Can't implement .jslib functions in WebGL project, crash occurs on build

Hello,
I need to access local storage of browser in order to get some data. So I followed the official Unity guide
( https://docs.unity3d.com/Manual/webgl-interactingwithbrowserscripting.html )
I wrote a .jslib file with needed functions:

Code (JavaScript):

1. mergeInto(LibraryManager.library, {
2.  
3.     SetAccessToken: function(){
4.         window.localStorage.setItem("accessToken", "tokenForAccess");
5.         window.localStorage.setItem("user", "userData");
6.     },
7.  
8.     GetAccessToken: function(){
9.         var data;
10.         data["accessToken"] = window.localStorage.getItem("custom-token");
11.         data["user"] = window.localStorage.getItem("user");
12.         return data;
13.     },
14.  
15.     PrintSomething: function(str){
16.         console.log(str);
17.     },
18. });

Then imported into my Unity project under folder Assets/Plugins.
This is my C# Script in which I try calling the implemented js functions:

Code (CSharp):

1. using UnityEngine;
2. using System.Runtime.InteropServices;
3.  
4. public class LoginController : MonoBehaviour
5. {
6.     [DllImport("__internal")]
7.     private static extern void SetAccessToken();
8.  
9.     [DllImport("__Internal")]
10.     private static extern void PrintSomething(string str);
11.  
12.     [DllImport("__Internal")]
13.     private static extern string GetAccessToken();
14.  
15.     private void Start()
16.     {
17.         SetAccessToken();
18.         string userData = GetAccessToken();
19.         PrintSomething(userData);
20.     }
21. }
22.  

When I build into WebGL locally and run in Mozzila's Firefox (I've set up the privacy.file_unique_origin to false) I get the following error:

An error occurred running the Unity content on this page. See your browser JavaScript console for more info. The error was:
uncaught exception: abort("To use dlopen, you need to use Emscripten's linking support, see https://github.com/kripken/emscripten/wiki/Linking") at jsStackTrace (UnityWebGLBuild.wasm.framework.unityweb:8:15620)
stackTrace (UnityWebGLBuild.wasm.framework.unityweb:8:15791)
onAbort@http://localhost:51474/Build/UnityLoader.js:4:11199
abort (UnityWebGLBuild.wasm.framework.unityweb:8:515994)
_dlopen (UnityWebGLBuild.wasm.framework.unityweb:8:170718)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[60596]:0x12c55dc (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[62016]:0x13049a6)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[63063]:0x1334da7 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[63062]:0x1334d3d)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[63066]:0x1334dfe (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[25168]:0xba44c8)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[63528]:0x1351dd1
UnityModule [UnityModule/Module.dynCall_iiiii] (UnityWebGLBuild.wasm.framework.unityweb:8:486880)
invoke_iiiii (UnityWebGLBuild.wasm.framework.unityweb:8:347250)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[61183]:0x12e23e0 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[60495]:0x12c1d82)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[4415]:0x1c6f54 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[4413]:0x1c6c2c)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[8083]:0x304bd8 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[8080]:0x3039fa)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10567]:0x410de7 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[8396]:0x32a5e8)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10952]:0x43d9e7 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10666]:0x41ac62)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10666]:0x41ac77 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10661]:0x41a780)
@blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[10654]:0x418708 (blob:http://localhost:51474/23094b0d-8d77-4761-857d-9a784ad41696 line 8 > WebAssembly.instantiate:wasm-function[63546]:0x13520cf)
UnityModule [UnityModule/Module.dynCall_v] (UnityWebGLBuild.wasm.framework.unityweb:8:496436)
browserIterationFunc (UnityWebGLBuild.wasm.framework.unityweb:8:174940)
runIter (UnityWebGLBuild.wasm.framework.unityweb:8:178013)
Browser_mainLoop_runner (UnityWebGLBuild.wasm.framework.unityweb:8:176475)

These are the libraries we use for our WebAPI if that is of any matter:

Code (CSharp):

1. using System;
2. using Newtonsoft.Json;
3. using UnityEngine.Networking;

 

It could have something to do with syncing the filesystem.
I use the solution from this thread . the HandleIO.jslib script
But now I sometimes get the "Two fs sync happening at once" message. Not sure if it's that plugin.

