src/Model/Contact/Relation.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Model\Contact;
  23
  24 use Exception;
  25 use Friendica\Core\Logger;
  26 use Friendica\Core\Protocol;
  27 use Friendica\Database\Database;
  28 use Friendica\Database\DBA;
  29 use Friendica\DI;
  30 use Friendica\Model\APContact;
  31 use Friendica\Model\Contact;
  32 use Friendica\Model\Profile;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\ActivityPub;
  35 use Friendica\Util\DateTimeFormat;
  36 use Friendica\Util\Strings;
  37
  38 /**
  39  * This class provides relationship information based on the `contact-relation` table.
  40  * This table is directional (cid = source, relation-cid = target), references public contacts (with uid=0) and records both
  41  * follows and the last interaction (likes/comments) on public posts.
  42  */
  43 class Relation
  44 {
  45         /**
  46          * No discovery of followers/followings
  47          */
  48         const DISCOVERY_NONE = 0;
  49         /**
  50          * Discover followers/followings of local contacts
  51          */
  52         const DISCOVERY_LOCAL = 1;
  53         /**
  54          * Discover followers/followings of local contacts and contacts that visibly interacted on the system
  55          */
  56         const DISCOVERY_INTERACTOR = 2;
  57         /**
  58          * Discover followers/followings of all contacts
  59          */
  60         const DISCOVERY_ALL = 3;
  61
  62         public static function store(int $target, int $actor, string $interaction_date)
  63         {
  64                 if ($actor == $target) {
  65                         return;
  66                 }
  67
  68                 DBA::insert('contact-relation', ['last-interaction' => $interaction_date, 'cid' => $target, 'relation-cid' => $actor], Database::INSERT_UPDATE);
  69         }
  70
  71         /**
  72          * Fetches the followers of a given profile and adds them
  73          *
  74          * @param string $url URL of a profile
  75          * @return void
  76          */
  77         public static function discoverByUrl(string $url)
  78         {
  79                 $contact = Contact::getByURL($url);
  80                 if (empty($contact)) {
  81                         Logger::info('Contact not found', ['url' => $url]);
  82                         return;
  83                 }
  84
  85                 if (!self::isDiscoverable($url, $contact)) {
  86                         Logger::info('Contact is not discoverable', ['url' => $url]);
  87                         return;
  88                 }
  89
  90                 $uid = User::getIdForURL($url);
  91                 if (!empty($uid)) {
  92                         Logger::info('Fetch the followers/followings locally', ['url' => $url]);
  93                         $followers = self::getContacts($uid, [Contact::FOLLOWER, Contact::FRIEND]);
  94                         $followings = self::getContacts($uid, [Contact::SHARING, Contact::FRIEND]);
  95                 } elseif (!Contact::isLocal($url)) {
  96                         Logger::info('Fetch the followers/followings by polling the endpoints', ['url' => $url]);
  97                         $apcontact = APContact::getByURL($url, false);
  98
  99                         if (!empty($apcontact['followers']) && is_string($apcontact['followers'])) {
 100                                 $followers = ActivityPub::fetchItems($apcontact['followers']);
 101                         } else {
 102                                 $followers = [];
 103                         }
 104
 105                         if (!empty($apcontact['following']) && is_string($apcontact['following'])) {
 106                                 $followings = ActivityPub::fetchItems($apcontact['following']);
 107                         } else {
 108                                 $followings = [];
 109                         }
 110                 } else {
 111                         Logger::notice('Contact seems to be local but could not be found here', ['url' => $url]);
 112                         $followers = [];
 113                         $followings = [];
 114                 }
 115
 116                 if (empty($followers) && empty($followings)) {
 117                         Contact::update(['last-discovery' => DateTimeFormat::utcNow()], ['id' => $contact['id']]);
 118                         Logger::info('The contact does not offer discoverable data', ['id' => $contact['id'], 'url' => $url, 'network' => $contact['network']]);
 119                         return;
 120                 }
 121
 122                 $target = $contact['id'];
 123
 124                 if (!empty($followers)) {
 125                         // Clear the follower list, since it will be recreated in the next step
 126                         DBA::update('contact-relation', ['follows' => false], ['cid' => $target]);
 127                 }
 128
 129                 $contacts = [];
 130                 foreach (array_merge($followers, $followings) as $contact) {
