Load and Convert Files Using the API

This page explains how to load and convert AsciiDoc-formatted files using the API.

Load an AsciiDoc file

When you load AsciiDoc using the API, you’re telling Asciidoctor to parse the document (down to the block level) and return an Asciidoctor::Document object. This object contains the full block structure of the AsciiDoc document.

Loading a document currently does not parse the inline content. That processing is deferred until the parsed document is converted.

Let’s assume we’re working with the following AsciiDoc document:

Example 1. document.adoc
= Document Title

The main content.

To parse this source file into an Asciidoctor::Document object, use the following API call:

doc = Asciidoctor.load_file 'document.adoc', safe: :safe

Using the object assigned to the doc variable, you can get information about the document, such as the document title.

puts doc.doctitle
# => "Document Title"

You can also inspect all the document attributes:

pp doc.attributes

Going deeper, you can find blocks in the document, such as all the paragraph blocks, using the find_by method:

puts doc.find_by context: :paragraph
# => #<Asciidoctor::Block@1001 {context: :paragraph, content_model: :simple, style: nil, lines: 1}>

However, if you’re only interested in converting the AsciiDoc source when using the API, then it’s better to use the convert_file entrypoint.

Convert an AsciiDoc file

When you convert AsciiDoc using the API, you’re telling Asciidoctor to parse and convert the document to the output format determined by the specified backend. If you don’t specify a backend, like with the CLI, Asciidoctor will produce HTML.

Let’s again assume we’re working with the following AsciiDoc document:

Example 2. document.adoc
= Document Title

The main content.

To convert this source file to HTML5, use the following API call:

Asciidoctor.convert_file 'document.adoc', safe: :safe

The command will output HTML to the file my-sample.html in the same directory. If you want Asciidoctor to output to a different file, you can specify it using the :to_file option:

Asciidoctor.convert_file 'document.adoc', safe: :safe, to_file: 'out.html'

You can convert the file to DocBook by setting the :backend option to 'docbook':

Asciidoctor.convert_file 'document.adoc', safe: :safe, backend: 'docbook'

In this case, Asciidoctor will output DocBook to the file my-sample.xml in the same directory. As before, you can use the :to_file option to control the output file.

Asciidoctor.convert_file 'document.adoc', safe: :safe, backend: 'docbook', to_file: 'out.html'

That covers the basics of loading and converting AsciiDoc using the API.