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Module: Redis::Commands::Transactions

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In:
::Redis, ::Redis::Commands, ::Redis::MultiConnection, ::Redis::PipelinedConnection
Defined in: lib/redis/commands/transactions.rb

Instance Method Summary

Instance Method Details

#discard ⇒ String

Discard all commands issued after MULTI.

Returns:

  • (String) —

    "OK"

See Also:

[ GitHub ] 

  


# File 'lib/redis/commands/transactions.rb', line 110



def discard
  send_command([:discard])
end


  








  

    #exec  ⇒ nil, Array<...> 
  



  

    
Execute all commands issued after MULTI.



Only call this method when #multi was called without a block.


  





  
Returns:


    
  
  • 
    (nil, Array<...>)
—    
      

    • when commands were not executed, nil
      • 

    • when commands were executed, an array with their replies
      • 

    

    
  
    • 


  
See Also:

  



  [ GitHub ]


  

  


# File 'lib/redis/commands/transactions.rb', line 100



def exec
  send_command([:exec])
end


  








  

    #multi {|multi| ... } ⇒ Array<...> 
  



  

    
Mark the start of a transaction block.


  





    

    
Examples:

        
With a block



      
redis.multi do |multi|
  multi.set("key", "value")
  multi.incr("counter")
end # => ["OK", 6]

  


Yields:


    
  
  • 
    (multi)
—    
    the commands that are called inside this block are cached
and written to the server upon returning from it
    

    
  
    • 



Yield Parameters:



Returns:


    
  
  • 
    (Array<...>)
—    
      

    • an array with replies
      • 

    

    
  
    • 


  
See Also:

  



  [ GitHub ]


  

  


# File 'lib/redis/commands/transactions.rb', line 23



def multi
  synchronize do |client|
    client.multi do |raw_transaction|
      yield MultiConnection.new(raw_transaction)
    end
  end
end


  








  

    #unwatch  ⇒ String 
  



  

    
Forget about all watched keys.


  





  
Returns:


    
  
  • 
    (String)
—    
    OK
    

    
  
    • 


  
See Also:

  



  [ GitHub ]


  

  


# File 'lib/redis/commands/transactions.rb', line 86



def unwatch
  send_command([:unwatch])
end


  








  

    #watch(*keys)  ⇒ Object, String 
  



  

    
Watch the given keys to determine execution of the MULTI/EXEC block.



Using a block is optional, but is necessary for thread-safety.



An #unwatch is automatically issued if an exception is raised within the
block that is a subclass of StandardError and is not a ::Redis::ConnectionError.


  





    

    
Examples:

        
With a block



      
redis.watch("key") do
  if redis.get("key") == "some value"
    redis.multi do |multi|
      multi.set("key", "other value")
      multi.incr("counter")
    end
  else
    redis.unwatch
  end
end
  # => ["OK", 6]

        
Without a block



      
redis.watch("key")
  # => "OK"

  


Parameters:


    
  
  • 
    keys
    (String, Array<String>)
—    
    one or more keys to watch
    

    
  
    • 



Returns:


    
  
  • 
    (Object)
—    
    if using a block, returns the return value of the block
    

    
  
    • 
  
  • 
    (String)
—    
    if not using a block, returns OK
    

    
  
    • 


  
See Also:

  



  [ GitHub ]


  

  


# File 'lib/redis/commands/transactions.rb', line 61



def watch(*keys)
  synchronize do |client|
    res = client.call_v([:watch] + keys)

    if block_given?
      begin
        yield(self)
      rescue ConnectionError
        raise
      rescue StandardError
        unwatch
        raise
      end
    else
      res
    end
  end
end