33 lines
598 B
Go
33 lines
598 B
Go
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package main
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import (
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"context"
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"fmt"
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)
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type myKey struct{} // use private type to restrict access to this package
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func WithUser(ctx context.Context, user string) context.Context {
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return context.WithValue(ctx, myKey{}, user)
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}
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// Export type-safe interface for users of this value
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func ContextUser(ctx context.Context) (string, bool) {
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v := ctx.Value(myKey{})
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s, ok := v.(string)
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return s, ok
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}
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// OMIT
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func main() {
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ctx := context.Background()
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user, ok := ContextUser(ctx)
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fmt.Println(ok, user)
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ctx = WithUser(ctx, "petya")
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user, ok = ContextUser(ctx)
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fmt.Println(ok, user)
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}
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