1// Copyright 2017 Google Inc. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//    http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package main
16
17import (
18	"encoding/json"
19	"errors"
20	"strings"
21)
22
23// APIsListServiceURL is the URL for the Google APIs Discovery Service
24const APIsListServiceURL = "https://www.googleapis.com/discovery/v1/apis"
25
26// A List represents the results of a call to the apis/list API.
27// https://developers.google.com/discovery/v1/reference/apis/list
28type List struct {
29	Kind             string `json:"kind"`
30	DiscoveryVersion string `json:"discoveryVersion"`
31	APIs             []*API `json:"items"`
32}
33
34// NewList unmarshals the bytes into a Document.
35func NewList(bytes []byte) (*List, error) {
36	var listResponse List
37	err := json.Unmarshal(bytes, &listResponse)
38	return &listResponse, err
39}
40
41// An API represents the an API description returned by the apis/list API.
42type API struct {
43	Kind              string            `json:"kind"`
44	ID                string            `json:"id"`
45	Name              string            `json:"name"`
46	Version           string            `json:"version"`
47	Title             string            `json:"title"`
48	Description       string            `json:"description"`
49	DiscoveryRestURL  string            `json:"discoveryRestUrl"`
50	DiscoveryLink     string            `json:"discoveryLink"`
51	Icons             map[string]string `json:"icons"`
52	DocumentationLink string            `json:"documentationLink"`
53	Labels            []string          `json:"labels"`
54	Preferred         bool              `json:"preferred"`
55}
56
57// APIWithNameAndVersion returns the API with a specified name and version.
58// If version is the empty string, the API name must be unique.
59func (a *List) APIWithNameAndVersion(name string, version string) (*API, error) {
60	var api *API                  // the API to return
61	versions := make([]string, 0) // the matching version names
62	// Scan the list for matching APIs and versions.
63	for _, item := range a.APIs {
64		if item.Name == name {
65			if version == "" || version == item.Version {
66				api = item
67				versions = append(versions, item.Version)
68			}
69		}
70	}
71	switch {
72	case len(versions) == 0:
73		return nil, errors.New(name + " was not found.")
74	case len(versions) > 1:
75		return nil, errors.New(name + " has multiple versions: " + strings.Join(versions, ", "))
76	default:
77		return api, nil
78	}
79}
80