1/* snac - A simple, minimalistic ActivityPub instance */
  2/* copyright (c) 2022 - 2026 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#include "xs_http.h"
  9
 10#include "snac.h"
 11
 12int webfinger_request_signed(snac *snac, const char *qs, xs_str **actor, xs_str **user)
 13/* queries the webfinger for qs and fills the required fields */
 14{
 15    int status;
 16    xs *payload = NULL;
 17    int p_size = 0;
 18    xs *headers = xs_dict_new();
 19    xs *l = NULL;
 20    const char *host = NULL;
 21    xs *resource = NULL;
 22
 23    if (xs_startswith(qs, "https:/") || xs_startswith(qs, "http:/")) {
 24        /* actor query: pick the host */
 25        xs *s1 = xs_replace_n(qs, "http:/" "/", "", 1);
 26        xs *s = xs_replace_n(s1, "https:/" "/", "", 1);
 27
 28        l = xs_split_n(s, "/", 1);
 29
 30        host     = xs_list_get(l, 0);
 31        resource = xs_dup(qs);
 32    }
 33    else {
 34        /* it's a user */
 35        xs *s = xs_strip_chars_i(xs_dup(qs), "@.");
 36
 37        l = xs_split_n(s, "@", 1);
 38
 39        if (xs_list_len(l) == 2) {
 40            host     = xs_list_get(l, 1);
 41            resource = xs_fmt("acct:%s", s);
 42        }
 43    }
 44
 45    if (host == NULL || resource == NULL)
 46        return HTTP_STATUS_BAD_REQUEST;
 47
 48    headers = xs_dict_append(headers, "accept",     "application/json");
 49    headers = xs_dict_append(headers, "user-agent", USER_AGENT);
 50
 51    xs *obj = NULL;
 52
 53    xs *cached_qs = xs_fmt("webfinger:%s", qs);
 54
 55    /* is it cached? */
 56    if (valid_status(status = object_get(cached_qs, &obj))) {
 57        /* nothing more to do */
 58    }
 59    else
 60    /* is it a query about one of us? */
 61    if (strcmp(host, xs_dict_get(srv_config, "host")) == 0) {
 62        /* route internally */
 63        xs *req    = xs_dict_new();
 64        xs *q_vars = xs_dict_new();
 65        char *ctype;
 66
 67        q_vars = xs_dict_append(q_vars, "resource", resource);
 68        req    = xs_dict_append(req, "q_vars", q_vars);
 69
 70        status = webfinger_get_handler(req, "/.well-known/webfinger",
 71                                       &payload, &p_size, &ctype);
 72    }
 73    else {
 74        const char *proto = xs_dict_get_def(srv_config, "protocol", "https");
 75
 76        xs *url = xs_fmt("%s:/" "/%s/.well-known/webfinger?resource=%s", proto, host, resource);
 77
 78        if (snac == NULL)
 79            xs_free(xs_http_request("GET", url, headers, NULL, 0, &status, &payload, &p_size, 0));
 80        else
 81            xs_free(http_signed_request(snac, "GET", url, headers, NULL, 0, &status, &payload, &p_size, 0));
 82    }
 83
 84    if (obj == NULL && valid_status(status) && payload) {
 85        obj = xs_json_loads(payload);
 86
 87        if (obj)
 88            object_add(cached_qs, obj);
 89        else
 90            status = HTTP_STATUS_BAD_REQUEST;
 91    }
 92
 93    if (obj) {
 94        if (user != NULL) {
 95            const char *subject = xs_dict_get(obj, "subject");
 96
 97            if (subject && xs_startswith(subject, "acct:"))
 98                *user = xs_replace_n(subject, "acct:", "", 1);
 99        }
100
101        if (actor != NULL) {
102            const xs_list *list = xs_dict_get(obj, "links");
103            int c = 0;
104            const char *v;
105
106            while (xs_list_next(list, &v, &c)) {
107                if (xs_type(v) == XSTYPE_DICT) {
108                    const char *type = xs_dict_get(v, "type");
109
110                    if (type && (strcmp(type, "application/activity+json") == 0 ||
111                                 strcmp(type, "application/ld+json; profile=\"https:/"
112                                    "/www.w3.org/ns/activitystreams\"") == 0)) {
113                        *actor = xs_dup(xs_dict_get(v, "href"));
114                        break;
115                    }
116                }
117            }
118        }
119    }
120
121    return status;
122}
123
124
125int webfinger_request(const char *qs, xs_str **actor, xs_str **user)
126/* queries the webfinger for qs and fills the required fields */
127{
128    return webfinger_request_signed(NULL, qs, actor, user);
129}
130
131
132int webfinger_request_fake(const char *qs, xs_str **actor, xs_str **user)
