Retry Contact messages 20 time (about two weeks)

* Work on the data downloads: Fixed general layout of buttons, added a timestamp and implemented auto-deletion of old exports [#7684](https://github.com/diaspora/diaspora/pull/7684)

* Increase Twitter character limit to 280 [#7694](https://github.com/diaspora/diaspora/pull/7694)

* Improve password autocomplete with password managers [#7642](https://github.com/diaspora/diaspora/pull/7642)

* Removed the limit of participants in private conversations [#7705](https://github.com/diaspora/diaspora/pull/7705)

* Send blocks to the blocked persons pod for better UX [#7705](https://github.com/diaspora/diaspora/pull/7705)

## Bug fixes

* Fix invite link on the contacts page when the user has no contacts [#7690](https://github.com/diaspora/diaspora/pull/7690)

    protected

    def schedule_retry(retry_count, sender_id, obj_str, failed_urls)

      if retry_count < MAX_RETRIES

      if retry_count < (obj_str.start_with?("Contact") ? MAX_RETRIES + 10 : MAX_RETRIES)

        yield(seconds_to_delay(retry_count), retry_count)

      else

        logger.warn "status=abandon sender=#{sender_id} obj=#{obj_str} failed_urls='[#{failed_urls.join(', ')}]'"

  end

  it "increases the interval for each retry" do

    expect(Workers::SendBase.new.send(:seconds_to_delay, 2)).to be >= 625

    expect(Workers::SendBase.new.send(:seconds_to_delay, 3)).to be >= 1_296

    expect(Workers::SendBase.new.send(:seconds_to_delay, 4)).to be >= 2_401

    expect(Workers::SendBase.new.send(:seconds_to_delay, 5)).to be >= 4_096

    expect(Workers::SendBase.new.send(:seconds_to_delay, 6)).to be >= 6_561

    expect(Workers::SendBase.new.send(:seconds_to_delay, 7)).to be >= 10_000

    expect(Workers::SendBase.new.send(:seconds_to_delay, 8)).to be >= 14_641

    (2..19).each do |count|

      expect(Workers::SendBase.new.send(:seconds_to_delay, count)).to be >= ((count + 3)**4)

    end

    # lets make some tests with explicit numbers to make sure the formula above works correctly

    # and increases the delay with the expected result

    expect(Workers::SendBase.new.send(:seconds_to_delay, 9)).to be >= 20_736

    expect(Workers::SendBase.new.send(:seconds_to_delay, 19)).to be >= 234_256

  end

end

      Workers::SendPrivate.new.perform(sender_id, obj_str, targets, 9)

    }.to raise_error Workers::SendBase::MaxRetriesReached

  end

  it "retries contact entities 20 times" do

    contact = Fabricate(:contact_entity, author: sender_id, recipient: alice.diaspora_handle)

    obj_str = contact.to_s

    targets = {"https://example.org/receive/user/guid" => "<xml>post</xml>"}

    expect(DiasporaFederation::Federation::Sender).to receive(:private).with(

      sender_id, obj_str, targets

    ).and_return(targets).twice

    expect(Workers::SendPrivate).to receive(:perform_in).with(a_kind_of(Numeric), sender_id, obj_str, targets, 19)

    Workers::SendPrivate.new.perform(sender_id, obj_str, targets, 18)

    expect(Workers::SendPrivate).not_to receive(:perform_in)

    expect {

      Workers::SendPrivate.new.perform(sender_id, obj_str, targets, 19)

    }.to raise_error Workers::SendBase::MaxRetriesReached

  end

end