mirror of
https://github.com/hanzoai/commerce.git
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zeekay
1943f1c093
Multi-tenant commerce and billing: orders, subscriptions, invoices, plans, usage metering and a credit ledger. One Go binary. MIT OR Apache-2.0. Claude-Session: https://claude.ai/code/session_01SAtaDFm8VDiWrhYHNNtxMw
106 lines
2.5 KiB
Go
106 lines
2.5 KiB
Go
package rand
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import (
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"crypto/rand"
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"encoding/base64"
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"fmt"
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mathrand "math/rand"
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"strings"
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"time"
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)
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// Returns short, url-friendly Id
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func ShortPassword() string {
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size := 16
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rb := make([]byte, size)
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if _, err := rand.Read(rb); err != nil {
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fmt.Printf("Failed to genrate random characters: %v", err)
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}
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return strings.Trim(base64.URLEncoding.EncodeToString(rb), "=")
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}
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// Returns short, url-friendly Id
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func ShortId() string {
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size := 8
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rb := make([]byte, size)
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if _, err := rand.Read(rb); err != nil {
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fmt.Printf("Failed to genrate random characters: %v", err)
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}
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return strings.Trim(base64.URLEncoding.EncodeToString(rb), "=")
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}
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func SecretKey() string {
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// 75% of 256 bytes
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size := 192
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rb := make([]byte, size)
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if _, err := rand.Read(rb); err != nil {
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fmt.Printf("Failed to genrate random characters: %v", err)
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}
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return strings.Trim(base64.URLEncoding.EncodeToString(rb), "=")
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}
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// String returns exactly n characters drawn uniformly from alphabet.
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//
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// It is the primitive to reach for when the output has a shape someone will
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// read back or type in — a referral code, a coupon — rather than base64 with
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// the awkward characters filtered out afterwards. Filtering is what made
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// referral codes "eight characters, unless the draw happened to contain four
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// of '-' and '_', in which case seven or fewer".
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//
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// Rejection sampling keeps the draw uniform. Folding a byte modulo the
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// alphabet size would favour its first 256 % len(alphabet) characters, and a
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// code with a lopsided alphabet is a code with less entropy than its length
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// advertises.
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func String(n int, alphabet string) string {
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if n <= 0 || len(alphabet) == 0 {
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return ""
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}
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// The largest multiple of len(alphabet) representable in a byte. Draws at
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// or above it are discarded rather than folded.
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limit := 256 - 256%len(alphabet)
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out := make([]byte, 0, n)
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buf := make([]byte, n)
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for len(out) < n {
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// crypto/rand.Read is documented never to fail; it crashes the program
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// itself if the system source is unavailable, which is the right
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// outcome here — a code from a broken source must never be issued.
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rand.Read(buf)
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for _, b := range buf {
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if int(b) >= limit {
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continue
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}
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out = append(out, alphabet[int(b)%len(alphabet)])
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if len(out) == n {
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break
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}
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}
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}
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return string(out)
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}
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func Int() int {
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return mathrand.Int()
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}
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func Int32() int32 {
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return mathrand.Int31()
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}
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func Int64() int64 {
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return mathrand.Int63()
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}
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func init() {
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mathrand.Seed(time.Now().UTC().UnixNano())
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}
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