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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2015-2019 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package agent
import (
"encoding/json"
"fmt"
"net/http"
"github.com/snapcore/snapd/logger"
)
// TODO: clean up unused code further after we have progressed enough
// to have a clear sense of what is untested and uneeded here
// ResponseType is the response type
type ResponseType string
// "there are three standard return types: Standard return value,
// Background operation, Error", each returning a JSON object with the
// following "type" field:
const (
ResponseTypeSync ResponseType = "sync"
ResponseTypeAsync ResponseType = "async"
ResponseTypeError ResponseType = "error"
)
// Response knows how to serve itself, and how to find itself
type Response interface {
ServeHTTP(w http.ResponseWriter, r *http.Request)
}
type resp struct {
Status int // HTTP status code
Type ResponseType
Result any
}
type respJSON struct {
Type ResponseType `json:"type"`
Result any `json:"result"`
}
func (r *resp) MarshalJSON() ([]byte, error) {
return json.Marshal(respJSON{
Type: r.Type,
Result: r.Result,
})
}
func (r *resp) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
status := r.Status
bs, err := r.MarshalJSON()
if err != nil {
logger.Noticef("cannot marshal %#v to JSON: %v", *r, err)
bs = nil
status = 500
}
hdr := w.Header()
if r.Status == 202 || r.Status == 201 {
if m, ok := r.Result.(map[string]any); ok {
if location, ok := m["resource"]; ok {
if location, ok := location.(string); ok && location != "" {
hdr.Set("Location", location)
}
}
}
}
hdr.Set("Content-Type", "application/json")
w.WriteHeader(status)
w.Write(bs)
}
type errorKind string
const (
errorKindLoginRequired = errorKind("login-required")
errorKindServiceControl = errorKind("service-control")
errorKindServiceStatus = errorKind("service-status")
)
type errorValue any
type errorResult struct {
Message string `json:"message"` // mandatory in error responses
Kind errorKind `json:"kind,omitempty"`
Value errorValue `json:"value,omitempty"`
}
// SyncResponse builds a "sync" response from the given result.
func SyncResponse(result any) Response {
if err, ok := result.(error); ok {
return InternalError("internal error: %v", err)
}
if rsp, ok := result.(Response); ok {
return rsp
}
return &resp{
Type: ResponseTypeSync,
Status: 200,
Result: result,
}
}
// AsyncResponse builds an "async" response from the given *Task
func AsyncResponse(result map[string]any) Response {
return &resp{
Type: ResponseTypeAsync,
Status: 202,
Result: result,
}
}
// makeErrorResponder builds an errorResponder from the given error status.
func makeErrorResponder(status int) errorResponder {
return func(format string, v ...any) Response {
res := &errorResult{}
if len(v) == 0 {
res.Message = format
} else {
res.Message = fmt.Sprintf(format, v...)
}
if status == 401 {
res.Kind = errorKindLoginRequired
}
return &resp{
Type: ResponseTypeError,
Result: res,
Status: status,
}
}
}
// errorResponder is a callable that produces an error Response.
// e.g., InternalError("something broke: %v", err), etc.
type errorResponder func(string, ...any) Response
// standard error responses
var (
Unauthorized = makeErrorResponder(401)
NotFound = makeErrorResponder(404)
BadRequest = makeErrorResponder(400)
MethodNotAllowed = makeErrorResponder(405)
InternalError = makeErrorResponder(500)
NotImplemented = makeErrorResponder(501)
Forbidden = makeErrorResponder(403)
Conflict = makeErrorResponder(409)
)
|
