]> git.mxchange.org Git - friendica.git/blob - mod/display.php
Merge pull request #2263 from tobiasd/20160118-messages
[friendica.git] / mod / display.php
1 <?php
2
3 function display_init(&$a) {
4
5         if((get_config('system','block_public')) && (! local_user()) && (! remote_user())) {
6                 return;
7         }
8
9         $nick = (($a->argc > 1) ? $a->argv[1] : '');
10         $profiledata = array();
11
12         // If there is only one parameter, then check if this parameter could be a guid
13         if ($a->argc == 2) {
14                 $nick = "";
15                 $itemuid = 0;
16
17                 // Does the local user have this item?
18                 if (local_user()) {
19                         $r = q("SELECT `id`, `parent`, `author-name`, `author-link`, `author-avatar`, `network`, `body`, `uid` FROM `item`
20                                 WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
21                                         AND `guid` = '%s' AND `uid` = %d", dbesc($a->argv[1]), local_user());
22                         if (count($r)) {
23                                 $nick = $a->user["nickname"];
24                                 $itemuid = local_user();
25                         }
26                 }
27
28                 // Or is it anywhere on the server?
29                 if ($nick == "") {
30                         $r = q("SELECT `user`.`nickname`, `item`.`id`, `item`.`parent`, `item`.`author-name`,
31                                 `item`.`author-link`, `item`.`author-avatar`, `item`.`network`, `item`.`uid`, `item`.`body`
32                                 FROM `item` INNER JOIN `user` ON `user`.`uid` = `item`.`uid`
33                                 WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
34                                         AND `item`.`allow_cid` = ''  AND `item`.`allow_gid` = ''
35                                         AND `item`.`deny_cid`  = '' AND `item`.`deny_gid`  = ''
36                                         AND `item`.`private` = 0 AND NOT `user`.`hidewall`
37                                         AND `item`.`guid` = '%s'", dbesc($a->argv[1]));
38                                 //      AND `item`.`private` = 0 AND `item`.`wall` = 1
39                         if (count($r)) {
40                                 $nick = $r[0]["nickname"];
41                                 $itemuid = $r[0]["uid"];
42                         }
43                 }
44
45                 // Is it an item with uid=0?
46                 if ($nick == "") {
47                         $r = q("SELECT `item`.`id`, `item`.`parent`, `item`.`author-name`,
48                                 `item`.`author-link`, `item`.`author-avatar`, `item`.`network`, `item`.`uid`, `item`.`body`
49                                 FROM `item` WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
50                                         AND `item`.`allow_cid` = ''  AND `item`.`allow_gid` = ''
51                                         AND `item`.`deny_cid`  = '' AND `item`.`deny_gid`  = ''
52                                         AND `item`.`private` = 0 AND `item`.`uid` = 0
53                                         AND `item`.`guid` = '%s'", dbesc($a->argv[1]));
54                                 //      AND `item`.`private` = 0 AND `item`.`wall` = 1
55                 }
56                 if (count($r)) {
57                         if ($r[0]["id"] != $r[0]["parent"])
58                                 $r = q("SELECT `id`, `author-name`, `author-link`, `author-avatar`, `network`, `body`, `uid` FROM `item`
59                                         WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
60                                                 AND `id` = %d", $r[0]["parent"]);
61
62                         $profiledata = display_fetchauthor($a, $r[0]);
63
64                         if (strstr(normalise_link($profiledata["url"]), normalise_link($a->get_baseurl()))) {
65                                 $nickname = str_replace(normalise_link($a->get_baseurl())."/profile/", "", normalise_link($profiledata["url"]));
66
67                                 if (($nickname != $a->user["nickname"])) {
68                                         $r = q("SELECT `profile`.`uid` AS `profile_uid`, `profile`.* , `contact`.`avatar-date` AS picdate, `user`.* FROM `profile`
69                                                 INNER JOIN `contact` on `contact`.`uid` = `profile`.`uid` INNER JOIN `user` ON `profile`.`uid` = `user`.`uid`
70                                                 WHERE `user`.`nickname` = '%s' AND `profile`.`is-default` = 1 and `contact`.`self` = 1 LIMIT 1",
71                                                 dbesc($nickname)
72                                         );
73                                         if (count($r))
74                                                 $profiledata = $r[0];
75
76                                         $profiledata["network"] = NETWORK_DFRN;
77                                 } else
78                                         $profiledata = array();
79                         }
80                 } else {
81                         $a->error = 404;
82                         notice( t('Item not found.') . EOL);
83                         return;
84                 }
85         }
86
87         profile_load($a, $nick, 0, $profiledata);
88
89 }
90
91 function display_fetchauthor($a, $item) {
92
93         $profiledata = array();
94         $profiledata["uid"] = -1;
95         $profiledata["nickname"] = $item["author-name"];
96         $profiledata["name"] = $item["author-name"];
97         $profiledata["picdate"] = "";
98         $profiledata["photo"] = $item["author-avatar"];
99         $profiledata["url"] = $item["author-link"];
100         $profiledata["network"] = $item["network"];
101
102         // Check for a repeated message
103         $skip = false;
104         $body = trim($item["body"]);
105
106         // Skip if it isn't a pure repeated messages
107         // Does it start with a share?
