lib/controller/router/response.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         "net/http"
  11         "regexp"
  12         "strings"
  13         "time"
  14
  15         "git.arvados.org/arvados.git/sdk/go/arvados"
  16         "git.arvados.org/arvados.git/sdk/go/httpserver"
  17 )
  18
  19 const rfc3339NanoFixed = "2006-01-02T15:04:05.000000000Z07:00"
  20
  21 type responseOptions struct {
  22         Select []string
  23         Count  string
  24 }
  25
  26 func (rtr *router) responseOptions(opts interface{}) (responseOptions, error) {
  27         var rOpts responseOptions
  28         switch opts := opts.(type) {
  29         case *arvados.GetOptions:
  30                 rOpts.Select = opts.Select
  31         case *arvados.ListOptions:
  32                 rOpts.Select = opts.Select
  33                 rOpts.Count = opts.Count
  34         }
  35         return rOpts, nil
  36 }
  37
  38 func applySelectParam(selectParam []string, orig map[string]interface{}) map[string]interface{} {
  39         if len(selectParam) == 0 {
  40                 return orig
  41         }
  42         selected := map[string]interface{}{}
  43         for _, attr := range selectParam {
  44                 if v, ok := orig[attr]; ok {
  45                         selected[attr] = v
  46                 }
  47         }
  48         // Some keys are always preserved, even if not requested
  49         for _, k := range []string{"etag", "kind", "writable_by"} {
  50                 if v, ok := orig[k]; ok {
  51                         selected[k] = v
  52                 }
  53         }
  54         return selected
  55 }
  56
  57 func (rtr *router) sendResponse(w http.ResponseWriter, req *http.Request, resp interface{}, opts responseOptions) {
  58         var tmp map[string]interface{}
  59
  60         if resp, ok := resp.(http.Handler); ok {
  61                 // resp knows how to write its own http response
  62                 // header and body.
  63                 resp.ServeHTTP(w, req)
  64                 return
  65         }
  66
  67         err := rtr.transcode(resp, &tmp)
  68         if err != nil {
  69                 rtr.sendError(w, err)
  70                 return
  71         }
  72
  73         respKind := kind(resp)
  74         if respKind != "" {
  75                 tmp["kind"] = respKind
  76         }
  77         defaultItemKind := ""
  78         if strings.HasSuffix(respKind, "List") {
  79                 defaultItemKind = strings.TrimSuffix(respKind, "List")
  80         }
  81
  82         if items, ok := tmp["items"].([]interface{}); ok {
  83                 for i, item := range items {
  84                         // Fill in "kind" by inspecting UUID/PDH if
  85                         // possible; fall back on assuming each
  86                         // Items[] entry in an "arvados#fooList"
  87                         // response should have kind="arvados#foo".
  88                         item, _ := item.(map[string]interface{})
  89                         infix := ""
  90                         if uuid, _ := item["uuid"].(string); len(uuid) == 27 {
  91                                 infix = uuid[6:11]
  92                         }
  93                         if k := kind(infixMap[infix]); k != "" {
  94                                 item["kind"] = k
  95                         } else if pdh, _ := item["portable_data_hash"].(string); pdh != "" {
  96                                 item["kind"] = "arvados#collection"
  97                         } else if defaultItemKind != "" {
  98                                 item["kind"] = defaultItemKind
  99                         }
 100                         items[i] = applySelectParam(opts.Select, item)
 101                 }
 102                 if opts.Count == "none" {
 103                         delete(tmp, "items_available")
 104                 }
 105         } else {
 106                 tmp = applySelectParam(opts.Select, tmp)
 107         }
 108
 109         // Format non-nil timestamps as rfc3339NanoFixed (by default
 110         // they will have been encoded to time.RFC3339Nano, which
 111         // omits trailing zeroes).
 112         for k, v := range tmp {
 113                 if !strings.HasSuffix(k, "_at") {
 114                         continue
 115                 }
 116                 switch tv := v.(type) {
 117                 case *time.Time:
 118                         if tv == nil {
 119                                 break
 120                         }
 121                         tmp[k] = tv.Format(rfc3339NanoFixed)
 122                 case time.Time:
 123                         tmp[k] = tv.Format(rfc3339NanoFixed)
 124                 case string:
 125                         t, err := time.Parse(time.RFC3339Nano, tv)
 126                         if err != nil {
 127                                 break
 128                         }
 129                         tmp[k] = t.Format(rfc3339NanoFixed)
 130                 }
 131         }
 132         w.Header().Set("Content-Type", "application/json")
 133         enc := json.NewEncoder(w)
 134         enc.SetEscapeHTML(false)
 135         enc.Encode(tmp)
 136 }
 137
 138 func (rtr *router) sendError(w http.ResponseWriter, err error) {
 139         code := http.StatusInternalServerError
 140         if err, ok := err.(interface{ HTTPStatus() int }); ok {
 141                 code = err.HTTPStatus()
 142         }
 143         httpserver.Error(w, err.Error(), code)
 144 }
 145
 146 var infixMap = map[string]interface{}{
 147         "4zz18": arvados.Collection{},
 148         "j7d0g": arvados.Group{},
 149 }
 150
 151 var mungeKind = regexp.MustCompile(`\..`)
 152
 153 func kind(resp interface{}) string {
 154         t := fmt.Sprintf("%T", resp)
 155         if !strings.HasPrefix(t, "arvados.") {
 156                 return ""
 157         }
 158         return mungeKind.ReplaceAllStringFunc(t, func(s string) string {
 159                 // "arvados.CollectionList" => "arvados#collectionList"
 160                 return "#" + strings.ToLower(s[1:])
 161         })
 162 }