133/* queries the webfinger and, if it fails, a user is faked if possible */
134{
135    int status;
136
137    if (!valid_status(status = webfinger_request(qs, actor, user))) {
138        if (xs_startswith(qs, "https:/") || xs_startswith(qs, "http:/")) {
139            xs *l = xs_split(qs, "/");
140
141            if (xs_list_len(l) > 3) {
142                srv_debug(1, xs_fmt("webfinger error querying %s %d -- faking it", qs, status));
143
144                /* i'll end up in hell for this */
145                *user = xs_fmt("%s@%s", xs_list_get(l, -1), xs_list_get(l, 2));
146                status = HTTP_STATUS_RESET_CONTENT;
147
148            }
149        }
150    }
151
152    return status;
153}
154
155
156int webfinger_get_handler(const xs_dict *req, const char *q_path,
157                           xs_val **body, int *b_size, char **ctype)
158/* serves webfinger queries */
159{
160    int status;
161
162    (void)b_size;
163
164    if (strcmp(q_path, "/.well-known/webfinger") != 0)
165        return 0;
166
167    const char *q_vars   = xs_dict_get(req, "q_vars");
168    const char *resource = xs_dict_get(q_vars, "resource");
169
170    if (resource == NULL)
171        return HTTP_STATUS_BAD_REQUEST;
172
173    snac snac;
174    int found = 0;
175
176    if (xs_startswith(resource, "https:/") || xs_startswith(resource, "http:/")) {
177        /* actor search: find a user with this actor */
178        xs *l = xs_split(resource, "/");
179        const char *uid = xs_list_get(l, -1);
180
181        if (uid)
182            found = user_open(&snac, uid);
183    }
184    else
185    if (xs_startswith(resource, "acct:")) {
186        /* it's an account name */
187        xs *an = xs_replace_n(resource, "acct:", "", 1);
188        xs *l = NULL;
189
190        /* strip a possible leading @ */
191        if (xs_startswith(an, "@"))
192            an = xs_crop_i(an, 1, 0);
193
194        l = xs_split_n(an, "@", 1);
195
196        if (xs_list_len(l) == 2) {
197            const char *uid  = xs_list_get(l, 0);
198            const char *host = xs_list_get(l, 1);
199
200            if (strcmp(host, xs_dict_get(srv_config, "host")) == 0)
201                found = user_open(&snac, uid);
202        }
203    }
204
205    if (found) {
206        /* build the object */
207        xs *acct;
208        xs *aaj   = xs_dict_new();
209        xs *prof  = xs_dict_new();
210        xs *links = xs_list_new();
211        xs *obj   = xs_dict_new();
212
213        acct = xs_fmt("acct:%s@%s",
214            xs_dict_get(snac.config, "uid"), xs_dict_get(srv_config, "host"));
215
216        aaj = xs_dict_append(aaj, "rel",  "self");
217        aaj = xs_dict_append(aaj, "type", "application/activity+json");
218        aaj = xs_dict_append(aaj, "href", snac.actor);
219
220        links = xs_list_append(links, aaj);
221
222        /* duplicate with the ld+json type */
223        aaj = xs_dict_set(aaj, "type", "application/ld+json; profile=\"https:/"
224                                    "/www.w3.org/ns/activitystreams\"");
225
226        links = xs_list_append(links, aaj);
227
228        prof = xs_dict_append(prof, "rel", "http://webfinger.net/rel/profile-page");
229        prof = xs_dict_append(prof, "type", "text/html");
230        prof = xs_dict_append(prof, "href", snac.actor);
231
232        links = xs_list_append(links, prof);
233
234        const char *avatar = xs_dict_get(snac.config, "avatar");
235        if (!xs_is_null(avatar) && *avatar) {
236            xs *d = xs_dict_new();
237
238            d = xs_dict_append(d, "rel",  "http:/" "/webfinger.net/rel/avatar");
239            d = xs_dict_append(d, "type", xs_mime_by_ext(avatar));
240            d = xs_dict_append(d, "href", avatar);
241
242            links = xs_list_append(links, d);
243        }
244
245        obj = xs_dict_append(obj, "subject", acct);
246        obj = xs_dict_append(obj, "links",   links);
247
248        xs_str *j = xs_json_dumps(obj, 4);
249
250        user_free(&snac);
251
252        status = HTTP_STATUS_OK;
253        *body  = j;
254        *ctype = "application/jrd+json";
255    }
256    else
257        status = HTTP_STATUS_NOT_FOUND;
258
259    srv_debug(1, xs_fmt("webfinger_get_handler resource=%s %d", resource, status));
260
261    return status;
262}