108         if (!$skip AND strpos($body, "[share") > 0)
109                 $skip = true;
110
111         // Does it end with a share?
112         if (!$skip AND (strlen($body) > (strrpos($body, "[/share]") + 8)))
113                 $skip = true;
114
115         if (!$skip) {
116                 $attributes = preg_replace("/\[share(.*?)\]\s?(.*?)\s?\[\/share\]\s?/ism","$1",$body);
117                 // Skip if there is no shared message in there
118                 if ($body == $attributes)
119                         $skip = true;
120         }
121
122         if (!$skip) {
123                 $author = "";
124                 preg_match("/author='(.*?)'/ism", $attributes, $matches);
125                 if ($matches[1] != "")
126                         $profiledata["name"] = html_entity_decode($matches[1],ENT_QUOTES,'UTF-8');
127
128                 preg_match('/author="(.*?)"/ism', $attributes, $matches);
129                 if ($matches[1] != "")
130                         $profiledata["name"] = html_entity_decode($matches[1],ENT_QUOTES,'UTF-8');
131
132                 $profile = "";
133                 preg_match("/profile='(.*?)'/ism", $attributes, $matches);
134                 if ($matches[1] != "")
135                         $profiledata["url"] = $matches[1];
136
137                 preg_match('/profile="(.*?)"/ism', $attributes, $matches);
138                 if ($matches[1] != "")
139                         $profiledata["url"] = $matches[1];
140
141                 $avatar = "";
142                 preg_match("/avatar='(.*?)'/ism", $attributes, $matches);
143                 if ($matches[1] != "")
144                         $profiledata["photo"] = $matches[1];
145
146                 preg_match('/avatar="(.*?)"/ism', $attributes, $matches);
147                 if ($matches[1] != "")
148                         $profiledata["photo"] = $matches[1];
149
150                 $profiledata["nickname"] = $profiledata["name"];
151                 $profiledata["network"] = GetProfileUsername($profiledata["url"], "", false, true);
152
153                 $profiledata["address"] = "";
154                 $profiledata["about"] = "";
155         }
156
157         // Don't show details from Diaspora contacts if you don't follow the contact
158         $showdetails = ($profiledata["network"] != NETWORK_DIASPORA);
159
160         // Fetching further contact data from the contact table
161         $r = q("SELECT `uid`, `network`, `name`, `photo`, `nick`, `addr`, `location`, `about`, `gender`, `keywords`
162                 FROM `contact` WHERE `nurl` = '%s' AND `uid` = %d AND `network` = '%s' AND `rel` IN (%d, %d)",
163                 dbesc(normalise_link($profiledata["url"])), intval(local_user()), dbesc($item["network"]),
164                 intval(CONTACT_IS_SHARING), intval(CONTACT_IS_FRIEND));
165         if (!count($r))
166                 $r = q("SELECT `uid`, `network`, `name`, `photo`, `nick`, `addr`, `location`, `about`, `gender`, `keywords`
167                         FROM `contact` WHERE `nurl` = '%s' AND `uid` = %d AND `rel` IN (%d, %d)",
168                         dbesc(normalise_link($profiledata["url"])), intval(local_user()),
169                         intval(CONTACT_IS_SHARING), intval(CONTACT_IS_FRIEND));
170
171         if (count($r)) {
172                 $profiledata["name"] = $r[0]["name"];
173                 $profiledata["photo"] = $r[0]["photo"];
174                 $profiledata["nickname"] = $r[0]["nick"];
175                 $profiledata["addr"] = $r[0]["addr"];
176                 $profiledata["keywords"] = $r[0]["keywords"];
177                 $profiledata["network"] = $r[0]["network"];
178
179                 if (local_user() OR $showdetails) {
180                         $showdetails = true;
181                         $profiledata["address"] = $r[0]["location"];
