Add support for offset in table rows endpoint, dry up code

pkg/api/api.go

@@ -4,7 +4,6 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
-	"strconv"
 	"strings"
 	"time"
 
@@ -109,27 +108,21 @@ func GetTable(c *gin.Context) {
 }
 
 func GetTableRows(c *gin.Context) {
-	limit := 1000 // Number of rows to fetch
-	limitVal := c.Request.FormValue("limit")
+	offset, err := parseIntFormValue(c, "offset", 0)
+	if err != nil {
+		c.JSON(400, NewError(err))
+		return
+	}
 
-	if limitVal != "" {
-		num, err := strconv.Atoi(limitVal)
-
-		if err != nil {
-			c.JSON(400, Error{"Invalid limit value"})
-			return
-		}
-
-		if num <= 0 {
-			c.JSON(400, Error{"Limit should be greater than 0"})
-			return
-		}
-
-		limit = num
+	limit, err := parseIntFormValue(c, "limit", 100)
+	if err != nil {
+		c.JSON(400, NewError(err))
+		return
 	}
 
 	opts := client.RowsOptions{
 		Limit:      limit,
+		Offset:     offset,
 		SortColumn: c.Request.FormValue("sort_column"),
 		SortOrder:  c.Request.FormValue("sort_order"),
 	}

pkg/api/helpers.go

@@ -1,9 +1,11 @@
 package api
 
 import (
+	"fmt"
 	"log"
 	"mime"
 	"path/filepath"
+	"strconv"
 
 	"github.com/gin-gonic/gin"
 	"github.com/sosedoff/pgweb/pkg/data"
@@ -33,6 +35,25 @@ func getQueryParam(c *gin.Context, name string) string {
 	return result
 }
 
+func parseIntFormValue(c *gin.Context, name string, defValue int) (int, error) {
+	val := c.Request.FormValue(name)
+
+	if val == "" {
+		return defValue, nil
+	}
+
+	num, err := strconv.Atoi(val)
+	if err != nil {
+		return defValue, fmt.Errorf("%s must be a number", name)
+	}
+
+	if num < 1 {
+		return defValue, fmt.Errorf("%s must be greated than 0", name)
+	}
+
+	return num, nil
+}
+
 func assetContentType(name string) string {
 	ext := filepath.Ext(name)
 	result := mime.TypeByExtension(ext)