diff options
| -rw-r--r-- | include/Scrape.php | 2 | ||||
| -rwxr-xr-x | include/diaspora.php | 97 | ||||
| -rw-r--r-- | include/lock.php | 76 | ||||
| -rw-r--r-- | update.php | 12 |
4 files changed, 166 insertions, 21 deletions
diff --git a/include/Scrape.php b/include/Scrape.php index 4f53effe9..b784650cd 100644 --- a/include/Scrape.php +++ b/include/Scrape.php @@ -432,7 +432,7 @@ function probe_url($url, $mode = PROBE_NORMAL) { intval(local_user()) ); if(count($x) && count($r)) { - $mailbox = construct_mailbox_name($r[0]); + $mailbox = construct_mailbox_name($r[0]); $password = ''; openssl_private_decrypt(hex2bin($r[0]['pass']),$password,$x[0]['prvkey']); $mbox = email_connect($mailbox,$r[0]['user'],$password); diff --git a/include/diaspora.php b/include/diaspora.php index 5ab0ee674..29846eedf 100755 --- a/include/diaspora.php +++ b/include/diaspora.php @@ -5,6 +5,7 @@ require_once('include/items.php'); require_once('include/bb2diaspora.php'); require_once('include/contact_selectors.php'); require_once('include/queue_fn.php'); +require_once('include/lock.php'); function diaspora_dispatch_public($msg) { @@ -113,27 +114,83 @@ function diaspora_get_contact_by_handle($uid,$handle) { } function find_diaspora_person_by_handle($handle) { + + $person = false; $update = false; - $r = q("select * from fcontact where network = '%s' and addr = '%s' limit 1", - dbesc(NETWORK_DIASPORA), - dbesc($handle) - ); - if(count($r)) { - logger('find_diaspora_person_by handle: in cache ' . print_r($r,true), LOGGER_DEBUG); - // update record occasionally so it doesn't get stale - $d = strtotime($r[0]['updated'] . ' +00:00'); - if($d > strtotime('now - 14 days')) - return $r[0]; - $update = true; - } - logger('find_diaspora_person_by_handle: refresh',LOGGER_DEBUG); - require_once('include/Scrape.php'); - $r = probe_url($handle, PROBE_DIASPORA); - if((count($r)) && ($r['network'] === NETWORK_DIASPORA)) { - add_fcontact($r,$update); - return ($r); - } - return false; + $got_lock = false; + + do { + $r = q("select * from fcontact where network = '%s' and addr = '%s' limit 1", + dbesc(NETWORK_DIASPORA), + dbesc($handle) + ); + if(count($r)) { + $person = $r[0]; + logger('find_diaspora_person_by handle: in cache ' . print_r($r,true), LOGGER_DEBUG); + + // update record occasionally so it doesn't get stale + $d = strtotime($person['updated'] . ' +00:00'); + if($d < strtotime('now - 14 days')) + $update = true; + } + + + // FETCHING PERSON INFORMATION FROM REMOTE SERVER + // + // If the person isn't in our 'fcontact' table, or if he/she is but + // his/her information hasn't been updated for more than 14 days, then + // we want to fetch the person's information from the remote server. + // + // Note that $person isn't changed by this block of code unless the + // person's information has been successfully fetched from the remote + // server. So if $person was 'false' to begin with (because he/she wasn't + // in the local cache), it'll stay false, and if $person held the local + // cache information to begin with, it'll keep that information. That way + // if there's a problem with the remote fetch, we can at least use our + // cached information--it's better than nothing. + + if((! $person) || ($update)) { + // Lock the function to prevent race conditions if multiple items + // come in at the same time from a person who doesn't exist in + // fcontact + $got_lock = lock_function('find_diaspora_person_by_handle', false); + + if($got_lock) { + logger('find_diaspora_person_by_handle: create or refresh', LOGGER_DEBUG); + require_once('include/Scrape.php'); + $r = probe_url($handle, PROBE_DIASPORA); + + // Note that Friendica contacts can return a "Diaspora person" + // if Diaspora connectivity is enabled on their server + if((count($r)) && ($r['network'] === NETWORK_DIASPORA)) { + add_fcontact($r,$update); + $person = ($r); + } + + unlock_function('find_diaspora_person_by_handle'); + } + else { + logger('find_diaspora_person_by_handle: couldn\'t lock function', LOGGER_DEBUG); + if(! $person) + block_on_function_lock('find_diaspora_person_by_handle'); + } + } + } while((! $person) && (! $got_lock)); + // We need to try again if the person wasn't in 'fcontact' but the function was locked. + // The fact that the function was locked may mean that another process was creating the + // person's record. It could also mean another process was creating or updating an unrelated + // person. + // + // At any rate, we need to keep trying until we've either got the person or had a chance to + // try to fetch his/her remote information. But we don't want to block on locking the + // function, because if the other process is creating the record, then when we acquire the lock + // we'll dive right into creating another, duplicate record. We DO want to at least wait + // until the lock is released, so we don't flood the database with requests. + // + // If the person was in the 'fcontact' table, don't try again. It's not worth the time, since + // we do have some information for the person + + return $person; } diff --git a/include/lock.php b/include/lock.php new file mode 100644 index 000000000..be6130e1d --- /dev/null +++ b/include/lock.php @@ -0,0 +1,76 @@ +<?php + +// Provide some ability to lock a PHP function so that multiple processes +// can't run the function concurrently +// The function must have a line inserted into the 'lock' table with the +// function's name in the 'name' field +if(! function_exists('lock_function')) { +function lock_function($fn_name, $block = true, $wait_sec = 2) { + if( $wait_sec == 0 ) + $wait_sec = 2; // don't let the user pick a value that's likely to crash the system + + $got_lock = false; + + do { + q("LOCK TABLE lock WRITE"); + $r = q("SELECT locked FROM lock WHERE name = '%s' LIMIT 1", + dbesc($fn_name) + ); + + if((count($r)) && (! $r[0]['locked'])) { + q("UPDATE lock SET locked = 1 WHERE name = '%s' LIMIT 1", + dbesc($fn_name) + ); + $got_lock = true; + } + elseif(! $r) { // the Boolean value for count($r) should be equivalent to the Boolean value of $r + q("INSERT INTO lock ( name, locked ) VALUES ( '%s', 1 )", + dbesc($fn_name) + ); + $got_lock = true; + } + + q("UNLOCK TABLES"); + + if(($block) && (! $got_lock)) + sleep($wait_sec); + + } while(($block) && (! $got_lock)); + + logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock, LOGGER_DEBUG); + + return $got_lock; +}} + + +if(! function_exists('block_on_function_lock')) { +function block_on_function_lock($fn_name, $wait_sec = 2) { + if( $wait_sec == 0 ) + $wait_sec = 2; // don't let the user pick a value that's likely to crash the system + + do { + $r = q("SELECT locked FROM lock WHERE name = '%s' LIMIT 1", + dbesc(fn_name) + ); + + if(count($r) && $r[0]['locked']) + sleep($wait_sec); + + } while(count($r) && $r[0]['locked']); + + return; +}} + + +if(! function_exists('unlock_function')) { +function unlock_function(fn_name) { + //$r = q("LOCK TABLE lock WRITE"); + $r = q("UPDATE lock SET locked = 0 WHERE name = '%s' LIMIT 1", + dbesc(fn_name) + ); + //$r = q("UNLOCK TABLES"); + + logger('unlock_function: released lock for function ' . fn_name, LOGGER_DEBUG); + + return; +}} diff --git a/update.php b/update.php index b8e247f57..5e5ec3e86 100644 --- a/update.php +++ b/update.php @@ -1307,3 +1307,15 @@ function update_1150() { return UPDATE_SUCCESS; } + +function update_1151() { + $r = q("CREATE TABLE IF NOT EXISTS lock ( + id INT NOT NULL AUTO_INCREMENT PRIMARY KEY , + name CHAR(128) NOT NULL , + locked TINYINT(1) NOT NULL DEFAULT '0' + ) ENGINE = MYISAM DEFAULT CHARSET=utf8 "); + if (!$r) + return UPDATE_FAILED; + return UPDATE_SUCCESS; +} + |