Implement parsing of the <id> element in OPDS 1.x feeds

[x0000ff]

The OPDS 1.x is based on Atom, and Atom’s Feed must contain an id tag. I found it useful to parse the <id> tag.

1.1. Introduction
The Open Publication Distribution System (OPDS) Catalog format is a syndication format for electronic publications based on Atom [RFC4287] and HTTP [RFC2616].

atom:feed elements MUST contain exactly one atom:id element.

I left it as optional to avoid breaking compatibility with existing clients.

• ✅ Tests are updated

[mickael-menu]

Looking good, thank you. Please note that we will revamp the OPDS models next year, and this kind of information will be available as part of the extension models for metadata instead of a native property.

[x0000ff]

Thanks a lot for merging my PRs, @mickael-menu!

Looking good, thank you. Please note that we will revamp the OPDS models next year, and this kind of information will be available as part of the extension models for metadata instead of a native property.

Can I find this written somewhere, such as in the issues? I’m about to submit another PR and don’t want to waste your time reviewing something that isn’t aligned with future plans.

[mickael-menu]

It's not documented anywhere but it should look like the otherMetadata in the Publication's Metadata models:

swift-toolkit/Sources/Shared/Publication/Metadata.swift

Lines 64 to 71 in 8875768

	/// Additional properties for extensions.
	public var otherMetadata: JSONDictionary.Wrapped {
	get { otherMetadataJSON.json }
	set { otherMetadataJSON = JSONDictionary(newValue) ?? JSONDictionary() }
	}
	// Trick to keep the struct equatable despite [String: Any]
	private var otherMetadataJSON: JSONDictionary

and the metadata keys will be expanded with the XML namespace, similarly to this with EPUB:

swift-toolkit/Tests/StreamerTests/Parser/EPUB/EPUBManifestParserTests.swift

Lines 48 to 67 in 8875768

	otherMetadata: [
	"http://purl.org/dc/terms/source": [
	"Feedbooks",
	[
	"@value": "Web",
	"http://my.url/#scheme": "http",
	],
	"Internet",
	] as [Any],
	"http://purl.org/dc/terms/rights": "Public Domain",
	"http://idpf.org/epub/vocab/package/#type": "article",
	"http://my.url/#customProperty": [
	"@value": "Custom property",
	"http://my.url/#refine1": "Refine 1",
	"http://my.url/#refine2": "Refine 2",
	],
	"http://purl.org/dc/terms/format": "application/epub+zip",
	"http://www.idpf.org/vocab/rendition/#flow": "scrolled-doc",
	"http://www.idpf.org/vocab/rendition/#orientation": "landscape",
	"http://www.idpf.org/vocab/rendition/#spread": "both",