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-rw-r--r--MCServer/Plugins/APIDump/APIDesc.lua377
-rw-r--r--MCServer/Plugins/APIDump/WebWorldThreads.html60
-rw-r--r--MCServer/Plugins/APIDump/main.lua14
3 files changed, 445 insertions, 6 deletions
diff --git a/MCServer/Plugins/APIDump/APIDesc.lua b/MCServer/Plugins/APIDump/APIDesc.lua
index dc04d3e81..12665888b 100644
--- a/MCServer/Plugins/APIDump/APIDesc.lua
+++ b/MCServer/Plugins/APIDump/APIDesc.lua
@@ -546,7 +546,7 @@ World:ForEachChestInChunk(Player:GetChunkX(), Player:GetChunkZ(),
Desc = [[
This class is used to represent a crafting recipe, either a built-in one, or one created dynamically in a plugin. It is used only as a parameter for {{OnCraftingNoRecipe|OnCraftingNoRecipe}}, {{OnPostCrafting|OnPostCrafting}} and {{OnPreCrafting|OnPreCrafting}} hooks. Plugins may use it to inspect or modify a crafting recipe that a player views in their crafting window, either at a crafting table or the survival inventory screen.
</p>
- <p>Internally, the class contains a {{cItem|cItem}} for the result.
+ <p>Internally, the class contains a {{cCraftingGrid}} for the ingredients and a {{cItem}} for the result.
]],
Functions =
{
@@ -2136,6 +2136,381 @@ end;
the second value is not provided, the original message is used.
]],
}, -- HOOK_CHAT
+
+ HOOK_CHUNK_AVAILABLE =
+ {
+ CalledWhen = "A chunk has just been added to world, either generated or loaded. ",
+ DefaultFnName = "OnChunkAvailable", -- also used as pagename
+ Desc = [[
+ This hook is called after a chunk is either generated or loaded from the disk. The chunk is
+ already available for manipulation using the {{cWorld}} API. This is a notification-only callback,
+ there is no behavior that plugins could override.
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world to which the chunk belongs" },
+ { Name = "ChunkX", Type = "number", Notes = "X-coord of the chunk" },
+ { Name = "ChunkZ", Type = "number", Notes = "Z-coord of the chunk" },
+ },
+ Returns = [[
+ If the function returns false or no value, the next plugin's callback is called. If the function
+ returns true, no other callback is called for this event.
+ ]],
+ }, -- HOOK_CHUNK_AVAILABLE
+
+ HOOK_CHUNK_GENERATED =
+ {
+ CalledWhen = "After a chunk was generated. Notification only.",
+ DefaultFnName = "OnChunkGenerated", -- also used as pagename
+ Desc = [[
+ This hook is called when world generator finished its work on a chunk. The chunk data has already
+ been generated and is about to be stored in the {{cWorld|world}}. A plugin may provide some
+ last-minute finishing touches to the generated data. Note that the chunk is not yet stored in the
+ world, so regular {{cWorld}} block API will not work! Instead, use the {{cChunkDesc}} object
+ received as the parameter.</p>
+ <p>
+ See also the {{OnChunkGenerating|HOOK_CHUNK_GENERATING}} hook.
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world to which the chunk will be added" },
+ { Name = "ChunkX", Type = "number", Notes = "X-coord of the chunk" },
+ { Name = "ChunkZ", Type = "number", Notes = "Z-coord of the chunk" },
+ { Name = "ChunkDesc", Type = "{{cChunkDesc}}", Notes = "Generated chunk data. Plugins may still modify the chunk data contained." },
+ },
+ Returns = [[
+ If the plugin returns false or no value, MCServer will call other plugins' callbacks for this event.
+ If a plugin returns true, no other callback is called for this event.</p>
+ <p>
+ In either case, MCServer will then store the data from ChunkDesc as the chunk's contents in the world.
