Issue 695 Support empty manifest URLs when pulling forms

[ggalmazor]

Closes #695

What has been done to verify that this works as intended?

On Onadata

• Create an account at https://odk.ona.io/
• Upload the form pizza_questionnaire.xlsx

On Briefcase

• Configure the aggregate server with https://odk.ona.io/{username} (and your Ona credentials)
• Pull form

Why is this the best possible solution? Were any other approaches considered?

This is a small change to check that whatever value coming on the manifestUrl is an url. This will prevent trying to get manifests when the server reports a <manifest/> tag when downloading a blank form (which is the default behavior in Ona).

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

N/A

Does this change require updates to documentation? If so, please file an issue at https://github.com/opendatakit/docs/issues/new and include the link below.

No

[yanokwa]

Didn't test, but this LGTM. I would have done fd.getManifestUrl().isEmpty(). @dcbriccetti whatcha think?

[kkrawczyk123]

I have verified pr and master with steps described in #695 on Ubuntu, Mac and Windows and on all I have the same results, successfully pulled form in all tries. I wasn't able to reproduce the issue.
The only Failed try was when I copied ona url directly (extra / at the and of the url) but I had Authentication error then. Interesting was also then even if status was failed, the form was pulled to sd.
So pr is verified but I am not sure if additional testing won't be necessary.
cc @yanokwa

[dcbriccetti]

Didn't test, but this LGTM. I would have done fd.getManifestUrl().isEmpty(). @dcbriccetti whatcha think?

LGTM? I searched for it but doubt you’re saying “looks like garbage to me” because that’s not your style. :-)

isEmpty instead of isUrl? Yes, assuming no self-respecting RemoteFormDefinition would accept and save an invalid URL. It would be nice to assume that if one is set, it is valid.

[ggalmazor]

isEmpty instead of isUrl? Yes, assuming no self-respecting RemoteFormDefinition would accept and save an invalid URL. It would be nice to assume that if one is set, it is valid.

We don't have fancy value object features in place yet, but yes: RemoteFormDefinition should do that work for us and reject any offending value. Don't know when, but it will happen :)

[kkrawczyk123]

@opendatakit-bot unlabel "needs testing"