src/ReverseProxy/Transforms/QueryParameterTransform.cs - main - aprogrammer/reverse-proxy-ms-yarp

src/ReverseProxy/Transforms/QueryParameterTransform.cs

66 строк2 KB

Kahbazi

Use is null instead of == null (#1565)

29 мар 2022, 02:51

29 мар 2022, 02:519bbdf5e

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Primitives;

namespace Yarp.ReverseProxy.Transforms;

public abstract class QueryParameterTransform : RequestTransform
{
    public QueryParameterTransform(QueryStringTransformMode mode, string key)
    {
        if (string.IsNullOrEmpty(key))
        {
            throw new ArgumentException($"'{nameof(key)}' cannot be null or empty.", nameof(key));
        }

        Mode = mode;
        Key = key;
    }

    internal QueryStringTransformMode Mode { get; }

    internal string Key { get; }

    /// <inheritdoc/>
    public override ValueTask ApplyAsync(RequestTransformContext context)
    {
        if (context is null)
        {
            throw new ArgumentNullException(nameof(context));
        }

        var value = GetValue(context);
        if (value is not null)
        {
            switch (Mode)
            {
                case QueryStringTransformMode.Append:
                    StringValues newValue = value;
                    if (context.Query.Collection.TryGetValue(Key, out var currentValue))
                    {
                        newValue = StringValues.Concat(currentValue, value);
                    }
                    context.Query.Collection[Key] = newValue;
                    break;
                case QueryStringTransformMode.Set:
                    context.Query.Collection[Key] = value;
                    break;
                default:
                    throw new NotImplementedException(Mode.ToString());
            }
        }

        return default;
    }

    protected abstract string? GetValue(RequestTransformContext context);
}

public enum QueryStringTransformMode
{
    Append,
    Set
}