 

1. [DllImport("__internal")] -> [DllImport("__Internal")]
   
2. GetAccessToken() returns the object type, but the jslib function can basically only return numbers (including pointers) and strings.
   So if you convert it to a JSON string and return it, the function caller will convert it from JSON to an object.
   If you want to return a string, you need to convert it to a pointer and then return it.
3. PrintSomething() it is passed as an argument instead of a string. Therefore, you need to convert the pointer to a string.

Fixed code

Code (CSharp):

1. using UnityEngine;
2. using System.Runtime.InteropServices;
3.  
4. public class LoginController : MonoBehaviour
5. {
6.     [DllImport("__Internal")]
7.     private static extern void SetAccessToken();
8.  
9.     [DllImport("__Internal")]
10.     private static extern void PrintSomething(string str);
11.  
12.     [DllImport("__Internal")]
13.     private static extern string GetAccessToken();
14.  
15.     private class UserData
16.     {
17.         public string accessToken;
18.         public string user;
19.     }
20.  
21.     private void Start()
22.     {
23.         SetAccessToken();
24.         string userDataJson = GetAccessToken();
25.         PrintSomething(userDataJson);
26.         var userData = JsonUtility.FromJson<UserData>(userDataJson);
27.         Debug.Log($"accessToken: {userData.accessToken}");
28.         Debug.Log($"user: {userData.user}");
29.     }
30. }

Code (JavaScript):

1. mergeInto(LibraryManager.library, {
2.     SetAccessToken: function(){
3.         window.localStorage.setItem("accessToken", "tokenForAccess");
4.         window.localStorage.setItem("user", "userData");
5.     },
6.     GetAccessToken: function(){
7.         var data = {};
8.         data["accessToken"] = window.localStorage.getItem("accessToken");
9.         data["user"] = window.localStorage.getItem("user");
10.         var json = JSON.stringify(data);
11.         var size = lengthBytesUTF8(json) + 1;
12.         var ptr = _malloc(size);
13.         stringToUTF8(json, ptr, size);
14.         return ptr;
15.     },
16.     PrintSomething: function(strPtr){
17.         var str = UTF8ToString(strPtr);
18.         console.log(str);
19.     }
20. });

 

Thank you! Works well now

 

Does anyone know why this code fails to build. No doubt doing something dumb but I can't see it

Code (CSharp):

1.    
2.      CopyToClipboard : function(strPtr, message, failed)
3.      {
4.      
5.           var type = "text/plain";
6.           var text = UTF8ToString(strPtr);
7.           var blob = new Blob([text], { type });
8.           var data = [new ClipboardItem({ [type]: blob })];
9.        
10.           navigator.clipboard.write(data).then(
11.              function ()
12.              {
13.                    window.alert(UTF8ToString(message));
14.              },
15.              function ()
16.              {
17.                    window.alert(UTF8ToString(failed));
18.              }
19.          );
20.      }
21.  

Code (CSharp):

1.  
2. [DllImport("__Internal")]
3.     private static extern void CopyToClipboard(string url, string message, string failed);
4.  

For context I was using navigator.clipboard.writeText but that doesn't work on the mac

 

(Not confirmed)
Maybe

Code (JavaScript):

1. {[type]: blob}

I think that part is bad.

Since the version of emscripten before Unity2022 is old, ES6 + syntax cannot be used.
Please rewrite it as follows and try it.

Code (JavaScript):

1. var obj = {};
2. obj [type] = blob;
3. var data = [new ClipboardItem (obj)];

 

Sadly that still fails

 

I've found some much cleaner code that seems to work in Safari

https://www.javascripture.com/ClipboardItem

Trying something based on that, taking into account your suggestion.....