defines which model attributes can be used in Ransack searches.
For example, only the order_number, status, and business_unit fields can be used in Ransack searches.

Code

def self.ransackable_attributes(auth_object = nil)
    %w[order_number status business_unit]
  end


ransackable_associations: Specifies which model associations are accessible for searching.
For examle, only the customer and vendor associations are allowed for searching.

Code

def self.ransackable_associations(auth_object = nil)
    %w[customer vendor]
  end


ransortable_attributes: Lists which attributes can be used for sorting results.
In this example, sorting is allowed only by order_number and created_at

Code

def self.ransortable_attributes(auth_object = nil)
    %w[order_number created_at]
  end


ransackable_scopes: Determines which custom scopes can be applied in searches.

#rails #ransack #search
Published
Author
user-image
Sujay
In postgres, current_setting() function is used to get the value of a configuration parameter.

Code

Set rls.tenant_id = 1;
SET

select current_setting('rls.tenant_id');
 current_setting
-----------------
 1
(1 row)


#postgres
Published
Author
user-image
Syed Sibtain
System Analyst
Namespaces in Rails help organize our application by grouping related controllers, models, and views into separate directories. Using namespaces with scaffolding keeps our codebase structured and manageable, especially in larger applications.

Example.
rails generate scaffold Order::PurchaseOrder order_number:string business_unit:string ...

This will create files under the Order namespace, including controllers, models, and views. This approach keeps our codebase structured, with Order as a namespace, making it easier to manage related components and maintain clarity in larger applications.


Ruby

app/
├── controllers/
│   └── order/
│       └── purchase_orders_controller.rb
├── models/
│   └── order/
│       └── purchase_order.rb
├── views/
│   └── order/
│       └── purchase_orders/
│           ├── _form.html.erb
│           ├── edit.html.erb
│           ├── index.html.erb
│           ├── new.html.erb
│


#rails #namespace
Published
Author
user-image
Vaibhav Yadav
Senior System Analyst
Cross browser regular expression issue:

Recently I came across a regular expression that would cause the page to crash on iphone Safari browser, the regex was for obscuring email.

Problematic Regex:

JavaScript

const obscuredEmail = email.replace(/(?<=.1}).(?=[^@]*@)/g, '*');


Fix:

Code

const obscuredEmail = email.replace(/(.)(?=.*@)/g, (match, p1, offset, string) => offset < string.indexOf('@') - 1 ? '*' : p1);


Lesson: Even a browser can cause browser compatibility issues.

#regex #browserCompatibility #safari #javascript

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