Sablon

Is a document template processor for Word docx files. It leverages Word's built-in formatting and layouting capabilities to make template creation easy and efficient.

Note: Sablon is still in early development. Please report if you encounter any issues along the way.

Installation

Add this line to your application's Gemfile:

gem 'sablon'

Usage

require "sablon"
template = Sablon.template(File.expand_path("~/Desktop/template.docx"))
context = {
  title: "Fabulous Document",
  technologies: ["Ruby", "Markdown", "ODF"]
}
template.render_to_file File.expand_path("~/Desktop/output.docx"), context

Writing Templates

Sablon templates are normal Word documents (.docx) sprinkled with MailMerge fields to perform operations. The following section uses the notation «=title» to refer to Word MailMerge fields.

Content Insertion

The most basic operation is to insert content. The contents of a context variable can be inserted using a field like:

«=title»

It's also possible to call a method on a context object using:

«=post.title»

NOTE: The dot operator can also be used to perform a hash lookup. This means that it's not possible to call methods on a hash instance. Sablon will always try to make a lookup instead.

This works for chained method calls and nested hash lookup as well:

«=buyer.address.street»

WordProcessingML

Generally Sablon tries to reuse the formatting defined in the template. However, there are situations where more fine grained control is needed. Imagine you need to insert a body of text containing different formats. If you can't decide the format ahead of processing time (in the template) you can insert WordProcessingML directly.

It's enough to use a simply insertion operation in the template:

«=long_description»

To insert WordProcessingML prepare the context accordingly:

word_processing_ml = <<-XML.gsub("\n", "")
<w:p>
<w:r w:rsidRPr="00B97C39">
<w:rPr>
<w:b />
</w:rPr>
<w:t>this is bold text</w:t>
</w:r>
</w:p>
XML

context = {
  long_description: Sablon.content(:word_ml, word_processing_ml)
}
template.render_to_file File.expand_path("~/Desktop/output.docx"), context

IMPORTANT: This feature is very much experimental. Currently, the insertion will replace the containing paragraph. This means that other content in the same paragraph is discarded.

Markdown

Similar to WordProcessingML it's possible to use markdown while processing the tempalte. You don't need to modify your templates, a simple insertion operation is sufficient:

«=article.body»

To use Markdown insertion prepare the context like so:

markdown_body = <<-MD
This text can contain *additional formatting*
according to the **Markdown** specification.
MD
context = {
  article: { body: Sablon.content(:markdown, markdown_body) }
}
template.render_to_file File.expand_path("~/Desktop/output.docx"), context

Markdown insertion has built-in support for:

• Headers
• Paragraphs
• Emphasis and strong emphasis
• Hard line breaks
• Lists

For headings and lists to function properly it is necessary that the template defines specific styles. Headings use styles called Heading1, Heading2, etc. according to the header level. Ordered lists will use the style ListNumber and unordered lists use ListBullet. Nested lists are not supported. Normal text paragraphs use the style Paragraph. It's not necessary to have that style in the template. Word will fall back to using the Normal style.

IMPORTANT: This feature is very much experimental. Currently, the insertion will replace the containing paragraph. This means that other content in the same paragraph is discarded.

Conditionals

Sablon can render parts of the template conditonally based on the value of a context variable. Conditional fields are inserted around the content.

«technologies:if»
    ... arbitrary document markup ...
«technologies:endIf»

This will render the enclosed markup only if the expression is truthy. Note that nil, false and [] are considered falsy. Everything else is truthy.

For more complex conditionals you can use a predicate like so:

«body:if(present?)»
    ... arbitrary document markup ...
«body:endIf»

Loops

Loops repeat parts of the document.

«technologies:each(technology)»
    ... arbitrary document markup ...
    ... use `technology` to refer to the current item ...
«technologies:endEach»

Loops can be used to repeat table rows or list enumerations. The fields need to be placed in within table cells or enumeration items enclosing the rows or items to repeat. Have a look at the example template for more details.

Nesting

It is possible to nest loops and conditionals.

Executable

The sablon executable can be used to process templates on the command-line. The usage is as follows:

cat <context path>.json | sablon <template path> <output path>

If no <output path> is given, the document will be printed to stdout.

Have a look at this test for examples.

Examples

Using a Ruby script

There is a sample template in the repository, which illustrates the functionality of sablon:

Processing this template with some sample data yields the following output document. For more details, check out this test case.

Using the sablon executable

The executable test showcases the sablon executable.

The template

is rendered using a json context to provide the data. Following is the resulting output:

Contributing

1. Fork it ( https://github.com/senny/sablon/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Inspiration

These projects address a similar goal and inspired the work on Sablon:

• ruby-docx-templater
• docx_mailmerge