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 186ac3bf 2024-03-12 o // NormContext is a URL referencing the
 20 186ac3bf 2024-03-12 o // normative Activity Streams 2.0 JSON-LD @context definition.
 21 186ac3bf 2024-03-12 o // All [Activity] variables should have their AtContext field set to this value.
 22 186ac3bf 2024-03-12 o // See [Activity Streams 2.0] section 2.1.
 23 186ac3bf 2024-03-12 o //
 24 186ac3bf 2024-03-12 o // [Activity Streams 2.0]: https://www.w3.org/TR/activitystreams-core/
 25 186ac3bf 2024-03-12 o const NormContext string = "https://www.w3.org/ns/activitystreams"
 26 1d5ddf5d 2024-02-20 o 
 27 25fed994 2024-03-12 o // ContentType is the MIME media type for ActivityPub.
 28 1d5ddf5d 2024-02-20 o const ContentType string = "application/activity+json"
 29 1d5ddf5d 2024-02-20 o 
 30 25fed994 2024-03-12 o // PublicCollection is the ActivityPub ID for the special collection indicating public access.
 31 25fed994 2024-03-12 o // Any Activity addressed to this collection is meant to be available to all users,
 32 25fed994 2024-03-12 o // authenticated or not.
 33 77918b00 2024-03-07 o // See W3C Recommendation ActivityPub Section 5.6.
 34 77918b00 2024-03-07 o const PublicCollection string = "https://www.w3.org/ns/activitystreams#Public"
 35 1d5ddf5d 2024-02-20 o 
 36 71191436 2024-02-28 o var ErrNotExist = errors.New("no such activity")
 37 71191436 2024-02-28 o 
 38 186ac3bf 2024-03-12 o // Activity represents the Activity Streams Object core type.
 39 186ac3bf 2024-03-12 o // See Activity Streams 2.0, section 4.1.
 40 1d5ddf5d 2024-02-20 o type Activity struct {
 41 1d5ddf5d 2024-02-20 o 	AtContext    string     `json:"@context"`
 42 421e5894 2024-03-15 o 	ID           string     `json:"id,omitempty"`
 43 1d5ddf5d 2024-02-20 o 	Type         string     `json:"type"`
 44 1d5ddf5d 2024-02-20 o 	Name         string     `json:"name,omitempty"`
 45 1d5ddf5d 2024-02-20 o 	Actor        string     `json:"actor,omitempty"`
 46 1d5ddf5d 2024-02-20 o 	Username     string     `json:"preferredUsername,omitempty"`
 47 77918b00 2024-03-07 o 	Summary      string     `json:"summary,omitempty"`
 48 1d5ddf5d 2024-02-20 o 	Inbox        string     `json:"inbox,omitempty"`
 49 1d5ddf5d 2024-02-20 o 	Outbox       string     `json:"outbox,omitempty"`
 50 1d5ddf5d 2024-02-20 o 	To           []string   `json:"to,omitempty"`
 51 1d5ddf5d 2024-02-20 o 	CC           []string   `json:"cc,omitempty"`
 52 77918b00 2024-03-07 o 	Followers    string     `json:"followers,omitempty"`
 53 1d5ddf5d 2024-02-20 o 	InReplyTo    string     `json:"inReplyTo,omitempty"`
 54 1d5ddf5d 2024-02-20 o 	Published    *time.Time `json:"published,omitempty"`
 55 1d5ddf5d 2024-02-20 o 	AttributedTo string     `json:"attributedTo,omitempty"`
 56 1d5ddf5d 2024-02-20 o 	Content      string     `json:"content,omitempty"`
 57 1d5ddf5d 2024-02-20 o 	MediaType    string     `json:"mediaType,omitempty"`
 58 1d5ddf5d 2024-02-20 o 	Source       struct {
 59 1d5ddf5d 2024-02-20 o 		Content   string `json:"content,omitempty"`
 60 1d5ddf5d 2024-02-20 o 		MediaType string `json:"mediaType,omitempty"`
 61 1d5ddf5d 2024-02-20 o 	} `json:"source,omitempty"`
 62 421e5894 2024-03-15 o 	PublicKey *PublicKey `json:"publicKey,omitempty"`
 63 421e5894 2024-03-15 o 	Audience  string     `json:"audience,omitempty"`
 64 421e5894 2024-03-15 o 	Href      string     `json:"href,omitempty"`
 65 421e5894 2024-03-15 o 	Tag       []Activity `json:"tag,omitempty"`
 66 8403ab16 2024-03-21 o 	Endpoints Endpoints  `json:"endpoints,omitempty"`
 67 186ac3bf 2024-03-12 o 	// Contains a JSON-encoded Activity, or a URL as a JSON string
 68 186ac3bf 2024-03-12 o 	// pointing to an Activity. Use Activity.Unwrap() to access
 69 186ac3bf 2024-03-12 o 	// the enclosed, decoded value.
