[twitter] add support for nitter.net URLs in pattern

[iamleot]

This pull request add support for nitter.net URLs.
Nitter is an alternative front-end to Twitter - free and open-source available
at: https://github.com/zedeus/nitter

nitter.net is the official public instance.

[iamleot]

JFTR, despite the results test fails all corresponding Twitter tests passes both locally and on Travis CI, copypasting corresponding lines regarding the Travis CI one:

[...]
837 test_TwitterBookmarkExtractor_1 (test.test_results.TestExtractorResults) ... ok
838 test_TwitterLikesExtractor_1 (test.test_results.TestExtractorResults) ... ok
839 test_TwitterMediaExtractor_1 (test.test_results.TestExtractorResults) ... ok
840 test_TwitterMediaExtractor_2 (test.test_results.TestExtractorResults) ... ok
841 test_TwitterSearchExtractor_1 (test.test_results.TestExtractorResults) ... ok
842 test_TwitterTimelineExtractor_1 (test.test_results.TestExtractorResults) ... ok
843 test_TwitterTimelineExtractor_2 (test.test_results.TestExtractorResults) ... ok
844 test_TwitterTweetExtractor_1 (test.test_results.TestExtractorResults) ... ok
845 test_TwitterTweetExtractor_10 (test.test_results.TestExtractorResults) ... ok
846 test_TwitterTweetExtractor_2 (test.test_results.TestExtractorResults) ... ok
847 test_TwitterTweetExtractor_3 (test.test_results.TestExtractorResults) ... ok
848 test_TwitterTweetExtractor_4 (test.test_results.TestExtractorResults) ... ok
849 test_TwitterTweetExtractor_5 (test.test_results.TestExtractorResults) ... ok
850 test_TwitterTweetExtractor_6 (test.test_results.TestExtractorResults) ... ok
851 test_TwitterTweetExtractor_7 (test.test_results.TestExtractorResults) ... ok
852 test_TwitterTweetExtractor_8 (test.test_results.TestExtractorResults) ... ok
853 test_TwitterTweetExtractor_9 (test.test_results.TestExtractorResults) ... ok
[...]

So possible failures should be unrelated to this pull request.

[mikf]

Since the first 2 lines of each regex pattern now share the same code, could you add a global BASE_PATTERN value and simplify the regexs like in, for example, DeviantArt and Imgur?

gallery-dl/gallery_dl/extractor/deviantart.py

Lines 22 to 26 in cb0132e

	BASE_PATTERN = (
	r"(?:https?://)?(?:"
	r"(?:www\.)?deviantart\.com/([\w-]+)|"
	r"(?!www\.)([\w-]+)\.deviantart\.com)"
	)

gallery-dl/gallery_dl/extractor/imgur.py

Line 15 in cb0132e

BASE_PATTERN = r"(?:https?://)?(?:www\.|[im]\.)?imgur\.com"

[iamleot]

Yes! I was unsure to do that given that there was only an extra domain but that's indeed much more possibly easily factorable if there will be more nitter instances or similar.

I will change it in the next couple of minutes and force push to the pull request!

[iamleot]

Thanks @mikf, I have just updated the pull request based on your comment and I will keep an eye on the Travis CI results to spot if there is any possible regression (locally testing them seems fine).

[mikf]

I think you'll have to put an r before each string after BASE_PATTERN + … to allow \d etc without flake8 complaining, i.e. BASE_PATTERN + r"/..."

[iamleot]

@mikf Whoops, sorry! I have just added them. Thanks again!