Phase 2: Subsonic REST API framework (auth, response formatting, error handling, routing) plus user permission model

internal/subsonic/params.go

@@ -0,0 +1,82 @@
+package subsonic
+
+import (
+	"net/url"
+	"strconv"
+)
+
+// params wraps the request's merged query+form values with typed,
+// error-producing accessors, so handlers never hand-roll parameter
+// parsing/validation.
+type params struct {
+	values url.Values
+}
+
+func (p params) Get(name string) string {
+	return p.values.Get(name)
+}
+
+func (p params) GetAll(name string) []string {
+	return p.values[name]
+}
+
+func (p params) Has(name string) bool {
+	_, ok := p.values[name]
+	return ok
+}
+
+func (p params) Required(name string) (string, *apiError) {
+	v := p.values.Get(name)
+	if v == "" {
+		return "", errMissingParameter(name)
+	}
+	return v, nil
+}
+
+func (p params) Int(name string, def int) int {
+	v := p.values.Get(name)
+	if v == "" {
+		return def
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return def
+	}
+	return n
+}
+
+func (p params) RequiredInt(name string) (int, *apiError) {
+	v := p.values.Get(name)
+	if v == "" {
+		return 0, errMissingParameter(name)
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, errMissingParameter(name)
+	}
+	return n, nil
+}
+
+func (p params) Int64(name string, def int64) int64 {
+	v := p.values.Get(name)
+	if v == "" {
+		return def
+	}
+	n, err := strconv.ParseInt(v, 10, 64)
+	if err != nil {
+		return def
+	}
+	return n
+}
+
+func (p params) Bool(name string, def bool) bool {
+	v := p.values.Get(name)
+	if v == "" {
+		return def
+	}
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		return def
+	}
+	return b
+}