Class: Redis::Counter
- Inherits:
-
BaseObject
- Object
- BaseObject
- Redis::Counter
- Includes:
- Helpers::CoreCommands
- 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 collapse
-
#key ⇒ Object
readonly
Returns the value of attribute key.
-
#options ⇒ Object
readonly
Returns the value of attribute options.
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 included from Helpers::CoreCommands
#delete, #exists?, #expire, #expireat, #marshal, #move, #persist, #rename, #renamenx, #sort, #ttl, #type, #unmarshal
Methods inherited from BaseObject
#allow_expiration, #as_json, #redis, #set_expiration, #to_hash, #to_json
Constructor Details
#initialize(key, *args) ⇒ Counter
Returns a new instance of Counter.
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# File 'lib/redis/counter.rb', line 16 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 Attribute Details
#key ⇒ Object (readonly)
Returns the value of attribute key.
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# File 'lib/redis/counter.rb', line 15 def key @key end |
#options ⇒ Object (readonly)
Returns the value of attribute options.
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# File 'lib/redis/counter.rb', line 15 def @options 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 106 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 86 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 38 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 97 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 72 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 125 %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 118 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 27 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 63 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 115 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 46 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 51 def value=(val) allow_expiration do if val.nil? delete else redis.set key, val end end end |