2.83
webfinger.c
1/* snac - A simple, minimalistic ActivityPub instance */
2/* copyright (c) 2022 - 2025 grunfink et al. / MIT license */
3
4#include "xs.h"
5#include "xs_json.h"
6#include "xs_curl.h"
7#include "xs_mime.h"
8
9#include "snac.h"
10
11int webfinger_request_signed(snac *snac, const char *qs, xs_str **actor, xs_str **user)
12/* queries the webfinger for qs and fills the required fields */
13{
14 int status;
15 xs *payload = NULL;
16 int p_size = 0;
17 xs *headers = xs_dict_new();
18 xs *l = NULL;
19 const char *host = NULL;
20 xs *resource = NULL;
21
22 if (xs_startswith(qs, "https:/") || xs_startswith(qs, "http:/")) {
23 /* actor query: pick the host */
24 xs *s1 = xs_replace_n(qs, "http:/" "/", "", 1);
25 xs *s = xs_replace_n(s1, "https:/" "/", "", 1);
26
27 l = xs_split_n(s, "/", 1);
28
29 host = xs_list_get(l, 0);
30 resource = xs_dup(qs);
31 }
32 else {
33 /* it's a user */
34 xs *s = xs_strip_chars_i(xs_dup(qs), "@.");
35
36 l = xs_split_n(s, "@", 1);
37
38 if (xs_list_len(l) == 2) {
39 host = xs_list_get(l, 1);
40 resource = xs_fmt("acct:%s", s);
41 }
42 }
43
44 if (host == NULL || resource == NULL)
45 return HTTP_STATUS_BAD_REQUEST;
46
47 headers = xs_dict_append(headers, "accept", "application/json");
48 headers = xs_dict_append(headers, "user-agent", USER_AGENT);
49
50 xs *obj = NULL;
51
52 xs *cached_qs = xs_fmt("webfinger:%s", qs);
53
54 /* is it cached? */
55 if (valid_status(status = object_get(cached_qs, &obj))) {
56 /* nothing more to do */
57 }
58 else
59 /* is it a query about one of us? */
60 if (strcmp(host, xs_dict_get(srv_config, "host")) == 0) {
61 /* route internally */
62 xs *req = xs_dict_new();
63 xs *q_vars = xs_dict_new();
64 char *ctype;
65
66 q_vars = xs_dict_append(q_vars, "resource", resource);
67 req = xs_dict_append(req, "q_vars", q_vars);
68
69 status = webfinger_get_handler(req, "/.well-known/webfinger",
70 &payload, &p_size, &ctype);
71 }
72 else {
73 const char *proto = xs_dict_get_def(srv_config, "protocol", "https");
74
75 xs *url = xs_fmt("%s:/" "/%s/.well-known/webfinger?resource=%s", proto, host, resource);
76
77 if (snac == NULL)
78 xs_http_request("GET", url, headers, NULL, 0, &status, &payload, &p_size, 0);
79 else
80 http_signed_request(snac, "GET", url, headers, NULL, 0, &status, &payload, &p_size, 0);
81 }
82
83 if (obj == NULL && valid_status(status) && payload) {
84 obj = xs_json_loads(payload);
85
86 if (obj)
87 object_add(cached_qs, obj);
88 else
89 status = HTTP_STATUS_BAD_REQUEST;
90 }
91
92 if (obj) {
93 if (user != NULL) {
94 const char *subject = xs_dict_get(obj, "subject");
95
96 if (subject && xs_startswith(subject, "acct:"))
97 *user = xs_replace_n(subject, "acct:", "", 1);
98 }
99
100 if (actor != NULL) {
101 const xs_list *list = xs_dict_get(obj, "links");
102 int c = 0;
103 const char *v;
104
105 while (xs_list_next(list, &v, &c)) {
106 if (xs_type(v) == XSTYPE_DICT) {
107 const char *type = xs_dict_get(v, "type");
108
109 if (type && (strcmp(type, "application/activity+json") == 0 ||
110 strcmp(type, "application/ld+json; profile=\"https:/"
111 "/www.w3.org/ns/activitystreams\"") == 0)) {
112 *actor = xs_dup(xs_dict_get(v, "href"));
113 break;
114 }
115 }
116 }
117 }
118 }
119
120 return status;
121}
122
123
124int webfinger_request(const char *qs, xs_str **actor, xs_str **user)
125/* queries the webfinger for qs and fills the required fields */
126{
127 return webfinger_request_signed(NULL, qs, actor, user);
128}
129
130
131int webfinger_request_fake(const char *qs, xs_str **actor, xs_str **user)