 70 421e5894 2024-03-15 o 	Object json.RawMessage `json:"object,omitempty"`
 71 1d5ddf5d 2024-02-20 o }
 72 1d5ddf5d 2024-02-20 o 
 73 1d5ddf5d 2024-02-20 o func (act *Activity) UnmarshalJSON(b []byte) error {
 74 1d5ddf5d 2024-02-20 o 	type Alias Activity
 75 1d5ddf5d 2024-02-20 o 	aux := &struct {
 76 1d5ddf5d 2024-02-20 o 		AtContext interface{} `json:"@context"`
 77 1d5ddf5d 2024-02-20 o 		Object    interface{}
 78 1d5ddf5d 2024-02-20 o 		*Alias
 79 1d5ddf5d 2024-02-20 o 	}{
 80 1d5ddf5d 2024-02-20 o 		Alias: (*Alias)(act),
 81 1d5ddf5d 2024-02-20 o 	}
 82 1d5ddf5d 2024-02-20 o 	if err := json.Unmarshal(b, &aux); err != nil {
 83 1d5ddf5d 2024-02-20 o 		return err
 84 1d5ddf5d 2024-02-20 o 	}
 85 1d5ddf5d 2024-02-20 o 	switch v := aux.AtContext.(type) {
 86 1d5ddf5d 2024-02-20 o 	case string:
 87 1d5ddf5d 2024-02-20 o 		act.AtContext = v
 88 1d5ddf5d 2024-02-20 o 	case []interface{}:
 89 1d5ddf5d 2024-02-20 o 		if vv, ok := v[0].(string); ok {
 90 1d5ddf5d 2024-02-20 o 			act.AtContext = vv
 91 1d5ddf5d 2024-02-20 o 		}
 92 1d5ddf5d 2024-02-20 o 	}
 93 1d5ddf5d 2024-02-20 o 	return nil
 94 1d5ddf5d 2024-02-20 o }
 95 1d5ddf5d 2024-02-20 o 
 96 25fed994 2024-03-12 o // Unwrap returns the JSON-encoded Activity, if any, enclosed in act.
 97 25fed994 2024-03-12 o // The Activity may be referenced by ID,
 98 25fed994 2024-03-12 o // in which case the activity is looked up by client or by
 99 25fed994 2024-03-12 o // apub.defaultClient if client is nil.
