GraphQLHttpClientOptions.cs

using System.Net;
using System.Net.Http.Headers;
using System.Net.WebSockets;
using GraphQL.Client.Http.Websocket;

namespace GraphQL.Client.Http;

/// <summary>
/// The Options that the <see cref="GraphQLHttpClient"/> will use.
/// </summary>
public class GraphQLHttpClientOptions
{
    /// <summary>
    /// The GraphQL EndPoint to be used
    /// </summary>
    public Uri? EndPoint { get; set; }

    /// <summary>
    /// The GraphQL EndPoint to be used for websocket connections
    /// </summary>
    public Uri? WebSocketEndPoint { get; set; }

    /// <summary>
    /// The GraphQL websocket protocol to be used. Defaults to the older "graphql-ws" protocol to not break old code. 
    /// </summary>
    public string? WebSocketProtocol { get; set; } = WebSocketProtocols.AUTO_NEGOTIATE;

    /// <summary>
    /// The <see cref="System.Net.Http.HttpMessageHandler"/> that is going to be used
    /// </summary>
    public HttpMessageHandler HttpMessageHandler { get; set; } = new HttpClientHandler();

    /// <summary>
    /// The <see cref="MediaTypeHeaderValue"/> that will be send on POST
    /// </summary>
    public string MediaType { get; set; } = "application/json"; // This should be "application/graphql" also "application/x-www-form-urlencoded" is Accepted

    /// <summary>
    /// The back-off strategy for automatic websocket/subscription reconnects. Calculates the delay before the next connection attempt is made.<br/>
    /// default formula: min(n, 5) * 1,5 * random(0.0, 1.0)
    /// </summary>
    public Func<int, TimeSpan> BackOffStrategy { get; set; } = n =>
    {
        var rnd = new Random();
        return TimeSpan.FromSeconds(Math.Min(n, 5) * 1.5 + rnd.NextDouble());
    };

    /// <summary>
    /// If <see langword="true"/>, the websocket connection is also used for regular queries and mutations
    /// </summary>
    public bool UseWebSocketForQueriesAndMutations { get; set; } = false;

    /// <summary>
    /// Request preprocessing function. Can be used i.e. to inject authorization info into a GraphQL request payload.
    /// </summary>
    public Func<GraphQLRequest, GraphQLHttpClient, Task<GraphQLHttpRequest>> PreprocessRequest { get; set; } = (request, client) =>
        Task.FromResult(request is GraphQLHttpRequest graphQLHttpRequest ? graphQLHttpRequest : new GraphQLHttpRequest(request));

    /// <summary>
    /// Delegate to determine if GraphQL response may be properly deserialized into <see cref="GraphQLResponse{T}"/>.
    /// Note that compatible to the draft graphql-over-http spec GraphQL Server MAY return 4xx status codes (401/403, etc.)
    /// with well-formed GraphQL response containing errors collection.
    /// </summary>
    public Func<HttpResponseMessage, bool> IsValidResponseToDeserialize { get; set; } = DefaultIsValidResponseToDeserialize;

    private static readonly IReadOnlyCollection<string> _acceptedResponseContentTypes = new[] { "application/graphql+json", "application/json", "application/graphql-response+json" };

    public static bool DefaultIsValidResponseToDeserialize(HttpResponseMessage r)
    {
        if (r.Content.Headers.ContentType?.MediaType != null && !_acceptedResponseContentTypes.Contains(r.Content.Headers.ContentType.MediaType))
            return false;

        return r.IsSuccessStatusCode || r.StatusCode == HttpStatusCode.BadRequest;
    }

    /// <summary>
    /// This callback is called after successfully establishing a websocket connection but before any regular request is made.
    /// </summary>
    public Func<GraphQLHttpClient, Task> OnWebsocketConnected { get; set; } = client => Task.CompletedTask;

    /// <summary>
    /// Configure additional websocket options (i.e. headers). This will not be invoked on Windows 7 when targeting .NET Framework 4.x.
    /// </summary>
    public Action<ClientWebSocketOptions> ConfigureWebsocketOptions { get; set; } = options => { };

    /// <summary>
    /// Sets the `ConnectionParams` object sent with the GQL_CONNECTION_INIT message on establishing a GraphQL websocket connection.
    /// See https://github.com/apollographql/subscriptions-transport-ws/blob/master/PROTOCOL.md#gql_connection_init.
    /// </summary>
    public Func<GraphQLHttpClientOptions, object?> ConfigureWebSocketConnectionInitPayload { get; set; } = options => null;

    /// <summary>
    /// The default user agent request header.
    /// Default to the GraphQL client assembly.
    /// </summary>
    public ProductInfoHeaderValue? DefaultUserAgentRequestHeader { get; set; }
        = new ProductInfoHeaderValue(typeof(GraphQLHttpClient).Assembly.GetName().Name, typeof(GraphQLHttpClient).Assembly.GetName().Version.ToString());
}