Read/Write text files from Unity Webplayer

Unity Engine
1

Hi all,

my question is about reading or writing external files from Unity. I searched all topics about that and find solutions. They work fine until I build my application as a web application.

Sure there are reasons that an application is not allowed to write to users drives from web. But how can I read or write text files from web.

string path = Application.dataPath + @"/test.txt";
Debug.Log("Pfad: " + path);
if(!File.Exists(path)) {
  StreamWriter sw = File.CreateText(path);	
}

When I start the application in the IE I get following Exception in the web log:

090312 14:46:36 ------------------------------------------------------------
090312 14:46:36 Instance starting, version 2.5.0f1_21077
090312 14:46:36 Datafile file:///E:/UserData/Georg/work/Unity/Levels/Assets/GuiText.unity3d
Direct3D:
Version: Direct3D 9.0c [nv4_disp.dll 6.14.11.6921]
Renderer: NVIDIA GeForce 8800 GTS 512 (Omega 2.169.21)
Vendor: NVIDIA
VRAM: 512 MB
Audio devices: Generic Hardware (default: Generic Hardware)
web: load mono
web: start, src=GuiText.unity3d abs=file:///E:/UserData/Georg/work/Unity/Levels/Assets/GuiText.unity3d
Player: init engine
web: sucessfully initialized
090312 14:46:37 loader: start ok
web: parent window change: 90768 1024x768
desktop: 1280x1024 75Hz; virtual: 1280x1024 at 0,0
Game Awake
UnityEngine.Debug:Log(Object)
Game:Awake()

(Filename: …..\Runtime\Export\Generated\BaseClass.cpp Line: 1658)
Loader Script Awake
UnityEngine.Debug:Log(Object)
Loader:Awake()

(Filename: …..\Runtime\Export\Generated\BaseClass.cpp Line: 1658)
Loader Script started
UnityEngine.Debug:Log(Object)
Loader:Start()

(Filename: …..\Runtime\Export\Generated\BaseClass.cpp Line: 1658)
Pfad: file:///E:/UserData/Georg/work/Unity/Levels/Assets/test.txt
UnityEngine.Debug:Log(Object)
Loader:Start()

(Filename: …..\Runtime\Export\Generated\BaseClass.cpp Line: 1658)
IOException: Win32 IO returned 50. Path: file:///E:/UserData/Georg/work/Unity/Levels/Assets
System.IO.Directory.Exists (System.String path)
System.IO.StreamWriter…ctor (System.String path, Boolean append, System.Text.Encoding encoding, Int32 bufferSize)
System.IO.StreamWriter…ctor (System.String path, Boolean append)
(wrapper remoting-invoke-with-check) System.IO.StreamWriter:.ctor (string,bool)
System.IO.File.CreateText (System.String path)
Loader.Start ()

(Filename: Line: -1)

Thanks for help.
regards Vince

2

The web player cannot use filesystem stuff (this has been disabled on purpose). Use PlayerPrefs or WWW calls instead.

3

Thanks for the fast replay.

Ok, I tried it with WWW and it works. Here is the code:

	void Start () {
		Debug.Log("Loader Script started");
		
		string url = Application.dataPath + @"/Test.txt";
		WWW request = new WWW(url);
		
		while(!request.isDone) {
			Debug.Log("Loading...");
		}
		
		Debug.Log("Data: " + request.data);
		
		// Initialize the Game class
		Game.Instance.Setup();
		
		Application.LoadLevel(LevelToLoad);
	}

But how can I write to such a file with WWW?

best regards
Georg

4

You can’t just “write file to the internet”. You usually send a WWW request to your server with some data, then some script on your web server processes the request parameters and creates a file (on server), or puts something into a database, or …

You can’t write files into the player’s machine in web player, period. If you want to store small amount of data (e.g. game preferences) on player’s machine, use PlayerPrefs class.

5

Ok, thanks a lot. That made things clear.

I use it only as a test scenario for now, later we will have a database.

best regards
Vince

6

This code reads the file “Test.txt” from the local application folder… right? It’s not reading from the server… right?

7

No, in the webplayer Application.dataPath returns the path on the webserver where the unity3d file is located. It wouldn’t make much sense to return a local path since your application sits inside a security box. All you can access is your own stuff (from your webserver) which includes the website the player runs in.

8

for a single system playerprefs working fine, if build stored in local system and played from other systems datas not carry forward from one to another system. How can i read/write file without having server which have database (php server)

9

you can’t, anything that is meant to work across users or machines requires a server backend.

the data the webplayer stores are local to the user account on the machine

10

You could print a file as text in a textbox and print a copy to clipboard.

you select all the text edit window, it can copy all txt, i.e. save object mesh files!. it may lag / crash on many kb / mb.

11

I would do this by writing a php script and posting to it, even once you get a database I would write to the database via php scripts.

12

Please give details of above process.