mirror of
https://github.com/pocket-id/pocket-id.git
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113 lines
2.8 KiB
Go
113 lines
2.8 KiB
Go
package utils
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import (
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"crypto/rand"
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"errors"
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"fmt"
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"io"
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"net/url"
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"regexp"
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"strings"
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"unicode"
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)
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// GenerateRandomAlphanumericString generates a random alphanumeric string of the given length
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func GenerateRandomAlphanumericString(length int) (string, error) {
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const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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if length <= 0 {
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return "", errors.New("length must be a positive integer")
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}
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// The algorithm below is adapted from https://stackoverflow.com/a/35615565
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const (
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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)
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result := strings.Builder{}
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result.Grow(length)
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// Because we discard a bunch of bytes, we read more in the buffer to minimize the changes of performing additional IO
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bufferSize := int(float64(length) * 1.3)
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randomBytes := make([]byte, bufferSize)
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for i, j := 0, 0; i < length; j++ {
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// Fill the buffer if needed
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if j%bufferSize == 0 {
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_, err := io.ReadFull(rand.Reader, randomBytes)
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if err != nil {
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return "", fmt.Errorf("failed to generate random bytes: %w", err)
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}
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}
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// Discard bytes that are outside of the range
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// This allows making sure that we maintain uniform distribution
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idx := int(randomBytes[j%length] & letterIdxMask)
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if idx < len(charset) {
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result.WriteByte(charset[idx])
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i++
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}
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}
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return result.String(), nil
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}
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func GetHostnameFromURL(rawURL string) string {
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parsedURL, err := url.Parse(rawURL)
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if err != nil {
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return ""
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}
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return parsedURL.Hostname()
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}
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// StringPointer creates a string pointer from a string value
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func StringPointer(s string) *string {
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return &s
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}
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func CapitalizeFirstLetter(str string) string {
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if str == "" {
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return ""
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}
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result := strings.Builder{}
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result.Grow(len(str))
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for i, r := range str {
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if i == 0 {
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result.WriteRune(unicode.ToUpper(r))
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} else {
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result.WriteRune(r)
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}
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}
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return result.String()
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}
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var (
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reAcronymBoundary = regexp.MustCompile(`([A-Z]+)([A-Z][a-z])`) // ABCd -> AB_Cd
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reLowerToUpper = regexp.MustCompile(`([a-z0-9])([A-Z])`) // aB -> a_B
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)
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func CamelCaseToSnakeCase(s string) string {
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s = reAcronymBoundary.ReplaceAllString(s, "${1}_${2}")
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s = reLowerToUpper.ReplaceAllString(s, "${1}_${2}")
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return strings.ToLower(s)
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}
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func CamelCaseToScreamingSnakeCase(s string) string {
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s = reAcronymBoundary.ReplaceAllString(s, "${1}_${2}")
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s = reLowerToUpper.ReplaceAllString(s, "${1}_${2}")
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return strings.ToUpper(s)
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}
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// GetFirstCharacter returns the first non-whitespace character of the string, correctly handling Unicode
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func GetFirstCharacter(str string) string {
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for _, c := range str {
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if unicode.IsSpace(c) {
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continue
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}
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return string(c)
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}
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// Empty string case
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return ""
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}
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