1/* snac - A simple, minimalistic ActivityPub instance */
  2/* copyright (c) 2025 grunfink et al. / MIT license */
  3
  4#include "xs.h"
  5#include "xs_html.h"
  6#include "xs_regex.h"
  7#include "xs_time.h"
  8#include "xs_match.h"
  9#include "xs_curl.h"
 10#include "xs_openssl.h"
 11#include "xs_json.h"
 12
 13#include "snac.h"
 14
 15xs_str *rss_from_timeline(snac *user, const xs_list *timeline,
 16                        const char *title, const char *link, const char *desc)
 17/* converts a timeline to rss */
 18{
 19    xs_html *rss = xs_html_tag("rss",
 20        xs_html_attr("xmlns:content", "http:/" "/purl.org/rss/1.0/modules/content/"),
 21        xs_html_attr("version",       "2.0"),
 22        xs_html_attr("xmlns:atom",    "http:/" "/www.w3.org/2005/Atom"));
 23
 24    xs_html *channel = xs_html_tag("channel",
 25        xs_html_tag("title",
 26            xs_html_text(title)),
 27        xs_html_tag("language",
 28            xs_html_text("en")),
 29        xs_html_tag("link",
 30            xs_html_text(link)),
 31        xs_html_sctag("atom:link",
 32            xs_html_attr("href", link),
 33            xs_html_attr("rel", "self"),
 34            xs_html_attr("type", "application/rss+xml")),
 35        xs_html_tag("generator",
 36            xs_html_text(USER_AGENT)),
 37        xs_html_tag("description",
 38            xs_html_text(desc)));
 39
 40    xs_html_add(rss, channel);
 41
 42    int cnt = 0;
 43    const char *v;
 44
 45    xs_list_foreach(timeline, v) {
 46        xs *msg = NULL;
 47
 48        if (user) {
 49            if (!valid_status(timeline_get_by_md5(user, v, &msg)))
 50                continue;
 51        }
 52        else {
 53            if (!valid_status(object_get_by_md5(v, &msg)))
 54                continue;
 55        }
 56
 57        const char *id = xs_dict_get(msg, "id");
 58        const char *content = xs_dict_get(msg, "content");
 59        const char *published = xs_dict_get(msg, "published");
 60
 61        if (user && !xs_startswith(id, user->actor))
 62            continue;
 63
 64        if (!id || !content || !published)
 65            continue;
 66
 67        /* create a title with the first line of the content */
 68        xs *title = xs_replace(content, "<br>", "\n");
 69        title = xs_regex_replace_i(title, "<[^>]+>", " ");
 70        title = xs_regex_replace_i(title, "&[^;]+;", " ");
 71        int i;
 72
 73        for (i = 0; title[i] && title[i] != '\n' && i < 50; i++);
 74
 75        if (title[i] != '\0') {
 76            title[i] = '\0';
 77            title = xs_str_cat(title, "...");
 78        }
 79
 80        title = xs_strip_i(title);
 81
 82        /* convert the date */
 83        time_t t = xs_parse_iso_date(published, 0);
 84        xs *rss_date = xs_str_utctime(t, "%a, %d %b %Y %T +0000");
 85
 86        /* if it's the first one, add it to the header */
 87        if (cnt == 0)
 88            xs_html_add(channel,
 89                xs_html_tag("lastBuildDate",
 90                    xs_html_text(rss_date)));
 91
 92        xs_html_add(channel,
 93            xs_html_tag("item",
 94                xs_html_tag("title",
 95                    xs_html_text(title)),
 96                xs_html_tag("link",
 97                    xs_html_text(id)),
 98                xs_html_tag("guid",
 99                    xs_html_text(id)),
100                xs_html_tag("pubDate",
101                    xs_html_text(rss_date)),
102                xs_html_tag("description",
103                    xs_html_text(content))));
104
105        cnt++;
106    }
107
108    return xs_html_render_s(rss, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
109}
110
111
112void rss_to_timeline(snac *user, const char *url)
113/* reads an RSS and inserts all ActivityPub posts into the user's timeline */
114{
115    if (!xs_startswith(url, "https:/") && !xs_startswith(url, "http:/"))
116        return;
117
118    xs *hdrs = xs_dict_new();
119    hdrs = xs_dict_set(hdrs, "accept",     "application/rss+xml");
120    hdrs = xs_dict_set(hdrs, "user-agent", USER_AGENT);
121
122    /* get the RSS metadata */
123    xs *md5 = xs_md5_hex(url, strlen(url));
124    xs *rss_md_fn = xs_fmt("%s/rss", user->basedir);
125    mkdirx(rss_md_fn);
126    rss_md_fn = xs_str_cat(rss_md_fn, "/", md5, ".json");
127
128    xs *rss_md = NULL;
129    const char *etag = NULL;
130
131    FILE *f;
132    if ((f = fopen(rss_md_fn, "r")) != NULL) {