+ ]],
+ CodeExamples =
+ {
+ {
+ Title = "Generate emerald ore",
+ Desc = "This example callback function generates one block of emerald ore in each chunk, under the condition that the randomly chosen location is in an ExtremeHills biome.",
+ Code = [[
+function OnChunkGenerated(a_World, a_ChunkX, a_ChunkZ, a_ChunkDesc)
+ -- Generate a psaudorandom value that is always the same for the same X/Z pair, but is otherwise random enough:
+ -- This is actually similar to how MCServer does its noise functions
+ local PseudoRandom = (a_ChunkX * 57 + a_ChunkZ) * 57 + 19785486
+ PseudoRandom = PseudoRandom * 8192 + PseudoRandom;
+ PseudoRandom = ((PseudoRandom * (PseudoRandom * PseudoRandom * 15731 + 789221) + 1376312589) % 0x7fffffff;
+ PseudoRandom = PseudoRandom / 7;
+
+ -- Based on the PseudoRandom value, choose a location for the ore:
+ local OreX = PseudoRandom % 16;
+ local OreY = 2 + ((PseudoRandom / 16) % 20);
+ local OreZ = (PseudoRandom / 320) % 16;
+
+ -- Check if the location is in ExtremeHills:
+ if (a_ChunkDesc:GetBiome(OreX, OreZ) ~= biExtremeHills) then
+ return false;
+ end
+
+ -- Only replace allowed blocks with the ore:
+ local CurrBlock = a_ChunDesc:GetBlockType(OreX, OreY, OreZ);
+ if (
+ (CurrBlock == E_BLOCK_STONE) or
+ (CurrBlock == E_BLOCK_DIRT) or
+ (CurrBlock == E_BLOCK_GRAVEL)
+ ) then
+ a_ChunkDesc:SetBlockTypeMeta(OreX, OreY, OreZ, E_BLOCK_EMERALD_ORE, 0);
+ end
+end;
+ ]],
+ },
+ } , -- CodeExamples
+ }, -- HOOK_CHUNK_GENERATED
+
+ HOOK_CHUNK_GENERATING =
+ {
+ CalledWhen = "A chunk is about to be generated. Plugin can override the built-in generator.",
+ DefaultFnName = "OnChunkGenerating", -- also used as pagename
+ Desc = [[
+ This hook is called before the world generator starts generating a chunk. The plugin may provide
+ some or all parts of the generation, by-passing the built-in generator. The function is given access
+ to the {{cChunkDesc|ChunkDesc}} object representing the contents of the chunk. It may override parts
+ of the built-in generator by using the object's <i>SetUseDefaultXXX(false)</i> functions. After all
+ the callbacks for a chunk have been processed, the server will generate the chunk based on the
+ {{cChunkDesc|ChunkDesc}} description - those parts that are set for generating (by default
+ everything) are generated, the rest are read from the ChunkDesc object.</p>
+ <p>
+ See also the {{OnChunkGenerated|HOOK_CHUNK_GENERATED}} hook.
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world to which the chunk will be added" },
+ { Name = "ChunkX", Type = "number", Notes = "X-coord of the chunk" },
+ { Name = "ChunkZ", Type = "number", Notes = "Z-coord of the chunk" },
+ { Name = "ChunkDesc", Type = "{{cChunkDesc}}", Notes = "Generated chunk data." },
+ },
+ Returns = [[
+ If this function returns true, the server will not call any other plugin with the same chunk. If
+ this function returns false, the server will call the rest of the plugins with the same chunk,
+ possibly overwriting the ChunkDesc's contents.
+ ]],
+ }, -- HOOK_CHUNK_GENERATING
+
+ HOOK_CHUNK_UNLOADED =
+ {
+ CalledWhen = "A chunk has been unloaded from the memory.",
+ DefaultFnName = "OnChunkUnloaded", -- also used as pagename
+ Desc = [[
+ This hook is called when a chunk is unloaded from the memory. Though technically still in memory,
+ the plugin should behave as if the chunk was already not present. In particular, {{cWorld}} block
+ API should not be used in the area of the specified chunk.
