1 1d5ddf5d 2024-02-20 o // apub is an implementation of the ActivityPub protocol.
  2 1d5ddf5d 2024-02-20 o //
  3 1d5ddf5d 2024-02-20 o // https://www.w3.org/TR/activitypub/
  4 1d5ddf5d 2024-02-20 o // https://www.w3.org/TR/activitystreams-core/
  5 1d5ddf5d 2024-02-20 o // https://www.w3.org/TR/activitystreams-vocabulary/
  6 1d5ddf5d 2024-02-20 o package apub
  7 1d5ddf5d 2024-02-20 o 
  8 1d5ddf5d 2024-02-20 o import (
  9 1d5ddf5d 2024-02-20 o 	"bytes"
 10 1d5ddf5d 2024-02-20 o 	"encoding/json"
 11 1d5ddf5d 2024-02-20 o 	"errors"
 12 1d5ddf5d 2024-02-20 o 	"fmt"
 13 1d5ddf5d 2024-02-20 o 	"io"
 14 1d5ddf5d 2024-02-20 o 	"net/mail"
 15 1d5ddf5d 2024-02-20 o 	"strings"
 16 1d5ddf5d 2024-02-20 o 	"time"
 17 1d5ddf5d 2024-02-20 o )
 18 1d5ddf5d 2024-02-20 o 
 19 1d5ddf5d 2024-02-20 o // @context
 20 1d5ddf5d 2024-02-20 o const AtContext string = "https://www.w3.org/ns/activitystreams"
 21 1d5ddf5d 2024-02-20 o 
 22 25fed994 2024-03-12 o // ContentType is the MIME media type for ActivityPub.
 23 1d5ddf5d 2024-02-20 o const ContentType string = "application/activity+json"
 24 1d5ddf5d 2024-02-20 o 
 25 25fed994 2024-03-12 o // PublicCollection is the ActivityPub ID for the special collection indicating public access.
 26 25fed994 2024-03-12 o // Any Activity addressed to this collection is meant to be available to all users,
 27 25fed994 2024-03-12 o // authenticated or not.
 28 77918b00 2024-03-07 o // See W3C Recommendation ActivityPub Section 5.6.
 29 77918b00 2024-03-07 o const PublicCollection string = "https://www.w3.org/ns/activitystreams#Public"
 30 1d5ddf5d 2024-02-20 o 
 31 71191436 2024-02-28 o var ErrNotExist = errors.New("no such activity")
 32 71191436 2024-02-28 o 
 33 1d5ddf5d 2024-02-20 o type Activity struct {
 34 1d5ddf5d 2024-02-20 o 	AtContext    string     `json:"@context"`
 35 1d5ddf5d 2024-02-20 o 	ID           string     `json:"id"`
 36 1d5ddf5d 2024-02-20 o 	Type         string     `json:"type"`
 37 1d5ddf5d 2024-02-20 o 	Name         string     `json:"name,omitempty"`
 38 1d5ddf5d 2024-02-20 o 	Actor        string     `json:"actor,omitempty"`
 39 1d5ddf5d 2024-02-20 o 	Username     string     `json:"preferredUsername,omitempty"`
 40 77918b00 2024-03-07 o 	Summary      string     `json:"summary,omitempty"`
 41 1d5ddf5d 2024-02-20 o 	Inbox        string     `json:"inbox,omitempty"`
 42 1d5ddf5d 2024-02-20 o 	Outbox       string     `json:"outbox,omitempty"`
 43 1d5ddf5d 2024-02-20 o 	To           []string   `json:"to,omitempty"`
 44 1d5ddf5d 2024-02-20 o 	CC           []string   `json:"cc,omitempty"`
 45 77918b00 2024-03-07 o 	Followers    string     `json:"followers,omitempty"`
 46 1d5ddf5d 2024-02-20 o 	InReplyTo    string     `json:"inReplyTo,omitempty"`
 47 1d5ddf5d 2024-02-20 o 	Published    *time.Time `json:"published,omitempty"`
 48 1d5ddf5d 2024-02-20 o 	AttributedTo string     `json:"attributedTo,omitempty"`
 49 1d5ddf5d 2024-02-20 o 	Content      string     `json:"content,omitempty"`
 50 1d5ddf5d 2024-02-20 o 	MediaType    string     `json:"mediaType,omitempty"`
 51 1d5ddf5d 2024-02-20 o 	Source       struct {
 52 1d5ddf5d 2024-02-20 o 		Content   string `json:"content,omitempty"`
 53 1d5ddf5d 2024-02-20 o 		MediaType string `json:"mediaType,omitempty"`
 54 1d5ddf5d 2024-02-20 o 	} `json:"source,omitempty"`
 55 77918b00 2024-03-07 o 	PublicKey *PublicKey      `json:"publicKey,omitempty"`
