/* snac - A simple, minimalistic ActivityPub instance */ /* copyright (c) 2022 - 2024 grunfink et al. / MIT license */ #include "xs.h" #include "xs_regex.h" #include "xs_mime.h" #include "xs_html.h" #include "xs_json.h" #include "xs_time.h" #include "snac.h" /* emoticons, people laughing and such */ const char *smileys[] = { ":-)", "🙂", ":-D", "😀", "X-D", "😆", ";-)", "😉", "B-)", "😎", ">:-(", "😡", ":-(", "😞", ":-*", "😘", ":-/", "😕", "8-o", "😲", "%-)", "🤪", ":_(", "😢", ":-|", "😐", "<3", "❤️", ":facepalm:", "🤦", ":shrug:", "🤷", ":shrug2:", "¯\\_(ツ)_/¯", ":eyeroll:", "🙄", ":beer:", "🍺", ":beers:", "🍻", ":munch:", "😱", ":thumb:", "👍", NULL, NULL }; xs_dict *emojis(void) /* returns a dict with the emojis */ { xs *fn = xs_fmt("%s/emojis.json", srv_basedir); FILE *f; if (mtime(fn) == 0) { /* file does not exist; create it with the defaults */ xs *d = xs_dict_new(); const char **emo = smileys; while (*emo) { d = xs_dict_append(d, emo[0], emo[1]); emo += 2; } if ((f = fopen(fn, "w")) != NULL) { xs_json_dump(d, 4, f); fclose(f); } else srv_log(xs_fmt("Error creating '%s'", fn)); } xs_dict *d = NULL; if ((f = fopen(fn, "r")) != NULL) { d = xs_json_load(f); fclose(f); if (d == NULL) srv_log(xs_fmt("JSON parse error in '%s'", fn)); } else srv_log(xs_fmt("Error opening '%s'", fn)); return d; } static xs_str *format_line(const char *line, xs_list **attach) /* formats a line */ { xs_str *s = xs_str_new(NULL); char *p; const char *v; /* split by markup */ xs *sm = xs_regex_split(line, "(" "`[^`]+`" "|" "\\*\\*?[^\\*]+\\*?\\*" "|" "\\[[^]]+\\]\\([^\\)]+\\)" "|" "https?:/" "/[^[:space:]]+" ")"); int n = 0; p = sm; while (xs_list_iter(&p, &v)) { if ((n & 0x1)) { /* markup */ if (xs_startswith(v, "`")) { xs *s1 = xs_crop_i(xs_dup(v), 1, -1); xs *e1 = encode_html(s1); xs *s2 = xs_fmt("%s", e1); s = xs_str_cat(s, s2); } else if (xs_startswith(v, "**")) { xs *s1 = xs_crop_i(xs_dup(v), 2, -2); xs *s2 = xs_fmt("%s", s1); s = xs_str_cat(s, s2); } else if (xs_startswith(v, "*")) { xs *s1 = xs_crop_i(xs_dup(v), 1, -1); xs *s2 = xs_fmt("%s", s1); s = xs_str_cat(s, s2); } else if (xs_startswith(v, "http")) { xs *u = xs_replace(v, "#", "#"); xs *v2 = xs_strip_chars_i(xs_dup(u), ".,)"); const char *mime = xs_mime_by_ext(v2); if (attach != NULL && xs_startswith(mime, "image/")) { /* if it's a link to an image, insert it as an attachment */ xs *d = xs_dict_new(); d = xs_dict_append(d, "mediaType", mime); d = xs_dict_append(d, "url", v2); d = xs_dict_append(d, "name", ""); d = xs_dict_append(d, "type", "Image"); *attach = xs_list_append(*attach, d); } else { xs *s1 = xs_fmt("%s", v2, u); s = xs_str_cat(s, s1); } } else if (*v == '[') { /* markdown-like links [label](url) */ xs *w = xs_strip_chars_i(xs_dup(v), "[)"); xs *l = xs_split(w, "]("); xs *link = xs_fmt("%s", xs_list_get(l, 1), xs_list_get(l, 0)); s = xs_str_cat(s, link); } else s = xs_str_cat(s, v); } else /* surrounded text, copy directly */ s = xs_str_cat(s, v); n++; } return s; } xs_str *not_really_markdown(const char *content, xs_list **attach, xs_list **tag) /* formats a content using some Markdown rules */ { xs_str *s = xs_str_new(NULL); int in_pre = 0; int in_blq = 0; xs *list; char *p; const char *v; /* work by lines */ list = xs_split(content, "\n"); p = list; while (xs_list_iter(&p, &v)) { xs *ss = NULL; if (strcmp(v, "```") == 0) { if (!in_pre) s = xs_str_cat(s, "
");
            else
                s = xs_str_cat(s, "
"); in_pre = !in_pre; continue; } if (in_pre) { // Encode all HTML characters when we're in pre element until we are out. ss = encode_html(v); s = xs_str_cat(s, ss); s = xs_str_cat(s, "
"); continue; } else ss = xs_strip_i(format_line(v, attach)); if (xs_startswith(ss, "---")) { /* delete the --- */ ss = xs_strip_i(xs_crop_i(ss, 3, 0)); s = xs_str_cat(s, "
"); s = xs_str_cat(s, ss); continue; } if (xs_startswith(ss, ">")) { /* delete the > and subsequent spaces */ ss = xs_strip_i(xs_crop_i(ss, 1, 0)); if (!in_blq) { s = xs_str_cat(s, "
"); in_blq = 1; } s = xs_str_cat(s, ss); s = xs_str_cat(s, "
"); continue; } if (in_blq) { s = xs_str_cat(s, "
"); in_blq = 0; } s = xs_str_cat(s, ss); s = xs_str_cat(s, "
"); } if (in_blq) s = xs_str_cat(s, ""); if (in_pre) s = xs_str_cat(s, ""); /* some beauty fixes */ s = xs_replace_i(s, "

