code gen for postgres

g_appcode.go

@@ -34,6 +34,28 @@ const (
 	O_ROUTER
 )
 
+// DbTransformer has method to reverse engineer a database schema to restful api code
+type DbTransformer interface {
+	GetTableNames(conn *sql.DB) []string
+	GetConstraints(conn *sql.DB, table *Table, blackList map[string]bool)
+	GetColumns(conn *sql.DB, table *Table, blackList map[string]bool)
+	GetGoDataType(sqlType string) string
+}
+
+// MysqlDB is the MySQL version of DbTransformer
+type MysqlDB struct {
+}
+
+// PostgresDB is the PostgreSQL version of DbTransformer
+type PostgresDB struct {
+}
+
+// dbDriver maps a DBMS name to its version of DbTransformer
+var dbDriver = map[string]DbTransformer{
+	"mysql":    &MysqlDB{},
+	"postgres": &PostgresDB{},
+}
+
 type MvcPath struct {
 	ModelPath      string
 	ControllerPath string
@@ -91,12 +113,16 @@ var typeMappingPostgres = map[string]string{
 	"date":                        "time.Time", // time
 	"time":                        "time.Time",
 	"timestamp":                   "time.Time",
+	"timestamp without time zone": "time.Time",
 	"real":             "float32", // float & decimal
 	"double precision": "float64",
 	"decimal":          "float64",
 	"numeric":          "float64",
 	"money":            "float64", // money
 	"bytea":            "string",  // binary
+	"tsvector":         "string",  // fulltext
+	"ARRAY":            "string",  // array
+	"USER-DEFINED":     "string",  // user defined
 }
 
 // Table represent a table in a database
@@ -264,9 +290,10 @@ func gen(dbms, connStr string, mode byte, selectedTableNames map[string]bool, cu
 		os.Exit(2)
 	}
 	defer db.Close()
+	if trans, ok := dbDriver[dbms]; ok {
 		ColorLog("[INFO] Analyzing database tables...\n")
-	tableNames := getTableNames(db)
+		tableNames := trans.GetTableNames(db)
-	tables := getTableObjects(tableNames, db)
+		tables := getTableObjects(tableNames, db, trans)
 		mvcPath := new(MvcPath)
 		mvcPath.ModelPath = path.Join(currpath, "models")
 		mvcPath.ControllerPath = path.Join(currpath, "controllers")
@@ -274,10 +301,14 @@ func gen(dbms, connStr string, mode byte, selectedTableNames map[string]bool, cu
 		createPaths(mode, mvcPath)
 		pkgPath := getPackagePath(currpath)
 		writeSourceFiles(pkgPath, tables, mode, mvcPath, selectedTableNames)
+	} else {
+		ColorLog("[ERRO] Generating app code from %s database is not supported yet.\n", dbms)
+		os.Exit(2)
+	}
 }
 
 // getTables gets a list table names in current database
-func getTableNames(db *sql.DB) (tables []string) {
+func (*MysqlDB) GetTableNames(db *sql.DB) (tables []string) {
 	rows, err := db.Query("SHOW TABLES")
 	if err != nil {
 		ColorLog("[ERRO] Could not show tables\n")
@@ -297,7 +328,7 @@ func getTableNames(db *sql.DB) (tables []string) {
 }
 
 // getTableObjects process each table name
-func getTableObjects(tableNames []string, db *sql.DB) (tables []*Table) {
+func getTableObjects(tableNames []string, db *sql.DB, dbTransformer DbTransformer) (tables []*Table) {
 	// if a table has a composite pk or doesn't have pk, we can't use it yet
 	// these tables will be put into blacklist so that other struct will not
 	// reference it.
@@ -308,19 +339,19 @@ func getTableObjects(tableNames []string, db *sql.DB) (tables []*Table) {
 		tb := new(Table)
 		tb.Name = tableName
 		tb.Fk = make(map[string]*ForeignKey)
-		getConstraints(db, tb, blackList)
+		dbTransformer.GetConstraints(db, tb, blackList)
 		tables = append(tables, tb)
 	}
 	// process columns, ignoring blacklisted tables
 	for _, tb := range tables {
-		getColumns(db, tb, blackList)
+		dbTransformer.GetColumns(db, tb, blackList)
 	}
 	return
 }
 
 // getConstraints gets primary key, unique key and foreign keys of a table from information_schema
 // and fill in Table struct
-func getConstraints(db *sql.DB, table *Table, blackList map[string]bool) {
+func (*MysqlDB) GetConstraints(db *sql.DB, table *Table, blackList map[string]bool) {
 	rows, err := db.Query(
 		`SELECT 
 			c.constraint_type, u.column_name, u.referenced_table_schema, u.referenced_table_name, referenced_column_name, u.ordinal_position
@@ -368,7 +399,7 @@ func getConstraints(db *sql.DB, table *Table, blackList map[string]bool) {
 