 56 77918b00 2024-03-07 o 	Audience  string          `json:"audience,omitempty"`
 57 77918b00 2024-03-07 o 	Object    json.RawMessage `json:"object,omitempty"`
 58 1d5ddf5d 2024-02-20 o }
 59 1d5ddf5d 2024-02-20 o 
 60 1d5ddf5d 2024-02-20 o func (act *Activity) UnmarshalJSON(b []byte) error {
 61 1d5ddf5d 2024-02-20 o 	type Alias Activity
 62 1d5ddf5d 2024-02-20 o 	aux := &struct {
 63 1d5ddf5d 2024-02-20 o 		AtContext interface{} `json:"@context"`
 64 1d5ddf5d 2024-02-20 o 		Object    interface{}
 65 1d5ddf5d 2024-02-20 o 		*Alias
 66 1d5ddf5d 2024-02-20 o 	}{
 67 1d5ddf5d 2024-02-20 o 		Alias: (*Alias)(act),
 68 1d5ddf5d 2024-02-20 o 	}
 69 1d5ddf5d 2024-02-20 o 	if err := json.Unmarshal(b, &aux); err != nil {
 70 1d5ddf5d 2024-02-20 o 		return err
 71 1d5ddf5d 2024-02-20 o 	}
 72 1d5ddf5d 2024-02-20 o 	switch v := aux.AtContext.(type) {
 73 1d5ddf5d 2024-02-20 o 	case string:
 74 1d5ddf5d 2024-02-20 o 		act.AtContext = v
 75 1d5ddf5d 2024-02-20 o 	case []interface{}:
 76 1d5ddf5d 2024-02-20 o 		if vv, ok := v[0].(string); ok {
 77 1d5ddf5d 2024-02-20 o 			act.AtContext = vv
 78 1d5ddf5d 2024-02-20 o 		}
 79 1d5ddf5d 2024-02-20 o 	}
 80 1d5ddf5d 2024-02-20 o 	return nil
 81 1d5ddf5d 2024-02-20 o }
 82 1d5ddf5d 2024-02-20 o 
 83 25fed994 2024-03-12 o // Unwrap returns the JSON-encoded Activity, if any, enclosed in act.
 84 25fed994 2024-03-12 o // The Activity may be referenced by ID,
 85 25fed994 2024-03-12 o // in which case the activity is looked up by client or by
 86 25fed994 2024-03-12 o // apub.defaultClient if client is nil.
 87 1d5ddf5d 2024-02-20 o func (act *Activity) Unwrap(client *Client) (*Activity, error) {
 88 1d5ddf5d 2024-02-20 o 	if act.Object == nil {
 89 1d5ddf5d 2024-02-20 o 		return nil, errors.New("no wrapped activity")
 90 1d5ddf5d 2024-02-20 o 	}
 91 1d5ddf5d 2024-02-20 o 
 92 1d5ddf5d 2024-02-20 o 	var buf io.Reader
 93 1d5ddf5d 2024-02-20 o 	buf = bytes.NewReader(act.Object)
 94 1d5ddf5d 2024-02-20 o 	if strings.HasPrefix(string(act.Object), "https") {
 95 1d5ddf5d 2024-02-20 o 		if client == nil {
 96 1d5ddf5d 2024-02-20 o 			return Lookup(string(act.Object))
 97 1d5ddf5d 2024-02-20 o 		}
 98 1d5ddf5d 2024-02-20 o 		return client.Lookup(string(act.Object))
 99 1d5ddf5d 2024-02-20 o 	}
100 1d5ddf5d 2024-02-20 o 	return Decode(buf)
101 1d5ddf5d 2024-02-20 o }
102 1d5ddf5d 2024-02-20 o 
103 1d5ddf5d 2024-02-20 o func Decode(r io.Reader) (*Activity, error) {
104 1d5ddf5d 2024-02-20 o 	var a Activity
105 1d5ddf5d 2024-02-20 o 	if err := json.NewDecoder(r).Decode(&a); err != nil {
106 1d5ddf5d 2024-02-20 o 		return nil, fmt.Errorf("decode activity: %w", err)
107 1d5ddf5d 2024-02-20 o 	}
108 1d5ddf5d 2024-02-20 o 	return &a, nil
109 1d5ddf5d 2024-02-20 o }
110 1d5ddf5d 2024-02-20 o 
111 71191436 2024-02-28 o func DecodeActor(r io.Reader) (*Actor, error) {
112 71191436 2024-02-28 o 	a, err := Decode(r)
113 71191436 2024-02-28 o 	if err != nil {
114 71191436 2024-02-28 o 		return nil, err
115 71191436 2024-02-28 o 	}
116 71191436 2024-02-28 o 	return activityToActor(a), nil
117 71191436 2024-02-28 o }
118 71191436 2024-02-28 o 
119 1d5ddf5d 2024-02-20 o type Actor struct {
120 71191436 2024-02-28 o 	AtContext string     `json:"@context"`
121 71191436 2024-02-28 o 	ID        string     `json:"id"`
122 71191436 2024-02-28 o 	Type      string     `json:"type"`
