github.com/vmware/govmomi@v0.43.0/vapi/rest/resource.go (about) 1 /* 2 Copyright (c) 2019 VMware, Inc. All Rights Reserved. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package rest 18 19 import ( 20 "bytes" 21 "encoding/json" 22 "io" 23 "net/http" 24 "net/url" 25 ) 26 27 const ( 28 Path = "/rest" 29 ) 30 31 // Resource wraps url.URL with helpers 32 type Resource struct { 33 u *url.URL 34 } 35 36 func (r *Resource) String() string { 37 return r.u.String() 38 } 39 40 // WithSubpath appends the provided subpath to the URL.Path 41 func (r *Resource) WithSubpath(subpath string) *Resource { 42 r.u.Path += "/" + subpath 43 return r 44 } 45 46 // WithID appends id to the URL.Path 47 func (r *Resource) WithID(id string) *Resource { 48 r.u.Path += "/id:" + id 49 return r 50 } 51 52 // WithAction sets adds action to the URL.RawQuery 53 func (r *Resource) WithAction(action string) *Resource { 54 return r.WithParam("~action", action) 55 } 56 57 // WithParam adds one parameter on the URL.RawQuery 58 func (r *Resource) WithParam(name string, value string) *Resource { 59 // ParseQuery handles empty case, and we control access to query string so shouldn't encounter an error case 60 params, err := url.ParseQuery(r.u.RawQuery) 61 if err != nil { 62 panic(err) 63 } 64 params[name] = append(params[name], value) 65 r.u.RawQuery = params.Encode() 66 return r 67 } 68 69 // WithPathEncodedParam appends a parameter on the URL.RawQuery, 70 // For special cases where URL Path-style encoding is needed 71 func (r *Resource) WithPathEncodedParam(name string, value string) *Resource { 72 t := &url.URL{Path: value} 73 encodedValue := t.String() 74 t = &url.URL{Path: name} 75 encodedName := t.String() 76 // ParseQuery handles empty case, and we control access to query string so shouldn't encounter an error case 77 params, err := url.ParseQuery(r.u.RawQuery) 78 if err != nil { 79 panic(err) 80 } 81 // Values.Encode() doesn't escape exactly how we want, so we need to build the query string ourselves 82 if len(params) >= 1 { 83 r.u.RawQuery = r.u.RawQuery + "&" + encodedName + "=" + encodedValue 84 } else { 85 r.u.RawQuery = r.u.RawQuery + encodedName + "=" + encodedValue 86 } 87 return r 88 } 89 90 // Request returns a new http.Request for the given method. 91 // An optional body can be provided for POST and PATCH methods. 92 func (r *Resource) Request(method string, body ...interface{}) *http.Request { 93 rdr := io.MultiReader() // empty body by default 94 if len(body) != 0 { 95 rdr = encode(body[0]) 96 } 97 req, err := http.NewRequest(method, r.u.String(), rdr) 98 if err != nil { 99 panic(err) 100 } 101 return req 102 } 103 104 type errorReader struct { 105 e error 106 } 107 108 func (e errorReader) Read([]byte) (int, error) { 109 return -1, e.e 110 } 111 112 // encode body as JSON, deferring any errors until io.Reader is used. 113 func encode(body interface{}) io.Reader { 114 var b bytes.Buffer 115 err := json.NewEncoder(&b).Encode(body) 116 if err != nil { 117 return errorReader{err} 118 } 119 return &b 120 }