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world from which the chunk is unloading" },
+ { Name = "ChunkX", Type = "number", Notes = "X-coord of the chunk" },
+ { Name = "ChunkZ", Type = "number", Notes = "Z-coord of the chunk" },
+ },
+ Returns = [[
+ If the function returns false or no value, the next plugin's callback is called. If the function
+ returns true, no other callback is called for this event. There is no behavior that plugins could
+ override.
+ ]],
+ }, -- HOOK_CHUNK_UNLOADED
+
+ HOOK_CHUNK_UNLOADING =
+ {
+ CalledWhen = " A chunk is about to be unloaded from the memory. Plugins may refuse the unload.",
+ DefaultFnName = "OnChunkUnloading", -- also used as pagename
+ Desc = [[
+ MCServer calls this function when a chunk is about to be unloaded from the memory. A plugin may
+ force MCServer to keep the chunk in memory by returning true.</p>
+ <p>
+ FIXME: The return value should be used only for event propagation stopping, not for the actual
+ decision whether to unload.
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world from which the chunk is unloading" },
+ { Name = "ChunkX", Type = "number", Notes = "X-coord of the chunk" },
+ { Name = "ChunkZ", Type = "number", Notes = "Z-coord of the chunk" },
+ },
+ Returns = [[
+ If the function returns false or no value, the next plugin's callback is called and finally MCServer
+ unloads the chunk. If the function returns true, no other callback is called for this event and the
+ chunk is left in the memory.
+ ]],
+ }, -- HOOK_CHUNK_UNLOADING
+
+ HOOK_COLLECTING_PICKUP =
+ {
+ CalledWhen = "Player is about to collect a pickup. Plugin can refuse / override behavior. ",
+ DefaultFnName = "OnCollectingPickup", -- also used as pagename
+ Desc = [[
+ This hook is called when a player is about to collect a pickup. Plugins may refuse the action.</p>
+ <p>
+ Pickup collection happens within the world tick, so if the collecting is refused, it will be tried
+ again in the next world tick, as long as the player is within reach of the pickup.</p>
+ <p>
+ FIXME: There is no OnCollectedPickup() callback.</p>
+ <p>
+ FIXME: This callback is called even if the pickup doesn't fit into the player's inventory.</p>
+ ]],
+ Params =
+ {
+ { Name = "Player", Type = "{{cPlayer}}", Notes = "The player who's collecting the pickup" },
+ { Name = "Pickup", Type = "{{cPickup}}", Notes = "The pickup being collected" },
+ },
+ Returns = [[
+ If the function returns false or no value, MCServer calls other plugins' callbacks and finally the
+ pickup is collected. If the function returns true, no other plugins are called for this event and
+ the pickup is not collected.
+ ]],
+ }, -- HOOK_COLLECTING_PICKUP
+
+ HOOK_CRAFTING_NO_RECIPE =
+ {
+ CalledWhen = " No built-in crafting recipe is found. Plugin may provide a recipe.",
+ DefaultFnName = "OnCraftingNoRecipe", -- also used as pagename
+ Desc = [[
+ This callback is called when a player places items in their {{cCraftingGrid|crafting grid}} and
+ MCServer cannot find a built-in {{cCraftingRecipe|recipe}} for the combination. Plugins may provide
+ a recipe for the ingredients given.
+ ]],
+ Params =
+ {
+ { Name = "Player", Type = "{{cPlayer}}", Notes = "The player whose crafting is reported in this hook" },
+ { Name = "Grid", Type = "{{cCraftingGrid}}", Notes = "Contents of the player's crafting grid" },
+ { Name = "Recipe", Type = "{{cCraftingRecipe}}", Notes = "The recipe that will be used (can be filled by plugins)" },
+ },
+ Returns = [[
+ If the function returns false or no value, no recipe will be used. If the function returns true, no
+ other plugin will have their callback called for this event and MCServer will use the crafting
+ recipe in Recipe.</p>
+ <p>
+ FIXME: To allow plugins give suggestions and overwrite other plugins' suggestions, we should change
+ the behavior with returning false, so that the recipe will still be used, but fill the recipe with
+ empty values by default.
