MediaWiki REL1_28
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24if ( PHP_SAPI != 'cli-server' ) {
25 die( "This script can only be run by php's cli-server sapi." );
28ini_set( 'display_errors', 1 );
29error_reporting( E_ALL );
31if ( isset( $_SERVER["SCRIPT_FILENAME"] ) ) {
32 # Known resource, sometimes a script sometimes a file
34} elseif ( isset( $_SERVER["SCRIPT_NAME"] ) ) {
35 # Usually unknown, document root relative rather than absolute
36 # Happens with some cases like /wiki/File:Image.png
37 if ( is_readable( $_SERVER['DOCUMENT_ROOT'] . $_SERVER["SCRIPT_NAME"] ) ) {
38 # Just in case this actually IS a file, set it here
40 } else {
41 # Otherwise let's pretend that this is supposed to go to index.php
42 $file = $_SERVER['DOCUMENT_ROOT'] . '/index.php';
43 }
44} else {
45 # Meh, we'll just give up
46 return false;
49# And now do handling for that $file
51if ( !is_readable( $file ) ) {
52 # Let the server throw the error if it doesn't exist
53 return false;
55$ext = pathinfo( $file, PATHINFO_EXTENSION );
56if ( $ext == 'php' || $ext == 'php5' ) {
57 # Execute php files
58 # We use require and return true here because when you return false
59 # the php webserver will discard post data and things like login
60 # will not function in the dev environment.
61 require $file;
63 return true;
65$mime = false;
66// Borrow mime type file from MimeAnalyzer
67$lines = explode( "\n", file_get_contents( "includes/libs/mime/mime.types" ) );
68foreach ( $lines as $line ) {
69 $exts = explode( " ", $line );
70 $mime = array_shift( $exts );
71 if ( in_array( $ext, $exts ) ) {
72 break; # this is the right value for $mime
73 }
74 $mime = false;
76if ( !$mime ) {
77 $basename = basename( $file );
78 if ( $basename == strtoupper( $basename ) ) {
79 # IF it's something like README serve it as text
80 $mime = "text/plain";
81 }
83if ( $mime ) {
84 # Use custom handling to serve files with a known MIME type
85 # This way we can serve things like .svg files that the built-in
86 # PHP webserver doesn't understand.
87 # ;) Nicely enough we just happen to bundle a mime.types file
88 $f = fopen( $file, 'rb' );
89 if ( preg_match( '#^text/#', $mime ) ) {
90 # Text should have a charset=UTF-8 (php's webserver does this too)
91 header( "Content-Type: $mime; charset=UTF-8" );
92 } else {
93 header( "Content-Type: $mime" );
94 }
95 header( "Content-Length: " . filesize( $file ) );
96 // Stream that out to the browser
97 fpassthru( $f );
99 return true;
102# Let the php server handle things on its own otherwise
103return false;
Definition cdb.php:59
We use the convention $dbr for read and $dbw for write to help you keep track of whether the database object is a the world will explode Or to be a subsequent write query which succeeded on the master may fail when replicated to the slave due to a unique key collision Replication on the slave will stop and it may take hours to repair the database and get it back online Setting read_only in my cnf on the slave will avoid this but given the dire we prefer to have as many checks as possible We provide a but the wrapper functions like please read the documentation for except in special pages derived from QueryPage It s a common pitfall for new developers to submit code containing SQL queries which examine huge numbers of rows Remember that COUNT * is(N), counting rows in atable is like counting beans in a bucket.------------------------------------------------------------------------ Replication------------------------------------------------------------------------The largest installation of MediaWiki, Wikimedia, uses a large set ofslave MySQL servers replicating writes made to a master MySQL server. Itis important to understand the issues associated with this setup if youwant to write code destined for Wikipedia.It 's often the case that the best algorithm to use for a given taskdepends on whether or not replication is in use. Due to our unabashedWikipedia-centrism, we often just use the replication-friendly version, but if you like, you can use wfGetLB() ->getServerCount() > 1 tocheck to see if replication is in use.===Lag===Lag primarily occurs when large write queries are sent to the master.Writes on the master are executed in parallel, but they are executed inserial when they are replicated to the slaves. The master writes thequery to the binlog when the transaction is committed. The slaves pollthe binlog and start executing the query as soon as it appears. They canservice reads while they are performing a write query, but will not readanything more from the binlog and thus will perform no more writes. Thismeans that if the write query runs for a long time, the slaves will lagbehind the master for the time it takes for the write query to complete.Lag can be exacerbated by high read load. MediaWiki 's load balancer willstop sending reads to a slave when it is lagged by more than 30 seconds.If the load ratios are set incorrectly, or if there is too much loadgenerally, this may lead to a slave permanently hovering around 30seconds lag.If all slaves are lagged by more than 30 seconds, MediaWiki will stopwriting to the database. All edits and other write operations will berefused, with an error returned to the user. This gives the slaves achance to catch up. Before we had this mechanism, the slaves wouldregularly lag by several minutes, making review of recent editsdifficult.In addition to this, MediaWiki attempts to ensure that the user seesevents occurring on the wiki in chronological order. A few seconds of lagcan be tolerated, as long as the user sees a consistent picture fromsubsequent requests. This is done by saving the master binlog positionin the session, and then at the start of each request, waiting for theslave to catch up to that position before doing any reads from it. Ifthis wait times out, reads are allowed anyway, but the request isconsidered to be in "lagged slave mode". Lagged slave mode can bechecked by calling wfGetLB() ->getLaggedSlaveMode(). The onlypractical consequence at present is a warning displayed in the pagefooter.===Lag avoidance===To avoid excessive lag, queries which write large numbers of rows shouldbe split up, generally to write one row at a time. Multi-row INSERT ...SELECT queries are the worst offenders should be avoided altogether.Instead do the select first and then the insert.===Working with lag===Despite our best efforts, it 's not practical to guarantee a low-lagenvironment. Lag will usually be less than one second, but mayoccasionally be up to 30 seconds. For scalability, it 's very importantto keep load on the master low, so simply sending all your queries tothe master is not the answer. So when you have a genuine need forup-to-date data, the following approach is advised:1) Do a quick query to the master for a sequence number or timestamp 2) Run the full query on the slave and check if it matches the data you gotfrom the master 3) If it doesn 't, run the full query on the masterTo avoid swamping the master every time the slaves lag, use of thisapproach should be kept to a minimum. In most cases you should just readfrom the slave and let the user deal with the delay.------------------------------------------------------------------------ Lock contention------------------------------------------------------------------------Due to the high write rate on Wikipedia(and some other wikis), MediaWiki developers need to be very careful to structure their writesto avoid long-lasting locks. By default, MediaWiki opens a transactionat the first query, and commits it before the output is sent. Locks willbe held from the time when the query is done until the commit. So youcan reduce lock time by doing as much processing as possible before youdo your write queries.Often this approach is not good enough, and it becomes necessary toenclose small groups of queries in their own transaction. Use thefollowing syntax:$dbw=wfGetDB(DB_MASTER
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition injection.txt:37
if( $ext=='php'|| $ext=='php5') $mime
Definition router.php:65
Definition router.php:67
if(!is_readable( $file)) $ext
Definition router.php:55