---
title: "Complete guide to generating PDFs with gem wicked_pdf"
author: "Yaroslav Shmarov"
date: "2021-05-24"
canonical_url: "https://blog.superails.com/gem-wicked-pdf"
markdown_url: "https://blog.superails.com/gem-wicked-pdf.md"
description: "wicked_pdf - gem to generate PDF from HTML. It is based on wkhtmltopdf technology."
tags: ["ruby","rails","ruby-on-rails","pdf","wicked_pdf"]
license: "GNU AGPL v3. Credit Yaroslav Shmarov and link the canonical URL."
video_url: "https://www.youtube.com/watch?v=tFvtwEmW-GE"
---
# Complete guide to generating PDFs with gem wicked_pdf
[wicked_pdf](https://github.com/mileszs/wicked_pdf) - gem to generate PDF from HTML.
It is based on `wkhtmltopdf` technology.
By the end of the post we will be able to:
1. Generate PDF from posts/index.html.erb
2. Style your PDFs
3. Customize your PDF generations
4. Generate PDF from posts/show.html.erb
5. Email a PDF as an attachment
6. It will work on heroku!
### Level 1. Basic installation
Gemfile
```ruby
gem 'wicked_pdf'
gem "wkhtmltopdf-binary", group: :development
gem "wkhtmltopdf-heroku", group: :production
```
```shell
# terminal
bundle
rails g wicked_pdf
echo > app/assets/stylesheets/pdf.scss
```
Now you can test the installation by running something like `wkhtmltopdf http://google.com google.pdf` to generate a pdf from this URL
To make the initializer work correctly on Heroku:
```ruby
# config/initializers/wicked_pdf.rb
WickedPdf.config ||= {}
WickedPdf.config.merge!({
layout: "pdf.html.erb",
})
```
Optionally you might need to add a mime type:
```ruby
# config/initializers/mime_types.rb
Mime::Type.register "application/pdf", :pdf
```
Create a separate HTML layout file for generating your PDFs:
```ruby
# app/views/layouts/pdf.html.erb
Appname
<%= csrf_meta_tags %>
<%= csp_meta_tag %>
<%= wicked_pdf_stylesheet_link_tag "pdf" %>
<%= yield %>
```
```ruby
# app/controllers/posts_controller.rb
def index
@posts = Post.all
respond_to do |format|
format.html
format.pdf do
# Rails 6
# render template: "posts/index.html.erb",
# pdf: "Posts: #{@posts.count}"
# Rails 7
# https://github.com/mileszs/wicked_pdf/issues/1005
render pdf: "Posts: #{@posts.count}", # filename
template: "hello/print_pdf",
formats: [:html],
disposition: :inline,
layout: 'pdf'
end
end
end
```
```ruby
# app/views/posts/index.html.erb
<%= link_to "PDF", posts_path(format: :pdf) %>
```
## Level 2. Style your PDFs
```css
/* app/assets/stylesheets/pdf.css */
body {
background-color: green;
}
table, th, td {
border: 1px solid black;
border-collapse: collapse;
}
table {
width: 100%;
}
```
You might want to REMOVE this line from application.css, so that `pdf.css` is not available anywhere else around the app:
```diff
- *= require_tree .
```
## Level 3. Customize your PDF generations
```ruby
# config/initializers/wicked_pdf.rb
WickedPdf.config ||= {}
WickedPdf.config.merge!({
layout: "pdf.html.erb",
orientation: "Landscape", # Portrait
page_size: "A4",
lowquality: true,
zoom: 1,
dpi: 75
})
```
[all options](https://github.com/mileszs/wicked_pdf#advanced-usage-with-all-available-options)
`disposition: 'attachment'` - by default download PDF
`disposition: 'inline'` - by default open PDF in browser
## Level 4. Generate PDF from posts/show.html.erb
```ruby
# app/controllers/posts_controller.rb
def show
respond_to do |format|
format.html
format.pdf do
# Rails 6:
# render template: "posts/show.html.erb",
# pdf: "Post ID: #{@post.id}"
# Rails 7:
render pdf: [@post.id, @post.name].join('-'),
template: "posts/show.html.erb",
formats: [:html],
disposition: :inline,
layout: 'pdf'
end
end
end
```
```ruby
# app/views/posts/index.html.erb
<%= link_to 'This post in PDF', post_path(post, format: :pdf) %>
```
You can also have a separate template for PDF-only like `render template: "pdfs/payment_received.html.erb"`
## Level 5. Email a PDF as an attachment
```shell
# terminal
rails g mailer PostMailer new_post
```
action to trigger the mailer (in any controller, for example posts#show):
```ruby
PostMailer.new_post.deliver_later
```
```ruby
# app/mailers/post_mailer.rb
# def pdf_attachment_method(post_id)
def new_post
# post = Post.find(post_id)
# @post = Post.first
post = Post.first
attachments["post_#{post.id}.pdf"] = WickedPdf.new.pdf_from_string(
render_to_string(template: 'posts/show.html.erb', layout: 'pdf.html.erb', pdf: 'filename')
)
mail to: "to@example.org"
end
end
```
& now if you navigate to the email preview path `rails/mailers/post_mailer/new_post`, you will see an attachment!
## That's it!
****
Part 2 of this post would potentially be wicked_pdf + AWS S3:
* save the PDF on AWS S3
* current post to have a relation to this PDF on AWS S3
* button to download the PDF from AWS S3