is a chapter automatically registered if it appears in a book registration as a content item given it has a doi_data composite?
Yes, <content_item> contains the metadata for a given chapter along with its DOI and resolution URL which are nested inside its <doi_data> element.
if so it that the only way to register chapters via xml/json file upload?
XML metadata deposits are the only way to register any content, regardless of its type. We don’t support metadata deposits in JSON.
However, if you’re unable to create XML in the required format, you can use our Web Deposit Form to manually enter the metadata. The form will transform the metadata you enter into Crossref XML and automatically submit it.
Broadly speaking, to register a DOI for a book on the web deposit form, use the following steps:
Select the Book data type
Enter the Book-level on the first page of the form. At minimum this includes Book type, title, DOI, URL, Publisher, ISBN, and at least one (print or online) publication year
Select ‘Add Chapters’
On the second page of the form, enter the metadata for your first chapter (chapter title, authors, page numbers if available), the chapter DOI URL
Click ‘Add Another Chapter’
Continue to enter article metadata, DOIs, and URLs until you’ve entered all chapters for the given book.
Enter your username and password and click Login
Enter your email address and click ‘Deposit’
If you don’t want to register a separate DOI for each book chapter, you can skip steps 3 through 6.