182                         $profiledata["about"] = $r[0]["about"];
183                         $profiledata["gender"] = $r[0]["gender"];
184                 }
185         }
186
187         // Fetching profile data from global contacts
188         if ($profiledata["network"] != NETWORK_FEED) {
189                 $r = q("SELECT `name`, `photo`, `nick`, `addr`, `location`, `about`, `gender`, `keywords`, `network` FROM `gcontact` WHERE `nurl` = '%s'", dbesc(normalise_link($profiledata["url"])));
190                 if (count($r)) {
191                         $profiledata["name"] = $r[0]["name"];
192                         $profiledata["photo"] = $r[0]["photo"];
193                         $profiledata["nickname"] = $r[0]["nick"];
194                         $profiledata["addr"] = $r[0]["addr"];
195                         $profiledata["keywords"] = $r[0]["keywords"];
196                         $profiledata["network"] = $r[0]["network"];
197
198                         if ($showdetails) {
199                                 $profiledata["address"] = $r[0]["location"];
200                                 $profiledata["about"] = $r[0]["about"];
201                                 $profiledata["gender"] = $r[0]["gender"];
202                         }
203                 }
204         }
205
206         if (local_user()) {
207                 if (in_array($profiledata["network"], array(NETWORK_DFRN, NETWORK_DIASPORA, NETWORK_OSTATUS)))
208                         $profiledata["remoteconnect"] = $a->get_baseurl()."/follow?url=".urlencode($profiledata["url"]);
209         } elseif ($profiledata["network"] == NETWORK_DFRN) {
210                 $connect = str_replace("/profile/", "/dfrn_request/", $profiledata["url"]);
211                 $profiledata["remoteconnect"] = $connect;
212         }
213
214         return($profiledata);
215 }
216
217 function display_content(&$a, $update = 0) {
218
219         if((get_config('system','block_public')) && (! local_user()) && (! remote_user())) {
220                 notice( t('Public access denied.') . EOL);
221                 return;
222         }
223
224         require_once('include/security.php');
225         require_once('include/conversation.php');
226         require_once('include/acl_selectors.php');
227
228
229         $o = '';
230
231         $a->page['htmlhead'] .= replace_macros(get_markup_template('display-head.tpl'), array());
232
233
234         if($update) {
235                 $nick = $_REQUEST['nick'];
236         }
237         else {
238                 $nick = (($a->argc > 1) ? $a->argv[1] : '');
239         }
240
241         if($update) {
242                 $item_id = $_REQUEST['item_id'];
243                 $a->profile = array('uid' => intval($update), 'profile_uid' => intval($update));
244         }
245         else {
246                 $item_id = (($a->argc > 2) ? $a->argv[2] : 0);
247
248                 if ($a->argc == 2) {
249                         $nick = "";
250
251                         if (local_user()) {
252                                 $r = q("SELECT `id` FROM `item`
253                                         WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
254                                                 AND `guid` = '%s' AND `uid` = %d", dbesc($a->argv[1]), local_user());
255                                 if (count($r)) {
256                                         $item_id = $r[0]["id"];
257                                         $nick = $a->user["nickname"];
258                                 }
259                         }
260
261                         if ($nick == "") {
262                                 $r = q("SELECT `user`.`nickname`, `item`.`id` FROM `item` INNER JOIN `user` ON `user`.`uid` = `item`.`uid`
263                                         WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