132/* queries the webfinger and, if it fails, a user is faked if possible */
133{
134 int status;
135
136 if (!valid_status(status = webfinger_request(qs, actor, user))) {
137 if (xs_startswith(qs, "https:/") || xs_startswith(qs, "http:/")) {
138 xs *l = xs_split(qs, "/");
139
140 if (xs_list_len(l) > 3) {
141 srv_debug(1, xs_fmt("webfinger error querying %s %d -- faking it", qs, status));
142
143 /* i'll end up in hell for this */
144 *user = xs_fmt("%s@%s", xs_list_get(l, -1), xs_list_get(l, 2));
145 status = HTTP_STATUS_RESET_CONTENT;
146
147 }
148 }
149 }
150
151 return status;
152}
153
154
155int webfinger_get_handler(const xs_dict *req, const char *q_path,
156 xs_val **body, int *b_size, char **ctype)
157/* serves webfinger queries */
158{
159 int status;
160
161 (void)b_size;
162
163 if (strcmp(q_path, "/.well-known/webfinger") != 0)
164 return 0;
165
166 const char *q_vars = xs_dict_get(req, "q_vars");
167 const char *resource = xs_dict_get(q_vars, "resource");
168
169 if (resource == NULL)
170 return HTTP_STATUS_BAD_REQUEST;
171
172 snac snac;
173 int found = 0;
174
175 if (xs_startswith(resource, "https:/") || xs_startswith(resource, "http:/")) {
176 /* actor search: find a user with this actor */
177 xs *l = xs_split(resource, "/");
178 const char *uid = xs_list_get(l, -1);
179
180 if (uid)
181 found = user_open(&snac, uid);
182 }
183 else
184 if (xs_startswith(resource, "acct:")) {
185 /* it's an account name */
186 xs *an = xs_replace_n(resource, "acct:", "", 1);
187 xs *l = NULL;
188
189 /* strip a possible leading @ */
190 if (xs_startswith(an, "@"))
191 an = xs_crop_i(an, 1, 0);
192
193 l = xs_split_n(an, "@", 1);
194
195 if (xs_list_len(l) == 2) {
196 const char *uid = xs_list_get(l, 0);
197 const char *host = xs_list_get(l, 1);
198
199 if (strcmp(host, xs_dict_get(srv_config, "host")) == 0)
200 found = user_open(&snac, uid);
201 }
202 }
203
204 if (found) {
205 /* build the object */
206 xs *acct;
207 xs *aaj = xs_dict_new();
208 xs *prof = xs_dict_new();
209 xs *links = xs_list_new();
210 xs *obj = xs_dict_new();
211
212 acct = xs_fmt("acct:%s@%s",
213 xs_dict_get(snac.config, "uid"), xs_dict_get(srv_config, "host"));
214
215 aaj = xs_dict_append(aaj, "rel", "self");
216 aaj = xs_dict_append(aaj, "type", "application/activity+json");
217 aaj = xs_dict_append(aaj, "href", snac.actor);
218
219 links = xs_list_append(links, aaj);
220
221 /* duplicate with the ld+json type */
222 aaj = xs_dict_set(aaj, "type", "application/ld+json; profile=\"https:/"
223 "/www.w3.org/ns/activitystreams\"");
224
225 links = xs_list_append(links, aaj);
226
227 prof = xs_dict_append(prof, "rel", "http://webfinger.net/rel/profile-page");
228 prof = xs_dict_append(prof, "type", "text/html");
229 prof = xs_dict_append(prof, "href", snac.actor);
230
231 links = xs_list_append(links, prof);
232
233 const char *avatar = xs_dict_get(snac.config, "avatar");
234 if (!xs_is_null(avatar) && *avatar) {
235 xs *d = xs_dict_new();
236
237 d = xs_dict_append(d, "rel", "http:/" "/webfinger.net/rel/avatar");
238 d = xs_dict_append(d, "type", xs_mime_by_ext(avatar));
239 d = xs_dict_append(d, "href", avatar);
240
241 links = xs_list_append(links, d);
242 }
243
244 obj = xs_dict_append(obj, "subject", acct);
245 obj = xs_dict_append(obj, "links", links);
246
247 xs_str *j = xs_json_dumps(obj, 4);
248
249 user_free(&snac);
250
251 status = HTTP_STATUS_OK;
252 *body = j;
253 *ctype = "application/jrd+json";
254 }
255 else
256 status = HTTP_STATUS_NOT_FOUND;
257
258 srv_debug(1, xs_fmt("webfinger_get_handler resource=%s %d", resource, status));
259
260 return status;
261}