 131                         if (is_string($contact)) {
 132                                 $contacts[] = $contact;
 133                         } elseif (!empty($contact['url']) && is_string($contact['url'])) {
 134                                 $contacts[] = $contact['url'];
 135                         }
 136                 }
 137                 $contacts = array_unique($contacts);
 138
 139                 $follower_counter = 0;
 140                 $following_counter = 0;
 141
 142                 Logger::info('Discover contacts', ['id' => $target, 'url' => $url, 'contacts' => count($contacts)]);
 143                 foreach ($contacts as $contact) {
 144                         $actor = Contact::getIdForURL($contact);
 145                         if (!empty($actor)) {
 146                                 if (in_array($contact, $followers)) {
 147                                         $fields = ['cid' => $target, 'relation-cid' => $actor, 'follows' => true, 'follow-updated' => DateTimeFormat::utcNow()];
 148                                         DBA::insert('contact-relation', $fields, Database::INSERT_UPDATE);
 149                                         $follower_counter++;
 150                                 }
 151
 152                                 if (in_array($contact, $followings)) {
 153                                         $fields = ['cid' => $actor, 'relation-cid' => $target, 'follows' => true, 'follow-updated' => DateTimeFormat::utcNow()];
 154                                         DBA::insert('contact-relation', $fields, Database::INSERT_UPDATE);
 155                                         $following_counter++;
 156                                 }
 157                         }
 158                 }
 159
 160                 if (!empty($followers)) {
 161                         // Delete all followers that aren't followers anymore (and aren't interacting)
 162                         DBA::delete('contact-relation', ['cid' => $target, 'follows' => false, 'last-interaction' => DBA::NULL_DATETIME]);
 163                 }
 164
 165                 Contact::update(['last-discovery' => DateTimeFormat::utcNow()], ['id' => $target]);
 166                 Logger::info('Contacts discovery finished', ['id' => $target, 'url' => $url, 'follower' => $follower_counter, 'following' => $following_counter]);
 167                 return;
 168         }
 169
 170         /**
 171          * Fetch contact url list from the given local user
 172          *
 173          * @param integer $uid
 174          * @param array $rel
 175          * @return array contact list
 176          */
 177         private static function getContacts(int $uid, array $rel): array
 178         {
 179                 $list = [];
 180                 $profile = Profile::getByUID($uid);
 181                 if (!empty($profile['hide-friends'])) {
 182                         return $list;
 183                 }
 184
 185                 $condition = [
 186                         'rel' => $rel,
 187                         'uid' => $uid,
 188                         'self' => false,
 189                         'deleted' => false,
 190                         'hidden' => false,
 191                         'archive' => false,
 192                         'pending' => false,
 193                 ];
 194                 $condition = DBA::mergeConditions($condition, ["`url` IN (SELECT `url` FROM `apcontact`)"]);
 195                 $contacts = DBA::select('contact', ['url'], $condition);
 196                 while ($contact = DBA::fetch($contacts)) {
 197                         $list[] = $contact['url'];
 198                 }
 199                 DBA::close($contacts);
 200
 201                 return $list;
 202         }
 203
 204         /**
 205          * Tests if a given contact url is discoverable
 206          *
 207          * @param string $url     Contact url
 208          * @param array  $contact Contact array
 209          * @return boolean True if contact is discoverable
 210          */
 211         public static function isDiscoverable(string $url, array $contact = []): bool
 212         {
 213                 $contact_discovery = DI::config()->get('system', 'contact_discovery');
 214
 215                 if ($contact_discovery == self::DISCOVERY_NONE) {
 216                         return false;
 217                 }
 218
 219                 if (empty($contact)) {
 220                         $contact = Contact::getByURL($url, false);
 221                 }
 222
 223                 if (empty($contact)) {
 224                         return false;
 225                 }
 226
 227                 if ($contact['last-discovery'] > DateTimeFormat::utc('now - 1 month')) {
 228                         Logger::info('No discovery - Last was less than a month ago.', ['id' => $contact['id'], 'url' => $url, 'discovery' => $contact['last-discovery']]);
 229                         return false;
 230                 }
 231