+ ]],
+ }, -- HOOK_CRAFTING_NO_RECIPE
+
+ HOOK_DISCONNECT =
+ {
+ CalledWhen = "A player has explicitly disconnected.",
+ DefaultFnName = "OnDisconnect", -- also used as pagename
+ Desc = [[
+ This hook is called when a client sends the disconnect packet and is about to be disconnected from
+ the server.</p>
+ <p>
+ Note that this callback is not called if the client drops the connection or is kicked by the
+ server.</p>
+ <p>
+ FIXME: There is no callback for "client destroying" that would be called in all circumstances.</p>
+ ]],
+ Params =
+ {
+ { Name = "Player", Type = "{{cPlayer}}", Notes = "The player who has disconnected" },
+ { Name = "Reason", Type = "string", Notes = "The reason that the client has sent in the disconnect packet" },
+ },
+ Returns = [[
+ If the function returns false or no value, MCServer calls other plugins' callbacks for this event
+ and finally broadcasts a disconnect message to the player's world. If the function returns true, no
+ other plugins are called for this event and the disconnect message is not broadcast. In either case,
+ the player is disconnected.
+ ]],
+ }, -- HOOK_DISCONNECT
+
+ HOOK_EXECUTE_COMMAND =
+ {
+ CalledWhen = "A player executes an in-game command, or the admin issues a console command. Note that built-in console commands are exempt to this hook - they are always performed and the hook is not called.",
+ DefaultFnName = "OnExecuteCommand", -- also used as pagename
+ Desc = [[
+ A plugin may implement a callback for this hook to intercept both in-game commands executed by the
+ players and console commands executed by the server admin. The function is called for every in-game
+ command sent from any player and for those server console commands that are not built in in the
+ server.</p>
+ <p>
+ If the command is in-game, the first parameter to the hook function is the {{cPlayer|player}} who's
+ executing the command. If the command comes from the server console, the first parameter is nil.
+ ]],
+ Params =
+ {
+ { Name = "Player", Type = "{{cPlayer}}", Notes = "For in-game commands, the player who has sent the message. For console commands, nil" },
+ { Name = "Command", Type = "table of strings", Notes = "The command and its parameters, broken into a table by spaces" },
+ },
+ Returns = [[
+ If the plugin returns true, the command will be blocked and none of the remaining hook handlers will
+ be called. If the plugin returns false, MCServer calls all the remaining hook handlers and finally
+ the command will be executed.
+ ]],
+ }, -- HOOK_EXECUTE_COMMAND
+
+ HOOK_EXPLODED =
+ {
+ CalledWhen = "An explosion has happened",
+ DefaultFnName = "OnExploded", -- also used as pagename
+ Desc = [[
+ This hook is called after an explosion has been processed in a world.</p>
+ <p>
+ See also {{OnHookExploding|HOOK_EXPLODING}} for a similar hook called before the explosion.</p>
+ <p>
+ The explosion carries with it the type of its source - whether it's a creeper exploding, or TNT,
+ etc. It also carries the identification of the actual source. The exact type of the identification
+ depends on the source kind:
+ <table>
+ <tr><th>Source</th><th>SourceData Type</th><th>Notes</th></tr>
+ <tr><td>esPrimedTNT</td><td>{{cTNTEntity}}</td><td>An exploding primed TNT entity</td></tr>
+ <tr><td>esCreeper</td><td>{{cCreeper}}</td><td>An exploding creeper or charged creeper</td></tr>
+ <tr><td>esBed</td><td>{{Vector3i}}</td><td>A bed exploding in the Nether or in the End. The bed coords are given.</td></tr>
+ <tr><td>esEnderCrystal</td><td>{{Vector3i}}</td><td>An ender crystal exploding upon hit. The block coords are given.</td></tr>
+ <tr><td>esGhastFireball</td><td>{{cGhastFireballEntity}}</td><td>A ghast fireball hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherSkullBlack</td><td><i>TBD</i></td><td>A black wither skull hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherSkullBlue</td><td><i>TBD</i></td><td>A blue wither skull hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherBirth</td><td><i>TBD</i></td><td>A wither boss being created</td></tr>
+ <tr><td>esOther</td><td><i>TBD</i></td><td>Any other previously unspecified type.</td></tr>
