api_helpers.go

/*
Copyright (c) 2019-2021 GMO GlobalSign Pte. Ltd.

Licensed under the MIT License (the "License"); you may not use this file except
in compliance with the License. You may obtain a copy of the License at

https://opensource.org/licenses/MIT

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 hvclient

import (
	"fmt"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"
	"time"
)

// headerFromResponse retrieves the value of a header from an HTTP response. If there
// is more than one header value, only the first is returned.
func headerFromResponse(r *http.Response, name string) (string, error) {
	var value = r.Header.Get(name)
	if value == "" {
		return "", fmt.Errorf("no values in HTTP response for header %s", name)
	}

	return value, nil
}

// basePathHeaderFromResponse retrieves the base part of the path value contained in a
// header in an HTTP response. If there is more than one header value, only
// the first is returned.
func basePathHeaderFromResponse(r *http.Response, name string) (string, error) {
	var location, err = headerFromResponse(r, name)
	if err != nil {
		return "", err
	}

	return filepath.Base(location), nil
}

// intHeaderFromResponse retrieves the integer value of a header from an HTTP
// response. If there is more than one header value, only the first is
// returned.
func intHeaderFromResponse(r *http.Response, name string) (int64, error) {
	var s, err = headerFromResponse(r, name)
	if err != nil {
		return 0, err
	}

	var n int64
	n, err = strconv.ParseInt(s, 10, 64)
	if err != nil {
		return 0, err
	}

	return n, nil
}

// paginationString builds a query string for paginated API requests.
// perPage, from and to are optional.
func paginationString(
	page, perPage int,
	from, to time.Time,
) string {
	var builder strings.Builder
	builder.WriteString(fmt.Sprintf("?page=%d", page))

	if perPage > 0 {
		builder.WriteString(fmt.Sprintf("&per_page=%d", perPage))
	}

	if !from.IsZero() {
		builder.WriteString(fmt.Sprintf("&from=%d", from.Unix()))
	}

	if !to.IsZero() {
		builder.WriteString(fmt.Sprintf("&to=%d", to.Unix()))
	}

	return builder.String()
}