Class: Redis::Counter
- Inherits:
-
BaseObject
- Object
- BaseObject
- Redis::Counter
- Defined in:
- lib/redis/counter.rb
Overview
Class representing a Redis counter. This functions like a proxy class, in that you can say @object.counter_name to get the value and then directly, or you can use the counter :foo class method in your class to define a counter.
Instance Attribute Summary
Attributes inherited from BaseObject
Instance Method Summary collapse
-
#decrbyfloat(by = 1.0, &block) ⇒ Object
Decrement a floating point counter atomically.
-
#decrement(by = 1, &block) ⇒ Object
(also: #decr, #decrby)
Decrement the counter atomically and return the new value.
-
#getset(to = ) ⇒ Object
Reset the counter to its starting value, and return previous value.
-
#incrbyfloat(by = 1.0, &block) ⇒ Object
Increment a floating point counter atomically.
-
#increment(by = 1, &block) ⇒ Object
(also: #incr, #incrby)
Increment the counter atomically and return the new value.
-
#initialize(key, *args) ⇒ Counter
constructor
A new instance of Counter.
-
#m ⇒ Object
Math ops This needs to handle +/- either actual integers or other Redis::Counters.
- #nil? ⇒ Boolean
-
#reset(to = ) ⇒ Object
Reset the counter to its starting value.
-
#to_f ⇒ Object
Like .value but casts to float since Redis addresses these differently.
-
#to_s ⇒ Object
Proxy methods to help make @object.counter == 10 work.
-
#value ⇒ Object
(also: #get, #to_i)
Returns the current value of the counter.
- #value=(val) ⇒ Object (also: #set)
Methods inherited from BaseObject
#allow_expiration, #as_json, #redis, #set_expiration, #to_hash, #to_json
Methods included from Helpers::CoreCommands
#delete, #exists, #exists?, #expire, #expireat, #marshal, #move, #persist, #rename, #renamenx, #serializer, #ttl, #type, #unmarshal
Constructor Details
#initialize(key, *args) ⇒ Counter
Returns a new instance of Counter.
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# File 'lib/redis/counter.rb', line 12 def initialize(key, *args) super(key, *args) @options[:start] ||= @options[:default] || 0 raise ArgumentError, "Marshalling redis counters does not make sense" if @options[:marshal] redis.setnx(key, @options[:start]) unless @options[:start] == 0 || @options[:init] === false end |
Instance Method Details
#decrbyfloat(by = 1.0, &block) ⇒ Object
Decrement a floating point counter atomically. Redis uses separate API’s to interact with integers vs floats.
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# File 'lib/redis/counter.rb', line 102 def decrbyfloat(by=1.0, &block) allow_expiration do val = redis.incrbyfloat(key, -by).to_f block_given? ? rewindable_block(:incrbyfloat, by, val, &block) : val end end |
#decrement(by = 1, &block) ⇒ Object Also known as: decr, decrby
Decrement the counter atomically and return the new value. If passed a block, that block will be evaluated with the new value of the counter as an argument. If the block returns nil or throws an exception, the counter will automatically be incremented to its previous value. This method is aliased as decr() for brevity.
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# File 'lib/redis/counter.rb', line 82 def decrement(by=1, &block) allow_expiration do val = redis.decrby(key, by).to_i block_given? ? rewindable_block(:increment, by, val, &block) : val end end |
#getset(to = ) ⇒ Object
Reset the counter to its starting value, and return previous value. Use this to “reap” the counter and save it somewhere else. This is atomic in that no increments or decrements are lost if you process the returned value.
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# File 'lib/redis/counter.rb', line 34 def getset(to=[:start]) redis.getset(key, to.to_i).to_i end |
#incrbyfloat(by = 1.0, &block) ⇒ Object
Increment a floating point counter atomically. Redis uses separate API’s to interact with integers vs floats.
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# File 'lib/redis/counter.rb', line 93 def incrbyfloat(by=1.0, &block) allow_expiration do val = redis.incrbyfloat(key, by).to_f block_given? ? rewindable_block(:decrbyfloat, by, val, &block) : val end end |
#increment(by = 1, &block) ⇒ Object Also known as: incr, incrby
Increment the counter atomically and return the new value. If passed a block, that block will be evaluated with the new value of the counter as an argument. If the block returns nil or throws an exception, the counter will automatically be decremented to its previous value. This method is aliased as incr() for brevity.
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# File 'lib/redis/counter.rb', line 68 def increment(by=1, &block) allow_expiration do val = redis.incrby(key, by).to_i block_given? ? rewindable_block(:decrement, by, val, &block) : val end end |
#m ⇒ Object
Math ops This needs to handle +/- either actual integers or other Redis::Counters
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# File 'lib/redis/counter.rb', line 121 %w(+ - == < > <= >=).each do |m| class_eval <<-EndOverload def #{m}(what) value.to_i #{m} what.to_i end EndOverload end |
#nil? ⇒ Boolean
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# File 'lib/redis/counter.rb', line 114 def nil? !redis.exists?(key) end |
#reset(to = ) ⇒ Object
Reset the counter to its starting value. Not atomic, so use with care. Normally only useful if you’re discarding all sub-records associated with a parent and starting over (for example, restarting a game and disconnecting all players).
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# File 'lib/redis/counter.rb', line 23 def reset(to=[:start]) allow_expiration do redis.set key, to.to_i true # hack for redis-rb regression end end |
#to_f ⇒ Object
Like .value but casts to float since Redis addresses these differently.
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# File 'lib/redis/counter.rb', line 59 def to_f redis.get(key).to_f end |
#to_s ⇒ Object
Proxy methods to help make @object.counter == 10 work
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# File 'lib/redis/counter.rb', line 111 def to_s; value.to_s; end |
#value ⇒ Object Also known as: get, to_i
Returns the current value of the counter. Normally just calling the counter will lazily fetch the value, and only update it if increment or decrement is called. This forces a network call to redis-server to get the current value.
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# File 'lib/redis/counter.rb', line 42 def value redis.get(key).to_i end |
#value=(val) ⇒ Object Also known as: set
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# File 'lib/redis/counter.rb', line 47 def value=(val) allow_expiration do if val.nil? delete else redis.set key, val end end end |