133        rss_md = xs_json_load(f);
134        fclose(f);
135
136        etag = xs_dict_get(rss_md, "etag");
137
138        if (xs_is_string(etag))
139            hdrs = xs_dict_set(hdrs, "if-none-match", etag);
140    }
141
142    if (rss_md == NULL)
143        rss_md = xs_dict_new();
144
145    xs *payload = NULL;
146    int status;
147    int p_size;
148
149    xs *rsp = xs_http_request("GET", url, hdrs, NULL, 0, &status, &payload, &p_size, 0);
150
151    snac_log(user, xs_fmt("parsing RSS %s %d", url, status));
152
153    if (!valid_status(status) || !xs_is_string(payload))
154        return;
155
156    /* not an RSS? done */
157    const char *ctype = xs_dict_get(rsp, "content-type");
158    if (!xs_is_string(ctype) || xs_str_in(ctype, "application/rss+xml") == -1)
159        return;
160
161    /* yes, parsing is done with regexes (now I have two problems blah blah blah) */
162    xs *links = xs_regex_select(payload, "<link>[^<]+</link>");
163    const char *link;
164
165    xs_list_foreach(links, link) {
166        xs *l = xs_replace(link, "<link>", "");
167        char *p = strchr(l, '<');
168
169        if (p == NULL)
170            continue;
171        *p = '\0';
172
173        /* skip this same URL */
174        if (strcmp(l, url) == 0)
175            continue;
176
177        /* skip crap */
178        if (!xs_startswith(l, "https:/") && !xs_startswith(l, "http:/"))
179            continue;
180
181        snac_debug(user, 1, xs_fmt("RSS link: %s", l));
182
183        if (timeline_here(user, l)) {
184            snac_debug(user, 1, xs_fmt("RSS entry already in timeline %s", l));
185            continue;
186        }
187
188        /* special trick for Mastodon: convert from the alternate format */
189        if (strchr(l, '@') != NULL) {
190            xs *l2 = xs_split(l, "/");
191
192            if (xs_list_len(l2) == 5) {
193                const char *uid = xs_list_get(l2, 3);
194                if (*uid == '@') {
195                    xs *guessed_id = xs_fmt("https:/" "/%s/users/%s/statuses/%s",
196                        xs_list_get(l2, 2), uid + 1, xs_list_get(l2, -1));
197
198                    if (timeline_here(user, guessed_id)) {
199                        snac_debug(user, 1, xs_fmt("RSS entry already in timeline (alt) %s", guessed_id));
200                        continue;
201                    }
202                }
203            }
204        }
205
206        xs *obj = NULL;
207
208        if (!valid_status(object_get(l, &obj))) {
209            /* object is not here: bring it */
210            if (!valid_status(activitypub_request(user, l, &obj)))
211                continue;
212        }
213
214        if (xs_is_dict(obj)) {
215            const char *id      = xs_dict_get(obj, "id");
216            const char *type    = xs_dict_get(obj, "type");
217            const char *attr_to = get_atto(obj);
218
219            if (!xs_is_string(id) || !xs_is_string(type) || !xs_is_string(attr_to))
220                continue;
221
222            if (!xs_match(type, POSTLIKE_OBJECT_TYPE))
223                continue;
224
225            if (timeline_here(user, id)) {
226                snac_debug(user, 1, xs_fmt("RSS entry already in timeline (id) %s", id));
227                continue;
228            }
229
230            enqueue_actor_refresh(user, attr_to, 0);
231
232            timeline_add(user, id, obj);
233
234            snac_log(user, xs_fmt("new '%s' (RSS) %s %s", type, attr_to, id));
235        }
236    }
237
238    /* update the RSS metadata */
239    etag = xs_dict_get(rsp, "etag");
240
241    if (xs_is_string(etag)) {
242        rss_md = xs_dict_set(rss_md, "etag", etag);
243        rss_md = xs_dict_set(rss_md, "url", url);
244        if ((f = fopen(rss_md_fn, "w")) != NULL) {
245            xs_json_dump(rss_md, 4, f);
246            fclose(f);
247        }
248    }
249}
250
251
252void rss_poll_hashtags(void)
253/* parses all RSS from all users */
254{
255    xs *list = user_list();
256    const char *uid;
257
258    xs_list_foreach(list, uid) {
259        snac user;
260
261        if (user_open(&user, uid)) {
262            const xs_list *rss = xs_dict_get(user.config, "followed_hashtags");
263
264            if (xs_is_list(rss)) {
265                const char *url;
266
267                xs_list_foreach(rss, url)
268                    rss_to_timeline(&user, url);
269            }
270
271            user_free(&user);
272        }
273    }
274}