 232                 if ($contact_discovery != self::DISCOVERY_ALL) {
 233                         $local = DBA::exists('contact', ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($url), 0]);
 234                         if (($contact_discovery == self::DISCOVERY_LOCAL) && !$local) {
 235                                 Logger::info('No discovery - This contact is not followed/following locally.', ['id' => $contact['id'], 'url' => $url]);
 236                                 return false;
 237                         }
 238
 239                         if ($contact_discovery == self::DISCOVERY_INTERACTOR) {
 240                                 $interactor = DBA::exists('contact-relation', ["`relation-cid` = ? AND `last-interaction` > ?", $contact['id'], DBA::NULL_DATETIME]);
 241                                 if (!$local && !$interactor) {
 242                                         Logger::info('No discovery - This contact is not interacting locally.', ['id' => $contact['id'], 'url' => $url]);
 243                                         return false;
 244                                 }
 245                         }
 246                 } elseif ($contact['created'] > DateTimeFormat::utc('now - 1 day')) {
 247                         // Newly created contacts are not discovered to avoid DDoS attacks
 248                         Logger::info('No discovery - Contact record is less than a day old.', ['id' => $contact['id'], 'url' => $url, 'discovery' => $contact['created']]);
 249                         return false;
 250                 }
 251
 252                 if (!in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::OSTATUS])) {
 253                         $apcontact = APContact::getByURL($url, false);
 254                         if (empty($apcontact)) {
 255                                 Logger::info('No discovery - The contact does not seem to speak ActivityPub.', ['id' => $contact['id'], 'url' => $url, 'network' => $contact['network']]);
 256                                 return false;
 257                         }
 258                 }
 259
 260                 return true;
 261         }
 262
 263         /**
 264          * Returns an array of sugguested contacts for given user id
 265          *
 266          * @param int $uid   User id
 267          * @param int $start optional, default 0
 268          * @param int $limit optional, default 80
 269          * @return array
 270          */
 271         static public function getSuggestions(int $uid, int $start = 0, int $limit = 80): array
 272         {
 273                 $cid = Contact::getPublicIdByUserId($uid);
 274                 $totallimit = $start + $limit;
 275                 $contacts = [];
 276
 277                 Logger::info('Collecting suggestions', ['uid' => $uid, 'cid' => $cid, 'start' => $start, 'limit' => $limit]);
 278
 279                 $diaspora = DI::config()->get('system', 'diaspora_enabled') ? Protocol::DIASPORA : Protocol::ACTIVITYPUB;
 280                 $ostatus = !DI::config()->get('system', 'ostatus_disabled') ? Protocol::OSTATUS : Protocol::ACTIVITYPUB;
 281
 282                 // The query returns contacts where contacts interacted with whom the given user follows.
 283                 // Contacts who already are in the user's contact table are ignored.
 284                 $results = DBA::select('contact', [], ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` IN
 285                                 (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ?)
 286                                         AND NOT `cid` IN (SELECT `id` FROM `contact` WHERE `uid` = ? AND `nurl` IN
 287                                                 (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))))
 288                         AND NOT `hidden` AND `network` IN (?, ?, ?, ?)",
 289                         $cid,
 290                         0,
 291                         $uid,
 292                         Contact::FRIEND,
 293                         Contact::SHARING,
 294                         Protocol::ACTIVITYPUB,
 295                         Protocol::DFRN,
 296                         $diaspora,
 297                         $ostatus,
 298                         ], [
 299                                 'order' => ['last-item' => true],
 300                                 'limit' => $totallimit,
 301                         ]
 302                 );
 303
 304                 while ($contact = DBA::fetch($results)) {
 305                         $contacts[$contact['id']] = $contact;
 306                 }
 307
 308                 DBA::close($results);
 309
 310                 Logger::info('Contacts of contacts who are followed by the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 311
 312                 if (count($contacts) >= $totallimit) {
 313                         return array_slice($contacts, $start, $limit);
 314                 }
 315
 316                 // The query returns contacts where contacts interacted with whom also interacted with the given user.
