build spotify-to-navidrome migrator with recovery flow

internal/qobuz/signer.go

@@ -0,0 +1,101 @@
+package qobuz
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"net/url"
+	"sort"
+	"strings"
+	"time"
+)
+
+func signGet(path, appSecret string, query url.Values) (requestTS, requestSig string) {
+	ts := nowTS()
+	method := methodName(path)
+
+	keys := make([]string, 0, len(query))
+	for k := range query {
+		if k == "app_id" || k == "request_ts" || k == "request_sig" {
+			continue
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	b := strings.Builder{}
+	b.WriteString(method)
+	for _, k := range keys {
+		vals := query[k]
+		if len(vals) == 0 {
+			continue
+		}
+		b.WriteString(k)
+		b.WriteString(vals[0])
+	}
+	b.WriteString(ts)
+	b.WriteString(appSecret)
+
+	h := md5.Sum([]byte(b.String()))
+	return ts, hex.EncodeToString(h[:])
+}
+
+func signPost(path, appSecret string, form url.Values, includeValues bool) (requestTS, requestSig string) {
+	ts := nowTS()
+	method := methodName(path)
+
+	keys := make([]string, 0, len(form))
+	for k := range form {
+		if k == "app_id" || k == "request_ts" || k == "request_sig" {
+			continue
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	b := strings.Builder{}
+	b.WriteString(method)
+	for _, k := range keys {
+		b.WriteString(k)
+		if includeValues {
+			vals := form[k]
+			if len(vals) > 0 {
+				b.WriteString(vals[0])
+			}
+		}
+	}
+	b.WriteString(ts)
+	b.WriteString(appSecret)
+
+	h := md5.Sum([]byte(b.String()))
+	return ts, hex.EncodeToString(h[:])
+}
+
+func methodName(path string) string {
+	return strings.ReplaceAll(strings.Trim(path, "/"), "/", "")
+}
+
+func nowTS() string {
+	return strconvI64(time.Now().Unix())
+}
+
+func strconvI64(v int64) string {
+	if v == 0 {
+		return "0"
+	}
+	neg := v < 0
+	if neg {
+		v = -v
+	}
+	buf := [20]byte{}
+	i := len(buf)
+	for v > 0 {
+		i--
+		buf[i] = byte('0' + v%10)
+		v /= 10
+	}
+	if neg {
+		i--
+		buf[i] = '-'
+	}
+	return string(buf[i:])
+}