1 package apub
2 
3 import (
4 	"bytes"
5 	"crypto/rsa"
6 	"encoding/json"
7 	"errors"
8 	"fmt"
9 	"io"
10 	"net/http"
11 	"os"
12 	"strings"
13 )
14 
15 var defaultClient Client = Client{Client: http.DefaultClient}
16 
17 func Lookup(id string) (*Activity, error) {
18 	return defaultClient.Lookup(id)
19 }
20 
21 func LookupActor(id string) (*Actor, error) {
22 	return defaultClient.LookupActor(id)
23 }
24 
25 type Client struct {
26 	*http.Client
27 	Key   *rsa.PrivateKey
28 	Actor *Actor
29 }
30 
31 func (c *Client) Lookup(id string) (*Activity, error) {
32 	if !strings.HasPrefix(id, "http") {
33 		return nil, fmt.Errorf("id is not a HTTP URL")
34 	}
35 	if c.Client == nil {
36 		c.Client = http.DefaultClient
37 	}
38 
39 	req, err := http.NewRequest(http.MethodGet, id, nil)
40 	if err != nil {
41 		return nil, err
42 	}
43 	req.Header.Set("Accept", ContentType)
44 	if c.Key != nil && c.Actor != nil {
45 		if err := Sign(req, c.Key, c.Actor.PublicKey.ID); err != nil {
46 			return nil, fmt.Errorf("sign http request: %w", err)
47 		}
48 	}
49 	resp, err := c.Do(req)
50 	if err != nil {
51 		return nil, err
52 	}
53 	defer resp.Body.Close()
54 	if resp.StatusCode == http.StatusNotFound {
55 		return nil, ErrNotExist
56 	} else if resp.StatusCode >= 400 {
57 		return nil, fmt.Errorf("non-ok response status %s", resp.Status)
58 	}
59 	return Decode(resp.Body)
60 }
61 
62 func (c *Client) LookupActor(id string) (*Actor, error) {
63 	activity, err := c.Lookup(id)
64 	if err != nil {
65 		return nil, err
66 	}
67 	return activityToActor(activity), nil
68 }
69 
70 func activityToActor(activity *Activity) *Actor {
71 	return &Actor{
72 		AtContext: activity.AtContext,
73 		ID:        activity.ID,
74 		Type:      activity.Type,
75 		Name:      activity.Name,
76 		Username:  activity.Username,
77 		Inbox:     activity.Inbox,
78 		Outbox:    activity.Outbox,
79 		Published: activity.Published,
80 		Summary:   activity.Summary,
81 	}
82 }
83 
84 func (c *Client) Send(inbox string, activity *Activity) (*Activity, error) {
85 	b, err := json.Marshal(activity)
86 	if err != nil {
87 		return nil, fmt.Errorf("encode outgoing activity: %w", err)
88 	}
89 	req, err := http.NewRequest(http.MethodPost, inbox, bytes.NewReader(b))
90 	if err != nil {
91 		return nil, err
92 	}
93 	req.Header.Set("Content-Type", ContentType)
94 	if err := Sign(req, c.Key, c.Actor.PublicKey.ID); err != nil {
95 		return nil, fmt.Errorf("sign outgoing request: %w", err)
96 	}
97 	resp, err := c.Do(req)
98 	if err != nil {
99 		return nil, err
100 	}
101 	switch resp.StatusCode {
102 	case http.StatusOK:
103 		if resp.ContentLength == 0 {
104 			return nil, nil
105 		}
106 		defer resp.Body.Close()
107 		activity, err := Decode(resp.Body)
108 		if errors.Is(err, io.EOF) {
109 			return nil, nil
110 		}
111 		return activity, err
112 	case http.StatusAccepted, http.StatusNoContent:
113 		return nil, nil
114 	case http.StatusNotFound:
115 		return nil, fmt.Errorf("no such inbox %s", inbox)
116 	default:
117 		io.Copy(os.Stderr, resp.Body)
118 		resp.Body.Close()
119 		return nil, fmt.Errorf("non-ok response status %s", resp.Status)
120 	}
121 }