+ <tr><td>esPlugin</td><td>object</td><td>An explosion created by a plugin. The plugin may specify any kind of data.</td></tr>
+ </table></p>
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world where the explosion happened" },
+ { Name = "ExplosionSize", Type = "number", Notes = "The relative explosion size" },
+ { Name = "CanCauseFire", Type = "bool", Notes = "True if the explosion has turned random air blocks to fire (such as a ghast fireball)" },
+ { Name = "X", Type = "number", Notes = "X-coord of the explosion center" },
+ { Name = "Y", Type = "number", Notes = "Y-coord of the explosion center" },
+ { Name = "Z", Type = "number", Notes = "Z-coord of the explosion center" },
+ { Name = "Source", Type = "eExplosionSource", Notes = "Source of the explosion. See the table above." },
+ { Name = "SourceData", Type = "varies", Notes = "Additional data for the source. The exact type varies by the source. See the table above." },
+ },
+ Returns = [[
+ If the function returns false or no value, the next plugin's callback is called. If the function
+ returns true, no other callback is called for this event. There is no overridable behaviour.
+ ]],
+ }, -- HOOK_EXPLODED
+
+ HOOK_EXPLODING =
+ {
+ CalledWhen = "An explosion is about to be processed",
+ DefaultFnName = "OnExploding", -- also used as pagename
+ Desc = [[
+ This hook is called before an explosion has been processed in a world.</p>
+ <p>
+ See also {{OnHookExploded|HOOK_EXPLODED}} for a similar hook called after the explosion.</p>
+ <p>
+ The explosion carries with it the type of its source - whether it's a creeper exploding, or TNT,
+ etc. It also carries the identification of the actual source. The exact type of the identification
+ depends on the source kind:
+ <table>
+ <tr><th>Source</th><th>SourceData Type</th><th>Notes</th></tr>
+ <tr><td>esPrimedTNT</td><td>{{cTNTEntity}}</td><td>An exploding primed TNT entity</td></tr>
+ <tr><td>esCreeper</td><td>{{cCreeper}}</td><td>An exploding creeper or charged creeper</td></tr>
+ <tr><td>esBed</td><td>{{Vector3i}}</td><td>A bed exploding in the Nether or in the End. The bed coords are given.</td></tr>
+ <tr><td>esEnderCrystal</td><td>{{Vector3i}}</td><td>An ender crystal exploding upon hit. The block coords are given.</td></tr>
+ <tr><td>esGhastFireball</td><td>{{cGhastFireballEntity}}</td><td>A ghast fireball hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherSkullBlack</td><td><i>TBD</i></td><td>A black wither skull hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherSkullBlue</td><td><i>TBD</i></td><td>A blue wither skull hitting ground or an {{cEntity|entity}}.</td></tr>
+ <tr><td>esWitherBirth</td><td><i>TBD</i></td><td>A wither boss being created</td></tr>
+ <tr><td>esOther</td><td><i>TBD</i></td><td>Any other previously unspecified type.</td></tr>
+ <tr><td>esPlugin</td><td>object</td><td>An explosion created by a plugin. The plugin may specify any kind of data.</td></tr>
+ </table></p>
+ ]],
+ Params =
+ {
+ { Name = "World", Type = "{{cWorld}}", Notes = "The world where the explosion happens" },
+ { Name = "ExplosionSize", Type = "number", Notes = "The relative explosion size" },
+ { Name = "CanCauseFire", Type = "bool", Notes = "True if the explosion will turn random air blocks to fire (such as a ghast fireball)" },
+ { Name = "X", Type = "number", Notes = "X-coord of the explosion center" },
+ { Name = "Y", Type = "number", Notes = "Y-coord of the explosion center" },
+ { Name = "Z", Type = "number", Notes = "Z-coord of the explosion center" },
+ { Name = "Source", Type = "eExplosionSource", Notes = "Source of the explosion. See the table above." },
+ { Name = "SourceData", Type = "varies", Notes = "Additional data for the source. The exact type varies by the source. See the table above." },
+ },
+ Returns = [[
+ If the function returns false or no value, the next plugin's callback is called, and finally
+ MCServer will process the explosion - destroy blocks and push + hurt entities. If the function
+ returns true, no other callback is called for this event and the explosion will not occur.
