Merge pull request #94 from nyaruka/dbutil_scan

Add `dbutil.ScanAllSlice` and `ScanAllMap`

dbutil/json.go → dbutil/scan.go

@@ -1,17 +1,17 @@
 package dbutil
 
 import (
+	"database/sql"
 	"encoding/json"
 
 	"github.com/go-playground/validator/v10"
-	"github.com/jmoiron/sqlx"
 	"github.com/pkg/errors"
 )
 
 var validate = validator.New()
 
 // ScanJSON scans a row which is JSON into a destination struct
-func ScanJSON(rows *sqlx.Rows, destination any) error {
+func ScanJSON(rows *sql.Rows, destination any) error {
 	var raw json.RawMessage
 	err := rows.Scan(&raw)
 	if err != nil {
@@ -27,7 +27,7 @@ func ScanJSON(rows *sqlx.Rows, destination any) error {
 }
 
 // ScanAndValidateJSON scans a row which is JSON into a destination struct and validates it
-func ScanAndValidateJSON(rows *sqlx.Rows, destination any) error {
+func ScanAndValidateJSON(rows *sql.Rows, destination any) error {
 	if err := ScanJSON(rows, destination); err != nil {
 		return err
 	}
@@ -39,3 +39,34 @@ func ScanAndValidateJSON(rows *sqlx.Rows, destination any) error {
 
 	return nil
 }
+
+// ScanAllSlice scans a single value from each single column row into the given slice
+func ScanAllSlice[V any](rows *sql.Rows, s []V) ([]V, error) {
+	defer rows.Close()
+
+	var v V
+
+	for rows.Next() {
+		if err := rows.Scan(&v); err != nil {
+			return nil, err
+		}
+		s = append(s, v)
+	}
+	return s, rows.Err()
+}
+
+// ScanAllMap scans a key and value from each two column row into the given map
+func ScanAllMap[K comparable, V any](rows *sql.Rows, m map[K]V) error {
+	defer rows.Close()
+
+	var k K
+	var v V
+
+	for rows.Next() {
+		if err := rows.Scan(&k, &v); err != nil {
+			return err
+		}
+		m[k] = v
+	}
+	return rows.Err()
+}

dbutil/json_test.go → dbutil/scan_test.go

@@ -2,9 +2,9 @@ package dbutil_test
 
 import (
 	"context"
+	"database/sql"
 	"testing"
 
-	"github.com/jmoiron/sqlx"
 	"github.com/nyaruka/gocommon/dbutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -29,8 +29,8 @@ func TestScanJSON(t *testing.T) {
 		Age  int    `json:"age" validate:"min=0"`
 	}
 
-	queryRows := func(sql string, args ...any) *sqlx.Rows {
-		rows, err := db.QueryxContext(ctx, sql, args...)
+	queryRows := func(sql string, args ...any) *sql.Rows {
+		rows, err := db.QueryContext(ctx, sql, args...)
 		require.NoError(t, err)
 		require.True(t, rows.Next())
 		return rows
@@ -65,7 +65,7 @@ func TestScanJSON(t *testing.T) {
 	assert.EqualError(t, err, "error unmarshalling row JSON: json: cannot unmarshal string into Go struct field foo.age of type int")
 
 	// error if rows aren't ready to be scanned - e.g. next hasn't been called
-	rows, err = db.QueryxContext(ctx, `SELECT ROW_TO_JSON(r) FROM (SELECT f.uuid as uuid, f.name AS name FROM foo f WHERE id = 1) r`)
+	rows, err = db.QueryContext(ctx, `SELECT ROW_TO_JSON(r) FROM (SELECT f.uuid as uuid, f.name AS name FROM foo f WHERE id = 1) r`)
 	require.NoError(t, err)
 	err = dbutil.ScanAndValidateJSON(rows, f)
 	assert.EqualError(t, err, "error scanning row JSON: sql: Scan called without calling Next")
@@ -85,3 +85,57 @@ func TestScanJSON(t *testing.T) {
 	assert.Equal(t, "George", f.Name)
 	assert.Equal(t, -1, f.Age)
 }
+
+func TestScanAllSlice(t *testing.T) {
+	db := getTestDB()
+
+	defer func() { db.MustExec(`DROP TABLE foo`) }()
+
+	db.MustExec(`CREATE TABLE foo (id serial NOT NULL PRIMARY KEY, name VARCHAR(10))`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Ann')`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Bob')`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Cat')`)
+
+	rows, err := db.Query(`SELECT id FROM foo ORDER BY id`)
+	require.NoError(t, err)
+
+	ids := make([]int, 0, 2)
+	ids, err = dbutil.ScanAllSlice(rows, ids)
+	require.NoError(t, err)
+	assert.Equal(t, []int{1, 2, 3}, ids)
+
+	rows, err = db.Query(`SELECT name FROM foo ORDER BY id DESC`)
+	require.NoError(t, err)
+
+	names := make([]string, 0, 2)
+	names, err = dbutil.ScanAllSlice(rows, names)
+	require.NoError(t, err)
+	assert.Equal(t, []string{"Cat", "Bob", "Ann"}, names)
+}
+
+func TestScanAllMap(t *testing.T) {
+	db := getTestDB()
+
+	defer func() { db.MustExec(`DROP TABLE foo`) }()
+
+	db.MustExec(`CREATE TABLE foo (id serial NOT NULL PRIMARY KEY, name VARCHAR(10))`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Ann')`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Bob')`)
+	db.MustExec(`INSERT INTO foo (name) VALUES('Cat')`)
+
+	rows, err := db.Query(`SELECT id, name FROM foo`)
+	require.NoError(t, err)
+
+	nameByID := make(map[int]string, 2)
+	err = dbutil.ScanAllMap(rows, nameByID)
+	require.NoError(t, err)
+	assert.Equal(t, map[int]string{1: "Ann", 2: "Bob", 3: "Cat"}, nameByID)
+
+	rows, err = db.Query(`SELECT name, id FROM foo`)
+	require.NoError(t, err)
+
+	idByName := make(map[string]int, 2)
+	err = dbutil.ScanAllMap(rows, idByName)
+	require.NoError(t, err)
+	assert.Equal(t, map[string]int{"Ann": 1, "Bob": 2, "Cat": 3}, idByName)
+}