diff --git a/go.sum b/go.sum
index 5e28c02..4e5629d 100644
--- a/go.sum
+++ b/go.sum
@@ -208,6 +208,10 @@ golang.org/x/tools v0.0.0-20200207183749-b753a1ba74fa/go.mod h1:TB2adYChydJhpapK
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898 h1:/atklqdjdhuosWIl6AIbOeHJjicWYPqR9bpxqxYG2pA=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20190606124116-d0a3d012864b h1:mSUCVIwDx4hfXJfWsOPfdzEHxzb2Xjl6BQ8YgPnazQA=
+golang.org/x/tools v0.0.0-20190606124116-d0a3d012864b/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 google.golang.org/appengine v1.3.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 gopkg.in/DATA-DOG/go-sqlmock.v1 v1.3.0/go.mod h1:OdE7CF6DbADk7lN8LIKRzRJTTZXIjtWgA5THM5lhBAw=
diff --git a/server/ctrlsubsonic/ctrl.go b/server/ctrlsubsonic/ctrl.go
index 9822fa1..68e4e14 100644
--- a/server/ctrlsubsonic/ctrl.go
+++ b/server/ctrlsubsonic/ctrl.go
@@ -50,7 +50,7 @@ func writeResp(w http.ResponseWriter, r *http.Request, resp *spec.Response) erro
 	res := metaResponse{Response: resp}
 	params := r.Context().Value(CtxParams).(params.Params)
 	ew := &errWriter{w: w}
-	switch params.Get("f") {
+	switch v, _ := params.Get("f"); v {
 	case "json":
 		w.Header().Set("Content-Type", "application/json")
 		data, err := json.Marshal(res)
diff --git a/server/ctrlsubsonic/handlers_by_folder.go b/server/ctrlsubsonic/handlers_by_folder.go
index b05561d..f303ca4 100644
--- a/server/ctrlsubsonic/handlers_by_folder.go
+++ b/server/ctrlsubsonic/handlers_by_folder.go
@@ -79,7 +79,7 @@ func (c *Controller) ServeGetMusicDirectory(r *http.Request) *spec.Response {
 		Find(&childTracks)
 	for _, c := range childTracks {
 		toAppend := spec.NewTCTrackByFolder(c, folder)
-		if params.Get("c") == "Jamstash" {
+		if v, _ := params.Get("c"); v == "Jamstash" {
 			// jamstash thinks it can't play flacs
 			toAppend.ContentType = "audio/mpeg"
 			toAppend.Suffix = "mp3"
diff --git a/server/ctrlsubsonic/params/params.go b/server/ctrlsubsonic/params/params.go
index e786152..2742122 100644
--- a/server/ctrlsubsonic/params/params.go
+++ b/server/ctrlsubsonic/params/params.go
@@ -1,79 +1,262 @@
 package params
 
+// {get, get first, get or} * {str, int, id} * {list, not list} = 18
+
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 )
 
-type Params struct {
-	values url.Values
+var (
+	ErrKeyNotFound = errors.New("key(s) not found")
+	ErrIDInvalid   = errors.New("invalid id")
+	ErrIDNotAnInt  = errors.New("not an int")
+)
+
+const IDSeparator = "-"
+
+type IDType string
+
+const (
+	// type values copied from subsonic
+	IDTypeArtist IDType = "ar"
+	IDTypeAlbum  IDType = "al"
+	IDTypeTrack  IDType = "tr"
+)
+
+type ID struct {
+	Type  IDType
+	Value int
 }
 