+ ]],
+ }, -- HOOK_EXPLODING
+
+ HOOK_HANDSHAKE =
+ {
+ CalledWhen = "A client is connecting.",
+ DefaultFnName = "OnHandshake", -- also used as pagename
+ Desc = [[
+ This hook is called when a client sends the Handshake packet. At this stage, only the client IP and
+ (unverified) username are known. Plugins may refuse access to the server based on this
+ information.</p>
+ <p>
+ Note that the username is not authenticated - the authentication takes place only after this hook is
+ processed.
+ ]],
+ Params =
+ {
+ { Name = "Client", Type = "{{cClientHandle}}", Notes = "The client handle representing the connection. Note that there's no {{cPlayer}} object for this client yet." },
+ { Name = "UserName", Type = "string", Notes = "The username presented in the packet. Note that this username is unverified." },
+ },
+ Returns = [[
+ If the function returns false, the user is let in to the server. If the function returns true, no
+ other plugin's callback is called, the user is kicked and the connection is closed.
+ ]],
+ }, -- HOOK_HANDSHAKE
+
}, -- Hooks[]
diff --git a/MCServer/Plugins/APIDump/WebWorldThreads.html b/MCServer/Plugins/APIDump/WebWorldThreads.html
index 1a593ad8d..a77209b0b 100644
--- a/MCServer/Plugins/APIDump/WebWorldThreads.html
+++ b/MCServer/Plugins/APIDump/WebWorldThreads.html
@@ -1,8 +1,64 @@
<html>
<head>
-<title>Webserver vs World threads</title>
+<title>MCServer - Webserver vs World threads</title>
+<script src="https://google-code-prettify.googlecode.com/svn/loader/run_prettify.js"></script>
+<script src="http://google-code-prettify.googlecode.com/svn/trunk/src/lang-lua.js"></script>
</head>
<body>
-This is a temporary test
+
+<h1>Webserver vs World threads</h1>
+<p>
+This article will explain the threading issues that arise between the webserver and world threads are of concern to plugin authors.</p>
+<p>
+Generally, plugins that provide webadmin pages should be quite careful about their interactions. Most operations on MCServer objects requires synchronization, that MCServer provides automatically and transparently to plugins - when a block is written, the chunkmap is locked, or when an entity is being manipulated, the entity list is locked. Each plugin also has a mutex lock, so that only one thread at a time may be executing plugin code.</p>
+<p>
+This locking can be a source of deadlocks for plugins that are not written carefully.</p>
+
+<h2>Example scenario</h2>
+<p>Consider the following example. A plugin provides a webadmin page that allows the admin to kick players off the server. When the admin presses the "Kick" button, the plugin calls cWorld:DoWithPlayer() with a callback to kick the player. Everything seems to be working fine now.</p>
+<p>
+A new feature is developed in the plugin, now the plugin adds a new in-game command so that the admins can kick players while they're playing the game. The plugin registers a command callback with cPluginManager.AddCommand(). Now there are problems bound to happen.</p>
+<p>
+Suppose that two admins are in, one is using the webadmin and the other is in-game. Both try to kick a player at the same time. The webadmin locks the plugin, so that it can execute the plugin code, but right at this moment the OS switches threads. The world thread locks the world so that it can access the list of in-game commands, receives the in-game command, it tries to lock the plugin. The plugin is already locked, so the world thread is put on hold. After a while, the webadmin thread is woken up again and continues processing. It tries to lock the world so that it can traverse the playerlist, but the lock is already held by the world thread. Now both threads are holding one lock each and trying to grab the other lock, and are therefore deadlocked.</p>
+
+<h2>How to avoid the deadlock</h2>
+<p>
