Treat symlinks to directories like directories

[hupfdule]

This allows symlinking to create additional subalbums.

Closes: #431

One drawback is that the files in the symlinked directories are scanned twice as they have different paths.
It would be nice if the applications identifies them as identical (e.g. based on an md5sum) and use the already scanned information for both subalbums (the real one and the symlink). But this is not part of this PR.

[codecov]

Codecov Report

Merging #432 (0129cb7) into master (2e4f83a) will decrease coverage by 0.89%.
The diff coverage is 58.33%.

@@            Coverage Diff             @@
##           master     #432      +/-   ##
==========================================
- Coverage   42.37%   41.47%   -0.90%     
==========================================
  Files          86       90       +4     
  Lines        3212     3315     +103     
  Branches      348      348              
==========================================
+ Hits         1361     1375      +14     
- Misses       1734     1819      +85     
- Partials      117      121       +4     

Flag	Coverage Δ
api	33.85% <58.33%> (-1.28%)	⬇️
ui	49.90% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
api/scanner/scanner_album.go	68.80% <40.00%> (-1.67%)	⬇️
api/scanner/scanner_user.go	55.63% <40.00%> (-0.89%)	⬇️
api/utils/utils.go	29.26% <71.42%> (ø)
api/utils/Throttle.go	0.00% <0.00%> (ø)
api/utils/environment_variables.go	0.00% <0.00%> (ø)
api/utils/Endpoints.go	0.00% <0.00%> (ø)

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[viktorstrate]

Looks good, thank you. Would you be up for writing some tests for the IsDirSymlink function?
If you don't want to, I'll still gladly merge and add it myself later.

Test setup:

• Make a api/utils/utils_test.go and add the following

func TestMain(m *testing.M) {
	os.Exit(test_utils.IntegrationTestRun(m))
}

• Then for each test within the api/ui directory that uses the file system add the line test_utils.FilesystemTest(t). This marks it as an integration test.

Take a look at scanner_test.go for inspiration.

[hupfdule]

OK, I tried writing a test case for that method.

I am not very used to Go, therefore the test may not be optimal. Feel free to adapt it if necessary.

[viktorstrate]

The tests look great, exactly what I imagined!
Although I think you forgot to clean up the TODO on line 20?

[hupfdule]

Although I think you forgot to clean up the TODO on line 20?

You're absolutely right. Fixed it now.

[viktorstrate]

Looks good, thank you!