outputting a .txt file which usually updates itself

loves_oi · August 2012

This code outputs the txt file in a url.

 
local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
local function onComplete(event)
 
	local myString=event.data      -- We got the string here.
 
        --local timer = Timer.new(1000, 8)
	--timer:addEventListener(Event.TIMER, onComplete)---
 
	local length = string.len(myString)
	local i = 1
 
	local echoString = ""
	while (i < length+1) do
 
		echoString = echoString .. string.sub(myString,i,i)
 
		i = i+1;
	end
	print (echoString)
 
	--timer:start()
 
end
 
local function onError()
    print("error")
end
 
local function onProgress(event)
    print("progress: " .. event.bytesLoaded .. " of " .. event.bytesTotal)
end
 
loader:addEventListener(Event.COMPLETE, onComplete)
loader:addEventListener(Event.ERROR, onError)
loader:addEventListener(Event.PROGRESS, onProgress)

I want to add a timer to the code and it is the code with timer.

 
local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
local function onComplete(event)
 
	local myString=event.data      -- We got the string here.
 
        local timer = Timer.new(1000, 8)
	timer:addEventListener(Event.TIMER, onComplete)---
 
	local length = string.len(myString)
	local i = 1
 
	local echoString = ""
	while (i < length) do
 
		echoString = echoString .. string.sub(myString,i,i)
 
		i = i+1;
	end
	print (echoString)
 
	timer:start()
 
end
 
local function onError()
    print("error")
end
 
local function onProgress(event)
    print("progress: " .. event.bytesLoaded .. " of " .. event.bytesTotal)
end
 
loader:addEventListener(Event.COMPLETE, onComplete)
loader:addEventListener(Event.ERROR, onError)
loader:addEventListener(Event.PROGRESS, onProgress)

It outputs the results correctly and then suddenly gave the error :

main.lua:9: bad argument #1 to 'len' (string expected, got nil)
stack traceback:

Why i'm taking this error? How could i fix it?
Thanks in advance

MikeHart · August 2012

You get this error because event.data contains no STRING. What puzzles me is why do you add another event listener to the onComplete event inside the onComplete function? I think it has something to do with this.

loves_oi · August 2012

Did you mean the lines :

timer:addEventListener(Event.TIMER, onComplete)
and
loader:addEventListener(Event.COMPLETE, onComplete)
?

When i did

--timer:addEventListener(Event.TIMER, onComplete)
and
loader:addEventListener(Event.COMPLETE, onComplete)

It gives the output correctly but doesn't update.

When i did

timer:addEventListener(Event.TIMER, onComplete)
and
--loader:addEventListener(Event.COMPLETE, onComplete)

There is no error but there is no output ,either.

MikeHart · August 2012

Stupid me. I didn't see that you tried to used the same handler for the Url and the timer. Within the handler, I think onComplete is NIL when LUA parses the file. If you need to have to use the same handler on different objects, then I would do this

local onComplete
...
onComplete = function(event)

MikeHart · August 2012

And as you use the same handler for 2 different events, make sure you check if the string is not NIL when you determine the length.

techdojo · August 2012

looks like a simple forward referencing problem - I always declare my function handlers the way @MikeHart suggests because often I assign handlers to both the COMPLETE and ERROR events and want each one to be able to remove both when they get called.

loves_oi · August 2012

You mean this ?

local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
 
local onComplete
 
--local function onComplete(event)
onComplete = function(event)
	local myString=event.data      
	--print (onComplete)
	print (myString)	
end
 
local timer = Timer.new(10000,100)
timer:addEventListener(Event.TIMER, onComplete)
timer:start()
 
local function onError()
    print("error")
end
 
local function onProgress(event)
    print("progress: " .. event.bytesLoaded .. " of " .. event.bytesTotal)
end
 
loader:addEventListener(Event.COMPLETE, onComplete)
loader:addEventListener(Event.ERROR, onError)
loader:addEventListener(Event.PROGRESS, onProgress)

This change doesn't seems to change anything @techdojo .
I'M outputting the myString , and you are right @MikeHart . myString gives the output correctly at first trying but then it only outputs nil .Namely:
(Correct Output)
nil
nil
nil
nil
nil
nil
nil
.
.
.
So interesting.. Why can't it get the txt file from the url after first trying? I would expect that it outputs the text again and again.
Thanks in advance

loves_oi · August 2012

what should i do ?

techdojo · August 2012

take up basket weaving?

loves_oi · August 2012

This is an snapshot while i am working

techdojo · August 2012

I wish mine could get that complex

I'm also having problems with the UrlLoader class - making multiple calls seems to really mess things up for me.

Am I right in thinking you want to periodically download the file and dump it's contents. it's something similar to what I'm currently trying (and failing) to do

loves_oi · August 2012

Yeah. There is a txt file which is usually updated . I want to output it and make it update itself

Scouser · August 2012

Maybe I'm looking at this all wrong but shouldn't onComplete only get called once, when the file has finished downloading?

