summary refs log tree commit diff
path: root/bin/title.c
blob: e070653abb542636de0a6710ff9229b246013f02 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/* Copyright (C) 2019  June McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <curl/curl.h>
#include <err.h>
#include <locale.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <wchar.h>

static regex_t regex(const char *pattern) {
	regex_t regex;
	int error = regcomp(&regex, pattern, REG_EXTENDED);
	if (!error) return regex;

	char buf[256];
	regerror(error, &regex, buf, sizeof(buf));
	errx(EX_SOFTWARE, "regcomp: %s: %s", buf, pattern);
}

static const struct Entity {
	wchar_t ch;
	const char *name;
} Entities[] = {
	{ L'"', "&quot;" },
	{ L'&', "&amp;" },
	{ L'<', "&lt;" },
	{ L'>', "&gt;" },
	{ L'␤', "&#10;" },
};

static wchar_t entity(const char *name) {
	for (size_t i = 0; i < sizeof(Entities) / sizeof(Entities[0]); ++i) {
		struct Entity entity = Entities[i];
		if (strncmp(name, entity.name, strlen(entity.name))) continue;
		return entity.ch;
	}
	if (!strncmp(name, "&#x", 3)) return strtoul(&name[3], NULL, 16);
	if (!strncmp(name, "&#", 2)) return strtoul(&name[2], NULL, 10);
	return 0;
}

static const char EntityPattern[] = {
	"[[:space:]]+|&([[:alpha:]]+|#([[:digit:]]+|x[[:xdigit:]]+));"
};
static regex_t EntityRegex;

static void showTitle(const char *title) {
	regmatch_t match = {0};
	for (; *title; title += match.rm_eo) {
		if (regexec(&EntityRegex, title, 1, &match, 0)) break;
		if (title[match.rm_so] != '&') {
			printf("%.*s ", (int)match.rm_so, title);
			continue;
		}
		wchar_t ch = entity(&title[match.rm_so]);
		if (ch) {
			printf("%.*s%lc", (int)match.rm_so, title, (wint_t)ch);
		} else {
			printf("%.*s", (int)match.rm_eo, title);
		}
	}
	printf("%s\n", title);
}

static CURL *curl;
static struct {
	char buf[8192];
	size_t len;
} body;

// HE COMES
static const char TitlePattern[] = "<title>([^<]*)</title>";
static regex_t TitleRegex;

static size_t handleBody(char *buf, size_t size, size_t nitems, void *user) {
	(void)user;

	size_t len = size * nitems;
	size_t cap = sizeof(body.buf) - body.len - 1;
	size_t new = (len < cap ? len : cap);
	if (!new) return 0;

	memcpy(&body.buf[body.len], buf, new);
	body.len += new;
	body.buf[body.len] = '\0';

	regmatch_t match[2];
	if (regexec(&TitleRegex, body.buf, 2, match, 0)) return len;
	body.buf[match[1].rm_eo] = '\0';
	showTitle(&body.buf[match[1].rm_so]);
	return 0;
}

static CURLcode fetchTitle(const char *url) {
	CURLcode code = curl_easy_setopt(curl, CURLOPT_URL, url);
	if (code) return code;

	curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
	code = curl_easy_perform(curl);
	if (code) return code;

	char *type;
	code = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &type);
	if (code) return code;
	if (!type || strncmp(type, "text/html", 9)) return CURLE_OK;

	body.len = 0;
	curl_easy_setopt(curl, CURLOPT_NOBODY, 0L);
	code = curl_easy_perform(curl);
	if (code == CURLE_WRITE_ERROR) return CURLE_OK;
	return code;
}

int main(int argc, char *argv[]) {
	EntityRegex = regex(EntityPattern);
	TitleRegex = regex(TitlePattern);

	setlocale(LC_CTYPE, "");
	setlinebuf(stdout);

	CURLcode code = curl_global_init(CURL_GLOBAL_ALL);
	if (code) errx(EX_OSERR, "curl_global_init: %s", curl_easy_strerror(code));

	curl = curl_easy_init();
	if (!curl) errx(EX_SOFTWARE, "curl_easy_init");

	curl_easy_setopt(curl, CURLOPT_PROTOCOLS, CURLPROTO_HTTP | CURLPROTO_HTTPS);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 3L);

	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, handleBody);

	if (argc > 1) {
		code = fetchTitle(argv[1]);
		if (!code) return EX_OK;
		errx(EX_DATAERR, "curl_easy_perform: %s", curl_easy_strerror(code));
	}

	char *buf = NULL;
	size_t cap = 0;

	regex_t urlRegex = regex("https?://[^[:space:]>\"]+");
	while (0 < getline(&buf, &cap, stdin)) {
		regmatch_t match = {0};
		for (char *url = buf; *url; url += match.rm_eo) {
			if (regexec(&urlRegex, url, 1, &match, 0)) break;
			url[match.rm_eo] = '\0';
			code = fetchTitle(&url[match.rm_so]);
			if (code) warnx("curl_easy_perform: %s", curl_easy_strerror(code));
			url[match.rm_eo] = ' ';
		}
	}
	if (ferror(stdin)) err(EX_IOERR, "getline");
}