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@ -8,81 +8,83 @@ be saved to and loaded from a file (or any io.Reader/Writer) to recover from
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downtime quickly.
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downtime quickly.
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== Installation
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== Installation
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goinstall github.com/pmylund/go-cache
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goinstall github.com/pmylund/go-cache
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== Usage
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== Usage
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import "github.com/pmylund/go-cache"
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// Create a cache with a default expiration time of 5 minutes, and which
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import "github.com/pmylund/go-cache"
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// purges expired items every 30 seconds
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c := cache.New(5*time.Minute, 30*time.Second)
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// Create a cache with a default expiration time of 5 minutes, and which
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// purges expired items every 30 seconds
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c := cache.New(5*time.Minute, 30*time.Second)
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// Set the value of the key "foo" to "bar", with the default expiration time
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// Set the value of the key "foo" to "bar", with the default expiration time
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c.Set("foo", "bar", 0)
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c.Set("foo", "bar", 0)
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// Set the value of the key "baz" to "yes", with no expiration time
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// Set the value of the key "baz" to "yes", with no expiration time
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// (the item won't be removed until it is re-set, or removed using
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// (the item won't be removed until it is re-set, or removed using
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// c.Delete("baz")
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// c.Delete("baz")
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c.Set("baz", "yes", -1)
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c.Set("baz", "yes", -1)
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// Get the string associated with the key "foo" from the cache
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// Get the string associated with the key "foo" from the cache
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foo, found := c.Get("foo")
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foo, found := c.Get("foo")
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if found {
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if found {
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fmt.Println(foo)
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fmt.Println(foo)
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}
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}
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// Since Go is statically typed, and cache values can be anything, type
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// Since Go is statically typed, and cache values can be anything, type
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// assertion is needed when values are being passed to functions that don't
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// assertion is needed when values are being passed to functions that don't
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// take arbitrary types, (i.e. interface{}). The simplest way to do this for
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// take arbitrary types, (i.e. interface{}). The simplest way to do this for
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// values which will only be used once--e.g. for passing to another
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// values which will only be used once--e.g. for passing to another
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// function--is:
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// function--is:
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foo, found := c.Get("foo")
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foo, found := c.Get("foo")
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if found {
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if found {
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MyFunction(foo.(string))
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MyFunction(foo.(string))
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}
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}
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// This gets tedious if the value is used several times in the same function.
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// This gets tedious if the value is used several times in the same function.
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// You might do either of the following instead:
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// You might do either of the following instead:
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if x, found := c.Get("foo"); found {
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if x, found := c.Get("foo"); found {
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foo := x.(string)
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foo := x.(string)
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...
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...
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}
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}
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// or
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// or
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var foo string
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var foo string
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if x, found := c.Get("foo"); found {
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if x, found := c.Get("foo"); found {
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foo = x.(string)
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foo = x.(string)
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}
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}
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...
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...
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// foo can then be passed around freely as a string
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// foo can then be passed around freely as a string
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// Want performance? Store pointers!
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// Want performance? Store pointers!
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c.Set("foo", &MyStruct, 0)
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c.Set("foo", &MyStruct, 0)
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if x, found := c.Get("foo"); found {
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if x, found := c.Get("foo"); found {
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foo := x.(*MyStruct)
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foo := x.(*MyStruct)
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...
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...
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}
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}
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// If you store a reference type like a pointer, slice, map or channel, you
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// If you store a reference type like a pointer, slice, map or channel, you
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// do not need to run Set if you modify the underlying data. The cached
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// do not need to run Set if you modify the underlying data. The cached
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// reference points to the same memory, so if you modify a struct whose
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// reference points to the same memory, so if you modify a struct whose
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// pointer you've stored in the cache, retrieving that pointer with Get will
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// pointer you've stored in the cache, retrieving that pointer with Get will
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// point you to the same data:
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// point you to the same data:
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foo := &MyStruct{Num: 1}
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foo := &MyStruct{Num: 1}
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c.Set("foo", foo, 0)
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c.Set("foo", foo, 0)
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...
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...
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x, _ := c.Get("foo")
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x, _ := c.Get("foo")
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foo := x.(*MyStruct)
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foo := x.(*MyStruct)
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fmt.Println(foo.Num)
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fmt.Println(foo.Num)
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...
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...
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foo.Num++
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foo.Num++
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...
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...
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x, _ := c.Get("foo")
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x, _ := c.Get("foo")
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foo := x.(*MyStruct)
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foo := x.(*MyStruct)
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foo.Println(foo.Num)
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foo.Println(foo.Num)
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// will print:
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// will print:
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1
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1
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2
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2
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== Reference
|
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== Reference
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