C# Extract json object from mixed data text/js file

September 1, 2022

I need to parse reactjs file in main.451e57c9.js to retrieve version number with C#.
This file contains mixed data, here is little part of it:

.....inally{if(s)throw i}}return a}}(e,t)||xe(e,t)||we()}var Se=
JSON.parse('{"shortVersion":"v3.1.56"}')
,Ne="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgA
AASAAAAAqCAYAAAATb4ZSAAAACXBIWXMAAAsTAAALEw.....

I need to extract json data of {"shortVersion":"v3.1.56"}

The last time I tried to simply find the string shortVersion and return a certain number of characters after, but it seems like I’m trying to create the bicycle from scratch. Is there proper way to identify and extract json from the mixed text?

public static void findVersion()
{
    var partialName = "main.*.js";
    string[] filesInDir = Directory.GetFiles(@pathToFile, partialName);

    var lines = File.ReadLines(filesInDir[0]);

    foreach (var line in File.ReadLines(filesInDir[0]))
    {
        string keyword = "shortVersion";
        int indx = line.IndexOf(keyword);

        if (indx != -1)
        {
            string code = line.Substring(indx + keyword.Length);
            Console.WriteLine(code);
        }
    }
}

RESULT

":"v3.1.56"}'),Ne="data:image/png;base64,iVBORw0KGgoAA.....

>Solution :

Try below method –

 public static object ExtractJsonFromText(string mixedStrng)
    {
        for (var i = mixedStrng.IndexOf('{'); i > -1; i = mixedStrng.IndexOf('{', i + 1))
        {
            for (var j = mixedStrng.LastIndexOf('}'); j > -1; j = mixedStrng.LastIndexOf("}", j -1))
            {
                var jsonProbe = mixedStrng.Substring(i, j - i + 1);
                try
                {
                    return JsonConvert.DeserializeObject(jsonProbe);
                }
                catch
                {                        
                }
            }
        }
        return null;
    }

Fiddle
https://dotnetfiddle.net/N1jiWH