Fix SQL parsing for MVT provider

provider/postgis/postgis.go

@@ -35,6 +35,7 @@ type Provider struct {
 const (
 	// We quote the field and table names to prevent colliding with postgres keywords.
 	stdSQL = `SELECT %[1]v FROM %[2]v WHERE "%[3]v" && ` + bboxToken
+	mvtSQL = `SELECT %[1]v FROM %[2]v`
 
 	// SQL to get the column names, without hitting the information_schema. Though it might be better to hit the information_schema.
 	fldsSQL = `SELECT * FROM %[1]v LIMIT 0;`
@@ -100,7 +101,7 @@ var isSelectQuery = regexp.MustCompile(`(?i)^((\s*)(--.*\n)?)*select`)
 // 			!BBOX! - [Required] will be replaced with the bounding box of the tile before the query is sent to the database.
 // 			!ZOOM! - [Optional] will be replaced with the "Z" (zoom) value of the requested tile.
 //
-func CreateProvider(config dict.Dicter) (*Provider, error) {
+func CreateProvider(config dict.Dicter, providerType string) (*Provider, error) {
 
 	host, err := config.String(ConfigKeyHost, nil)
 	if err != nil {
@@ -297,7 +298,7 @@ func CreateProvider(config dict.Dicter) (*Provider, error) {
 			// Tablename and Fields will be used to build the query.
 			// We need to do some work. We need to check to see Fields contains the geom and gid fields
 			// and if not add them to the list. If Fields list is empty/nil we will use '*' for the field list.
-			l.sql, err = genSQL(&l, p.pool, tblName, fields, true)
+			l.sql, err = genSQL(&l, p.pool, tblName, fields, true, providerType)
 			if err != nil {
 				return nil, fmt.Errorf("could not generate sql, for layer(%v): %v", lname, err)
 			}
@@ -420,9 +421,15 @@ func (p Provider) inspectLayerGeomType(l *Layer) error {
 	// https://github.com/go-spatial/tegola/issues/180
 	//
 	// case insensitive search
+
 	re := regexp.MustCompile(`(?i)ST_AsBinary`)
 	sql := re.ReplaceAllString(l.sql, "ST_GeometryType")
 
+	re = regexp.MustCompile(`(?i)(ST_AsMVTGeom\(.*\))`)
+	if re.MatchString(sql) {
+		sql = fmt.Sprintf("SELECT ST_GeometryType(%v) FROM (%v) as q", l.geomField, sql)
+	}
+
 	// we only need a single result set to sniff out the geometry type
 	sql = fmt.Sprintf("%v LIMIT 1", sql)
 
@@ -638,12 +645,21 @@ func (p Provider) MVTForLayers(ctx context.Context, tile provider.Tile, layers [
 
 		// ref: https://postgis.net/docs/ST_AsMVT.html
 		// bytea ST_AsMVT(anyelement row, text name, integer extent, text geom_name, text feature_id_name)
+
+		var featureIDName string
+
+		if l.IDFieldName() == "" {
+			featureIDName = "NULL"
+		} else {
+			featureIDName = fmt.Sprintf(`'%s'`, l.IDFieldName())
+		}
+
 		sqls = append(sqls, fmt.Sprintf(
-			`(SELECT ST_AsMVT(q,'%s',%d,'%s','%s') AS data FROM (%s) AS q)`,
+			`(SELECT ST_AsMVT(q,'%s',%d,'%s',%s) AS data FROM (%s) AS q)`,
 			layers[i].MVTName,
 			tegola.DefaultExtent,
 			l.GeomFieldName(),
-			l.IDFieldName(),
+			featureIDName,
 			sql,
 		))
 	}

provider/postgis/register.go

@@ -35,5 +35,9 @@ func init() {
 // 			!BBOX! - [Required] will be replaced with the bounding box of the tile before the query is sent to the database.
 // 			!ZOOM! - [Optional] will be replaced with the "Z" (zoom) value of the requested tile.
 //
-func NewTileProvider(config dict.Dicter) (provider.Tiler, error)       { return CreateProvider(config) }
-func NewMVTTileProvider(config dict.Dicter) (provider.MVTTiler, error) { return CreateProvider(config) }
+func NewTileProvider(config dict.Dicter) (provider.Tiler, error) {
+	return CreateProvider(config, "postgis")
+}
+func NewMVTTileProvider(config dict.Dicter) (provider.MVTTiler, error) {
+	return CreateProvider(config, "mvt_postgis")
+}

provider/postgis/util.go

@@ -16,8 +16,13 @@ import (
 	"github.com/jackc/pgx/pgtype"
 )
 
+// isMVT will return true if the provider is MVT based
+func isMVT(providerType string) bool {
+	return providerType == "mvt_postgis"
+}
+
 // genSQL will fill in the SQL field of a layer given a pool, and list of fields.
-func genSQL(l *Layer, pool *pgx.ConnPool, tblname string, flds []string, buffer bool) (sql string, err error) {
+func genSQL(l *Layer, pool *pgx.ConnPool, tblname string, flds []string, buffer bool, providerType string) (sql string, err error) {
 
 	// we need to hit the database to see what the fields are.
 	if len(flds) == 0 {
@@ -61,10 +66,19 @@ func genSQL(l *Layer, pool *pgx.ConnPool, tblname string, flds []string, buffer
 
 	// to avoid field names possibly colliding with Postgres keywords,
 	// we wrap the field names in quotes
+
 	if fgeom == -1 {
-		flds = append(flds, fmt.Sprintf(`ST_AsBinary("%v") AS "%[1]v"`, l.geomField))
+		if isMVT(providerType) {
+			flds = append(flds, fmt.Sprintf(`"%v" AS "%[1]v"`, l.geomField))
+		} else {
+			flds = append(flds, fmt.Sprintf(`ST_AsBinary("%v") AS "%[1]v"`, l.geomField))
+		}
 	} else {
-		flds[fgeom] = fmt.Sprintf(`ST_AsBinary("%v") AS "%[1]v"`, l.geomField)
+		if isMVT(providerType) {
+			flds[fgeom] = fmt.Sprintf(`"%v" AS "%[1]v"`, l.geomField)
+		} else {
+			flds[fgeom] = fmt.Sprintf(`ST_AsBinary("%v") AS "%[1]v"`, l.geomField)
+		}
 	}
 
 	// add required id field
@@ -74,7 +88,13 @@ func genSQL(l *Layer, pool *pgx.ConnPool, tblname string, flds []string, buffer
 
 	selectClause := strings.Join(flds, ", ")
 
-	return fmt.Sprintf(stdSQL, selectClause, tblname, l.geomField), nil
+	sqlTmpl := stdSQL
+
+	if isMVT(providerType) {
+		sqlTmpl = mvtSQL
+	}
+
+	return fmt.Sprintf(sqlTmpl, selectClause, tblname, l.geomField), nil
 }
 
 const (