123 71191436 2024-02-28 o 	Name      string     `json:"name"`
124 71191436 2024-02-28 o 	Username  string     `json:"preferredUsername"`
125 77918b00 2024-03-07 o 	Summary   string     `json:"summary,omitempty"`
126 71191436 2024-02-28 o 	Inbox     string     `json:"inbox"`
127 71191436 2024-02-28 o 	Outbox    string     `json:"outbox"`
128 77918b00 2024-03-07 o 	Followers string     `json:"followers"`
129 71191436 2024-02-28 o 	Published *time.Time `json:"published,omitempty"`
130 71191436 2024-02-28 o 	PublicKey PublicKey  `json:"publicKey"`
131 1d5ddf5d 2024-02-20 o }
132 1d5ddf5d 2024-02-20 o 
133 1d5ddf5d 2024-02-20 o type PublicKey struct {
134 1d5ddf5d 2024-02-20 o 	ID           string `json:"id"`
135 1d5ddf5d 2024-02-20 o 	Owner        string `json:"owner"`
136 1d5ddf5d 2024-02-20 o 	PublicKeyPEM string `json:"publicKeyPem"`
137 1d5ddf5d 2024-02-20 o }
138 1d5ddf5d 2024-02-20 o 
139 25fed994 2024-03-12 o // Address generates the most likely address of the Actor.
140 25fed994 2024-03-12 o // The Actor's name (not the username) is used as the address' proper name, if present.
141 25fed994 2024-03-12 o // Implementors should verify the address using WebFinger.
142 25fed994 2024-03-12 o // For example, the followers address for Actor ID
143 25fed994 2024-03-12 o // https://hachyderm.io/users/otl is:
144 25fed994 2024-03-12 o //
145 25fed994 2024-03-12 o //	"Oliver Lowe" <otl+followers@hachyderm.io>
146 1d5ddf5d 2024-02-20 o func (a *Actor) Address() *mail.Address {
147 71191436 2024-02-28 o 	if a.Username == "" && a.Name == "" {
148 71191436 2024-02-28 o 		return &mail.Address{"", a.ID}
149 71191436 2024-02-28 o 	}
150 1d5ddf5d 2024-02-20 o 	trimmed := strings.TrimPrefix(a.ID, "https://")
151 1d5ddf5d 2024-02-20 o 	host, _, _ := strings.Cut(trimmed, "/")
152 1d5ddf5d 2024-02-20 o 	addr := fmt.Sprintf("%s@%s", a.Username, host)
153 1d5ddf5d 2024-02-20 o 	return &mail.Address{a.Name, addr}
154 1d5ddf5d 2024-02-20 o }
155 77918b00 2024-03-07 o 
156 25fed994 2024-03-12 o // FollowersAddress generates a non-standard address representing the Actor's followers
157 25fed994 2024-03-12 o // using plus addressing.
158 25fed994 2024-03-12 o // It is the Actor's address username part with a "+followers" suffix.
159 25fed994 2024-03-12 o // The address cannot be resolved using WebFinger.
160 25fed994 2024-03-12 o //
161 25fed994 2024-03-12 o // For example, the followers address for Actor ID
162 25fed994 2024-03-12 o // https://hachyderm.io/users/otl is:
163 25fed994 2024-03-12 o //
164 25fed994 2024-03-12 o //	"Oliver Lowe (followers)" <otl+followers@hachyderm.io>
165 77918b00 2024-03-07 o func (a *Actor) FollowersAddress() *mail.Address {
166 77918b00 2024-03-07 o 	if a.Followers == "" {
167 77918b00 2024-03-07 o 		return &mail.Address{"", ""}
168 77918b00 2024-03-07 o 	}
169 77918b00 2024-03-07 o 	addr := a.Address()
170 77918b00 2024-03-07 o 	user, domain, found := strings.Cut(addr.Address, "@")
171 77918b00 2024-03-07 o 	if !found {
172 77918b00 2024-03-07 o 		return &mail.Address{"", ""}
173 77918b00 2024-03-07 o 	}
174 77918b00 2024-03-07 o 	addr.Address = fmt.Sprintf("%s+followers@%s", user, domain)
175 77918b00 2024-03-07 o 	if addr.Name != "" {
176 77918b00 2024-03-07 o 		addr.Name += " (followers)"
177 77918b00 2024-03-07 o 	}
178 77918b00 2024-03-07 o 	return addr
179 77918b00 2024-03-07 o }