Saxon » SaxonJS

Thanks for the example and additional details, I understand better what you are attempting, and hoping to achieve, now.

Yes, I'm afraid this is currently beyond the capabilities of the SaxonJS HTTP client (i.e. using ixsl:schedule-action/@http-request in SaxonJS 2). As it stands, the body of a request must be an XDM type (e.g. a document node for XML and HTML media types, or a string for text/plain, etc). We do not handle general JavaScript objects - even if they are objects that the underlying JavaScript HTTP API (which SaxonJS uses internally) could handle, e.g. as you say, XMLHttpRequest accepts File, Blob, etc. (and these are also accepted by the Fetch API which will be used in SaxonJS 3).

I'd say this is because rather than being "a wrapper for XMLHttpRequest", the design of the SaxonJS HTTP client was based on the EXPath HTTP Client module, which (understandably) doesn't really consider non-XDM items.

But I agree it would be a good idea to extend the SaxonJS HTTP client API to allow other kinds of JavaScript objects for request and response bodies, as permitted by the underlying JavaScript API. This was not something I had previously considered, because I didn't really understand the use case; but with some small API design and implementation changes it would be possible, and it is worth looking into.