264                                                 AND `item`.`allow_cid` = ''  AND `item`.`allow_gid` = ''
265                                                 AND `item`.`deny_cid`  = '' AND `item`.`deny_gid`  = ''
266                                                 AND `item`.`private` = 0  AND NOT `user`.`hidewall`
267                                                 AND `item`.`guid` = '%s'", dbesc($a->argv[1]));
268                                         //      AND `item`.`private` = 0 AND `item`.`wall` = 1
269                                 if (count($r)) {
270                                         $item_id = $r[0]["id"];
271                                         $nick = $r[0]["nickname"];
272                                 }
273                         }
274                         if ($nick == "") {
275                                 $r = q("SELECT `item`.`id` FROM `item`
276                                         WHERE `item`.`visible` = 1 AND `item`.`deleted` = 0 and `item`.`moderated` = 0
277                                                 AND `item`.`allow_cid` = ''  AND `item`.`allow_gid` = ''
278                                                 AND `item`.`deny_cid`  = '' AND `item`.`deny_gid`  = ''
279                                                 AND `item`.`private` = 0  AND `item`.`uid` = 0
280                                                 AND `item`.`guid` = '%s'", dbesc($a->argv[1]));
281                                         //      AND `item`.`private` = 0 AND `item`.`wall` = 1
282                                 if (count($r)) {
283                                         $item_id = $r[0]["id"];
284                                 }
285                         }
286                 }
287         }
288
289         if(! $item_id) {
290                 $a->error = 404;
291                 notice( t('Item not found.') . EOL);
292                 return;
293         }
294
295         $groups = array();
296
297         $contact = null;
298         $remote_contact = false;
299
300         $contact_id = 0;
301
302         if(is_array($_SESSION['remote'])) {
303                 foreach($_SESSION['remote'] as $v) {
304                         if($v['uid'] == $a->profile['uid']) {
305                                 $contact_id = $v['cid'];
306                                 break;
307                         }
308                 }
309         }
310
311         if($contact_id) {
312                 $groups = init_groups_visitor($contact_id);
313                 $r = q("SELECT * FROM `contact` WHERE `id` = %d AND `uid` = %d LIMIT 1",
314                         intval($contact_id),
315                         intval($a->profile['uid'])
316                 );
317                 if(count($r)) {
318                         $contact = $r[0];
319                         $remote_contact = true;
320                 }
321         }
322
323         if(! $remote_contact) {
324                 if(local_user()) {
325                         $contact_id = $_SESSION['cid'];
326                         $contact = $a->contact;
327                 }
328         }
329
330         $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `self` = 1 LIMIT 1",
331                 intval($a->profile['uid'])
332         );
333         if(count($r))
334                 $a->page_contact = $r[0];
335
336         $is_owner = ((local_user()) && (local_user() == $a->profile['profile_uid']) ? true : false);
337
338         if($a->profile['hidewall'] && (! $is_owner) && (! $remote_contact)) {
339                 notice( t('Access to this profile has been restricted.') . EOL);
340                 return;
341         }
342
343         // Why do we need this on the display page? We don't have the possibility to write new content here.
344         // Ad editing of posts work without this as well.
345         // We should remove this completely for the 3.5.1 release.
