ApiKeyAuthenticationProvider.cs

// ------------------------------------------------------------------------------
//  Copyright (c) Microsoft Corporation.  All Rights Reserved.  Licensed under the MIT License.  See License in the project root for license information.
// ------------------------------------------------------------------------------

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.Kiota.Abstractions.Authentication;

/// <summary>
/// This authentication provider authenticates requests using an API key.
/// </summary>
public class ApiKeyAuthenticationProvider : IAuthenticationProvider
{
    private readonly string ApiKey;
    private readonly string ParameterName;
    private readonly KeyLocation KeyLoc;
    private readonly AllowedHostsValidator AllowedHostsValidator;

    /// <summary>
    /// Instantiates a new <see cref="ApiKeyAuthenticationProvider"/> using the provided parameters.
    /// </summary>
    /// <param name="apiKey">The API key to use for authentication.</param>
    /// <param name="parameterName">The name of the query parameter or header to use for authentication.</param>
    /// <param name="keyLocation">The location of the API key.</param>
    /// <param name="allowedHosts">The hosts that are allowed to use the provided API key.</param>
    public ApiKeyAuthenticationProvider(string apiKey, string parameterName, KeyLocation keyLocation, params string[] allowedHosts)
    {
        if(string.IsNullOrEmpty(apiKey))
            throw new ArgumentNullException(nameof(apiKey));
        if(string.IsNullOrEmpty(parameterName))
            throw new ArgumentNullException(nameof(parameterName));
        if(allowedHosts == null)
            throw new ArgumentNullException(nameof(allowedHosts));
        ApiKey = apiKey;
        ParameterName = parameterName;
        KeyLoc = keyLocation;
        AllowedHostsValidator = new AllowedHostsValidator(allowedHosts);
    }
    private static ActivitySource _activitySource = new(typeof(RequestInformation).Namespace!);
    /// <inheritdoc />
    public Task AuthenticateRequestAsync(RequestInformation request, Dictionary<string, object>? additionalAuthenticationContext = default, CancellationToken cancellationToken = default)
    {
        if(request == null)
            throw new ArgumentNullException(nameof(request));
        using var span = _activitySource?.StartActivity(nameof(AuthenticateRequestAsync));
        if(!AllowedHostsValidator.IsUrlHostValid(request.URI))
        {
            span?.SetTag("com.microsoft.kiota.authentication.is_url_valid", false);
            return Task.CompletedTask;
        }

        var uri = request.URI;
        if(!uri.Scheme.Equals("https", StringComparison.OrdinalIgnoreCase))
        {
            span?.SetTag("com.microsoft.kiota.authentication.is_url_valid", false);
            throw new ArgumentException("Only https is supported");
        }

        switch(KeyLoc)
        {
            case KeyLocation.QueryParameter:
                var uriString = uri.OriginalString + (uri.Query != string.Empty ? "&" : "?") + $"{ParameterName}={ApiKey}";
                request.URI = new Uri(uriString);
                break;
            case KeyLocation.Header:
                request.Headers.Add(ParameterName, ApiKey);
                break;
            default:
                throw new ArgumentOutOfRangeException(nameof(KeyLoc));
        }
        span?.SetTag("com.microsoft.kiota.authentication.is_url_valid", true);
        return Task.CompletedTask;
    }
    /// <summary>
    /// The location of the API key parameter.
    /// </summary>
    public enum KeyLocation
    {
        /// <summary>
        /// The API key is passed as a query parameter.
        /// </summary>
        QueryParameter,
        /// <summary>
        /// The API key is passed as a header.
        /// </summary>
        Header
    }
}