When onComplete is called the complete downloaded file should be in event.data. If this is the only file to download then the loader:eventListeners should be removed.

I think that once a file is finished loading, it is sent to the Event.COMPLETE listener and then the string is cleared. If the listener is called again then this nil string is what will be sent. I may have this wrong but it makes sense in my head

techdojo · August 2012

By update itself - do you mean ensure the local copy always contains the latest info.

What I would say is use a different function for the Timer on complete event as opposed to the download on complete event (also makes the code easier to read).

I'm also struggling with multiple downloads using a single connection (which is basically what your doing). If I get any more info I'll post some more.

I was hoping @Atilim (or @Gorkem ) might jump in with the single bit of info I need to make it all work flawlessly but I guess they're a bit busy at the moment.

loves_oi · August 2012

By update itself - do you mean ensure the local copy always contains the latest info.

Exactly

loves_oi · August 2012

@Scouser
When i remove the line :

loader:addEventListener(Event.COMPLETE, onComplete)

It never give correct output , give all nil .

unless i remove , it gives at least one Correct output if we don't mind rest of it is all nil

techdojo · August 2012

If you remove the handler that get's called when the download completes then you'll not get any notification at all.

Something weird is going on here - I've been at this all day - making multiple calls to the same UrlLoader instance doesn't appear to work, after the second call to :load() is made, none of the event listeners seem to get called - can anyone else confirm this?

zvardin · August 2012

Are you debugging with the player on a PC or on a mobile device? A few weeks back I had been testing stuff using the REST API and noticed I got errors whenever running on a device, but no issues on the player on my PC.

techdojo · August 2012

Ok - well I've got something sorted at least but I suspect it won't help @loves_oi too much.

To download a single file you must create an instance of a UrlLoader and assign the appropriate event handlers to it.

Once the download is complete you are free to work with the data - BUT you can't reuse the connection (ie make a subsequent :load() call), other than removing the event handlers you also CAN'T do anything with the instance of the connection (ie the original return value from UrlLoader:new()) - you certainly can't create a NEW connection and assign it to the variable (don't ask me why!) otherwise the any attempt to download will just cause it to crash.

The way I got round the problem was to have a table of UrlLoader instances and create one per file.

Initially the table was empty - and I used a onEnterFrame listener to watch the state of a flag that was set each time a download completed and was then used to trigger the next load from the onEnterFrame listener.

Once all the files had been downloaded I then set a different flag which caused the onEnterFrame listener to pickup the fact that all the files had been downloaded and then nil out all the references to the UrlLoader instances before continuing.

I'm not sure if this the best method to use but until I get official word from those "in the know" it'll do.

I'll cross post this in the thread I started in case anyone else is struggling with this...

OZApps · August 2012

I am kind of confused at what you want. Here's what I think you want, you want a file to be downloaded/refreshed from the internet every so often to keep the contents fresh/updated, is that right?

if it is, then have two functions,
1. To download the file from the internet
2. A timer that will keep calling this function every XX period.

You will have to also keep in mind to start the timer only when the download is complete, so XX after the file download is completed. That way you will not have an overlap.

Hope that helps, BTW, Basket Weaving is quite an impressive task

loves_oi · August 2012

@zvardin , nope i'm testing on pc , not mobile phone.
@techdojo , you make me thought that it is impossible to do it :S
@OZApps ,you understand right. Moreover, I almost tried everywhere.I put the timer everywhere but didn't work . When i change the place of timer , the order of correct output change but it gives still only one correct output and rest all nil.For instance:

(correct output)
nil
nil
nil
.
.
.

or

nil
nil
(correct output)
nil
nil
.
.
.

or etc.

techdojo · August 2012

@loves_oi - @OzApps is bang on with his description. My advice to you - keep it as simple as possible.

You've already done the bit with the download - separate out the timer stuff and try and keep each section of your code as separate as possible, write a function that just get's called on a timer and do a print so that you know it's working ok, then look at calling your download function from within that timer callback. Just remember to create a NEW UrlLoader instance each time you want to download and DON'T try and schedule anything to do with the current UrlLoader instance from within the download complete callback.

