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pagination.go
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pagination.go
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// Copyright © 2022 Ory Corp
// SPDX-License-Identifier: Apache-2.0
package tokenpagination
import (
"encoding/base64"
"fmt"
"net/http"
"net/url"
"strconv"
"github.com/pkg/errors"
"github.com/tidwall/gjson"
"github.com/ory/x/pagination"
"github.com/ory/herodot"
)
func Encode(offset int64) string {
return base64.RawURLEncoding.EncodeToString([]byte(fmt.Sprintf(`{"offset":"%d","v":2}`, offset)))
}
func decode(s string) (int, error) {
b, err := base64.RawURLEncoding.DecodeString(s)
if err != nil {
return 0, errors.WithStack(herodot.ErrBadRequest.WithWrap(err).WithReasonf("Unable to parse pagination token: %s", err))
}
return int(gjson.Get(string(b), "offset").Int()), nil
}
type TokenPaginator struct {
MaxItems int
DefaultItems int
}
func (p *TokenPaginator) defaults() {
if p.MaxItems == 0 {
p.MaxItems = 1000
}
if p.DefaultItems == 0 {
p.DefaultItems = 250
}
}
// ParsePagination parses limit and page from *http.Request with given limits and defaults.
func (p *TokenPaginator) ParsePagination(r *http.Request) (page, itemsPerPage int) {
p.defaults()
var offset int
if offsetParam := r.URL.Query().Get("page_token"); len(offsetParam) > 0 {
offset, _ = decode(offsetParam)
}
if gotLimit, err := strconv.ParseInt(r.URL.Query().Get("page_size"), 10, 0); err == nil {
itemsPerPage = int(gotLimit)
} else {
itemsPerPage = p.DefaultItems
}
if itemsPerPage > p.MaxItems {
itemsPerPage = p.MaxItems
}
if itemsPerPage < 1 {
itemsPerPage = 1
}
if offset > 0 {
page = offset / itemsPerPage
}
if page < 0 {
page = 0
}
return
}
func header(u *url.URL, rel string, itemsPerPage, offset int64) string {
q := u.Query()
q.Set("page_size", fmt.Sprintf("%d", itemsPerPage))
q.Set("page_token", Encode(offset))
u.RawQuery = q.Encode()
return fmt.Sprintf("<%s>; rel=\"%s\"", u.String(), rel)
}
func PaginationHeader(w http.ResponseWriter, u *url.URL, total int64, page, itemsPerPage int) {
pagination.HeaderWithFormatter(w, u, total, page, itemsPerPage, header)
}