+There are two main ways to avoid such a deadlock. The first approach is using tasks: Everytime you need to execute a task inside a world, instead of executing it, queue it, using <a href="cWorld.html">cWorld</a>:QueueTask(). This handy utility can will call the given function inside the world's TickThread, thus eliminating the deadlock, because now there's only one thread. However, this approach will not let you get data back. You cannot query the player list, or the entities, or anything - because when the task runs, the webadmin page has already been served to the browser.</p>
+<p>
+To accommodate this, you'll need to use the second approach - preparing and caching data in the tick thread, possibly using callbacks. This means that the plugin will have global variables that will store the data, and update those variables when the data changes; then the webserver thread will only read those variables, instead of calling the world functions. For example, if a webpage was to display the list of currently connected players, the plugin should maintain a global variable, g_WorldPlayers, which would be a table of worlds, each item being a list of currently connected players. The webadmin handler would read this variable and create the page from it; the plugin would use HOOK_PLAYER_JOINED and HOOK_DISCONNECT to update the variable.</p>
+
+<h2>What to avoid</h2>
+<p>
+Now that we know what the danger is and how to avoid it, how do we know if our code is susceptible?</p>
+<p>
+The general rule of thumb is to avoid calling any functions that read or write lists of things in the webserver thread. This means most ForEach() and DoWith() functions. Only <a href="cRoot.html">cRoot</a>:ForEachWorld() is safe - because the list of worlds is not expected to change, so it is not guarded by a mutex. Getting and setting world's blocks is, naturally, unsafe, as is calling other plugins, or creating entities.</p>
+
+<h2>Example</h2>
+The Core has the facility to kick players using the web interface. It used the following code for the kicking (inside the webadmin handler):
+<pre class="prettyprint lang-lua">
+local KickPlayerName = Request.Params["players-kick"]
+local FoundPlayerCallback = function(Player)
+ if (Player:GetName() == KickPlayerName) then
+ Player:GetClientHandle():Kick("You were kicked from the game!")
+ end
+end
+cRoot:Get():FindAndDoWithPlayer(KickPlayerName, FoundPlayerCallback)
+</pre>
+The cRoot:FindAndDoWithPlayer() is unsafe and could have caused a deadlock. The new solution is queue a task; but since we don't know in which world the player is, we need to queue the task to all worlds:
+<pre class="prettyprint lang-lua">
+cRoot:Get():ForEachWorld( -- For each world...
+ function(World)
+ World:QueueTask( -- ... queue a task...
+ function(a_World)
+ a_World:DoWithPlayer(KickPlayerName, -- ... to walk the playerlist...
+ function (a_Player)
+ a_Player:GetClientHandle():Kick("You were kicked from the game!") -- ... and kick the player
+ end
+ )
+ end
+ )
+ end
+)
+</pre>
</body>
</html> \ No newline at end of file
diff --git a/MCServer/Plugins/APIDump/main.lua b/MCServer/Plugins/APIDump/main.lua
index 3827668e3..8c07144f2 100644
--- a/MCServer/Plugins/APIDump/main.lua
+++ b/MCServer/Plugins/APIDump/main.lua
@@ -327,10 +327,18 @@ function DumpAPIHtml()
f:write("\t\t" .. hook .. " =\n\t\t{\n");
f:write("\t\t\tCalledWhen = \"\",\n");
f:write("\t\t\tDefaultFnName = \"On\", -- also used as pagename\n");
- f:write("\t\t\tDesc = [[]],\n");
+ f:write("\t\t\tDesc = [[\n\t\t\t\t\n\t\t\t]],\n");
f:write("\t\t\tParams =\n\t\t\t{\n");
- f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n\t\t\t},\n");
- f:write("\t\t\tReturns = [[]],\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t\t{ Name = \"\", Type = \"\", Notes = \"\" },\n");
+ f:write("\t\t\t},\n");
+ f:write("\t\t\tReturns = [[\n\t\t\t\t\n\t\t\t]],\n");
f:write("\t\t}, -- " .. hook .. "\n");
end
end