XML invalid. Error: `xmlns: URI sap.m is not absolute`

[DerZyklop]

OpenUI5 version: latest

URL (minimal example if possible): http://codebeautify.org/xmlvalidator/cbc16a04

What is the expected result? No error.

What happens instead? Error: xmlns: URI sap.m is not absolute

Any other information? The XML-specification tells me that i shouldn't use relative URI‘s.

OpenUI5 tells my to use a relative URI.

My related StackOverflow question: http://stackoverflow.com/questions/37168684/how-do-i-allow-non-absolute-uri-in-xmllint?noredirect=1#comment67354380_37168684

Now i can choose to

• turn my validator off (i don‘t want that), or
• i can hack the validator to be quiet about the relative URI (even though i know its right about that rule) or
• i rewrite all my files to valid XML e.g. xmlns:m="sap.m".

I‘d prefer the last solution, but it doesn‘t fit to any of the tutorials, walkthroughs, snippets i have seen over the past years.

Why does OpenUI5 want me to use a relative URI?

[codeworrior]

Because it's shorter and easier to memorise than the usual URIs.

That might look like a poor excuse, but AFAIK it is the only reason.

We originally had another approach in mind regarding namespaces in XMLViews:

• one namespace URI per library, declared in library metadata
• standard pattern for URIs that would allow to identify the library name form the URI (needed for automated loading of a library while parsing an XMLView)
• (optionally) declaration of tag names for each control in the library (defaulting to the unqualified control name)
• one schema (XSD) per library, bound to the library URI

The XMLTemplateProcessor still contains code to deal with that structure, but the shorter, relative namespaces (based on package names) had been accepted and spread so quickly, that we abandoned the original idea and even switched the schemas to the short names.

Making the validator happy makes sense, although I don't get how your 3rd variant would do the trick.

One straight forward fix would be to allow (and ignore) some pseudo-protocol, e.g. xmlns:m="ui5:sap.m". Adding that protocol would fulfil the requirements of the validator and would be only a small additional effort for the developer. Still, it would be easy to memorize.

But the problem is with all the code and tooling that expects the current structure of namespaces.

... thinking and trying your example again ..

Ah, okay. Now I get your point reg. your third possible fix. Strangely, not using the default alias already makes xmllint happy. But if I get the spec (and esp. the proposal in the deprecation ballot) right, relative URLs are not only deprecated for the namespace used with the default alias but for any namespace. If that's true, then the validators are still too lax.

But the good news is: as long as you only want to make xmllint happy, your 3rd approach is the best what you can achieve currently. And OpenUI5 does not prevent you from that, it's totally valid. Our samples and tutorials just use the default namespace alias as it is more convenient (less writing).

The true problem IMHO remains: the namespaces in our XMLViews look like relative URIs and that's a deprecated feature of XML. As discussed above, I see no 100% compatible solution for that.

[DerZyklop]

Thanks for the Information, @codeworrior.

FYI: I chose to add some lines to the config of my (and my coworkers) editor to allow the line xmlns="sap.m" since other ways would probably confuse every new coworker.

[DMihaylova]

@DerZyklop, should we consider this issue as completed then?