Enum Collection Parse Help

[beantownace]

Hello all,

I need some intel and hoping someone may be able to help where I have some strings coming in via JSON this may be easy and not thinking about it right. I have a single enum that I am parsing fine where I do a:

Enum.Parse<CustomerGroup>("GroupA") //GroupA coming in a string via JSON this works well.

I then have a collection of enums where I am having some trouble how to parse it with strings with this Google Protobuf Collection. Here is what it has now without the strings.

Google.Protobuf.Collections.RepeatedField<CustomerOperation> customerOperations = { CustomerOperation.CreateCustomer, CustomerOperation.CreateCustomerGroup };

I need to pass this with strings so the enum values are as follows:

CustomerOperation.CreateCustomer = "CREATE_CUSTOMER"
CustomerOperation.CreateCustomerGroup = "CREATE_CUSTOMER_GROUP"

Any idea how to send this via JSON value it would be key "customerOperations" : [something here]
and how I can parse that to the enum collection.

Thanks all really appreciate any help hope this makes sense.

 

[Skydiver]

My understanding is that the Google.Protobuf.Collections.RepeatedField is effectively just a representation of an array.

Are you trying to parse back into a Google.Protobuf.Collections.RepeatedField field, or just any array or list like what would normally by parsed?

 

[Justin]

Hello all,

I need some intel and hoping someone may be able to help where I have some strings coming in via JSON this may be easy and not thinking about it right. I have a single enum that I am parsing fine where I do a:

Enum.Parse<CustomerGroup>("GroupA") //GroupA coming in a string via JSON this works well.

I then have a collection of enums where I am having some trouble how to parse it with strings with this Google Protobuf Collection. Here is what it has now without the strings.

Google.Protobuf.Collections.RepeatedField<CustomerOperation> customerOperations = { CustomerOperation.CreateCustomer, CustomerOperation.CreateCustomerGroup };

I need to pass this with strings so the enum values are as follows:

CustomerOperation.CreateCustomer = "CREATE_CUSTOMER"
CustomerOperation.CreateCustomerGroup = "CREATE_CUSTOMER_GROUP"

Any idea how to send this via JSON value it would be key "customerOperations" : [something here]
and how I can parse that to the enum collection.

Thanks all really appreciate any help hope this makes sense.

It sounds like you're dealing with enum values in Protobuf and how they interact with JSON serialization and deserialization. You're on the right track with Enum.Parse for single enums. For a collection, the process involves a similar idea, but handled through a list or Protobuf's RepeatedField.

Let's break down how to send (serialize) and parse (deserialize) a collection of enums as strings via JSON for your Google.Protobuf.Collections.RepeatedField<CustomerOperation>.

JSON Structure for the Collection:​

When a Google.Protobuf.Collections.RepeatedField<CustomerOperation> is serialized to JSON, it typically appears as a JSON array of strings, where each string is the name of the enum member.

Given your enum values:

• CustomerOperation.CreateCustomer maps to "CREATE_CUSTOMER"
• CustomerOperation.CreateCustomerGroup maps to "CREATE_CUSTOMER_GROUP"

The JSON structure for a key "customerOperations" would look like this:

{
  "customerOperations": [
    "CREATE_CUSTOMER",
    "CREATE_CUSTOMER_GROUP",
    "ANOTHER_OPERATION_STRING"
  ]
}

C# Parsing (Deserialization)​

There are two main scenarios for parsing this JSON array back into your RepeatedField<CustomerOperation>:

Scenario A: Using Protobuf's Built-in JSON Deserialization (Recommended)​

If you have a Protobuf message defined in your .proto file that contains the repeated CustomerOperation field, Protobuf's JsonParser will handle the conversion of string enum values to their corresponding C# enum members automatically.

