Prompt Title: Secure PDF Library System.

Great! Let's get started.

To build a secure web app with Ruby on Rails that allows users to read and download PDF articles, we will need to consider a few important factors such as authentication, authorization, and data encryption.

Firstly, we will need to create a user authentication system that ensures that only authorized users can access the system. We can use Devise, a popular Ruby gem for authentication, to handle user registration, login, and logout. Devise provides features like email confirmation, password recovery, and session management out-of-the-box, which makes it easy to implement secure authentication in our app.

Next, we will need to implement authorization to ensure that only users with appropriate permissions can access the PDF library system. We can use the CanCanCan gem to define user roles and permissions, and restrict access to certain actions or pages based on the user's role.

Now let's focus on the PDF library system itself. We can use the Prawn gem, which is a Ruby PDF generation library, to create PDF documents dynamically. We can store the PDF files in a secure location on the server, and provide links to the files on the website.

To allow users to search for articles, we can implement a basic and advanced search filter using the Ransack gem. Ransack provides powerful search features and allows users to search for articles based on various criteria such as title, author, date, and keywords.

To ensure data security, we can encrypt the PDF files using a symmetric encryption algorithm such as AES. We can use the OpenSSL library to implement the encryption and decryption functions, and store the encrypted files on the server.

Finally, to ensure the app's overall security, we will need to follow best practices for web development such as using strong passwords, protecting against cross-site scripting (XSS) and SQL injection attacks, and keeping the software and libraries up-to-date with security patches.

Here's a basic outline of the Ruby on Rails application architecture for this PDF library system:

• Use Devise for user authentication
• Use CanCanCan for user authorization
• Use Prawn for PDF generation
• Store encrypted PDF files on the server
• Use Ransack for basic and advanced search filters
• Implement additional security measures to prevent attacks

I hope this helps! Let me know if you have any questions or need any further assistance.

Thank you for letting me know! In that case, we can simplify the application architecture by removing the authorization step.

Here's a revised application architecture for the PDF library system:

• Use Devise for user authentication
• Use Prawn for PDF generation
• Store PDF files on the server
• Use Ransack for basic and advanced search filters
• Implement additional security measures to prevent attacks

With this revised architecture, users will be able to view and download PDFs without any special authorization. We can use the Prawn gem to generate the PDFs on-the-fly and store them on the server. The Ransack gem can be used to provide basic and advanced search filters.

We'll still need to ensure that the application is secure by implementing measures such as strong password policies, protection against XSS and SQL injection attacks, and keeping the software and libraries up-to-date with security patches.

Let me know if you have any questions or need any further assistance.

Thank you for letting me know! In that case, we can further simplify the application architecture by removing the authentication step.

Here's a revised application architecture for the PDF library system:

• Use Prawn for PDF generation
• Store PDF files on the server
• Use Ransack for basic and advanced search filters
• Implement additional security measures to prevent attacks

With this architecture, anyone will be able to view and download PDFs without any authentication. The Prawn gem can be used to generate the PDFs on-the-fly and store them on the server. The Ransack gem can be used to provide basic and advanced search filters.

We'll still need to ensure that the application is secure by implementing measures such as strong password policies, protection against XSS and SQL injection attacks, and keeping the software and libraries up-to-date with security patches.

Let me know if you have any questions or need any further assistance.

Sure, I'll provide a step-by-step guide and the necessary code snippets to implement the PDF library system.

Step 1: Setting up the Rails application

Let's create a new Rails application using the following command:

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rails new pdf_library_system

This will generate a new Rails application in a directory named pdf_library_system.

Step 2: Adding Prawn and Ransack to the Gemfile

Add the following lines to the Gemfile:

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gem 'prawn'
gem 'ransack'

Then run the following command to install the gems:

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bundle install

Step 3: Generating the PDFs

We'll use the Prawn gem to generate the PDFs on-the-fly. Let's create a new controller called ArticlesController that will be responsible for generating the PDFs. Here's the code for the controller:

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class ArticlesController < ApplicationController
  def show
    article = Article.find(params[:id])

    respond_to do |format|
      format.pdf do
        pdf = Prawn::Document.new
        pdf.text article.title
        pdf.text article.author
        pdf.text article.body
        send_data pdf.render, filename: "#{article.title}.pdf", type: 'application/pdf', disposition: 'inline'
      end
    end
  end
end

This code generates a PDF document using the Prawn::Document class and sends it to the user's browser using the send_data method. The show action is designed to handle PDF requests, and it finds the article by the ID passed in the URL.

Step 4: Uploading the PDFs

We'll need to store the PDF files on the server so that they can be downloaded later. Let's create a new model called Article to represent the PDF files. Here's the code for the model:

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class Article < ApplicationRecord
  has_one_attached :pdf_file
end

This code adds a pdf_file attachment to the Article model using Active Storage.

To upload a PDF file, we'll need to create a form that allows the user to upload the file. Here's the code for the form:

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<%= form_with(model: @article, local: true) do |form| %>
  <%= form.label :title %>
  <%= form.text_field :title %>

  <%= form.label :author %>
  <%= form.text_field :author %>

  <%= form.label :body %>
  <%= form.text_area :body %>

  <%= form.label :pdf_file %>
  <%= form.file_field :pdf_file %>

  <%= form.submit 'Create Article' %>
<% end %>

This code creates a form that allows the user to enter the article title, author, body, and upload a PDF file.

