GoToSocial/internal/util/paging.go

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/*
GoToSocial
Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
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"
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 params.NextMaxIDKey == "" {
params.NextMaxIDKey = "max_id"
}
if params.PrevMinIDKey == "" {
params.PrevMinIDKey = "min_id"
}
pageableResponse := EmptyPageableResponse()
if len(params.Items) == 0 {
return pageableResponse, nil
}
// items
pageableResponse.Items = params.Items
protocol := config.GetProtocol()
host := config.GetHost()
// next
nextRaw := params.NextMaxIDKey + "=" + params.NextMaxIDValue
if params.Limit != 0 {
nextRaw = fmt.Sprintf("limit=%d&", params.Limit) + nextRaw
}
for _, p := range params.ExtraQueryParams {
nextRaw = nextRaw + "&" + p
}
nextLink := &url.URL{
Scheme: protocol,
Host: host,
Path: params.Path,
RawQuery: nextRaw,
}
nextLinkString := nextLink.String()
pageableResponse.NextLink = nextLinkString
// prev
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 := &url.URL{
Scheme: protocol,
Host: host,
Path: params.Path,
RawQuery: prevRaw,
}
prevLinkString := prevLink.String()
pageableResponse.PrevLink = prevLinkString
// link header
next := fmt.Sprintf("<%s>; rel=\"next\"", nextLinkString)
prev := fmt.Sprintf("<%s>; rel=\"prev\"", prevLinkString)
pageableResponse.LinkHeader = next + ", " + prev
return pageableResponse, nil
}
// EmptyPageableResponse just returns an empty
// PageableResponse with no link header or items.
func EmptyPageableResponse() *apimodel.PageableResponse {
return &apimodel.PageableResponse{
Items: []interface{}{},
}
}