 317                 // Contacts who already are in the user's contact table are ignored.
 318                 $results = DBA::select('contact', [],
 319                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` IN
 320                                 (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 321                                         AND NOT `cid` IN (SELECT `id` FROM `contact` WHERE `uid` = ? AND `nurl` IN
 322                                                 (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))))
 323                         AND NOT `hidden` AND `network` IN (?, ?, ?, ?)",
 324                         $cid, 0, $uid, Contact::FRIEND, Contact::SHARING,
 325                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 326                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 327                 );
 328
 329                 while ($contact = DBA::fetch($results)) {
 330                         $contacts[$contact['id']] = $contact;
 331                 }
 332                 DBA::close($results);
 333
 334                 Logger::info('Contacts of contacts who are following the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 335
 336                 if (count($contacts) >= $totallimit) {
 337                         return array_slice($contacts, $start, $limit);
 338                 }
 339
 340                 // The query returns contacts that follow the given user but aren't followed by that user.
 341                 $results = DBA::select('contact', [],
 342                         ["`nurl` IN (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` = ?)
 343                         AND NOT `hidden` AND `uid` = ? AND `network` IN (?, ?, ?, ?)",
 344                         $uid, Contact::FOLLOWER, 0,
 345                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 346                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 347                 );
 348
 349                 while ($contact = DBA::fetch($results)) {
 350                         $contacts[$contact['id']] = $contact;
 351                 }
 352                 DBA::close($results);
 353
 354                 Logger::info('Followers that are not followed by the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 355
 356                 if (count($contacts) >= $totallimit) {
 357                         return array_slice($contacts, $start, $limit);
 358                 }
 359
 360                 // The query returns any contact that isn't followed by that user.
 361                 $results = DBA::select('contact', [],
 362                         ["NOT `nurl` IN (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))
 363                         AND NOT `hidden` AND `uid` = ? AND `network` IN (?, ?, ?, ?)",
 364                         $uid, Contact::FRIEND, Contact::SHARING, 0,
 365                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 366                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 367                 );
 368
 369                 while ($contact = DBA::fetch($results)) {
 370                         $contacts[$contact['id']] = $contact;
 371                 }
 372                 DBA::close($results);
 373
 374                 Logger::info('Any contact', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 375
 376                 return array_slice($contacts, $start, $limit);
 377         }
 378
 379         /**
 380          * Counts all the known follows of the provided public contact
 381          *
 382          * @param int   $cid       Public contact id
 383          * @param array $condition Additional condition on the contact table
 384          * @return int
 385          * @throws Exception
 386          */
 387         public static function countFollows(int $cid, array $condition = []): int
 388         {
 389                 $condition = DBA::mergeConditions($condition, [
 390                         '`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 391                         $cid,
 392                 ]);
 393
 394                 return DI::dba()->count('contact', $condition);
 395         }
 396
 397         /**
 398          * Returns a paginated list of contacts that are followed the provided public contact.
 399          *
 400          * @param int   $cid       Public contact id
 401          * @param array $condition Additional condition on the contact table
 402          * @param int   $count
 403          * @param int   $offset
 404          * @param bool  $shuffle
 405          * @return array
 406          * @throws Exception
 407          */
 408         public static function listFollows(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 409         {
 410                 $condition = DBA::mergeConditions($condition,
 411                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 412                         $cid]
 413                 );
 414
 415                 return DI::dba()->selectToArray('contact', [], $condition,
 416                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 417                 );
 418         }
 419
 420         /**
 421          * Counts all the known followers of the provided public contact
 422          *
 423          * @param int   $cid       Public contact id
 424          * @param array $condition Additional condition on the contact table
 425          * @return int
 426          * @throws Exception
 427          */
 428         public static function countFollowers(int $cid, array $condition = [])
 429         {
 430                 $condition = DBA::mergeConditions($condition,
 431                         ['`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 432                         $cid]
 433                 );
 434
 435                 return DI::dba()->count('contact', $condition);
 436         }
 437
 438         /**
 439          * Returns a paginated list of contacts that follow the provided public contact.
