1 7583dd64 2022-04-13 o package mailmux
 2 7583dd64 2022-04-13 o 
 3 7583dd64 2022-04-13 o import (
 4 7583dd64 2022-04-13 o 	"encoding/json"
 5 7583dd64 2022-04-13 o 	"errors"
 6 7583dd64 2022-04-13 o 	"io"
 7 7583dd64 2022-04-13 o 	"time"
 8 7583dd64 2022-04-13 o )
 9 7583dd64 2022-04-13 o 
10 7583dd64 2022-04-13 o const (
11 7583dd64 2022-04-13 o 	Tregister = 1 + iota
12 7583dd64 2022-04-13 o 	Rregister
13 7583dd64 2022-04-13 o 	Rerror
14 cb474497 2022-04-19 o 	Tcreate
15 cb474497 2022-04-19 o 	Rcreate
16 7583dd64 2022-04-13 o 	Tlist
17 7583dd64 2022-04-13 o 	Rlist
18 7583dd64 2022-04-13 o 	Tremove
19 cb474497 2022-04-19 o 	Rremove
20 71bdede3 2022-04-21 o 	Tauth
21 71bdede3 2022-04-21 o 	Rauth
22 7583dd64 2022-04-13 o )
23 7583dd64 2022-04-13 o 
24 c7ecbae7 2022-04-13 o // Mcall represents a message passed between mailmux clients and servers.
25 7583dd64 2022-04-13 o // Operations requested by clients are T-messages (such as Tregister).
26 c7ecbae7 2022-04-13 o // Servers respond with the corresponding R-message (such as Rregister).
27 c7ecbae7 2022-04-13 o // Servers may instead respond with Rerror to inform the client, with a diagnostic message,
28 c7ecbae7 2022-04-13 o // that the request was not completed successfully.
29 7583dd64 2022-04-13 o // This design is loosely based on the Plan 9 network file protocol 9P.
30 7583dd64 2022-04-13 o type Mcall struct {
31 5b8260a5 2022-04-13 o 	Type     uint
32 925168e0 2022-04-14 o 	Username string    `json:",omitempty"` // Tregister, Rregister
33 925168e0 2022-04-14 o 	Password string    `json:",omitempty"` // Tregister
34 925168e0 2022-04-14 o 	Error    string    `json:",omitempty"` // Rerror
35 925168e0 2022-04-14 o 	Aliases  []Alias   `json:",omitempty"` // Rnew, Rlist, Tremove
36 cb474497 2022-04-19 o 	Expiry   time.Time `json:",omitempty"` // Tcreate, Rnew
37 7583dd64 2022-04-13 o }
38 7583dd64 2022-04-13 o 
39 c7ecbae7 2022-04-13 o // ParseMcall parses and validates a JSON-encoded Mcall from r.
40 7583dd64 2022-04-13 o func ParseMcall(r io.Reader) (*Mcall, error) {
41 7583dd64 2022-04-13 o 	var mc Mcall
42 7583dd64 2022-04-13 o 	if err := json.NewDecoder(r).Decode(&mc); err != nil {
43 7583dd64 2022-04-13 o 		return nil, err
44 7583dd64 2022-04-13 o 	}
45 a7e7d1d5 2022-04-13 o 	switch mc.Type {
46 a7e7d1d5 2022-04-13 o 	case Rerror:
47 a7e7d1d5 2022-04-13 o 		if mc.Error == "" {
48 a7e7d1d5 2022-04-13 o 			return nil, errors.New("empty error message")
49 a7e7d1d5 2022-04-13 o 		}
50 71bdede3 2022-04-21 o 	case Tauth:
51 a7e7d1d5 2022-04-13 o 		if mc.Username == "" {
52 a7e7d1d5 2022-04-13 o 			return nil, errors.New("empty username")
53 71bdede3 2022-04-21 o 		}
54 71bdede3 2022-04-21 o 		if mc.Password == "" {
55 a7e7d1d5 2022-04-13 o 			return nil, errors.New("empty password")
56 a7e7d1d5 2022-04-13 o 		}
57 71bdede3 2022-04-21 o 	case Tregister, Tcreate, Tlist, Tremove:
58 71bdede3 2022-04-21 o 		// check required params
59 7583dd64 2022-04-13 o 	}
60 7583dd64 2022-04-13 o 	return &mc, nil
61 7583dd64 2022-04-13 o }
62 71bdede3 2022-04-21 o 
63 71bdede3 2022-04-21 o func writeMcall(w io.Writer, mcall *Mcall) error {
64 71bdede3 2022-04-21 o 	return json.NewEncoder(w).Encode(mcall)
65 71bdede3 2022-04-21 o }
66 71bdede3 2022-04-21 o 
67 71bdede3 2022-04-21 o // rerror writes a JSON-encoded Rerror message to the underlying writer
68 71bdede3 2022-04-21 o // with its Error field set to errormsg.
69 71bdede3 2022-04-21 o func rerror(w io.Writer, errormsg string) error {
70 71bdede3 2022-04-21 o 	rmsg := &Mcall{Type: Rerror, Error: errormsg}
71 71bdede3 2022-04-21 o 	return writeMcall(w, rmsg)
72 71bdede3 2022-04-21 o }