MetadataFieldStjConverter.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

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

namespace NuGet.Protocol.Converters
{
    /// <summary>
    /// Reads a JSON string or array of strings into a single comma-separated string.
    /// Equivalent to <see cref="MetadataFieldConverter"/> for System.Text.Json.
    /// </summary>
    /// <remarks>NSJ equivalent: <see cref="MetadataFieldConverter"/>.</remarks>
    internal sealed class MetadataFieldStjConverter : JsonConverter<string>
    {
        public override bool HandleNull => true;
        public override string Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType == JsonTokenType.Null)
            {
                return string.Empty;
            }

            if (reader.TokenType == JsonTokenType.StartArray)
            {
                var values = new List<string>();
                while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
                {
                    var s = reader.GetString();
                    if (!string.IsNullOrWhiteSpace(s))
                    {
                        values.Add(s!);
                    }
                }
                return string.Join(", ", values);
            }

            return reader.GetString() ?? string.Empty;
        }

        public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
            => throw new NotSupportedException();
    }
}