 440          *
 441          * @param int   $cid       Public contact id
 442          * @param array $condition Additional condition on the contact table
 443          * @param int   $count
 444          * @param int   $offset
 445          * @param bool  $shuffle
 446          * @return array
 447          * @throws Exception
 448          */
 449         public static function listFollowers(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 450         {
 451                 $condition = DBA::mergeConditions($condition,
 452                         ['`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)', $cid]
 453                 );
 454
 455                 return DI::dba()->selectToArray('contact', [], $condition,
 456                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 457                 );
 458         }
 459
 460         /**
 461          * Counts the number of contacts that are known mutuals with the provided public contact.
 462          *
 463          * @param int   $cid       Public contact id
 464          * @param array $condition Additional condition array on the contact table
 465          * @return int
 466          * @throws Exception
 467          */
 468         public static function countMutuals(int $cid, array $condition = [])
 469         {
 470                 $condition = DBA::mergeConditions($condition,
 471                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 472                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 473                         $cid, $cid]
 474                 );
 475
 476                 return DI::dba()->count('contact', $condition);
 477         }
 478
 479         /**
 480          * Returns a paginated list of contacts that are known mutuals with the provided public contact.
 481          *
 482          * @param int   $cid       Public contact id
 483          * @param array $condition Additional condition on the contact table
 484          * @param int   $count
 485          * @param int   $offset
 486          * @param bool  $shuffle
 487          * @return array
 488          * @throws Exception
 489          */
 490         public static function listMutuals(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 491         {
 492                 $condition = DBA::mergeConditions($condition,
 493                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 494                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 495                         $cid, $cid]
 496                 );
 497
 498                 return DI::dba()->selectToArray('contact', [], $condition,
 499                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 500                 );
 501         }
 502
 503
 504         /**
 505          * Counts the number of contacts with any relationship with the provided public contact.
 506          *
 507          * @param int   $cid       Public contact id
 508          * @param array $condition Additional condition array on the contact table
 509          * @return int
 510          * @throws Exception
 511          */
 512         public static function countAll(int $cid, array $condition = [])
 513         {
 514                 $condition = DBA::mergeConditions($condition,
 515                         ['(`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 516                         OR `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`))',
 517                                 $cid, $cid]
 518                 );
 519
 520                 return DI::dba()->count('contact', $condition);
 521         }
 522
 523         /**
 524          * Returns a paginated list of contacts with any relationship with the provided public contact.
 525          *
 526          * @param int   $cid       Public contact id
 527          * @param array $condition Additional condition on the contact table
 528          * @param int   $count
 529          * @param int   $offset
 530          * @param bool  $shuffle
 531          * @return array
 532          * @throws Exception
 533          */
 534         public static function listAll(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 535         {
 536                 $condition = DBA::mergeConditions($condition,
 537                         ['(`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 538                         OR `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`))',
 539                                 $cid, $cid]
 540                 );
 541
 542                 return DI::dba()->selectToArray('contact', [], $condition,
 543                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 544                 );
 545         }
 546
 547         /**
 548          * Counts the number of contacts that both provided public contacts have interacted with at least once.
 549          * Interactions include follows and likes and comments on public posts.