 // getColumns retrieve columns details from information_schema
 // and fill in the Column struct
-func getColumns(db *sql.DB, table *Table, blackList map[string]bool) {
+func (mysqlDB *MysqlDB) GetColumns(db *sql.DB, table *Table, blackList map[string]bool) {
 	// retrieve columns
 	colDefRows, _ := db.Query(
 		`SELECT
@@ -391,7 +422,7 @@ func getColumns(db *sql.DB, table *Table, blackList map[string]bool) {
 		// create a column
 		col := new(Column)
 		col.Name = camelCase(colName)
-		col.Type = getGoDataType(dataType)
+		col.Type = mysqlDB.GetGoDataType(dataType)
 		// Tag info
 		tag := new(OrmTag)
 		tag.Column = colName
@@ -426,7 +457,7 @@ func getColumns(db *sql.DB, table *Table, blackList map[string]bool) {
 				if isSQLSignedIntType(dataType) {
 					sign := extractIntSignness(columnType)
 					if sign == "unsigned" && extra != "auto_increment" {
-						col.Type = getGoDataType(dataType + " " + sign)
+						col.Type = mysqlDB.GetGoDataType(dataType + " " + sign)
 					}
 				}
 				if isSQLStringType(dataType) {
@@ -456,10 +487,204 @@ func getColumns(db *sql.DB, table *Table, blackList map[string]bool) {
 	}
 }
 
