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