--infer-page-count does not work

[nicolascyr]

With the current (latest) version, using --infer-page-count flag on the manifest does not work.

In previous versions, it would extract a number of pages, which was visible under metadata.numberOfPages. That key is no loger returned.

Command used: manifest --infer-a11y=split --infer-page-count path/to/file.epub.

[chocolatkey]

@nicolascyr I figured out what the issue is, obvious in hindsight. Because we are now removing all the services in order to not have unnecessary/invalid links to them in the manifest output, we no longer have the positions service available, which is used to calculate the page count:

pub, err := streamer.New(streamer.Config{
	InferA11yMetadata:  streamer.InferA11yMetadata(inferA11yFlag),
	InferPageCount:     inferPageCountFlag,
	InferIgnoredImages: ignoreImagesHashes,
	OnCreatePublication: func(builder *pub.Builder) error {
		builder.ServicesBuilder.RemoveExcept()
		return nil
	},
})

@mickael-menu (or @HadrienGardeur) Do you have any suggestions for how the API should be adjusted to account for this problem? Basically, we want to not output the positions link in the manifest, but we do want to have access to the positions service for things like the page count.

[mickael-menu]

Here's an idea: Every service should take a parameter to indicate whether the links must be added to the manifest. This is passed from the Streamer / PublicationOpener down to the PublicationParser instances. The default behavior is to not add the links, as it's only useful for the server.

Another possibility but needing more work: As it's only needed for the server, we could decouple the part that adds the links in the manifest and convert the service results into JSON responses from the Service implementations and add it as a new layer in the server package. It would go over the services available in the publication, and for known service interfaces, generate new links and an adapter layer to generate the JSON.

What do you think?

[chocolatkey]

@mickael-menu Thanks for the suggestions. I've taken an approach similar to your first idea, but not through PublicationParser. See PR

[chocolatkey]

mistaken auto-close