How to parse content get from Azure Blob into Dictionary<string, dynamic> using C#?

Question

I am trying to get contents from blob in Azure which is key-value pairs and transfer them into Dictionary<String, dynamic>. But it falled. My code is as follows:

static async Task Main()
        {   

            BlobServiceClient blobServiceClient = new BlobServiceClient("#");
            BlobContainerClient containerClient =  blobServiceClient.GetBlobContainerClient("#");
            var blobClient = containerClient.GetBlobClient("#");  
            var response = blobClient.DownloadContent();
            
            var data = response.Value.Content;
            var blobContents = Encoding.UTF8.GetString(data);
            var options = new JsonSerializerOptions { WriteIndented = true };
            var jsonString = System.Text.Json.JsonSerializer.Serialize(blobContents, options);
            Dictionary<string, dynamic>? values = JsonConvert.DeserializeObject<Dictionary<string, dynamic>>(jsonString);
}

But it shows that :

unhandled exception. Newtonsoft.Json.JsonSerializationException: Error converting value "{"key":"value","...} to type 'System.Collections.Generic.Dictionary`2[System.String,System.Object]'. Path '', line 1, position 104484.

I want to know how to fix it.Thank you!

Answer 1

    private async Task<string> GetBlob(BlobClient blobClient)
    {
        string file = string.Empty;
        MemoryStream fileStream = new MemoryStream();

        try
        {
            using (var stream = new MemoryStream())
            {
                await blobClient.DownloadToAsync(stream).ConfigureAwait(false);

                if (stream != null)
                {

                    stream.WriteTo(fileStream);
                    fileStream.Position = 0;

                    StreamReader reader = new StreamReader(fileStream);
                    file = reader.ReadToEnd();
                }

            }

            return file;
        }
        catch (Exception)
        {
            return string.Empty;
        }

    }
}

Answer 2

I think the issue is because you're mixing different libraries (Newtonsoft.Json and System.Text.Json).

I did a text using both and they are working fine.

System.Text.Json:

using System;
using System.Text.Json;
using System.Collections;
using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        string json = "{\"systemId\":\"P0700055\",\"sessionId\":\"ec322078-8934-441e-a090-9c43e255ccf7\",\"startDateTime\":\"2021-04-10T00:13:13.0008388+00:00\",\"timeSpanSec\":30,\"span\":\"00:00:30\",\"signals\":[]}";
        var values =  JsonSerializer.Deserialize<Dictionary<string, dynamic>>(json);
        
        foreach(var kvp in values)
            Console.WriteLine(kvp.Value.ToString());
            
    }
}

Newtonsoft.Json

using System;
using Newtonsoft.Json;
using System.Collections;
using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        string json = "{\"systemId\":\"P0700055\",\"sessionId\":\"ec322078-8934-441e-a090-9c43e255ccf7\",\"startDateTime\":\"2021-04-10T00:13:13.0008388+00:00\",\"timeSpanSec\":30,\"span\":\"00:00:30\",\"signals\":[]}";
        var values = JsonConvert.DeserializeObject<Dictionary<string, dynamic>>(json);
        
        foreach(var kvp in values)
            Console.WriteLine(kvp.Value.ToString());
            
    }
}

Answer 3

To fix the error, simply remove the following 2 lines of code:

var options = new JsonSerializerOptions { WriteIndented = true };
var jsonString = System.Text.Json.JsonSerializer.Serialize(blobContents, options);

and replace the following line of code:

Dictionary<string, dynamic>? values = JsonConvert.DeserializeObject<Dictionary<string, dynamic>>(jsonString);

with

Dictionary<string, dynamic>? values = JsonConvert.DeserializeObject<Dictionary<string, dynamic>>(blobContents);

So your code would be something like:

static async Task Main()
        {   

            BlobServiceClient blobServiceClient = new BlobServiceClient("#");
            BlobContainerClient containerClient =  blobServiceClient.GetBlobContainerClient("#");
            var blobClient = containerClient.GetBlobClient("#");  
            var response = blobClient.DownloadContent();
            
            var data = response.Value.Content;
            var blobContents = Encoding.UTF8.GetString(data);
            
            Dictionary<string, dynamic>? values = JsonConvert.DeserializeObject<Dictionary<string, dynamic>>(blobContents);
}