1 package apub
2 
3 import (
4 	"bytes"
5 	"crypto/rsa"
6 	"encoding/json"
7 	"fmt"
8 	"io"
9 	"net/http"
10 	"os"
11 	"strings"
12 )
13 
14 var defaultClient Client = Client{Client: http.DefaultClient}
15 
16 func Lookup(id string) (*Activity, error) {
17 	return defaultClient.Lookup(id)
18 }
19 
20 func LookupActor(id string) (*Actor, error) {
21 	return defaultClient.LookupActor(id)
22 }
23 
24 type Client struct {
25 	*http.Client
26 	// Key is a RSA private key which will be used to sign requests.
27 	Key *rsa.PrivateKey
28 	// PubKeyID is a URL where the corresponding public key of Key
29 	// may be accessed. This must be set if Key is also set.
30 	PubKeyID string // actor.PublicKey.ID
31 }
32 
33 func (c *Client) Lookup(id string) (*Activity, error) {
34 	if !strings.HasPrefix(id, "http") {
35 		return nil, fmt.Errorf("id is not a HTTP URL")
36 	}
37 	if c.Client == nil {
38 		c.Client = http.DefaultClient
39 	}
40 
41 	req, err := http.NewRequest(http.MethodGet, id, nil)
42 	if err != nil {
43 		return nil, err
44 	}
45 	req.Header.Set("Accept", ContentType)
46 	if c.Key != nil && c.PubKeyID != "" {
47 		if err := Sign(req, c.Key, c.PubKeyID); err != nil {
48 			return nil, fmt.Errorf("sign http request: %w", err)
49 		}
50 	}
51 	resp, err := c.Do(req)
52 	if err != nil {
53 		return nil, err
54 	}
55 	defer resp.Body.Close()
56 	if resp.StatusCode == http.StatusNotFound {
57 		return nil, ErrNotExist
58 	} else if resp.StatusCode >= 400 {
59 		return nil, fmt.Errorf("non-ok response status %s", resp.Status)
60 	}
61 	return Decode(resp.Body)
62 }
63 
64 func (c *Client) LookupActor(id string) (*Actor, error) {
65 	activity, err := c.Lookup(id)
66 	if err != nil {
67 		return nil, err
68 	}
69 	return activityToActor(activity), nil
70 }
71 
72 func activityToActor(activity *Activity) *Actor {
73 	actor := &Actor{
74 		AtContext: activity.AtContext,
75 		ID:        activity.ID,
76 		Type:      activity.Type,
77 		Name:      activity.Name,
78 		Username:  activity.Username,
79 		Inbox:     activity.Inbox,
80 		Outbox:    activity.Outbox,
81 		Followers: activity.Followers,
82 		Published: activity.Published,
83 		Summary:   activity.Summary,
84 	}
85 	if activity.PublicKey != nil {
86 		actor.PublicKey = *activity.PublicKey
87 	}
88 	return actor
89 }
90 
91 func (c *Client) Send(inbox string, activity *Activity) (*Activity, error) {
92 	b, err := json.Marshal(activity)
93 	if err != nil {
94 		return nil, fmt.Errorf("encode outgoing activity: %w", err)
95 	}
96 	req, err := http.NewRequest(http.MethodPost, inbox, bytes.NewReader(b))
97 	if err != nil {
98 		return nil, err
99 	}
100 	req.Header.Set("Content-Type", ContentType)
101 	if err := Sign(req, c.Key, c.PubKeyID); err != nil {
102 		return nil, fmt.Errorf("sign outgoing request: %w", err)
103 	}
104 	resp, err := c.Do(req)
105 	if err != nil {
106 		return nil, err
107 	}
108 	switch resp.StatusCode {
109 	case http.StatusOK, http.StatusAccepted, http.StatusNoContent:
110 		return nil, nil
111 	case http.StatusNotFound:
112 		return nil, fmt.Errorf("no such inbox %s", inbox)
113 	default:
114 		io.Copy(os.Stderr, resp.Body)
115 		resp.Body.Close()
116 		return nil, fmt.Errorf("non-ok response status %s", resp.Status)
117 	}
118 }