", "
"); s = xs_replace_i(s, "

", "
"); s = xs_replace_i(s, "
", ""); { /* traditional emoticons */ xs *d = emojis(); int c = 0; const char *k, *v; while (xs_dict_next(d, &k, &v, &c)) { const char *t = NULL; /* is it an URL to an image? */ if (xs_startswith(v, "https:/" "/") && xs_startswith((t = xs_mime_by_ext(v)), "image/")) { if (tag && xs_str_in(s, k) != -1) { /* add the emoji to the tag list */ xs *e = xs_dict_new(); xs *i = xs_dict_new(); xs *u = xs_str_utctime(0, ISO_DATE_SPEC); e = xs_dict_append(e, "id", v); e = xs_dict_append(e, "type", "Emoji"); e = xs_dict_append(e, "name", k); e = xs_dict_append(e, "updated", u); i = xs_dict_append(i, "type", "Image"); i = xs_dict_append(i, "mediaType", t); i = xs_dict_append(i, "url", v); e = xs_dict_append(e, "icon", i); *tag = xs_list_append(*tag, e); } } else s = xs_replace_i(s, k, v); } } return s; } const char *valid_tags[] = { "a", "p", "br", "br/", "blockquote", "ul", "ol", "li", "cite", "small", "span", "i", "b", "u", "s", "pre", "code", "em", "strong", "hr", "img", "del", "bdi", NULL }; xs_str *sanitize(const char *content) /* cleans dangerous HTML output */ { xs_str *s = xs_str_new(NULL); xs *sl; int n = 0; char *p; const char *v; sl = xs_regex_split(content, "]+>"); p = sl; n = 0; while (xs_list_iter(&p, &v)) { if (n & 0x1) { xs *s1 = xs_strip_i(xs_crop_i(xs_dup(v), v[1] == '/' ? 2 : 1, -1)); xs *l1 = xs_split_n(s1, " ", 1); xs *tag = xs_tolower_i(xs_dup(xs_list_get(l1, 0))); xs *s2 = NULL; int i; /* check if it's one of the valid tags */ for (i = 0; valid_tags[i]; i++) { if (strcmp(tag, valid_tags[i]) == 0) break; } if (valid_tags[i]) { /* accepted tag: rebuild it with only the accepted elements */ xs *el = xs_regex_select(v, "(src|href|rel|class|target)=\"[^\"]*\""); xs *s3 = xs_join(el, " "); s2 = xs_fmt("<%s%s%s%s>", v[1] == '/' ? "/" : "", tag, xs_list_len(el) ? " " : "", s3); s = xs_str_cat(s, s2); } else { /* treat end of divs as paragraph breaks */ if (strcmp(v, "")) s = xs_str_cat(s, "

"); } } else { /* non-tag */ s = xs_str_cat(s, v); } n++; } return s; } xs_str *encode_html(const char *str) /* escapes html characters */ { xs_str *encoded = xs_html_encode((char *)str); /* Restore only
. Probably safe. Let's hope nothing goes wrong with this. */ encoded = xs_replace_i(encoded, "<br>", "
"); return encoded; }