Tools for working with WACZs

[rebeccacremona]

See LIL-2863.

We recently started saving WACZs from Scoop instead of WARCs. We have long had some facility for users to download Perma Links' WARC files, both using the API and via the GUI. This PR adds identical functionality for WACZ files:

• wacz_size and wacz_download_url fields have been added to the Link and AuthenticatedLink serializers, so that any API route that includes information about Link objects will now return that info

• the warc_download_url field was updated: it will now be populated if a WARC or a WACZ is available for a given Perma Link, since the WARC can be extracted from the WACZ and served.

• a "Download WACZ" button has been added to the tray next to the "Download WARC" button, when a WACZ is available:

For compatibility, that "button" is a link pointing to a URL of the form https://perma.test:8000/B925-DU9S?type=wacz_download, following the pattern of the WARC "button", which is a URL of the form https://perma.test:8000/B925-DU9S?type=warc_download. (This pattern predates the existence of the /download API route.)

The only change in existing functionality: now, if a Perma Link redirects to another Perma Link (as with https://perma.cc/AAAA-AAAA), the file format will always be included in the query string of the redirected API request to download it (e.g. https://api.perma.cc/v1/archives/69AE-PWJB/download?file_format=warc).

[codecov]

Codecov Report

Attention: Patch coverage is 85.50725% with 10 lines in your changes missing coverage. Please review.

Project coverage is 69.45%. Comparing base (07d00eb) to head (432782b).
Report is 22 commits behind head on develop.

Files with missing lines	Patch %	Lines
perma_web/perma/models.py	40.00%	3 Missing ⚠️
perma_web/perma/utils.py	85.71%	3 Missing ⚠️
perma_web/api/utils.py	90.47%	2 Missing ⚠️
perma_web/perma/views/playback.py	50.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3670      +/-   ##
===========================================
+ Coverage    69.01%   69.45%   +0.43%     
===========================================
  Files           54       54              
  Lines         7478     7542      +64     
===========================================
+ Hits          5161     5238      +77     
+ Misses        2317     2304      -13     

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[rebeccacremona]

Edge case: I should double check (and add to the test suite) what happens when you manually request to download the WACZ of a Perma Link for which there is only a WARC. The button won't appear in the tray, and the API will report wacz_download_url: null, but the request shouldn't result in a RuntimeError...

[rebeccacremona]

the request shouldn't result in a RuntimeError...

Ah, yep, if you manually construct URLs like https://perma.test:8000/Y3YJ-4B9G?type=wacz_download or https://perma.test:8000/api/v1/archives/Y3YJ-4B9G/download?file_format=wacz for links without WACZs, say, old ones, or user loads, that's currently a 500 w/RuntimeError.

Fixing! Fixed.

[christiansmith]

Looks good to me! Nice work @rebeccacremona!