WoW API: ChatFrame:AddMessageEventFilter

From AddOn Studio
Jump to navigation Jump to search

WoW API < ChatFrame:AddMessageEventFilter

"I" iconThis function is implemented in Lua here FrameXML/ChatFrame.lua.

Manipulates FrameXML's list of chat event filters. 

ChatFrame_AddMessageEventFilter("event", filterFunc)
ChatFrame_RemoveMessageEventFilter("event", filterFunc)
filterFuncList = ChatFrame_GetMessageEventFilters("event")


String - name of the event to filter for
Function - your filtering function; see below for details


table - an array of filter functions. This is the same table as is used by the filtering system.


filter, arg1, arg2, arg3, ..., arg15 = myFilterFunc(chatFrame, event, arg1, arg2, arg3, ..., arg15);

For most chat events, arg1 is the message text.

Return values[edit]

Boolean: if true, the message is discarded.
arg1, arg2, ... arg15
Mixed: if filter is non-true, and arg1 is non-nil/false, the 15 returned values after filter replace the 15 arguments provided to the function for subsequent filtering purposes. Note that the environment arg1-arg15 aren't replaced: only the filter function arguments (and subsequent ChatFrame code) are affected.

Note that your function will be called once for every frame the message-event is registered for. It's possible to get two calls for whisper, say, and yell messages, and seven for channel messages. Due to this non-deterministic calling, your filter function should not have side-effects.

Example filter implementation[edit]

Writing a filter is fairly straightforward:

local function myChatFilter(self, event, msg, author, ...)
  if msg:find("buy gold") then
    return true
  if author == "Knownspammer" then
    return true
  if msg:find("lol") then
    return false, gsub(msg, "lol", ""), author, ...

ChatFrame_AddMessageEventFilter("CHAT_MSG_CHANNEL", myChatFilter)
ChatFrame_AddMessageEventFilter("CHAT_MSG_SAY", myChatFilter)
ChatFrame_AddMessageEventFilter("CHAT_MSG_YELL", myChatFilter)
ChatFrame_AddMessageEventFilter("CHAT_MSG_WHISPER", myChatFilter)

You should use the variables passed into the function rather than the global arg1, arg2 etc

Red exclamation mark icon3.1 change: The filter function is no longer passed "(msg)".
It is now passed the chat frame, the event and arg1, arg2 ... arg15.
If you return a non-nil arg1, you must also return all of arg2 ... arg15

Example Chatframe addon use[edit]

Chatframe addons / whisper managers etc should of course make use of these filters.

local function myChatEventHandler(self,event,arg1,...)
  local filterFuncList = ChatFrame_GetMessageEventFilters(event)
  if filterFuncList then
    for _, filterFunc in pairs(filterFuncList) do
      local filter, newarg1 = filterFunc(self,event,arg1,...)
      if filter then 
      if newarg1 then
        arg1 = newarg
        -- you should actually probably do this for all of arg2..arg11 since that's what framexml does

  -- whoop de do, not filtered, go about our business and display etc


This set of functions was added in patch 2.4. The arguments of the filter function were incompatibly changed in patch 3.1.

Re-adding an already-existing filter is harmless - the second addition is ignored.

Removing a filter that has not been added is harmless - there is no error.

You first have to define your filter function - local filterfunc(self,event,arg1,...) - and after that use ChatFrame_AddMessageEventFilter("event", filterfunc) in your lua code.

All possible chat events, that can be used are listed Events/Communication.