Scala.js cannot load XML

[darkfrog26]

I'm attempting to parse XML from a String in Scala.js and I get this compile-time error:

[error] Referring to non-existent class javax.xml.parsers.SAXParserFactory$
[error]   called from scala.xml.factory.XMLLoader.parser()javax.xml.parsers.SAXParser
[error]   called from scala.xml.XML$.parser()javax.xml.parsers.SAXParser
[error]   called from scala.xml.factory.XMLLoader.loadString(java.lang.String)scala.xml.Node
[error]   called from scala.xml.XML$.loadString(java.lang.String)scala.xml.Node

[ashawley]

The Java parser that the scala-xml library depends on isn't available from Scala.js at run time.

Note that if it's a literal string you're trying to parse, you should be able to use Scala's XML syntax to just declare your XML literal.

[SethTisue]

is this a feature an interested contributor could add...? (by substituting some JS thing for SAX?)

[darkfrog26]

@ashawley and if it's not a String literal?

[SethTisue]

fwiw, at #109 (comment) , @OlivierBlanvillain suggested using fastparse (https://github.com/lihaoyi/fastparse/blob/master/scalaparse/shared/src/main/scala/scalaparse/Xml.scala)

[SethTisue]

also relevant: #194, which suggests adding getting-started doc for Scala.js that would presumably cover this

[darkfrog26]

I don't mind using scalaparse.Xml, but honestly have no idea how to actually use it in this context.

[ashawley]

Perhaps, DOMParser could be used to handle XML strings in Javascript-land? We'd have to write a new "factory" to translate the Document to scala-xml objects.

[ashawley]

Outside of scala.xml.factory.XMLLoader, the only other way to parse XML strings is the scala.xml.parsing.ConstructingParser. It's a little clunky, so I'm less than inclined to recommend it. It also has tiny bit of Java in it, so just enough to make Scala.js barf.

[hansdejong]

You might try this. (And be the first, I guess, it's tested once in scala.js):
https://github.com/hansdejong/xml-parser-scalajs

[eed3si9n]

Coursier does something https://github.com/coursier/coursier/blob/9d0b191f0d97e055384ea94f850b98fb501a8cb1/modules/core/js/src/main/scala/coursier/core/compatibility/package.scala, but I suspect it's not aware of the XML namespace - coursier/coursier#1821

[odenzo]

I am working on doing this, with scalajs-dom, but running into a few issues. Just thought I would mention it here, opening separate issues,

[armanbilge]

👍 I understand that @odenzo's solution uses scala-js-dom. This would work in browsers only (not Node.js), so IMO it would make most sense as a separate module within this repo. scala-js-dom is very nearly a stdlib for the Scala.js ecosystem, and I can vouch for its stability as a maintainer, so I think it would be an acceptable dependency to take on here.

Edit: btw, I'd be happy to review such a PR.

[phdoerfler]

Also see xmls: https://index.scala-lang.org/flowtick/xmls/xmls/0.1.11?target=_2.13

[armanbilge]

FYI fs2-data has just released an integration with scala-xml including a pure Scala, streaming XML parser. Therefore it is fully supported on JVM and JS!

• https://github.com/satabin/fs2-data/releases/tag/v1.4.0
• https://index.scala-lang.org/satabin/fs2-data/artifacts/fs2-data-xml-scala