Reverse priorities for repeated properties in uniform format for opengraph

[ivanprado]

Some pages contain a duplicated definition of some properties like "og:image". See the following pages:
https://nerdist.com/article/star-wars-cast-reylo-episode-ix/
https://cleantechnica.com/2019/04/16/fukushimas-final-costs-will-approach-one-trillion-dollars-just-for-nuclear-disaster/

Extruct default behaviour seems to be keep the last one, meanwhile Facebook default behaviour seems to be keep the first one according to results at the developer tool (see https://developers.facebook.com/tools/debug/sharing/?q=https%3A%2F%2Fnerdist.com%2Farticle%2Fstar-wars-cast-reylo-episode-ix%2F for an example).

Extruct should mimic Facebook behaviour so this PR is reverting the priorities when flattening OpenGraph properties.

[ivanprado]

@lopuhin I see two Travis runs, one is succeeding and one is failing. I don't understand, what is the difference between both? (save for codecov)

[lopuhin]

@ivanprado this looks like a genuine failure on python 3.4 (likely due to dictionary iteration order or something similar). Not sure what does this "push" build represent, looking...

[lopuhin]

Aha this is the answer: https://stackoverflow.com/questions/41524861/travis-failed-push-but-passed-pr/41534988

[lopuhin]

So it could be that the failure is random, and one build was less lucky

[lopuhin]

Thanks @ivanprado that's a great catch! If I read the tests correctly, we don't test whether properties are reversed or not, right? If this is correct, could you please add such a test?

[codecov]

Codecov Report

Merging #115 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #115   +/-   ##
=======================================
  Coverage   87.63%   87.63%           
=======================================
  Files          11       11           
  Lines         469      469           
  Branches      101      101           
=======================================
  Hits          411      411           
  Misses         52       52           
  Partials        6        6

Impacted Files	Coverage Δ
extruct/uniform.py	93.22% <100%> (ø)	⬆️

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[ivanprado]

I see now the problem. It seems that PyRDFA is returning repeated properties in an inconsistent ordering.

[ivanprado]

@lopuhin thank you for your insights, very useful. It seems that the failure was caused because RDFa returns inconsistent ordering with duplicated properties. I have a filled an issue, created an xfail test and patched test so that is is not failing.

[lopuhin]

Great, thanks for taking care of this issue @ivanprado 👍

[lopuhin]

Great, thanks for the fix and for taking care of the test and extra issues that arose @ivanprado

[kmike]

I think this is not the only thing we need to do, as it breaks extraction on some websites. It seems we need to take first non-empty result. E.g. on https://www.triganostore.com/tente-de-camping-raclet-bora-4.html there are two og:description values, the first one is empty. https://developers.facebook.com/tools/debug/sharing/?q=https%3A%2F%2Fwww.triganostore.com%2Ftente-de-camping-raclet-bora-4.html shows that a non-empty one is extracted. Opened #117 for it.