100 1d5ddf5d 2024-02-20 o func (act *Activity) Unwrap(client *Client) (*Activity, error) {
101 1d5ddf5d 2024-02-20 o 	if act.Object == nil {
102 1d5ddf5d 2024-02-20 o 		return nil, errors.New("no wrapped activity")
103 1d5ddf5d 2024-02-20 o 	}
104 1d5ddf5d 2024-02-20 o 
105 1d5ddf5d 2024-02-20 o 	var buf io.Reader
106 1d5ddf5d 2024-02-20 o 	buf = bytes.NewReader(act.Object)
107 1d5ddf5d 2024-02-20 o 	if strings.HasPrefix(string(act.Object), "https") {
108 1d5ddf5d 2024-02-20 o 		if client == nil {
109 1d5ddf5d 2024-02-20 o 			return Lookup(string(act.Object))
110 1d5ddf5d 2024-02-20 o 		}
111 1d5ddf5d 2024-02-20 o 		return client.Lookup(string(act.Object))
112 1d5ddf5d 2024-02-20 o 	}
113 1d5ddf5d 2024-02-20 o 	return Decode(buf)
114 1d5ddf5d 2024-02-20 o }
115 1d5ddf5d 2024-02-20 o 
116 1d5ddf5d 2024-02-20 o func Decode(r io.Reader) (*Activity, error) {
117 1d5ddf5d 2024-02-20 o 	var a Activity
118 1d5ddf5d 2024-02-20 o 	if err := json.NewDecoder(r).Decode(&a); err != nil {
119 1d5ddf5d 2024-02-20 o 		return nil, fmt.Errorf("decode activity: %w", err)
120 1d5ddf5d 2024-02-20 o 	}
121 1d5ddf5d 2024-02-20 o 	return &a, nil
122 1d5ddf5d 2024-02-20 o }
123 1d5ddf5d 2024-02-20 o 
124 71191436 2024-02-28 o func DecodeActor(r io.Reader) (*Actor, error) {
125 71191436 2024-02-28 o 	a, err := Decode(r)
126 71191436 2024-02-28 o 	if err != nil {
127 71191436 2024-02-28 o 		return nil, err
128 71191436 2024-02-28 o 	}
129 71191436 2024-02-28 o 	return activityToActor(a), nil
130 71191436 2024-02-28 o }
131 71191436 2024-02-28 o 
132 1d5ddf5d 2024-02-20 o type Actor struct {
133 71191436 2024-02-28 o 	AtContext string     `json:"@context"`
134 71191436 2024-02-28 o 	ID        string     `json:"id"`
135 71191436 2024-02-28 o 	Type      string     `json:"type"`
136 71191436 2024-02-28 o 	Name      string     `json:"name"`
137 71191436 2024-02-28 o 	Username  string     `json:"preferredUsername"`
138 77918b00 2024-03-07 o 	Summary   string     `json:"summary,omitempty"`
139 71191436 2024-02-28 o 	Inbox     string     `json:"inbox"`
140 71191436 2024-02-28 o 	Outbox    string     `json:"outbox"`
141 77918b00 2024-03-07 o 	Followers string     `json:"followers"`
142 8403ab16 2024-03-21 o 	Endpoints Endpoints  `json:"endpoints,omitempty"`
143 71191436 2024-02-28 o 	Published *time.Time `json:"published,omitempty"`
144 71191436 2024-02-28 o 	PublicKey PublicKey  `json:"publicKey"`
145 1d5ddf5d 2024-02-20 o }
146 1d5ddf5d 2024-02-20 o 
147 1d5ddf5d 2024-02-20 o type PublicKey struct {
148 1d5ddf5d 2024-02-20 o 	ID           string `json:"id"`
149 1d5ddf5d 2024-02-20 o 	Owner        string `json:"owner"`
150 1d5ddf5d 2024-02-20 o 	PublicKeyPEM string `json:"publicKeyPem"`
151 1d5ddf5d 2024-02-20 o }
152 1d5ddf5d 2024-02-20 o 
153 25fed994 2024-03-12 o // Address generates the most likely address of the Actor.
154 25fed994 2024-03-12 o // The Actor's name (not the username) is used as the address' proper name, if present.
155 25fed994 2024-03-12 o // Implementors should verify the address using WebFinger.
156 945bf12e 2024-03-16 o // For example, the address for the Actor ID
157 25fed994 2024-03-12 o // https://hachyderm.io/users/otl is:
158 25fed994 2024-03-12 o //
159 945bf12e 2024-03-16 o //	"Oliver Lowe" <otl@hachyderm.io>
160 1d5ddf5d 2024-02-20 o func (a *Actor) Address() *mail.Address {
161 71191436 2024-02-28 o 	if a.Username == "" && a.Name == "" {
162 71191436 2024-02-28 o 		return &mail.Address{"", a.ID}
163 71191436 2024-02-28 o 	}
164 1d5ddf5d 2024-02-20 o 	trimmed := strings.TrimPrefix(a.ID, "https://")
165 1d5ddf5d 2024-02-20 o 	host, _, _ := strings.Cut(trimmed, "/")
166 1d5ddf5d 2024-02-20 o 	addr := fmt.Sprintf("%s@%s", a.Username, host)
167 1d5ddf5d 2024-02-20 o 	return &mail.Address{a.Name, addr}
168 1d5ddf5d 2024-02-20 o }
169 77918b00 2024-03-07 o 
170 25fed994 2024-03-12 o // FollowersAddress generates a non-standard address representing the Actor's followers
171 25fed994 2024-03-12 o // using plus addressing.
