Problem retrieving data from Json to a list.

Questions & Answers
1

Hello im using the following script to fill a json with some data from a open source API and when i try to load the data into a List it gives me a “IOException: Sharing violation on path” + my path. And i don’t know wat is happening.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.UI;
using System.IO;

public class APICall : MonoBehaviour
{
    readonly string url = "https://opentdb.com/api.php?amount=10&category=10&difficulty=easy&type=multiple";
    public List<QuestionItem> questions_;

    
    void Awake()
    {
        StartCoroutine(SimpleWebRequest());
    }

    private void Start()
    {
        string path = Application.persistentDataPath + "/" + "questions.json";
        string loadedquestion = JSONUtility.LoadJsonAsExternalResource(path);
        QuestionItem myloadedQuestion = JsonUtility.FromJson<QuestionItem>(loadedquestion);
        questions_.Add(myloadedQuestion);
    }

    IEnumerator SimpleWebRequest()
    {
        UnityWebRequest apiRequest = UnityWebRequest.Get(url);

        yield return apiRequest.SendWebRequest();

        if (apiRequest.isNetworkError || apiRequest.isHttpError)
        {
            Debug.Log(apiRequest.error);
        }
        else
        {
            JSONUtility.WriteJsonToExternalResources("questions.json", apiRequest.downloadHandler.text);
        }

    }
}

QuestionItem Script.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[System.Serializable]
public class QuestionItem 
{
    public string question; 
    public string correct_answer;
    public string[] incorrect_answers; 
    public string type;
    public string difficulty;
    public string category;
}

JSONUtilities Script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.IO;
using System.Text;

public class JSONUtility
{
   
    public static string LoadJsonFromFile(string path, bool isResource)
    {
        if (isResource)
        {
            return LoadJsonAsResource(path);
        }
        else
        {
            return LoadJsonAsExternalResource(path);
        }
    }

   public static string LoadJsonAsResource(string path)
    {
        string jsonFilePath = path.Replace(".json","");
        TextAsset loadedJsonFile = Resources.Load<TextAsset>(jsonFilePath);
        return loadedJsonFile.text;
    }
    
    public static string LoadJsonAsExternalResource(string path)
    {
        
        if (!File.Exists(path))
        {
            Debug.Log("File not found");
            return null;
        }
        StreamReader reader = new StreamReader(path);
        string response = "";
        while (!reader.EndOfStream)
        {
            response += reader.ReadLine();
        }
        return response;
    }

    public static void WriteJsonToExternalResources(string path,string content)
    {
        path = Application.persistentDataPath + "/" + path;
        FileStream stream = File.Create(path);
        byte[] contentBytes = new UTF8Encoding(true).GetBytes(content);
        stream.Write(contentBytes,0,contentBytes.Length);
    }

}

That everything im using in this problem.

Thank you for your time.

2

A shared path violation happens usually when you access a file that has a lock.
It probably has to do with the fact you don’t actually close your streams.

You have to add a using to your streams, that will make sure they are properly disposed.

using (FileStream stream = File.Create(path))
{
// logic
}

using (StreamReader reader = new StreamReader(path)) 
{
// logic
}

Also your web requests should be disposed aswel

using (UnityWebRequest apiRequest = UnityWebRequest.Get(url)) 
{

}

Also you might run into a race condition incase your coroutine hasn’t finished by the
time your start function runs, it might not have yet saved the json data.