Is there a nice way to add a URL from the Wayback machine?
I don't want to add HTML documents but rather PDFs etc.
The problem is that web.archive.org doesn't send a Content-Length header:

    $ curl -I http://web.archive.org/web/20171117120847/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg
    HTTP/1.1 200 OK
    Server: Tengine/2.1.0
    Date: Fri, 17 Nov 2017 12:09:35 GMT
    Content-Type: audio/ogg
    Connection: keep-alive
    X-Archive-Orig-content-length: 29784324
    X-Archive-Orig-accept-ranges: bytes
    X-Archive-Orig-server: Apache/2.4.29 (Debian)
    X-Archive-Orig-last-modified: Wed, 11 Feb 2015 01:31:47 GMT
    X-Archive-Orig-connection: close
    X-Archive-Orig-etag: "1c67904-50ec5f783257c"
    X-Archive-Orig-date: Fri, 17 Nov 2017 12:08:49 GMT
    Cache-Control: max-age=1800
    X-Archive-Guessed-Content-Type: audio/ogg
    Memento-Datetime: Fri, 17 Nov 2017 12:08:47 GMT
    Link: <https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="original", <http://web.archive.org/web/timemap/link/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="timemap"; type="application/link-format", <http://web.archive.org/web/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="timegate", <http://web.archive.org/web/20140426045733/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="first memento"; datetime="Sat, 26 Apr 2014 04:57:33 GMT", <http://web.archive.org/web/20170822174608/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="prev memento"; datetime="Tue, 22 Aug 2017 17:46:08 GMT", <http://web.archive.org/web/20171117120847/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="memento"; datetime="Fri, 17 Nov 2017 12:08:47 GMT", <http://web.archive.org/web/20171117120847/https://downloads.kitenet.net/videos/git-annex/git-annex_views_demo.ogg>; rel="last memento"; datetime="Fri, 17 Nov 2017 12:08:47 GMT"
    Content-Security-Policy: default-src 'self' 'unsafe-eval' 'unsafe-inline' data: archive.org web.archive.org analytics.archive.org
    X-App-Server: wwwb-app39
    X-ts: ----
    X-Archive-Playback: 0
    X-location: All
    X-Page-Cache: MISS

Therefore, I'd have to pass the `--relaxed` flag when calling `addurl`.
Is there maybe a way to tell git-annex to download the file before checking its size?
Or is there a way to use the Wayback machine via the S3 special remote?

Eventually, I'd like to have a script that automatically saves all web content in my repo
into the Wayback machine and adds the new URLs for redundancy.

This is what I've got so far:

    #! /usr/bin/env python3
    
    from subprocess import check_output, Popen, PIPE
    import json
    from urllib import request
    from sys import stdout
    
    output = check_output(['git-annex', 'find', '--in', 'web', '--json'])
    files = [json.loads(line)['file'] for line in output.split(b'\n')[:-1]]
    p = Popen(['git-annex', 'whereis', '--batch', '--json'], stdin=PIPE, stdout=PIPE)
    p.stdin.writelines(str.encode(f + '\n') for f in files)
    out, err = p.communicate()
    urls = []
    for line in out.split(b'\n')[:-1]:
        for loc in json.loads(line)['untrusted']:
            if loc['uuid'] == '00000000-0000-0000-0000-000000000001':
                url = loc['urls'][0]
                import urllib.request
                print('GET https://web.archive.org/save/' + url)
                r = request.urlopen('https://web.archive.org/save/' + url)
                assert(r.getcode() == 200)
                urls.append(r.geturl())
                break
    assert(len(files) == len(urls))
    p = Popen(['git-annex', 'addurl', '--batch', '--with-files', '--relaxed'], stdin=PIPE, stdout=stdout)
    p.stdin.writelines(str.encode(f + ' ' + u) for f, u in zip(urls, files))
    p.communicate()