172 25fed994 2024-03-12 o // It is the Actor's address username part with a "+followers" suffix.
173 25fed994 2024-03-12 o // The address cannot be resolved using WebFinger.
174 25fed994 2024-03-12 o //
175 25fed994 2024-03-12 o // For example, the followers address for Actor ID
176 25fed994 2024-03-12 o // https://hachyderm.io/users/otl is:
177 25fed994 2024-03-12 o //
178 25fed994 2024-03-12 o //	"Oliver Lowe (followers)" <otl+followers@hachyderm.io>
179 77918b00 2024-03-07 o func (a *Actor) FollowersAddress() *mail.Address {
180 77918b00 2024-03-07 o 	if a.Followers == "" {
181 77918b00 2024-03-07 o 		return &mail.Address{"", ""}
182 77918b00 2024-03-07 o 	}
183 77918b00 2024-03-07 o 	addr := a.Address()
184 77918b00 2024-03-07 o 	user, domain, found := strings.Cut(addr.Address, "@")
185 77918b00 2024-03-07 o 	if !found {
186 77918b00 2024-03-07 o 		return &mail.Address{"", ""}
187 77918b00 2024-03-07 o 	}
188 77918b00 2024-03-07 o 	addr.Address = fmt.Sprintf("%s+followers@%s", user, domain)
189 77918b00 2024-03-07 o 	if addr.Name != "" {
190 77918b00 2024-03-07 o 		addr.Name += " (followers)"
191 77918b00 2024-03-07 o 	}
192 77918b00 2024-03-07 o 	return addr
193 77918b00 2024-03-07 o }
194 8403ab16 2024-03-21 o 
195 8403ab16 2024-03-21 o type Endpoints struct {
196 8403ab16 2024-03-21 o 	SharedInbox string `json:"sharedInbox,omitempty"`
197 8403ab16 2024-03-21 o }
198 8403ab16 2024-03-21 o 
199 8403ab16 2024-03-21 o // Inboxes returns a deduplicated slice of inbox endpoints ActivityPub clients should send to.
200 8403ab16 2024-03-21 o // Shared inboxes, if present, are selected over an Actor's personal inbox.
201 8403ab16 2024-03-21 o // See W3C Recommendation ActivityPub Section 7.1.3 Shared Inbox Delivery.
202 8403ab16 2024-03-21 o func Inboxes(actors []Actor) []string {
203 8403ab16 2024-03-21 o 	var inboxes []string
204 8403ab16 2024-03-21 o 	for _, a := range actors {
205 8403ab16 2024-03-21 o 		box := a.Inbox
206 8403ab16 2024-03-21 o 		if a.Endpoints.SharedInbox != "" {
207 8403ab16 2024-03-21 o 			box = a.Endpoints.SharedInbox
208 8403ab16 2024-03-21 o 		}
209 8403ab16 2024-03-21 o 		var match bool
210 8403ab16 2024-03-21 o 		for i := range inboxes {
211 8403ab16 2024-03-21 o 			if inboxes[i] == box {
212 8403ab16 2024-03-21 o 				match = true
213 8403ab16 2024-03-21 o 				break
214 8403ab16 2024-03-21 o 			}
215 8403ab16 2024-03-21 o 		}
216 8403ab16 2024-03-21 o 		if match {
217 8403ab16 2024-03-21 o 			continue
218 8403ab16 2024-03-21 o 		}
219 8403ab16 2024-03-21 o 		inboxes = append(inboxes, box)
220 8403ab16 2024-03-21 o 	}
221 8403ab16 2024-03-21 o 	return inboxes
222 8403ab16 2024-03-21 o }