[metrics-bugs] #6946 [Metrics/Onionoo]: Allow filtering relays by OS

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#6946: Allow filtering relays by OS
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 Reporter:  rransom          |          Owner:  irl
     Type:  enhancement      |         Status:  needs_revision
 Priority:  Medium           |      Milestone:
Component:  Metrics/Onionoo  |        Version:
 Severity:  Normal           |     Resolution:
 Keywords:                   |  Actual Points:
Parent ID:                   |         Points:
 Reviewer:  karsten          |        Sponsor:
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Comment (by irl):

 Replying to [comment:15 karsten]:
 > Some things I noticed:
 >  - You're reusing `ResourceServlet#parseVersionParameter` for parsing
 the `os` parameter. Wouldn't it make more sense to reuse
 `#parseContactParameter` here? After all, we'll want to support searches
 for `"Linux"` as well as for `"Windows 95"` here, right? Also, maybe
 rename the method to `#parseContactOrOsParameter` to make it clear that
 the method is used for both.

 I've added a new `#parseOperatingSystemParameter` in a fixup commit. When
 we're looking at UTF-8 for
 [[https://gitweb.torproject.org/torspec.git/tree/proposals/285-utf-8.txt|proposal
 285]] it would be really good to refactor all the `#parseXParameter`
 functions into what they are actually doing, e.g. only printable UTF-8
 instead of what the parameter name is. I could not use
 `#parseContactParameter` as this was splitting on spaces.

 >  - Did you try out what happens when you search for strings that contain
 spaces? And did you also try out using the new `"os"` parameter in a
 qualified search term? IIRC, we did not fix the space issue in qualified
 search terms, and in this case it may bite us again. I don't have an easy
 fix for this.

 I've checked now that spaces do work. In the search string though, we can
 only search as far as the first space. We can ensure we don't hit any
 errors in Relay Search by never trying to build search strings that have
 spaces in the OS. It may not be the best solution but for now at least we
 do increase functionality, even if it's not to where it could be.

 >  - Do you mind extending `ResourceServletTest` to actually test
 different requests using the new parameter? Maybe the `#testContactXY`
 methods serve as a template.

 Ok. Will try to do this this afternoon or tomorrow morning. That looks
 easy enough.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6946#comment:16>
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