drone/app/api/render/header.go

104 lines
3.0 KiB
Go

// Copyright 2023 Harness, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package render
import (
"fmt"
"net/http"
"net/url"
"strconv"
)
// format string for the link header value.
var linkf = `<%s>; rel="%s"`
// Pagination writes the pagination and link headers to the http.Response.
func Pagination(r *http.Request, w http.ResponseWriter, page, size, total int) {
var (
last = pagelen(size, total)
)
// Add information that doesn't require total
PaginationNoTotal(r, w, page, size, page >= last)
// add information that requires total
uri := getPaginationBaseURL(r, page, size)
params := uri.Query()
// update the page query parameter and re-encode
params.Set("page", strconv.Itoa(last))
uri.RawQuery = params.Encode()
// write the page total to the header.
w.Header().Set("x-total", strconv.Itoa(total))
w.Header().Set("x-total-pages", strconv.Itoa(last))
w.Header().Add("Link", fmt.Sprintf(linkf, uri.String(), "last"))
}
// PaginationNoTotal writes the pagination and link headers to the http.Response when total is unknown.
func PaginationNoTotal(r *http.Request, w http.ResponseWriter, page int, size int, isLastPage bool) {
var (
next = page + 1
prev = max(page-1, 1)
)
// write basic headers
w.Header().Set("x-page", strconv.Itoa(page))
w.Header().Set("x-per-page", strconv.Itoa(size))
// write headers based on relative location of current page
uri := getPaginationBaseURL(r, page, size)
params := uri.Query()
if !isLastPage {
// update the page query parameter and re-encode
params.Set("page", strconv.Itoa(next))
uri.RawQuery = params.Encode()
// write the next page to the header.
w.Header().Set("x-next-page", strconv.Itoa(next))
w.Header().Add("Link", fmt.Sprintf(linkf, uri.String(), "next"))
}
if page > 1 {
// update the page query parameter and re-encode.
params.Set("page", strconv.Itoa(prev))
uri.RawQuery = params.Encode()
// write the previous page to the header.
w.Header().Set("x-prev-page", strconv.Itoa(prev))
w.Header().Add("Link", fmt.Sprintf(linkf, uri.String(), "prev"))
}
}
// PaginationLimit writes the x-total header.
func PaginationLimit(_ *http.Request, w http.ResponseWriter, total int) {
w.Header().Set("x-total", strconv.Itoa(total))
}
func getPaginationBaseURL(r *http.Request, page int, size int) url.URL {
uri := *r.URL
// parse the existing query parameters and
// sanize parameter list.
params := uri.Query()
params.Del("access_token")
params.Del("token")
params.Set("page", strconv.Itoa(page))
params.Set("limit", strconv.Itoa(size))
return uri
}