Caterpillar

This Ruby gem is a simple wrapper around the Caterpillar API. Caterpillar is a web service that allows you to convert html to pdf.

Installation

Add this line to your application's Gemfile:

gem 'caterpillar-ruby'

And then execute:

$ bundle

Or install it yourself as:

$ gem install caterpillar-ruby

Usage

Set the following attributes in you Ruby app:

Caterpillar.api_key = 'YOUR_CATERPILLAR_API_KEY' # required
Caterpillar.api_version = 'YOUR_API_VERSION' # optional, default: 'v1'
Caterpillar.base_uri = 'YOUR_API_BASE_URI' # optional, default: 'https://api.caterpillar.io'

For a Rails app you can execute:

$ rails generate caterpillar:install

or create an initializer config/initializers/caterpillar.rb:

Caterpillar.configure do |config|
  config.api_key = 'YOUR_CATERPILLAR_API_KEY'
end

Once set, you can create a PDF document by calling:

Caterpillar.create(source: content, grayscale: true, no_images: true)

You can also create test PDF documents by calling (header and footer options donot work in test mode):

Caterpillar.create(source: content, test: true)

The create call can also take a block, like so:

Caterpillar.create(source: content) do |file, response|
  # file is a tempfile holding the response body
  # response is the HTTParty response object
end

create will return an HTTParty response object, which will be the new file (or errors, if the request was not valid).

The only required parameter is:

• :source - a string containing the HTML or URL for creating the document

For a Rails app you can pass a view as source by converting it to an HTML string using render_to_string.

You might want to set other options in that hash:

Option	Type	Description
:copies	Number	Number of copies to print into the pdf
:grayscale	Boolean	PDF will be generated in grayscale
:margin_bottom	Number	Set the page bottom margin
:margin_left	Number	Set the page left margin (default 10mm)
:margin_right	Number	Set the page right margin (default 10mm)
:margin_top	Number	Set the page top margin
:orientation	String	Set orientation to Landscape or Portrait (default Portrait)
:page_size	String	Set paper size to: A4, Letter, etc. (default A4)
:background	Boolean	Do print background (default true)
:no_background	Boolean	Do not print background
:disable_external_links	Boolean	Do not make links to remote web pages
:enable_external_links	Boolean	Make links to remote web pages (default true)
:disable_forms	Boolean	Do not turn HTML form fields into pdf form fields (default true)
:enable_forms	Boolean	Turn HTML form fields into pdf form fields
:images	Boolean	Do load or print images (default true)
:no_images	Boolean	Do not load or print images
:disable_internal_links	Boolean	Do not make local links
:enable_internal_links	Boolean	Make local links (default true)
:disable_javascript	Boolean	Do not allow web pages to run javascript
:enable_javascript	Boolean	Do allow web pages to run javascript (default true)
:javascript_delay	Number	Wait some milliseconds for javascript finish (default 200)
:viewport_size	String	Set viewport size if you have custom scrollbars or css attribute overflow to emulate window size
:zoom	Number	Use this zoom factor (default 1)
:footer_center	Number/String	Centered footer text
:footer_font_name	Number/String	Set footer font name (default Arial)
:footer_font_size	Number/String	Set footer font size (default 12)
:footer_html	String	Adds a html footer
:footer_left	Number/String	Left aligned footer text
:footer_line	Boolean	Display line above the footer
:no_footer_line	Boolean	Do not display line above the footer (default true)
:footer_right	Number/String	Right aligned footer text
:footer_spacing	Number	Spacing between footer and content in mm (default 0)
:header_center	Number/String	Centered header text
:header_font_name	Number/String	Set header font name (default Arial)
:header_font_size	Number/String	Set header font size (default 12)
:header_html	String	Adds a html header
:header_left	Number/String	Left aligned header text
:header_line	Boolean	Display line below the header
:no_header_line	Boolean	Do not display line below the header (default true)
:header_right	Number/String	Right aligned header text
:header_spacing	Number	Spacing between header and content in mm (default 0)
:password_protect	Hash	Refer next section for more details

Password Protect

You can password protect PDF using AES 256, AES 128, RC4 (128 & 40) encryption algorithms supported by Adobe Reader.

To encrypt PDF you need to pass :password_protect hash in the create method call along with the following required parameters:

• :password - a string containing the secret password which will be further used to unlock the PDF
• :key_length - a number which defines the encryption algorithm to be used. Values can be 40, 128 and 256 only.

You might want to set other options for each encryption algorithm inside :restrictions hash:

Key Length: 40

Option	Value	Description
:print	'y', 'n'	Determines whether or not to allow printing.
:modify	'y', 'n'	Determines whether or not to allow document modification.
:extract	'y', 'n'	Determines whether or not to allow text/image extraction.
:annotate	'y', 'n'	Determines whether or not to allow comments and form fill-in and signing.

Key Length: 128

Option	Value	Description
:print	'full', 'low', 'none'	full: allow full printing. low: allow low-resolution printing only. none: disallow printing.
:modify	'all', 'annotate', 'form', 'assembly', 'none'	all: allow full document modification. annotate: allow comment authoring and form operations. form: allow form field fill-in and signing. assembly: allow document assembly only. none: allow no modifications.
:extract	'y', 'n'	Determines whether or not to allow text/image extraction.
:use_aes	'y', 'n'	AES encryption will be used instead of RC4 encryption.
:accessibility	'y', 'n'	Determines whether or not to allow accessibility to visually impaired.

Key Length: 256

Option	Value	Description
:print	'full', 'low', 'none'	full: allow full printing. low: allow low-resolution printing only. none: disallow printing.
:modify	'all', 'annotate', 'form', 'assembly', 'none'	all: allow full document modification. annotate: allow comment authoring and form operations. form: allow form field fill-in and signing. assembly: allow document assembly only. none: allow no modifications.
:extract	'y', 'n'	Determines whether or not to allow text/image extraction.
:accessibility	'y', 'n'	Determines whether or not to allow accessibility to visually impaired.

Example:

Caterpillar.create(
    source: content,
    password_protect: {
        password: 'YOUR_PASSWORD_HERE',
        key_length: 128,
        restrictions: {
            print: 'low',
            use_aes: 'y'
        }
    }
)

Meta

Maintained by KeepWorks

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/keepworks/caterpillar.

License

The gem is available as open source under the terms of the MIT License.