81 lines
1.7 KiB
Go
81 lines
1.7 KiB
Go
package cache
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"time"
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)
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type Cache[T any] struct {
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Path string
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}
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// New Cache where default path is os.TempDir()
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func New[T any](path string) *Cache[T] {
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if path == "" {
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path = os.TempDir()
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}
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return &Cache[T]{path}
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}
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// Add data as JSON-file into cache-dir, returns nil if success
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func (c *Cache[T]) Add(name string, data any) error {
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j, err := json.MarshalIndent(data, "", " ")
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if err != nil {
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return fmt.Errorf("Failed to convert data as JSON.")
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}
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err = os.MkdirAll(c.Path, 0646)
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if err != nil {
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return fmt.Errorf("Failed to ensure cache-dir is present.")
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}
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filePath := filepath.Join(c.Path, fmt.Sprintf("%s.json", name))
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d := []byte(j)
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err = os.WriteFile(filePath, d, 0646)
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if err != nil {
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return fmt.Errorf("Failed write data to cache-file.")
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}
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return nil
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}
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// Get data from JSON-file from cache-dir, returns nil if no result
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func (c *Cache[T]) Get(name string) (*T, error) {
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filePath := filepath.Join(c.Path, fmt.Sprintf("%s.json", name))
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if _, err := os.Stat(filePath); errors.Is(err, os.ErrNotExist) {
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return nil, nil
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}
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rawFile, err := os.Open(filePath)
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if err != nil {
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return nil, fmt.Errorf("Failed to read cache-file.")
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}
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var result T
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bytes, err := io.ReadAll(rawFile)
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if err != nil {
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return nil, fmt.Errorf("Failed to read data from cache-file.")
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}
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err = json.Unmarshal(bytes, &result)
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if err != nil {
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return nil, fmt.Errorf("Failed to parse JSON from cache-file.")
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}
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return &result, nil
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}
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// Returns if t is expired
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func IsExpired(expire time.Time, now *time.Time) bool {
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if now == nil {
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tmp := time.Now()
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now = &tmp
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}
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return now.Unix() >= expire.Unix()
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}
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