WoW API: ChatFrame:AddMessageEventFilter

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← WoW API < ChatFrame:AddMessageEventFilter

This 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")

Arguments

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

Returns

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

filterFunc

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

For most chat events, arg1 is the message text.

Return values

filter: 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

Writing a filter is fairly straightforward:

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

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

3.1 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

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 
        return
      end
      if newarg1 then
        arg1 = newarg
        -- you should actually probably do this for all of arg2..arg11 since that's what framexml does
      end
    end
  end

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

Details

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.