omit chunks on client HTTP error (like 404, 403,...)

[Alexander-Barth]

This PR resolves issue #131

[meggart]

Sorry for missing this issue, luckily you have found out already that currently we only assume a chunk is missing when the server returns 404, which IMO should be the correct code according to e.g. this list https://en.wikipedia.org/wiki/List_of_HTTP_status_codes and so far all providers I have worked with returned this for missing chunks.

All other codes might contain valuable information on why a request did not work, so I would also be hesitant to generally interpret these codes as missing.

I have just pushed a different solution and hope this would work as well for you. In this PR when 403 is returned accessing a chunk you would receive an informative error message and can add the error code to the list of allowed codes that are interpreted as missing chunks. Your example would look like this:

using Revise, Zarr

ds = Zarr.zopen("https://s3.waw3-1.cloudferro.com/mdl-arco-time/arco/MEDSEA_MULTIYEAR_PHY_006_004/med-cmcc-cur-rean-d_202012/timeChunked.zarr")

ds["uo"][:,:,1,1]
#Throws informative error

Zarr.missing_chunk_return_code!(ds.storage,403)
#alternative
Zarr.missing_chunk_return_code!(ds.storage,400:499)

ds["uo"][:,:,1,1]
#No error

[coveralls]

Pull Request Test Coverage Report for Build 7826978286

• 8 of 10 (80.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.3%) to 87.572%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/Storage/http.jl	8	10	80.0%

Files with Coverage Reduction	New Missed Lines	%
src/metadata.jl	1	88.66%

Totals
Change from base Build 6484107136:	0.3%
Covered Lines:	761
Relevant Lines:	869

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💛 - Coveralls

[Alexander-Barth]

Perfect, yes, your solution is better. For your information, I also informed the data provider (Copernicus Marine, https://marine.copernicus.eu/) about this issue, as the HTTP error 403 (permission denied) is indeed a bit confusing.