Example .proto file:

syntax = "proto3";

package Your.App.Namespace; // Adjust to your project's namespace

enum CustomerOperation {
  CUSTOMER_OPERATION_UNSPECIFIED = 0; // Good practice for default/unspecified value
  CREATE_CUSTOMER = 1;
  CREATE_CUSTOMER_GROUP = 2;
  DELETE_CUSTOMER = 3;
  UPDATE_CUSTOMER = 4;
}

message CustomerOperationsMessage {
  repeated CustomerOperation operations = 1;
  // You might have other fields here too
}

Deserialization Code:

Assuming CustomerOperationsMessage and CustomerOperation are generated C# classes from your .proto file:

using Google.Protobuf;
using Your.App.Namespace; // Replace with your actual generated namespace
using System;

public class JsonParsingExample
{
    public static void Main(string[] args)
    {
        string jsonString = @"
        {
            ""operations"": [
                ""CREATE_CUSTOMER"",
                ""CREATE_CUSTOMER_GROUP"",
                ""DELETE_CUSTOMER""
            ]
        }";

        try
        {
            // Use the generated Parser for your Protobuf message type
            var parser = new JsonParser(JsonParser.Settings.Default.WithIgnoreUnknownFields(true));
            CustomerOperationsMessage parsedMessage = parser.Parse<CustomerOperationsMessage>(jsonString);

            Console.WriteLine("Parsed Customer Operations:");
            foreach (var operation in parsedMessage.Operations)
            {
                Console.WriteLine($"- {operation}");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error parsing JSON with Protobuf JsonParser: {ex.Message}");
            // Handle specific parsing errors if needed
        }
    }
}

Scenario B: Manual Parsing of a String Array​

If you receive just a raw JSON array of strings (not wrapped in a Protobuf message) and you need to populate a RepeatedField<CustomerOperation>, you'll first deserialize the JSON array into a C# List<string> and then manually convert each string to the enum.

Option B# Deserialization Code:

using Google.Protobuf.Collections;
using Your.App.Namespace; // Replace with your actual generated namespace
using System;
using System.Collections.Generic;
using System.Text.Json; // For System.Text.Json (built-in .NET Core 3.1+ / .NET 5+)
// or using Newtonsoft.Json; // For Newtonsoft.Json (if using older .NET Framework or prefer it)

public class ManualParsingExample
{
    public static void Main(string[] args)
    {
        string jsonArrayString = @"[
            ""CREATE_CUSTOMER"",
            ""UPDATE_CUSTOMER"",
            ""INVALID_OPERATION"" // Example of an invalid string
        ]";

        // 1. Deserialize the JSON array of strings into a C# List<string>
        List<string> operationStrings = new List<string>();
        try
        {
            // Using System.Text.Json:
            operationStrings = JsonSerializer.Deserialize<List<string>>(jsonArrayString);

            // Or using Newtonsoft.Json:
            // operationStrings = Newtonsoft.Json.JsonConvert.DeserializeObject<List<string>>(jsonArrayString);

            Console.WriteLine("Deserialized JSON array to List<string>.");
        }
        catch (JsonException ex)
        {
            Console.WriteLine($"Error deserializing JSON array: {ex.Message}");
            return; // Exit if basic JSON deserialization fails
        }

        // 2. Manually parse each string into the enum and add to RepeatedField
        RepeatedField<CustomerOperation> customerOperationsCollection = new RepeatedField<CustomerOperation>();

        Console.WriteLine("\nConverting List<string> to RepeatedField<CustomerOperation>...");
        foreach (string opString in operationStrings)
        {
            try
            {
                // Use Enum.Parse<TEnum>(string value, bool ignoreCase) for robustness
                CustomerOperation op = (CustomerOperation)Enum.Parse(typeof(CustomerOperation), opString, true);
                customerOperationsCollection.Add(op);
                Console.WriteLine($"Successfully parsed '{opString}' to {op}");
            }
            catch (ArgumentException ex)
            {
                Console.WriteLine($"Warning: Could not parse '{opString}' to CustomerOperation enum. {ex.Message}");
                // Here you can decide how to handle invalid enum strings:
                // - Log the error
                // - Skip the invalid entry
                // - Throw a more specific exception
            }
        }

