add support for MapLibre Vector Tile (.mlt) (#271)

Author: bdon

pmtiles/directory.go

@@ -38,6 +38,7 @@ const (
 	Jpeg                     = 3
 	Webp                     = 4
 	Avif                     = 5
+	Mlt                      = 6
 )
 
 // HeaderV3LenBytes is the fixed-size binary header size.
@@ -97,6 +98,8 @@ func headerContentType(header HeaderV3) (string, bool) {
 		return "image/webp", true
 	case Avif:
 		return "image/avif", true
+	case Mlt:
+		return "application/vnd.maplibre-vector-tile", true
 	default:
 		return "", false
 	}
@@ -114,6 +117,8 @@ func tileTypeToString(t TileType) string {
 		return "webp"
 	case Avif:
 		return "avif"
+	case Mlt:
+		return "mlt"
 	default:
 		return ""
 	}
@@ -131,6 +136,8 @@ func stringToTileType(t string) TileType {
 		return Webp
 	case "avif":
 		return Avif
+	case "mlt":
+		return Mlt
 	default:
 		return UnknownTileType
 	}

pmtiles/directory_test.go

@@ -275,6 +275,7 @@ func TestStringifiedExtension(t *testing.T) {
 	assert.Equal(t, ".jpg", headerExt(HeaderV3{TileType: Jpeg}))
 	assert.Equal(t, ".webp", headerExt(HeaderV3{TileType: Webp}))
 	assert.Equal(t, ".avif", headerExt(HeaderV3{TileType: Avif}))
+	assert.Equal(t, ".mlt", headerExt(HeaderV3{TileType: Mlt}))
 }
 
 func TestStringToTileType(t *testing.T) {
@@ -283,6 +284,7 @@ func TestStringToTileType(t *testing.T) {
 	assert.Equal(t, "jpg", tileTypeToString(stringToTileType("jpg")))
 	assert.Equal(t, "webp", tileTypeToString(stringToTileType("webp")))
 	assert.Equal(t, "avif", tileTypeToString(stringToTileType("avif")))
+	assert.Equal(t, "mlt", tileTypeToString(stringToTileType("mlt")))
 	assert.Equal(t, "", tileTypeToString(stringToTileType("")))
 }
 

pmtiles/server.go

@@ -364,6 +364,10 @@ func (server *Server) getTileAttempt(ctx context.Context, httpHeaders map[string
 		if ext != "avif" {
 			return 400, httpHeaders, []byte("path mismatch: archive is type AVIF (.avif)"), ""
 		}
+	case Mlt:
+		if ext != "mlt" {
+			return 400, httpHeaders, []byte("path mismatch: archive is type MLT (.mlt)"), ""
+		}
 	}
 
 	tileID := ZxyToID(z, x, y)