Problem with empty content redirection from BNF errored crawls

[boogheta]

2021-10-28 11:29:12 [pages] DEBUG: Crawling on Web Archive using for prefix http://archivesinternet.bnf.fr/20210101120000/between 20201218000000 and 20210115235959
2021-10-28 11:29:12 [pages] INFO: Using proxy archivesinternet.bnf.fr:8090
2021-10-28 11:29:12 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/20210101120000/http://www.elysee.fr> (referer: None)
2021-10-28 11:29:15 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.elysee.fr&time=20210101120000> (referer: http://archivesinternet.bnf.fr/20210101120000/http://www.elysee.fr)
2021-10-28 11:29:16 [scrapy.core.engine] DEBUG: Crawled (301) <GET http://www.elysee.fr> (referer: http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.elysee.fr&time=20210101120000)
2021-10-28 11:29:16 [pages] DEBUG: Filtered duplicate request: <GET http://www.elysee.fr/> - no more duplicates will be shown (see DUPEFILTER_CLASS)

archive requested: 01/01/21 12:00
archive contains:

• 11h07 : empty so redirection to same page and wayback shifts to the next available
• 15h36 : empty so redirection to same page and wayback shifts to the next available
• 19h07 : ok

The manual solution relies in just changing the requested date by 1 day, hence collecting a functioning archive. But that's not user-guessable at all!

Since the redirection to the following is unannounced and only handled by the wayback through a query, we cannot guess the good one to test, and since we force our desired date to always remain close to it, we end up requesting duplicates on the empty page

A possible solution might be to:
catch line 234 more cases of redirection when using BNF archives by checking whether http code is between 300 & 400 and the response is empty; in those case run a new request with an extra argument that would tell to the _request function to remove the bnf prefix for this url in the next request, benefiting then from the wayback's intelligence

Other potential ideas:

• enable following automatically redirections only for BNF archives? (sounds like a bad idea...)
• use actual datetimes instead of only dates when crawling, allowing at least to use manually proper permalink (such as) from the wayback (sounds nice but probably a mess)
• just identify this kind of error and make the info available in the frontend's report so that the user knows to retry with a different date

[boogheta]

Another example with http/https redirections:

2021-11-02 14:46:32 [pages] DEBUG: Crawling on Web Archive using for prefix http://archivesinternet.bnf.fr/20211024120000/between 20090427120000 and 20340422115959
2021-11-02 14:46:32 [pages] INFO: Using proxy archivesinternet.bnf.fr:8090
2021-11-02 14:46:32 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/20211024120000/http://www.faire-du-theatre.fr> (referer: None)
2021-11-02 14:46:35 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.faire-du-theatre.fr&time=20211024120000> (referer: http://archivesinternet.bnf.fr/20211024120000/http://www.faire-du-theatre.fr)
2021-11-02 14:46:35 [scrapy.core.engine] DEBUG: Crawled (301) <GET http://www.faire-du-theatre.fr> (referer: http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.faire-du-theatre.fr&time=20211024120000)
2021-11-02 14:46:35 [pages] ERROR: Skipping archive page (http://www.faire-du-theatre.fr) within which BNF banner could not be found.
2021-11-02 14:46:35 [scrapy.core.engine] INFO: Closing spider (finished)

[boogheta]

New log with latests commits:

2021-11-04 10:17:42 [pages] DEBUG: Crawling on Web Archive using for prefix http://archivesinternet.bnf.fr/20211024120000/between 20090427120000 and 20340422115959
2021-11-04 10:17:42 [pages] INFO: Using proxy archivesinternet.bnf.fr:8090
2021-11-04 10:17:42 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/20211024120000/http://www.faire-du-theatre.fr> (referer: None)
2021-11-04 10:17:44 [scrapy.core.engine] DEBUG: Crawled (302) <GET http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.faire-du-theatre.fr&time=20211024120000> (referer: http://archivesinternet.bnf.fr/20211024120000/http://www.faire-du-theatre.fr)
2021-11-04 10:17:47 [scrapy.core.engine] DEBUG: Crawled (301) <GET http://www.faire-du-theatre.fr> (referer: http://archivesinternet.bnf.fr/session/startReplaySession.jsp?url=http%3A%2F%2Fwww.faire-du-theatre.fr&time=20211024120000)
2021-11-04 10:17:47 [pages] DEBUG: Filtered duplicate request: <GET http://www.faire-du-theatre.fr/> - no more duplicates will be shown (see DUPEFILTER_CLASS)
2021-11-04 10:17:47 [scrapy.core.engine] INFO: Closing spider (finished)