        Console.WriteLine("\nFinal RepeatedField<CustomerOperation> content:");
        foreach (var op in customerOperationsCollection)
        {
            Console.WriteLine($"- {op}");
        }
    }
}

Serialization (Sending)​

Scenario A: Serializing a Protobuf Message​

If you have a Protobuf message object containing the RepeatedField<CustomerOperation>, use Google.Protobuf.JsonFormatter to serialize it.

using Google.Protobuf;
using Your.App.Namespace; // Replace with your actual generated namespace
using System;

public class JsonSerializationExample
{
    public static void Main(string[] args)
    {
        // Create a Protobuf message instance and populate its RepeatedField
        CustomerOperationsMessage messageToSend = new CustomerOperationsMessage();
        messageToSend.Operations.Add(CustomerOperation.CREATE_CUSTOMER);
        messageToSend.Operations.Add(CustomerOperation.UPDATE_CUSTOMER);

        // Configure JsonFormatter to ensure enums are formatted as strings
        var jsonFormatter = new JsonFormatter(
            JsonFormatter.Settings.Default
                         .WithFormatEnumsAsInts(false) // This ensures enums are strings, not integers
        );

        string serializedJson = jsonFormatter.Format(messageToSend);
        Console.WriteLine("Protobuf Message serialized to JSON:\n" + serializedJson);
    }
}

Scenario B: Serializing a RepeatedField (or List<string>) directly as a JSON array​

If you only need to send the array of enum strings without a full Protobuf message wrapper, you can convert your RepeatedField<CustomerOperation> into a List<string> and then serialize that list using a standard JSON serializer.

using Google.Protobuf.Collections;
using Your.App.Namespace; // Replace with your actual generated namespace
using System;
using System.Collections.Generic;
using System.Text.Json; // For System.Text.Json

public class ManualSerializationExample
{
    public static void Main(string[] args)
    {
        // Assume you have your RepeatedField populated
        RepeatedField<CustomerOperation> customerOperations = new RepeatedField<CustomerOperation>
        {
            CustomerOperation.CREATE_CUSTOMER_GROUP,
            CustomerOperation.DELETE_CUSTOMER
        };

        // Convert the RepeatedField to a List<string> for serialization
        List<string> operationsAsStrings = new List<string>();
        foreach (var op in customerOperations)
        {
            operationsAsStrings.Add(op.ToString()); // Enum.ToString() will give you "CREATE_CUSTOMER_GROUP"
        }

        // Serialize the List<string> to JSON using System.Text.Json
        string customJsonArray = JsonSerializer.Serialize(operationsAsStrings, new JsonSerializerOptions { WriteIndented = true });
        Console.WriteLine("Manual List<string> serialized to JSON:\n" + customJsonArray);

        // If you wanted it nested under a key, you'd create an anonymous object or DTO
        var container = new { customerOperations = operationsAsStrings };
        string customJsonWithKey = JsonSerializer.Serialize(container, new JsonSerializerOptions { WriteIndented = true });
        Console.WriteLine("\nManual List<string> under a key serialized to JSON:\n" + customJsonWithKey);
    }
}

Summary:

For sending (serializing): Use Google.Protobuf.JsonFormatter if you have a Protobuf message. Otherwise, manually convert your RepeatedField to a List<string> and use System.Text.Json or Newtonsoft.Json to serialize it.

For parsing (deserializing): The most robust and recommended way is to let Protobuf's JsonParser handle it if the JSON represents a full Protobuf message. If you only have a raw JSON array of strings, deserialize it into a List<string> first, and then iterate through it, using Enum.Parse<CustomerOperation>(string_value, true) for each string to populate your RepeatedField.

 

[Skydiver]

@Justin : It looks like your AI (or is it @Rythorian 's AI) is hallucinating again. There is no WithFormatEnumsAsInts(false).

I get the following error with .NET 8.0:

'JsonFormatter.Settings' does not contain a definition for 'WithFormatEnumsAsInts' and no accessible extension method 'WithFormatEnumsAsInts' accepting a first argument of type 'JsonFormatter.Settings' could be found (are you missing a using directive or an assembly reference?)