+func IDArtist(id int) string { return fmt.Sprintf("%d-%s", id, IDTypeArtist) }
+func IDAlbum(id int) string  { return fmt.Sprintf("%d-%s", id, IDTypeAlbum) }
+func IDTrack(id int) string  { return fmt.Sprintf("%d-%s", id, IDTypeTrack) }
+
+// ** begin type parsing, support {[],}{string,int,ID} => 6 types
+
+func parse(values []string, i interface{}) error {
+	if len(values) == 0 {
+		return ErrKeyNotFound
+	}
+	var err error
+	switch v := i.(type) {
+	case *string:
+		*v, err = parseStr(values[0])
+	case *int:
+		*v, err = parseInt(values[0])
+	case *ID:
+		*v, err = parseID(values[0])
+	case *[]string:
+		for _, val := range values {
+			parsed, err := parseStr(val)
+			if err != nil {
+				return err
+			}
+			*v = append(*v, parsed)
+		}
+	case *[]int:
+		for _, val := range values {
+			parsed, err := parseInt(val)
+			if err != nil {
+				return err
+			}
+			*v = append(*v, parsed)
+		}
+	case *[]ID:
+		for _, val := range values {
+			parsed, err := parseID(val)
+			if err != nil {
+				return err
+			}
+			*v = append(*v, parsed)
+		}
+	}
+	return err
+}
+
+// ** begin parse funcs
+
+func parseStr(in string) (string, error) {
+	return in, nil
+}
+
+func parseInt(in string) (int, error) {
+	if v, err := strconv.Atoi(in); err == nil {
+		return v, nil
+	}
+	return 0, ErrIDNotAnInt
+}
+
+func parseID(in string) (ID, error) {
+	parts := strings.Split(in, IDSeparator)
+	if len(parts) != 2 {
+		return ID{}, fmt.Errorf("bad separator: %w", ErrIDInvalid)
+	}
+	partType := parts[0]
+	partValue := parts[1]
+	val, err := parseInt(partValue)
+	if err != nil {
+		return ID{}, fmt.Errorf("%s: %w", partValue, err)
+	}
+	switch partType {
+	case string(IDTypeArtist):
+		return ID{Type: IDTypeArtist, Value: val}, nil
+	case string(IDTypeAlbum):
+		return ID{Type: IDTypeAlbum, Value: val}, nil
+	case string(IDTypeTrack):
+		return ID{Type: IDTypeTrack, Value: val}, nil
+	}
+	return ID{}, ErrIDInvalid
+}
+
+type Params url.Values
+
 func New(r *http.Request) Params {
 	// first load params from the url
 	params := r.URL.Query()
 	// also if there's any in the post body, use those too
-	if err := r.ParseForm(); err != nil {
-		return Params{params}
+	if err := r.ParseForm(); err == nil {
+		for k, v := range r.Form {
+			params[k] = v
+		}
 	}
-	for k, v := range r.Form {
-		params[k] = v
-	}
-	return Params{params}
+	return Params(params)
 }
 
-func (p Params) Get(key string) string {
-	return p.values.Get(key)
+func (p Params) get(key string) []string {
+	return p[key]
 }
 
-func (p Params) GetOr(key, or string) string {
-	val := p.Get(key)
-	if val == "" {
-		return or
-	}
-	return val
-}
-
-func (p Params) GetInt(key string) (int, error) {
-	strVal := p.values.Get(key)
-	if strVal == "" {
-		return 0, fmt.Errorf("no param with key `%s`", key)
-	}
-	val, err := strconv.Atoi(strVal)
-	if err != nil {
-		return 0, fmt.Errorf("not an int `%s`", strVal)
-	}
-	return val, nil
-}
-
-func (p Params) GetIntOr(key string, or int) int {
-	val, err := p.GetInt(key)
-	if err != nil {
-		return or
-	}
-	return val
-}
-
-func (p Params) GetFirstList(keys ...string) []string {
-	for _, key := range keys {
-		if v, ok := p.values[key]; ok && len(v) > 0 {
+func (p Params) getFirst(keys []string) []string {
+	for _, k := range keys {
+		if v, ok := p[k]; ok {
 			return v
 		}
 	}
 	return nil
 }
 
