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Module: Redis::LibIdentity

Relationships & Source Files
Defined in: lib/redis/lib_identity.rb

Overview

Reports redis-rb as the connecting library via CLIENT SETINFO.

redis-client builds its own LIB-NAME as redis-client(<driver_info>) and always reports its own version as LIB-VER, which would identify redis-client rather than redis-rb to the server. We append a second pair of CLIENT SETINFO commands, which wins because the command is last-write-wins, so that CLIENT LIST / CLIENT INFO report lib-name=redis-rb and lib-ver=.

Libraries built on top of redis-rb can still identify themselves by passing .driver_info, in which case they are reported inside the parentheses, e.g. lib-name=redis-rb(my-gem_v1.0.0). The official convention for such suffixes is _v (matching (?<custom-name>[ -~]+)[ -~]v(?<custom-version>[\d\.]+)), with ; delimiting multiple suffixes and parentheses avoided inside them — see https://redis.io/docs/latest/commands/client-setinfo/. Passing driver_info: false disables CLIENT SETINFO entirely, for peers that can't tolerate unknown commands during the handshake (e.g. some proxies).

Applications that use redis-client directly are left untouched: the override only applies to configurations whose .driver_info was built by this module.

Constant Summary

Class Method Summary

Instance Method Summary

Class Method Details

.combine(downstream) (private)

[ GitHub ] 

  


# File 'lib/redis/lib_identity.rb', line 74



def combine(downstream)
  downstream = downstream.scrub(" ") # invalid byte sequences would make gsub raise
                         .gsub(/\A#{INVALID_CHARS}|#{INVALID_CHARS}\z/o, "")
                         .gsub(INVALID_CHARS, "_")
  downstream.empty? ? OWN_INFO : "#{OWN_PREFIX}#{downstream}"
end


  








  

    .driver_info(downstream = nil)  
  



  

    
Combines redis-rb's own identity with the driver_info a downstream library passed in,
so that both can be recovered when the connection prelude is built. false is passed
through untouched and, being falsy, turns CLIENT SETINFO off wholesale (redis-client
gates its own commands on driver_info too). Any other non-String, non-Array value is
also passed through, leaving redis-client to reject it.

  



  [ GitHub ]


  

  


# File 'lib/redis/lib_identity.rb', line 48



def driver_info(downstream = nil)
  case downstream
  when nil then OWN_INFO
  when String then combine(downstream)
  when Array then combine(downstream.join(SEPARATOR))
  else downstream
  end
end


  








  

    .lib_name(info)   (private)
  

  [ GitHub ]


  

  


# File 'lib/redis/lib_identity.rb', line 81



def lib_name(info)
  downstream = info == OWN_INFO ? nil : info.delete_prefix(OWN_PREFIX)
  downstream.nil? || downstream.empty? ? LIB_NAME : "#{LIB_NAME}(#{downstream})".freeze
end


  








  

    .ours?(info)  ⇒ Boolean 
  



  

    
True only for values .driver_info produced: exactly our own identity, or our identity
followed by a downstream library's. Matching on the bare MARKER prefix instead would
also capture a direct redis-client user whose own .driver_info merely starts with
redis-rb_v (say redis-rb_viewer-1.0) and would silently discard their identity.

  





  


  [ GitHub ]


  

  


# File 'lib/redis/lib_identity.rb', line 61



def ours?(info)
  info.is_a?(String) && (info == OWN_INFO || info.start_with?(OWN_PREFIX))
end


  








  

    .setinfo_commands(info)  
  

  [ GitHub ]


  

  


# File 'lib/redis/lib_identity.rb', line 65



def setinfo_commands(info)
  [
    ["CLIENT", "SETINFO", "LIB-NAME", lib_name(info)].freeze,
    ["CLIENT", "SETINFO", "LIB-VER", Redis::VERSION].freeze,
  ].freeze
end


  







Instance Method Details



  

    #connection_prelude  
  

  [ GitHub ]


  

  


# File 'lib/redis/lib_identity.rb', line 87



def connection_prelude
  prelude = super
  info = driver_info
  return prelude unless LibIdentity.ours?(info)

  # `CLIENT SETINFO` is last-write-wins, so appending after the commands `redis-client`
  # already built overrides them, without having to recognise or remove them.
  (prelude + LibIdentity.setinfo_commands(info)).freeze
end