346         /*
347         if ($is_owner) {
348                 $x = array(
349                         'is_owner' => true,
350                         'allow_location' => $a->user['allow_location'],
351                         'default_location' => $a->user['default-location'],
352                         'nickname' => $a->user['nickname'],
353                         'lockstate' => ( (is_array($a->user)) && ((strlen($a->user['allow_cid'])) || (strlen($a->user['allow_gid'])) || (strlen($a->user['deny_cid'])) || (strlen($a->user['deny_gid']))) ? 'lock' : 'unlock'),
354                         'acl' => populate_acl($a->user, true),
355                         'bang' => '',
356                         'visitor' => 'block',
357                         'profile_uid' => local_user(),
358                         'acl_data' => construct_acl_data($a, $a->user), // For non-Javascript ACL selector
359                 );
360                 $o .= status_editor($a,$x,0,true);
361         }
362         */
363
364         $sql_extra = item_permissions_sql($a->profile['uid'],$remote_contact,$groups);
365
366         //              AND `item`.`parent` = ( SELECT `parent` FROM `item` FORCE INDEX (PRIMARY, `uri`) WHERE ( `id` = '%s' OR `uri` = '%s' ))
367
368         if($update) {
369
370                 $r = q("SELECT id FROM item WHERE item.uid = %d
371                         AND `item`.`parent` = (SELECT `parent` FROM `item` WHERE (`id` = '%s' OR `uri` = '%s'))
372                         $sql_extra AND unseen = 1",
373                         intval($a->profile['uid']),
374                         dbesc($item_id),
375                         dbesc($item_id)
376                 );
377
378                 if(!$r)
379                         return '';
380         }
381
382         //      AND `item`.`parent` = ( SELECT `parent` FROM `item` FORCE INDEX (PRIMARY, `uri`) WHERE ( `id` = '%s' OR `uri` = '%s' )
383
384         $r = q("SELECT `item`.*, `item`.`id` AS `item_id`,  `item`.`network` AS `item_network`,
385                 `contact`.`name`, `contact`.`photo`, `contact`.`url`, `contact`.`rel`,
386                 `contact`.`network`, `contact`.`thumb`, `contact`.`self`, `contact`.`writable`,
387                 `contact`.`id` AS `cid`, `contact`.`uid` AS `contact-uid`
388                 FROM `item` INNER JOIN `contact` ON `contact`.`id` = `item`.`contact-id`
389                 AND `contact`.`blocked` = 0 AND `contact`.`pending` = 0
390                 WHERE `item`.`uid` = %d AND `item`.`visible` = 1 AND `item`.`deleted` = 0
391                 and `item`.`moderated` = 0
392                 AND `item`.`parent` = (SELECT `parent` FROM `item` WHERE (`id` = '%s' OR `uri` = '%s')
393                 AND uid = %d)
394                 $sql_extra
395                 ORDER BY `parent` DESC, `gravity` ASC, `id` ASC",
396                 intval($a->profile['uid']),
397                 dbesc($item_id),
398                 dbesc($item_id),
399                 intval($a->profile['uid'])
400         );
401
402         if(!$r && local_user()) {
403                 // Check if this is another person's link to a post that we have
404                 $r = q("SELECT `item`.uri FROM `item`
405                         WHERE (`item`.`id` = '%s' OR `item`.`uri` = '%s' )
406                         LIMIT 1",
407                         dbesc($item_id),
408                         dbesc($item_id)
409                 );
410                 if($r) {
411                         $item_uri = $r[0]['uri'];
412                         //      AND `item`.`parent` = ( SELECT `parent` FROM `item` FORCE INDEX (PRIMARY, `uri`) WHERE `uri` = '%s' AND uid = %d )
413
414                         $r = q("SELECT `item`.*, `item`.`id` AS `item_id`,  `item`.`network` AS `item_network`,
415                                 `contact`.`name`, `contact`.`photo`, `contact`.`url`, `contact`.`rel`,
416                                 `contact`.`network`, `contact`.`thumb`, `contact`.`self`, `contact`.`writable`,
417                                 `contact`.`id` AS `cid`, `contact`.`uid` AS `contact-uid`
418                                 FROM `item` INNER JOIN `contact` ON `contact`.`id` = `item`.`contact-id`
419                                 AND `contact`.`blocked` = 0 AND `contact`.`pending` = 0
420                                 WHERE `item`.`uid` = %d AND `item`.`visible` = 1 AND `item`.`deleted` = 0
421                                 and `item`.`moderated` = 0
422                                 AND `item`.`parent` = (SELECT `parent` FROM `item` WHERE `uri` = '%s' AND uid = %d)
423                                 ORDER BY `parent` DESC, `gravity` ASC, `id` ASC ",
424                                 intval(local_user()),
425                                 dbesc($item_uri),
426                                 intval(local_user())