 550          *
 551          * @param int   $sourceId  Public contact id
 552          * @param int   $targetId  Public contact id
 553          * @param array $condition Additional condition array on the contact table
 554          * @return int
 555          * @throws Exception
 556          */
 557         public static function countCommon(int $sourceId, int $targetId, array $condition = [])
 558         {
 559                 $condition = DBA::mergeConditions($condition,
 560                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 561                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)',
 562                         $sourceId, $targetId]
 563                 );
 564
 565                 return DI::dba()->count('contact', $condition);
 566         }
 567
 568         /**
 569          * Returns a paginated list of contacts that both provided public contacts have interacted with at least once.
 570          * Interactions include follows and likes and comments on public posts.
 571          *
 572          * @param int   $sourceId  Public contact id
 573          * @param int   $targetId  Public contact id
 574          * @param array $condition Additional condition on the contact table
 575          * @param int   $count
 576          * @param int   $offset
 577          * @param bool  $shuffle
 578          * @return array|bool Array on success, false on failure
 579          * @throws Exception
 580          */
 581         public static function listCommon(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 582         {
 583                 $condition = DBA::mergeConditions($condition,
 584                         ["`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 585                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)",
 586                         $sourceId, $targetId]
 587                 );
 588
 589                 return DI::dba()->selectToArray('contact', [], $condition,
 590                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 591                 );
 592         }
 593
 594         /**
 595          * Counts the number of contacts that are followed by both provided public contacts.
 596          *
 597          * @param int   $sourceId  Public contact id
 598          * @param int   $targetId  Public contact id
 599          * @param array $condition Additional condition array on the contact table
 600          * @return int
 601          * @throws Exception
 602          */
 603         public static function countCommonFollows(int $sourceId, int $targetId, array $condition = []): int
 604         {
 605                 $condition = DBA::mergeConditions($condition,
 606                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 607                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 608                         $sourceId, $targetId]
 609                 );
 610
 611                 return DI::dba()->count('contact', $condition);
 612         }
 613
 614         /**
 615          * Returns a paginated list of contacts that are followed by both provided public contacts.
 616          *
 617          * @param int   $sourceId  Public contact id
 618          * @param int   $targetId  Public contact id
 619          * @param array $condition Additional condition array on the contact table
 620          * @param int   $count
 621          * @param int   $offset
 622          * @param bool  $shuffle
 623          * @return array|bool Array on success, false on failure
 624          * @throws Exception
 625          */
 626         public static function listCommonFollows(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 627         {
 628                 $condition = DBA::mergeConditions($condition,
 629                         ["`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 630                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)",
 631                         $sourceId, $targetId]
 632                 );
 633
 634                 return DI::dba()->selectToArray('contact', [], $condition,
 635                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 636                 );
 637         }
 638
 639         /**
 640          * Counts the number of contacts that follow both provided public contacts.
 641          *
 642          * @param int   $sourceId  Public contact id
 643          * @param int   $targetId  Public contact id
 644          * @param array $condition Additional condition on the contact table
 645          * @return int
 646          * @throws Exception
 647          */
 648         public static function countCommonFollowers(int $sourceId, int $targetId, array $condition = []): int
 649         {
 650                 $condition = DBA::mergeConditions($condition,
 651                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)
 652                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)",
 653                         $sourceId, $targetId]
 654                 );
 655
 656                 return DI::dba()->count('contact', $condition);
 657         }
 658
 659         /**
 660          * Returns a paginated list of contacts that follow both provided public contacts.
 661          *
 662          * @param int   $sourceId  Public contact id
 663          * @param int   $targetId  Public contact id
 664          * @param array $condition Additional condition on the contact table
 665          * @param int   $count
 666          * @param int   $offset
 667          * @param bool  $shuffle
 668          * @return array|bool Array on success, false on failure
 669          * @throws Exception
 670          */
 671         public static function listCommonFollowers(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 672         {
 673                 $condition = DBA::mergeConditions($condition,
 674                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)
 675                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)",
 676                         $sourceId, $targetId]
 677                 );
 678
 679                 return DI::dba()->selectToArray('contact', [], $condition,
 680                         ['limit' => [$offset, $count],  'order' => [$shuffle ? 'RAND()' : 'name']]
 681                 );
 682         }
 683 }