Exporter Extensions

Assembler is a library responsible for merging AsciiDoc-based pages together to form assembly files. On it’s own, it doesn’t convert this content to an export format. That’s where the exporter extensions come in.

An exporter extension uses Assembler to handle the page merging, then converts the assembly files to the target format using an external command (e.g., asciidoctor-pdf). The way Assembler is designed, that external command doesn’t have to know anything about Antora. As far as it’s concerned, it’s just converting a single AsciiDoc document to another format.

Built-in exporters

Assembler provides the following exporter extensions:

@antora/pdf-extension: Converts assembly files to PDF, using Asciidoctor PDF by default.

Relationship to Assembler

Assembler is installed automatically when an exporter extension, such as the Antora PDF Extension, is installed. Assembler is a core library for writing Antora extensions that combine content from multiple pages into a single output file.

Assembler works by building self-contained AsciiDoc documents that consist of AsciiDoc merged from the pages listed in the navigation tree of each component version. An assembly is Antora-agnostic, which means it can be converted by any AsciiDoc converter, such as Asciidoctor PDF.

Assembler invokes the specified callback to convert these documents to an output format. In the case of the PDF extension, Assembler uses Asciidoctor PDF’s CLI (asciidoctor-pdf) to convert the documents to PDF. If publishing is enabled (the default), Assembler pushes the converted files back into the content catalog as exports to be published alongside the other files in the site.