gtsocial-umbx

paging.go (4412B)

---

 // GoToSocial
 // Copyright (C) GoToSocial Authors admin@gotosocial.org
 // SPDX-License-Identifier: AGPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU Affero General Public License for more details.
 //
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package util
 
 import (
 	"fmt"
 	"net/url"
 	"strings"
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 )
 
 // PageableResponseParams models the parameters to pass to PackagePageableResponse.
 //
 // The given items will be provided in the paged response.
 //
 // The other values are all used to create the Link header so that callers know
 // which endpoint to query next and previously in order to do paging.
 type PageableResponseParams struct {
 	Items            []interface{} // Sorted slice of items (statuses, notifications, etc)
 	Path             string        // path to use for next/prev queries in the link header
 	NextMaxIDKey     string        // key to use for the next max id query param in the link header, defaults to 'max_id'
 	NextMaxIDValue   string        // value to use for next max id
 	PrevMinIDKey     string        // key to use for the prev min id query param in the link header, defaults to 'min_id'
 	PrevMinIDValue   string        // value to use for prev min id
 	Limit            int           // limit number of entries to return
 	ExtraQueryParams []string      // any extra query parameters to provide in the link header, should be in the format 'example=value'
 }
 
 // PackagePageableResponse is a convenience function for returning
 // a bunch of pageable items (notifications, statuses, etc), as well
 // as a Link header to inform callers of where to find next/prev items.
 func PackagePageableResponse(params PageableResponseParams) (*apimodel.PageableResponse, gtserror.WithCode) {
 	if len(params.Items) == 0 {
 		// No items to page through.
 		return EmptyPageableResponse(), nil
 	}
 
 	// Set default paging values, if
 	// they weren't set by the caller.
 	if params.NextMaxIDKey == "" {
 		params.NextMaxIDKey = "max_id"
 	}
 
 	if params.PrevMinIDKey == "" {
 		params.PrevMinIDKey = "min_id"
 	}
 
 	var (
 		protocol        = config.GetProtocol()
 		host            = config.GetHost()
 		nextLink        string
 		prevLink        string
 		linkHeaderParts = make([]string, 0, 2)
 	)
 
 	// Parse next link.
 	if params.NextMaxIDValue != "" {
 		nextRaw := params.NextMaxIDKey + "=" + params.NextMaxIDValue
 
 		if params.Limit != 0 {
 			nextRaw = fmt.Sprintf("limit=%d&", params.Limit) + nextRaw
 		}
 
 		for _, p := range params.ExtraQueryParams {
 			nextRaw += "&" + p
 		}
 
 		nextLink = func() string {
 			u := &url.URL{
 				Scheme:   protocol,
 				Host:     host,
 				Path:     params.Path,
 				RawQuery: nextRaw,
 			}
 			return u.String()
 		}()
 
 		linkHeaderParts = append(linkHeaderParts, `<`+nextLink+`>; rel="next"`)
 	}
 
 	// Parse prev link.
 	if params.PrevMinIDValue != "" {
 		prevRaw := params.PrevMinIDKey + "=" + params.PrevMinIDValue
 
 		if params.Limit != 0 {
 			prevRaw = fmt.Sprintf("limit=%d&", params.Limit) + prevRaw
 		}
 
 		for _, p := range params.ExtraQueryParams {
 			prevRaw = prevRaw + "&" + p
 		}
 
 		prevLink = func() string {
 			u := &url.URL{
 				Scheme:   protocol,
 				Host:     host,
 				Path:     params.Path,
 				RawQuery: prevRaw,
 			}
 			return u.String()
 		}()
 
 		linkHeaderParts = append(linkHeaderParts, `<`+prevLink+`>; rel="prev"`)
 	}
 
 	return &apimodel.PageableResponse{
 		Items:      params.Items,
 		LinkHeader: strings.Join(linkHeaderParts, ", "),
 		NextLink:   nextLink,
 		PrevLink:   prevLink,
 	}, nil
 }
 
 // EmptyPageableResponse just returns an empty
 // PageableResponse with no link header or items.
 func EmptyPageableResponse() *apimodel.PageableResponse {
 	return &apimodel.PageableResponse{
 		Items: []interface{}{},
 	}
 }