rename dir (#283)

[bytom/vapor.git] / toolbar / federation / api / pagination.go

diff --git a/toolbar/federation/api/pagination.go b/toolbar/federation/api/pagination.go
new file mode 100644 (file)
index 0000000..f93c1bd
--- /dev/null
+++ b/toolbar/federation/api/pagination.go
@@ -0,0 +1,73 @@
+package api
+
+import (
+       "fmt"
+       "reflect"
+       "strconv"
+
+       "github.com/gin-gonic/gin"
+
+       "github.com/vapor/errors"
+)
+
+const (
+       defaultSatrtStr = "0"
+       defaultLimitStr = "10"
+       maxPageLimit    = 1000
+)
+
+var (
+       errParsePaginationStart = fmt.Errorf("parse pagination start")
+       errParsePaginationLimit = fmt.Errorf("parse pagination limit")
+)
+
+type PaginationQuery struct {
+       Start uint64 `json:"start"`
+       Limit uint64 `json:"limit"`
+}
+
+// parsePagination request meets the standard on https://developer.atlassian.com/server/confluence/pagination-in-the-rest-api/
+func parsePagination(c *gin.Context) (*PaginationQuery, error) {
+       startStr := c.DefaultQuery("start", defaultSatrtStr)
+       limitStr := c.DefaultQuery("limit", defaultLimitStr)
+
+       start, err := strconv.ParseUint(startStr, 10, 64)
+       if err != nil {
+               return nil, errors.Wrap(err, errParsePaginationStart)
+       }
+
+       limit, err := strconv.ParseUint(limitStr, 10, 64)
+       if err != nil {
+               return nil, errors.Wrap(err, errParsePaginationLimit)
+       }
+
+       if limit > maxPageLimit {
+               limit = maxPageLimit
+       }
+
+       return &PaginationQuery{
+               Start: start,
+               Limit: limit,
+       }, nil
+}
+
+type PaginationInfo struct {
+       Start   uint64
+       Limit   uint64
+       HasNext bool
+}
+
+func processPaginationIfPresent(fun handlerFun, args []interface{}, result []interface{}, context *gin.Context) bool {
+       ft := reflect.TypeOf(fun)
+       if ft.NumIn() != 3 {
+               return false
+       }
+
+       list := result[0]
+       size := reflect.ValueOf(list).Len()
+       query := args[2].(*PaginationQuery)
+
+       paginationInfo := &PaginationInfo{Start: query.Start, Limit: query.Limit, HasNext: size == int(query.Limit)}
+       respondSuccessPaginationResp(context, list, paginationInfo)
+       return true
+}