lib/controller/router/request.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package router
   6
   7 import (
   8         "encoding/json"
   9         "fmt"
  10         "io"
  11         "mime"
  12         "net/http"
  13         "strconv"
  14         "strings"
  15
  16         "github.com/julienschmidt/httprouter"
  17 )
  18
  19 // Parse req as an Arvados V1 API request and return the request
  20 // parameters.
  21 //
  22 // If the request has a parameter whose name is attrsKey (e.g.,
  23 // "collection"), it is renamed to "attrs".
  24 func (rtr *router) loadRequestParams(req *http.Request, attrsKey string) (map[string]interface{}, error) {
  25         err := req.ParseForm()
  26         if err != nil {
  27                 return nil, httpError(http.StatusBadRequest, err)
  28         }
  29         params := map[string]interface{}{}
  30
  31         // Load parameters from req.Form, which (after
  32         // req.ParseForm()) includes the query string and -- when
  33         // Content-Type is application/x-www-form-urlencoded -- the
  34         // request body.
  35         for k, values := range req.Form {
  36                 // All of these form values arrive as strings, so we
  37                 // need some type-guessing to accept non-string
  38                 // inputs:
  39                 //
  40                 // Values for parameters that take ints (limit=1) or
  41                 // bools (include_trash=1) are parsed accordingly.
  42                 //
  43                 // "null" and "" are nil.
  44                 //
  45                 // Values that look like JSON objects, arrays, or
  46                 // strings are parsed as JSON.
  47                 //
  48                 // The rest are left as strings.
  49                 for _, v := range values {
  50                         switch {
  51                         case intParams[k]:
  52                                 params[k], err = strconv.ParseInt(v, 10, 64)
  53                                 if err != nil {
  54                                         return nil, err
  55                                 }
  56                         case boolParams[k]:
  57                                 params[k] = stringToBool(v)
  58                         case v == "null" || v == "":
  59                                 params[k] = nil
  60                         case strings.HasPrefix(v, "["):
  61                                 var j []interface{}
  62                                 err := json.Unmarshal([]byte(v), &j)
  63                                 if err != nil {
  64                                         return nil, err
  65                                 }
  66                                 params[k] = j
  67                         case strings.HasPrefix(v, "{"):
  68                                 var j map[string]interface{}
  69                                 err := json.Unmarshal([]byte(v), &j)
  70                                 if err != nil {
  71                                         return nil, err
  72                                 }
  73                                 params[k] = j
  74                         case strings.HasPrefix(v, "\""):
  75                                 var j string
  76                                 err := json.Unmarshal([]byte(v), &j)
  77                                 if err != nil {
  78                                         return nil, err
  79                                 }
  80                                 params[k] = j
  81                         default:
  82                                 params[k] = v
  83                         }
  84                         // TODO: Need to accept "?foo[]=bar&foo[]=baz"
  85                         // as foo=["bar","baz"]?
  86                 }
  87         }
  88
  89         // Decode body as JSON if Content-Type request header is
  90         // missing or application/json.
  91         mt := req.Header.Get("Content-Type")
  92         if ct, _, err := mime.ParseMediaType(mt); err != nil && mt != "" {
  93                 return nil, fmt.Errorf("error parsing media type %q: %s", mt, err)
  94         } else if (ct == "application/json" || mt == "") && req.ContentLength != 0 {
  95                 jsonParams := map[string]interface{}{}
  96                 err := json.NewDecoder(req.Body).Decode(&jsonParams)
  97                 if err != nil {
  98                         return nil, httpError(http.StatusBadRequest, err)
  99                 }
 100                 for k, v := range jsonParams {
 101                         params[k] = v
 102                 }
 103                 if attrsKey != "" && params[attrsKey] == nil {
 104                         // Copy top-level parameters from JSON request
 105                         // body into params[attrsKey]. Some SDKs rely
 106                         // on this Rails API feature; see
 107                         // https://api.rubyonrails.org/v5.2.1/classes/ActionController/ParamsWrapper.html
 108                         params[attrsKey] = jsonParams
 109                 }
 110         }
 111
 112         routeParams, _ := req.Context().Value(httprouter.ParamsKey).(httprouter.Params)
 113         for _, p := range routeParams {
 114                 params[p.Key] = p.Value
 115         }
 116
 117         if v, ok := params[attrsKey]; ok && attrsKey != "" {
 118                 params["attrs"] = v
 119                 delete(params, attrsKey)
 120         }
 121
 122         if order, ok := params["order"].(string); ok {
 123                 // We must accept strings ("foo, bar desc") and arrays
 124                 // (["foo", "bar desc"]) because RailsAPI does.
 125                 // Convert to an array here before trying to unmarshal
 126                 // into options structs.
 127                 if order == "" {
 128                         delete(params, "order")
 129                 } else {
 130                         params["order"] = strings.Split(order, ",")
 131                 }
 132         }
 133
 134         return params, nil
 135 }
 136
 137 // Copy src to dst, using json as an intermediate format in order to
 138 // invoke src's json-marshaling and dst's json-unmarshaling behaviors.
 139 func (rtr *router) transcode(src interface{}, dst interface{}) error {
 140         var errw error
 141         pr, pw := io.Pipe()
 142         go func() {
 143                 defer pw.Close()
 144                 errw = json.NewEncoder(pw).Encode(src)
 145         }()
 146         defer pr.Close()
 147         err := json.NewDecoder(pr).Decode(dst)
 148         if errw != nil {
 149                 return errw
 150         }
 151         return err
 152 }
 153
 154 var intParams = map[string]bool{
 155         "limit":  true,
 156         "offset": true,
 157 }
 158
 159 var boolParams = map[string]bool{
 160         "distinct":             true,
 161         "ensure_unique_name":   true,
 162         "include_trash":        true,
 163         "include_old_versions": true,
 164 }
 165
 166 func stringToBool(s string) bool {
 167         switch s {
 168         case "", "false", "0":
 169                 return false
 170         default:
 171                 return true
 172         }
 173 }