Source file src/github.com/peterbourgon/diskv/v3/examples/advanced-transform/advanced-transform.go

Documentation: github.com/peterbourgon/diskv/v3/examples/advanced-transform

     1  package main
     2  
     3  import (
     4  	"fmt"
     5  	"strings"
     6  
     7  	"github.com/peterbourgon/diskv/v3"
     8  )
     9  
    10  func AdvancedTransformExample(key string) *diskv.PathKey {
    11  	path := strings.Split(key, "/")
    12  	last := len(path) - 1
    13  	return &diskv.PathKey{
    14  		Path:     path[:last],
    15  		FileName: path[last] + ".txt",
    16  	}
    17  }
    18  
    19  // If you provide an AdvancedTransform, you must also provide its
    20  // inverse:
    21  
    22  func InverseTransformExample(pathKey *diskv.PathKey) (key string) {
    23  	txt := pathKey.FileName[len(pathKey.FileName)-4:]
    24  	if txt != ".txt" {
    25  		panic("Invalid file found in storage folder!")
    26  	}
    27  	return strings.Join(pathKey.Path, "/") + pathKey.FileName[:len(pathKey.FileName)-4]
    28  }
    29  
    30  func main() {
    31  	d := diskv.New(diskv.Options{
    32  		BasePath:          "my-data-dir",
    33  		AdvancedTransform: AdvancedTransformExample,
    34  		InverseTransform:  InverseTransformExample,
    35  		CacheSizeMax:      1024 * 1024,
    36  	})
    37  	// Write some text to the key "alpha/beta/gamma".
    38  	key := "alpha/beta/gamma"
    39  	d.WriteString(key, "¡Hola!") // will be stored in "<basedir>/alpha/beta/gamma.txt"
    40  	fmt.Println(d.ReadString("alpha/beta/gamma"))
    41  }
    42  

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