Docinfo Processor

Docinfo Processors are primarily targeted for the HTML and DocBook5 target format. A Docinfo Processor basically allows to add content to the HTML header or at the end of the HTML body. For the DocBook5 target format a Docinfo Processor can add content to the info element or at the very end of the document, just before the closing tag of the root element.

Our example Docinfo Processor will add a robots meta tag to the head of the HTML output:

A Docinfo Processor that adds a robots meta tag

import org.asciidoctor.ast.Document;
import org.asciidoctor.extension.DocinfoProcessor;
import org.asciidoctor.extension.Location;
import org.asciidoctor.extension.LocationType;

@Location(LocationType.HEADER)                                    (1)
public class RobotsDocinfoProcessor extends DocinfoProcessor {    (2)

    @Override
    public String process(Document document) {
        return "<meta name=\"robots\" content=\"index,follow\">"; (3)
    }
}

1	The Location annotation defines whether the result of this Docinfo Processor should be added to the header or the footer of the document. Content is added to the header via `LocationType.HEADER` and to the footer via `LocationType.FOOTER`.
2	Every Docinfo Processor must extend the class `DocinfoProcessor` and implement the `process()` method.
3	Our example implementation simply returns the meta tag as a string.

For the example to work make sure:

header_footer option is not set to false, otherwise these will not be added to the document.
safe mode option is set to at least SECURE

Options configuration example

Options.builder()
        .headerFooter(true)
        .safe(SafeMode.SERVER)
        .build();