/
handlers.go
99 lines (85 loc) · 2.2 KB
/
handlers.go
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package handlers
import (
"encoding/json"
"fmt"
"strconv"
"strings"
"github.com/gin-gonic/gin"
"gorm.io/gorm"
)
const (
TotalCountHeader = "X-Total-Count"
)
type Query struct {
Sort string `form:"sort"`
Filter string `form:"filter"`
Range string `form:"range"`
}
func (q *Query) GetSort() (string, error) {
var parts []string
if err := json.Unmarshal([]byte(q.Sort), &parts); err != nil {
return "", err
}
if len(parts) != 2 {
return "", fmt.Errorf("too many parts")
}
return strings.Join(parts, " "), nil
}
func (q *Query) GetRange() (int, int, error) {
var parts []int
if err := json.Unmarshal([]byte(q.Range), &parts); err != nil {
return 0, 0, err
}
if len(parts) != 2 {
return 0, 0, fmt.Errorf("too many parts")
}
start := parts[0]
end := parts[1]
pageSize := end - start + 1
return pageSize, start, nil
}
func (q *Query) GetFilter() (map[string]interface{}, error) {
var parts map[string]interface{}
if err := json.Unmarshal([]byte(q.Filter), &parts); err != nil {
return parts, err
}
return parts, nil
}
func (q *Query) SetFilter(f map[string]interface{}) error {
b, err := json.Marshal(f)
if err != nil {
return err
}
q.Filter = string(b)
return nil
}
func FilterAndPaginate(db *gorm.DB, model interface{}, c *gin.Context, orderBy string) *gorm.DB {
var query Query
if err := c.ShouldBindQuery(&query); err != nil {
db.Error = err
return db
}
return FilterAndPaginateWithQuery(db, model, c, query, orderBy)
}
func FilterAndPaginateWithQuery(db *gorm.DB, model interface{}, c *gin.Context, query Query, defaultOrderBy string) *gorm.DB {
if order, err := query.GetSort(); err == nil {
db = db.Order(order)
} else if defaultOrderBy != "" {
db = db.Order(defaultOrderBy)
}
if filter, err := query.GetFilter(); err == nil {
db = db.Where(filter)
}
if pageSize, offset, err := query.GetRange(); err == nil {
var totalCount int64
countDBSession := db.Session(&gorm.Session{Initialized: true})
res := countDBSession.Model(model).Count(&totalCount)
if res.Error != nil {
return db
}
c.Header("Access-Control-Expose-Headers", TotalCountHeader)
c.Header(TotalCountHeader, strconv.Itoa(int(totalCount)))
db = db.Offset(offset).Limit(pageSize)
}
return db
}