+// getGoDataType maps an SQL data type to Golang data type
+func (*MysqlDB) GetGoDataType(sqlType string) (goType string) {
+	if v, ok := typeMappingMysql[sqlType]; ok {
+		return v
+	} else {
+		ColorLog("[ERRO] data type (%s) not found!\n", sqlType)
+		os.Exit(2)
+	}
+	return goType
+}
+
+// GetTableNames for PostgreSQL
+func (*PostgresDB) GetTableNames(db *sql.DB) (tables []string) {
+	rows, err := db.Query(`
+		SELECT table_name FROM information_schema.tables
+		WHERE table_catalog = current_database() and table_schema = 'public'`)
+	if err != nil {
+		ColorLog("[ERRO] Could not show tables: %s\n", err)
+		ColorLog("[HINT] Check your connection string\n")
+		os.Exit(2)
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			ColorLog("[ERRO] Could not show tables\n")
+			os.Exit(2)
+		}
+		tables = append(tables, name)
+	}
+	return
+}
+
+// GetConstraints for PostgreSQL
+func (*PostgresDB) GetConstraints(db *sql.DB, table *Table, blackList map[string]bool) {
+	rows, err := db.Query(
+		`SELECT 
+			c.constraint_type,
+			u.column_name,
+			cu.table_catalog AS referenced_table_catalog,
+			cu.table_name AS referenced_table_name,
+			cu.column_name AS referenced_column_name,
+			u.ordinal_position
+		FROM
+			information_schema.table_constraints c 
+		INNER JOIN
+			information_schema.key_column_usage u ON c.constraint_name = u.constraint_name
+		INNER JOIN
+			information_schema.constraint_column_usage cu ON cu.constraint_name =  c.constraint_name
+		WHERE
+			c.table_catalog = current_database() AND c.table_schema = 'public' AND c.table_name = $1 
+			AND u.table_catalog = current_database() AND u.table_schema = 'public' AND u.table_name = $2`,
+		table.Name, table.Name) //  u.position_in_unique_constraint,
+	if err != nil {
+		ColorLog("[ERRO] Could not query INFORMATION_SCHEMA for PK/UK/FK information: %s\n", err)
+		os.Exit(2)
+	}
+	for rows.Next() {
+		var constraintTypeBytes, columnNameBytes, refTableSchemaBytes, refTableNameBytes, refColumnNameBytes, refOrdinalPosBytes []byte
+		if err := rows.Scan(&constraintTypeBytes, &columnNameBytes, &refTableSchemaBytes, &refTableNameBytes, &refColumnNameBytes, &refOrdinalPosBytes); err != nil {
+			ColorLog("[ERRO] Could not read INFORMATION_SCHEMA for PK/UK/FK information\n")
+			os.Exit(2)
+		}
+		constraintType, columnName, refTableSchema, refTableName, refColumnName, refOrdinalPos :=
+			string(constraintTypeBytes), string(columnNameBytes), string(refTableSchemaBytes),
+			string(refTableNameBytes), string(refColumnNameBytes), string(refOrdinalPosBytes)
+		if constraintType == "PRIMARY KEY" {
+			if refOrdinalPos == "1" {
+				table.Pk = columnName
+			} else {
+				table.Pk = ""
+				// add table to blacklist so that other struct will not reference it, because we are not
+				// registering blacklisted tables
+				blackList[table.Name] = true
+			}
+		} else if constraintType == "UNIQUE" {
+			table.Uk = append(table.Uk, columnName)
+		} else if constraintType == "FOREIGN KEY" {
+			fk := new(ForeignKey)
+			fk.Name = columnName
+			fk.RefSchema = refTableSchema
+			fk.RefTable = refTableName
+			fk.RefColumn = refColumnName
+			table.Fk[columnName] = fk
+		}
+	}
+}
+
+// GetColumns for PostgreSQL
+func (postgresDB *PostgresDB) GetColumns(db *sql.DB, table *Table, blackList map[string]bool) {
+	// retrieve columns
+	colDefRows, _ := db.Query(
+		`SELECT
+			column_name,
+			data_type,
+			data_type ||
+			CASE
+				WHEN data_type = 'character' THEN '('||character_maximum_length||')'
+				WHEN data_type = 'numeric' THEN '(' || numeric_precision || ',' || numeric_scale ||')'
+				ELSE ''
+			END AS column_type,
+			is_nullable,
+			column_default,
+			'' AS extra
+		FROM
+			information_schema.columns 
+		WHERE
+			table_catalog = current_database() AND table_schema = 'public' AND table_name = $1`,
+		table.Name)
+	defer colDefRows.Close()
+	for colDefRows.Next() {
+		// datatype as bytes so that SQL <null> values can be retrieved
+		var colNameBytes, dataTypeBytes, columnTypeBytes, isNullableBytes, columnDefaultBytes, extraBytes []byte
+		if err := colDefRows.Scan(&colNameBytes, &dataTypeBytes, &columnTypeBytes, &isNullableBytes, &columnDefaultBytes, &extraBytes); err != nil {
+			ColorLog("[ERRO] Could not query INFORMATION_SCHEMA for column information\n")
+			os.Exit(2)
+		}
+		colName, dataType, columnType, isNullable, columnDefault, extra :=
+			string(colNameBytes), string(dataTypeBytes), string(columnTypeBytes), string(isNullableBytes), string(columnDefaultBytes), string(extraBytes)
+		// create a column
+		col := new(Column)
+		col.Name = camelCase(colName)
+		col.Type = postgresDB.GetGoDataType(dataType)
+		// Tag info
+		tag := new(OrmTag)
+		tag.Column = colName
+		if table.Pk == colName {
+			col.Name = "Id"
+			col.Type = "int"
+			if extra == "auto_increment" {
+				tag.Auto = true
+			} else {
+				tag.Pk = true
+			}
+		} else {
+			fkCol, isFk := table.Fk[colName]
+			isBl := false
+			if isFk {
+				_, isBl = blackList[fkCol.RefTable]
+			}
+			// check if the current column is a foreign key
+			if isFk && !isBl {
+				tag.RelFk = true
+				refStructName := fkCol.RefTable
+				col.Name = camelCase(colName)
+				col.Type = "*" + camelCase(refStructName)
+			} else {
+				// if the name of column is Id, and it's not primary key
+				if colName == "id" {
+					col.Name = "Id_RENAME"
+				}
+				if isNullable == "YES" {
+					tag.Null = true
+				}
+				if isSQLStringType(dataType) {
+					tag.Size = extractColSize(columnType)
+				}
+				if isSQLTemporalType(dataType) || strings.HasPrefix(dataType, "timestamp") {
+					tag.Type = dataType
+					//check auto_now, auto_now_add
+					if columnDefault == "CURRENT_TIMESTAMP" && extra == "on update CURRENT_TIMESTAMP" {
+						tag.AutoNow = true
+					} else if columnDefault == "CURRENT_TIMESTAMP" {
+						tag.AutoNowAdd = true
+					}
+					// need to import time package
+					table.ImportTimePkg = true
+				}
+				if isSQLDecimal(dataType) {
+					tag.Digits, tag.Decimals = extractDecimal(columnType)
+				}
+				if isSQLBinaryType(dataType) {
+					tag.Size = extractColSize(columnType)
+				}
+			}
+		}
+		col.Tag = tag
+		table.Columns = append(table.Columns, col)
+	}
+}
+func (*PostgresDB) GetGoDataType(sqlType string) (goType string) {
+	if v, ok := typeMappingPostgres[sqlType]; ok {
+		return v
+	} else {
+		ColorLog("[ERRO] data type (%s) not found!\n", sqlType)
+		os.Exit(2)
+	}
+	return goType
+}
+
 // deleteAndRecreatePaths removes several directories completely
 func createPaths(mode byte, paths *MvcPath) {
 	if (mode & O_MODEL) == O_MODEL {
-		os.Mkdir(paths.ModelPath, 0777)
+		err := os.Mkdir(paths.ModelPath, 0777)
+		if err != nil {
+			ColorLog("[ERRO]", err)
+			os.Exit(2)
+		}
 	}
 	if (mode & O_CONTROLLER) == O_CONTROLLER {
 		os.Mkdir(paths.ControllerPath, 0777)
@@ -663,17 +888,6 @@ func camelCase(in string) string {
 	return strings.Join(tokens, "")
 }
 
-// getGoDataType maps an SQL data type to Golang data type
-func getGoDataType(sqlType string) (goType string) {
-	if v, ok := typeMappingMysql[sqlType]; ok {
-		return v
-	} else {
-		fmt.Println("Error:", sqlType, "not found!")
-		os.Exit(1)
-	}
-	return goType
-}
-
 func isSQLTemporalType(t string) bool {
 	return t == "date" || t == "datetime" || t == "timestamp"
 }