To handle the form submission, we'll need to create a new controller action called create that saves the uploaded PDF file to the server. Here's the code for the create action:

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class ArticlesController < ApplicationController
  def create
    @article = Article.new(article_params)

    if @article.save
      redirect_to @article, notice: 'Article was successfully created.'
    else
      render :new
    end
  end

  private

  def article_params
    params.require(:article).permit(:title, :author, :body, :pdf_file)
  end
end

This code creates a new Article object with the attributes submitted through the form, and then saves the pdf_file attachment to the server using Active Storage.

Step 5: Downloading the PDFs

We

Step 5: Downloading the PDFs (continued)

We'll need to create a page that displays a list of all the articles, and allows the user to download the PDF file. Here's the code for the index action in the ArticlesController:

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class ArticlesController < ApplicationController
  def index
    @articles = Article.all
  end

  # ...
end

This code retrieves all the Article objects from the database and assigns them to an instance variable.

Next, we'll create a view that displays the list of articles and provides a link to download the PDF file. Here's the code for the view:

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<h1>Articles</h1>

<table>
  <thead>
    <tr>
      <th>Title</th>
      <th>Author</th>
      <th>Download PDF</th>
    </tr>
  </thead>
  <tbody>
    <% @articles.each do |article| %>
      <tr>
        <td><%= article.title %></td>
        <td><%= article.author %></td>
        <td><%= link_to 'Download', article_path(article, format: :pdf) %></td>
      </tr>
    <% end %>
  </tbody>
</table>

This code creates a table that displays the title and author of each article, and provides a link to download the PDF file. The link includes the format: :pdf option, which tells Rails to generate a PDF file instead of an HTML page.

Step 6: Adding basic and advanced search filters

We'll use the Ransack gem to provide basic and advanced search filters for the articles. Let's update the index action in the ArticlesController to filter the articles based on the search parameters:

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class ArticlesController < ApplicationController
  def index
    @q = Article.ransack(params[:q])
    @articles = @q.result(distinct: true)
  end

  # ...
end

This code uses Ransack to generate a new search object (@q) based on the search parameters submitted through the form. It then applies the search to the Article objects and assigns the result to the @articles variable.

Next, we'll create a form that allows the user to submit search parameters. Here's the code for the form:

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<%= search_form_for @q do |f| %>
  <%= f.label :title_cont %>
  <%= f.search_field :title_cont %>

  <%= f.label :author_cont %>
  <%= f.search_field :author_cont %>

  <%= f.label :body_cont %>
  <%= f.search_field :body_cont %>

  <%= f.submit 'Search' %>
<% end %>

This code creates a search form that allows the user to enter search parameters for the article title, author, and body.

Step 7: Additional security measures

Finally, we'll implement additional security measures to prevent attacks. Here are some best practices that we can follow:

• Use strong passwords and secure password storage techniques
• Protect against XSS attacks by sanitizing user input and using Rails' built-in security features such as h and sanitize
• Protect against SQL injection attacks by using ActiveRecord's built-in query sanitization
• Keep the software and libraries up-to-date with security patches

Here's an example of how to use the Rails' built-in sanitize method to protect against XSS attacks:

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class ArticlesController < ApplicationController
  def create
    @article = Article.new(article_params)

    if @article.save
      redirect_to @article, notice: 'Article was

successfully created.' else render :new end end

private

def article_params params.require(:article).permit(:title, :author, :body) .transform_values { |v| sanitize(v) } end end

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This code uses the `sanitize` method to sanitize the `title`, `author`, and `body` parameters before saving them to the database. This helps protect against XSS attacks.

Conclusion:

This is a basic implementation of a PDF library system using Ruby on Rails. Of course, there are many other features and security measures that could be added depending on the specific needs of the application. However, this should provide a good starting point for building a secure and functional system.

Good point, setting up the database is a crucial step for any Rails application. Here's how to set up the database for our PDF library system:

Step 1: Create the database

Assuming you have already installed PostgreSQL, you can create a new database by running the following command in your terminal:

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createdb pdf_library_development

This command will create a new database called pdf_library_development that we'll use for the development environment. You can also create databases for other environments like test and production.

Step 2: Define the database schema

We'll use Rails migrations to define the database schema. Here's the migration for creating the articles table:

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class CreateArticles < ActiveRecord::Migration[6.1]
  def change
    create_table :articles do |t|
      t.string :title
      t.string :author
      t.text :body
      t.timestamps
    end
  end
end

This migration creates a new table called articles with three columns (title, author, and body) and timestamps for tracking when the record was created and updated.

To run the migration, simply run the following command in your terminal:

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rails db:migrate

This will create the articles table in the pdf_library_development database.

Step 3: Seed the database

To populate the database with some sample data, we can use a Rails seed file. Here's an example of how to seed the database with some articles:

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# db/seeds.rb

10.times do
  Article.create(
    title: Faker::Lorem.sentence,
    author: Faker::Name.name,
    body: Faker::Lorem.paragraphs.join("\n\n")
  )
end

This code uses the Faker gem to generate some random article titles, authors, and bodies, and creates new Article objects with the generated data.

To run the seed file, simply run the following command in your terminal:

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rails db:seed

This will insert the sample data into the articles table in the pdf_library_development database.

That's it! Your database should now be set up and ready to go.