atilim · August 2012

Hi,

Yes you're right. Second call to load doesn't seem to work. It's a bug. The workaround is creating a new UrlLoader for each load:

local load = nil
 
local function onComplete(event)
 	print("size:", #event.data)
	load()
end
 
local function onError()
    print("error")
end
 
local function onProgress(event)
end
 
load = function()
	local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
	loader:addEventListener(Event.COMPLETE, onComplete)
	loader:addEventListener(Event.ERROR, onError)
	loader:addEventListener(Event.PROGRESS, onProgress)
end
 
load()

loves_oi · August 2012

@atilim , it works correctly but , it updates every seconds. I want to update the file every minute etc. , not every second :S it may cause server crash

techdojo · August 2012

See my comment in my other thread about UrlLoader - looks like I "accidentally" tripped over the workaround when I tried to create an example that doesn't work

atilim · August 2012

oh I see.. this loads the file every minute:

local alreadyLoading = false
 
local function onComplete(event)
	print("size:", #event.data)
	alreadyLoading = false
end
 
local function onError()
	print("error")
	alreadyLoading = false
end
 
local function load()
	if not alreadyLoading then
		local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
		loader:addEventListener(Event.COMPLETE, onComplete)
		loader:addEventListener(Event.ERROR, onError)
		alreadyLoading = true
	end
end
 
local timer = Timer.new(60 * 1000, 0)
timer:addEventListener(Event.TIMER, load)
timer:start()
load()

loves_oi · August 2012

@techdojo , i was trying what you said , but i couldn't do it

@atilim , it worked correctly , but it cause a new problem when It gives output on Simulator.
When it is updated with a new one , old and new textfields are seen . I should delete old one in every cycle . For this reason , where should i put " stage:removeChild(text) " I can't already put it in onComplete function .Also, I tried outside but it gives errors

local alreadyLoading = false
 
local function onComplete(event)
	local x = #event.data
	print("size:", x )
 
	local text = TextField.new(nil,"size : " .. x )
	text:setPosition(10, 265)
	text:setTextColor(0x007B25)
	stage:addChild(text)
 
	alreadyLoading = false
end
 
-- stage:removeChild(text)  ??????????
 
local function onError()
	print("error")
	alreadyLoading = false
end
 
local function load()
	if not alreadyLoading then
		local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
		loader:addEventListener(Event.COMPLETE, onComplete)
		loader:addEventListener(Event.ERROR, onError)
		alreadyLoading = true
	end
end
 
local timer = Timer.new(60 * 1000, 0)  --it is updated every minute 
timer:addEventListener(Event.TIMER, load)
timer:start()
load()

techdojo · August 2012

@Atilim - re your example don't you need to remove the eventListener's once they've been accessed or will that not cause a memory leak?

Scouser · August 2012

@loves_oi: Your errors might be because text is defined as local to your onComplete function. Try something like:

local alreadyLoading = false
-- This is now your text
local sizeText=nil
 
local function onComplete(event)
	local x = #event.data
	print("size:", x )
 
	-- If the text is on the stage already then remove it 
	if stage:contains(sizeText) then stage:removeChild(sizeText) end
	-- now create your new text
	sizeText = TextField.new(nil,"size : " .. x )
	sizeText:setPosition(10, 265)
	sizeText:setTextColor(0x007B25)
	stage:addChild(sizeText)
 
	alreadyLoading = false
end
 
-- stage:removeChild(text)  ??????????
 
local function onError()
	print("error")
	alreadyLoading = false
end
 
local function load()
	if not alreadyLoading then
		local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
		loader:addEventListener(Event.COMPLETE, onComplete)
		loader:addEventListener(Event.ERROR, onError)
		alreadyLoading = true
	end
end
 
local timer = Timer.new(60 * 1000, 0)  --it is updated every minute 
timer:addEventListener(Event.TIMER, load)
timer:start()
load()

loves_oi · August 2012

@Scouser , it doesn't compile. It gives the error:
main.lua:10: bad argument #1 to 'contains' (Sprite expected, got nil)
stack traceback:

When i define a new function and call it from somewhere, it gives the similar error:
Here is the code

 
local alreadyLoading = false
 
local function onComplete(event)
	local i = event.data
	print (i)
 
	text1 = TextField.new(nil,"size : " .. i )
	text1:setPosition(10, 125)
        text1:setTextColor(0x007B25)
        stage:addChild(text1)
	alreadyLoading = false
end
 
local function helper()
		stage:removeChild(text1)
end
	--stage:removeChild(text1)
 
local function onError()
	print("error")
	alreadyLoading = false
end
 
local function load()
	if not alreadyLoading then 
		local loader = UrlLoader.new("<a href="http://www.catonmat.net/download/awk.cheat.sheet.txt&quot" rel="nofollow">http://www.catonmat.net/download/awk.cheat.sheet.txt&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
		loader:addEventListener(Event.COMPLETE, onComplete)
		loader:addEventListener(Event.ERROR, onError)
		alreadyLoading = true
	end
end
 
local timer = Timer.new(30 * 1000, 0)  --it is updated every minute 
timer:addEventListener(Event.TIMER, load)
timer:start()
helper()
load()

It gives the error:
main.lua:20: bad argument #1 to 'removeChild' (Sprite expected, got nil)
stack traceback:

--- I hate nil

---
--- Maybe my brain dream it as if it was python :S ---

ar2rsawseen · August 2012

@loves_oi
but you try to remove text2:
stage:removeChild(text2)
Although you defined only variable text1
So text2 is nil

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