-func (p Params) GetFirstListInt(keys ...string) []int {
-	v := p.GetFirstList(keys...)
-	if v == nil {
-		return nil
-	}
-	ret := make([]int, 0, len(v))
-	for _, p := range v {
-		i, _ := strconv.Atoi(p)
-		ret = append(ret, i)
-	}
-	return ret
+// ** begin str {get, get first, get or}
+
+func (p Params) Get(key string) (string, error) {
+	var ret string
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirst(keys ...string) (string, error) {
+	var ret string
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOr(key string, or string) string {
+	var ret string
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
+}
+
+// ** begin []str {get, get first, get or}
+
+func (p Params) GetList(key string) ([]string, error) {
+	var ret []string
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirstList(keys ...string) ([]string, error) {
+	var ret []string
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOrList(key string, or []string) []string {
+	var ret []string
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
+}
+
+// ** begin int {get, get first, get or}
+
+func (p Params) GetInt(key string) (int, error) {
+	var ret int
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirstInt(keys ...string) (int, error) {
+	var ret int
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOrInt(key string, or int) int {
+	var ret int
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
+}
+
+// ** begin []int {get, get first, get or}
+
+func (p Params) GetIntList(key string) ([]int, error) {
+	var ret []int
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirstIntList(keys ...string) ([]int, error) {
+	var ret []int
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOrIntList(key string, or []int) []int {
+	var ret []int
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
+}
+
+// ** begin ID {get, get first, get or}
+
+func (p Params) GetID(key string) (ID, error) {
+	var ret ID
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirstID(keys ...string) (ID, error) {
+	var ret ID
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOrID(key string, or ID) ID {
+	var ret ID
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
+}
+
+// ** begin []ID {get, get first, get or}
+
+func (p Params) GetIDList(key string) ([]ID, error) {
+	var ret []ID
+	return ret, parse(p.get(key), &ret)
+}
+
+func (p Params) GetFirstIDList(keys ...string) ([]ID, error) {
+	var ret []ID
+	return ret, parse(p.getFirst(keys), &ret)
+}
+
+func (p Params) GetOrIDList(key string, or []ID) []ID {
+	var ret []ID
+	if err := parse(p.get(key), &ret); err == nil {
+		return ret
+	}
+	return or
 }
diff --git a/server/ctrlsubsonic/params/params_test.go b/server/ctrlsubsonic/params/params_test.go
new file mode 100644
index 0000000..cede1ae
--- /dev/null
+++ b/server/ctrlsubsonic/params/params_test.go
@@ -0,0 +1,55 @@
+package params
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestParseID(t *testing.T) {
+	tcases := []struct {
+		param    string
+		expType  IDType
+		expValue int
+		expErr   error
+	}{
+		{param: "al-45", expType: IDTypeAlbum, expValue: 45},
+		{param: "ar-2", expType: IDTypeArtist, expValue: 2},
+		{param: "tr-43", expType: IDTypeTrack, expValue: 43},
+		{param: "xx-1", expErr: ErrIDInvalid},
+		{param: "al-howdy", expErr: ErrIDNotAnInt},
+	}
+	for _, tcase := range tcases {
+		t.Run(tcase.param, func(t *testing.T) {
+			act, err := parseID(tcase.param)
+			if err != nil && !errors.Is(err, tcase.expErr) {
+				t.Fatalf("expected err %q, got %q", tcase.expErr, err)
+			}
+			if act.Value != tcase.expValue {
+				t.Errorf("expected value %d, got %d", tcase.expValue, act.Value)
+			}
+			if act.Type != tcase.expType {
+				t.Errorf("expected type %v, got %v", tcase.expType, act.Type)
+			}
+		})
+	}
+}
+
+// TODO?
+func TestGet(t *testing.T)             {}
+func TestGetFirst(t *testing.T)        {}
+func TestGetOr(t *testing.T)           {}
+func TestGetList(t *testing.T)         {}
+func TestGetFirstList(t *testing.T)    {}
+func TestGetOrList(t *testing.T)       {}
+func TestGetInt(t *testing.T)          {}
+func TestGetFirstInt(t *testing.T)     {}
+func TestGetOrInt(t *testing.T)        {}
+func TestGetIntList(t *testing.T)      {}
+func TestGetFirstIntList(t *testing.T) {}
+func TestGetOrIntList(t *testing.T)    {}
+func TestGetID(t *testing.T)           {}
+func TestGetFirstID(t *testing.T)      {}
+func TestGetOrID(t *testing.T)         {}
+func TestGetIDList(t *testing.T)       {}
+func TestGetFirstIDList(t *testing.T)  {}
+func TestGetOrIDList(t *testing.T)     {}