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77 lines
2.4 KiB
Plaintext
77 lines
2.4 KiB
Plaintext
go-cache is an in-memory key:value store/cache similar to memcached that is suitable for
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applications running on a single machine. Any object can be stored, for a given duration
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or forever, and the cache can be used safely by multiple goroutines.
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Installation:
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goinstall github.com/pmylund/go-cache
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Usage:
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// Create a cache with a default expiration time of 5 minutes, and which purges
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// 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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c.Set("foo", "bar", 0)
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// Set the value of the key "baz" to "yes", with no expiration time (the item
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// won't be removed until it is re-set, or removed using c.Delete("baz")
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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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foo, found := c.Get("foo")
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if found {
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fmt.Println(foo)
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}
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// Since Go is statically typed, and cache values can be anything, type assertion
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// is needed when values are being passed to functions that don't take arbitrary types,
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// (i.e. interface{}). The simplest way to do this for values which will only be used
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// once--e.g. for passing to another function--is:
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foo, found := c.Get("foo")
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if found {
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MyFunction(foo.(string))
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}
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// This gets tedious if the value is used several times in the same function. You
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// might do either of the following instead:
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if x, found := c.Get("foo"); found {
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foo := x.(string)
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...
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}
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// or
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var foo string
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if x, found := c.Get("foo"); found {
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foo = x.(string)
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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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// Want performance? Store pointers!
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c.Set("foo", &MyStruct, 0)
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if x, found := c.Get("foo"); found {
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foo := x.(*MyStruct)
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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 do not need to
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run Set if you modify the underlying data. The cache does not serialize its data, so if
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you modify a struct whose pointer you've stored in the cache, retrieving that pointer
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with Get will point you to the same data:
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foo := &MyStruct{Num: 1}
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c.Set("foo", foo, 0)
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...
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x, _ := c.Get("foo")
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foo := x.(MyStruct)
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fmt.Println(foo.Num)
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...
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foo.Num++
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...
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x, _ := c.Get("foo")
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foo := x.(MyStruct)
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foo.Println(foo.Num)
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will print:
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1
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2
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