427                         );
428                 }
429         }
430
431
432         if($r) {
433
434                 if((local_user()) && (local_user() == $a->profile['uid'])) {
435                         q("UPDATE `item` SET `unseen` = 0
436                                 WHERE `parent` = %d AND `unseen` = 1",
437                                 intval($r[0]['parent'])
438                         );
439                 }
440
441                 $items = conv_sort($r,"`commented`");
442
443                 if(!$update)
444                         $o .= "<script> var netargs = '?f=&nick=" . $nick . "&item_id=" . $item_id . "'; </script>";
445                 $o .= conversation($a,$items,'display', $update);
446
447                 // Preparing the meta header
448                 require_once('include/bbcode.php');
449                 require_once("include/html2plain.php");
450                 $description = trim(html2plain(bbcode($r[0]["body"], false, false), 0, true));
451                 $title = trim(html2plain(bbcode($r[0]["title"], false, false), 0, true));
452                 $author_name = $r[0]["author-name"];
453
454                 $image = "";
455                 if ($image == "")
456                         $image = $r[0]["thumb"];
457
458                 if ($title == "")
459                         $title = $author_name;
460
461                 $description = htmlspecialchars($description, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
462                 $title = htmlspecialchars($title, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
463                 $author_name = htmlspecialchars($author_name, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
464
465                 //<meta name="keywords" content="">
466                 $a->page['htmlhead'] .= '<meta name="author" content="'.$author_name.'" />'."\n";
467                 $a->page['htmlhead'] .= '<meta name="title" content="'.$title.'" />'."\n";
468                 $a->page['htmlhead'] .= '<meta name="fulltitle" content="'.$title.'" />'."\n";
469                 $a->page['htmlhead'] .= '<meta name="description" content="'.$description.'" />'."\n";
470
471                 // Schema.org microdata
472                 $a->page['htmlhead'] .= '<meta itemprop="name" content="'.$title.'" />'."\n";
473                 $a->page['htmlhead'] .= '<meta itemprop="description" content="'.$description.'" />'."\n";
474                 $a->page['htmlhead'] .= '<meta itemprop="image" content="'.$image.'" />'."\n";
475                 $a->page['htmlhead'] .= '<meta itemprop="author" content="'.$author_name.'" />'."\n";
476
477                 // Twitter cards
478                 $a->page['htmlhead'] .= '<meta name="twitter:card" content="summary" />'."\n";
479                 $a->page['htmlhead'] .= '<meta name="twitter:title" content="'.$title.'" />'."\n";
480                 $a->page['htmlhead'] .= '<meta name="twitter:description" content="'.$description.'" />'."\n";
481                 $a->page['htmlhead'] .= '<meta name="twitter:image" content="'.$image.'" />'."\n";
482                 $a->page['htmlhead'] .= '<meta name="twitter:url" content="'.$r[0]["plink"].'" />'."\n";
483
484                 // Dublin Core
485                 $a->page['htmlhead'] .= '<meta name="DC.title" content="'.$title.'" />'."\n";
486                 $a->page['htmlhead'] .= '<meta name="DC.description" content="'.$description.'" />'."\n";
487
488                 // Open Graph
489                 $a->page['htmlhead'] .= '<meta property="og:type" content="website" />'."\n";
490                 $a->page['htmlhead'] .= '<meta property="og:title" content="'.$title.'" />'."\n";
491                 $a->page['htmlhead'] .= '<meta property="og:image" content="'.$image.'" />'."\n";
492                 $a->page['htmlhead'] .= '<meta property="og:url" content="'.$r[0]["plink"].'" />'."\n";
493                 $a->page['htmlhead'] .= '<meta property="og:description" content="'.$description.'" />'."\n";
494                 $a->page['htmlhead'] .= '<meta name="og:article:author" content="'.$author_name.'" />'."\n";
495                 // article:tag
496
497                 return $o;
498         }
499
500         $r = q("SELECT `id`,`deleted` FROM `item` WHERE `id` = '%s' OR `uri` = '%s' LIMIT 1",
501                 dbesc($item_id),
502                 dbesc($item_id)
503         );
504         if($r) {
505                 if($r[0]['deleted']) {
506                         notice( t('Item has been removed.') . EOL );
507                 }
508                 else {
509                         notice( t('Permission denied.') . EOL );
510                 }
511         }
512         else {
513                 notice( t('Item not found.') . EOL );
514         }
515
516         return $o;
517 }
518