Net.Rest.Client addition

7 files changed, 547 insertions, 0 deletions

diff --git a/lib/Net.Rest.Client/src/ClientContract.cs b/lib/Net.Rest.Client/src/ClientContract.cs
new file mode 100644
index 0000000..0c61f8c
--- /dev/null
+++ b/lib/Net.Rest.Client/src/ClientContract.cs
@@ -0,0 +1,60 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: ClientContract.cs 
+*
+* ClientContract.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using RestSharp;
+using VNLib.Utils.Memory.Caching;
+using VNLib.Utils.Resources;
+
+namespace VNLib.Net.Rest.Client
+{
+    /// <summary>
+    /// Represents a RestClient least contract. When disposed,
+    /// releases it for use by other waiters
+    /// </summary>
+    public class ClientContract : OpenResourceHandle<RestClient>
+    {
+        private readonly RestClient _client;
+        private readonly ObjectRental<RestClient> _pool;
+
+        internal ClientContract(RestClient client, ObjectRental<RestClient> pool)
+        {
+            _client = client;
+            _pool = pool;
+        }
+        ///<inheritdoc/>
+        public override RestClient Resource
+        {
+            get
+            {
+                Check();
+                return _client;
+            }
+        }
+        ///<inheritdoc/>
+        protected override void Free()
+        {
+            _pool.Return(_client);
+        }
+    }
+}
diff --git a/lib/Net.Rest.Client/src/ClientPool.cs b/lib/Net.Rest.Client/src/ClientPool.cs
new file mode 100644
index 0000000..7d3bbd0
--- /dev/null
+++ b/lib/Net.Rest.Client/src/ClientPool.cs
@@ -0,0 +1,71 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: ClientPool.cs 
+*
+* ClientPool.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+
+using RestSharp;
+using RestSharp.Authenticators;
+
+using VNLib.Utils.Memory.Caching;
+
+#nullable enable
+
+namespace VNLib.Net.Rest.Client
+{
+    /// <summary>
+    /// Maintains a pool of lazy loaded <see cref="RestClient"/> instances to allow for concurrent client usage
+    /// </summary>
+    public class RestClientPool : ObjectRental<RestClient>
+    {
+        /// <summary>
+        /// Creates a new <see cref="RestClientPool"/> instance and creates the specified
+        /// number of clients with the same number of concurrency.
+        /// </summary>
+        /// <param name="maxClients">The maximum number of clients to create and authenticate, should be the same as the number of maximum allowed tokens</param>
+        /// <param name="options">A <see cref="RestClientOptions"/> used to initialze the pool of clients</param>
+        /// <param name="authenticator">An optional authenticator for clients to use</param>
+        /// <param name="initCb">An optional client initialzation callback</param>
+        public RestClientPool(int maxClients, RestClientOptions options, Action<RestClient>? initCb = null, IAuthenticator? authenticator = null)
+            : base(() =>
+            {
+                RestClient client = new(options);
+                //Add optional authenticator
+                if (authenticator != null)
+                {
+                    client.UseAuthenticator(authenticator);
+                }
+                //Invoke init callback
+                initCb?.Invoke(client);
+                return client;
+            }, null, null, maxClients)
+        {
+        }
+
+        /// <summary>
+        /// Obtains a new <see cref="ClientContract"/> for a reused, or new, <see cref="RestClient"/> instance
+        /// </summary>
+        /// <returns>The contract that manages the client</returns>
+        public ClientContract Lease() => new(base.Rent(), this);
+    }
+}
diff --git a/lib/Net.Rest.Client/src/OAuth2/Credential.cs b/lib/Net.Rest.Client/src/OAuth2/Credential.cs
new file mode 100644
index 0000000..3fd5da6
--- /dev/null
+++ b/lib/Net.Rest.Client/src/OAuth2/Credential.cs
@@ -0,0 +1,78 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: Credential.cs 
+*
+* Credential.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+
+using VNLib.Utils.Memory;
+
+namespace VNLib.Net.Rest.Client.OAuth2
+{
+    /// <summary>
+    /// Creates a disposeable "protected" credential object.
+    /// </summary>
+    /// <remarks>
+    /// Properties used after the instance has been disposed are
+    /// undefined
+    /// </remarks>
+    public class Credential : PrivateStringManager
+    {
+        /// <summary>
+        /// The credential username parameter
+        /// </summary>
+        public string UserName => this[0];
+        /// <summary>
+        /// The credential's password 
+        /// </summary>
+        public string Password => this[1];
+
+        private Credential(string uname, string pass) : base(2)
+        {
+            this[0] = uname;
+            this[1] = pass;
+        }
+
+        /// <summary>
+        /// Creates a new protected <see cref="Credential"/> 
+        /// that owns the memory to the supplied strings
+        /// </summary>
+        /// <param name="username">The username string to consume</param>
+        /// <param name="password">The password string to consume</param>
+        /// <returns>A new protected credential object</returns>
+        public static Credential CreateUnsafe(in string username, in string password)
+        {
+            return new Credential(username, password);
+        }
+        /// <summary>
+        /// Creates a new "safe" <see cref="Credential"/> by copying 
+        /// the values of the supplied credential properites
+        /// </summary>
+        /// <param name="username">The username value to copy</param>
+        /// <param name="password">The password value to copy</param>
+        /// <returns>A new protected credential object</returns>
+        public static Credential Create(ReadOnlySpan<char> username, ReadOnlySpan<char> password)
+        {
+            return new Credential(username.ToString(), password.ToString());
+        }
+    }
+}
diff --git a/lib/Net.Rest.Client/src/OAuth2/O2ErrorResponseMessage.cs b/lib/Net.Rest.Client/src/OAuth2/O2ErrorResponseMessage.cs
new file mode 100644
index 0000000..151c575
--- /dev/null
+++ b/lib/Net.Rest.Client/src/OAuth2/O2ErrorResponseMessage.cs
@@ -0,0 +1,80 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: O2ErrorResponseMessage.cs 
+*
+* O2ErrorResponseMessage.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace VNLib.Net.Rest.Client.OAuth2
+{
+    /// <summary>
+    /// An OAuth2 standard error message
+    /// </summary>
+    public class O2ErrorResponseMessage
+    {
+        /// <summary>
+        /// The OAuth2 error code
+        /// </summary>
+        [JsonPropertyName("error_code")]
+        public string ErrorCode { get; set; }
+        
+        /// <summary>
+        /// The OAuth2 human readable error description
+        /// </summary>
+        [JsonPropertyName("error_description")]
+        public string ErrorDescription { get; set; }
+        /// <summary>
+        /// Initializes a new <see cref="O2ErrorResponseMessage"/>
+        /// </summary>
+        public O2ErrorResponseMessage()
+        {}
+        /// <summary>
+        /// Initializes a new <see cref="O2ErrorResponseMessage"/>
+        /// </summary>
+        /// <param name="code">The OAuth2 error code</param>
+        /// <param name="description">The OAuth2 error description</param>
+        public O2ErrorResponseMessage(string code, string description)
+        {
+            this.ErrorCode = code;
+            ErrorDescription = description;
+        }
+
+        /// <summary>
+        /// Initializes a new <see cref="O2ErrorResponseMessage"/> instance
+        /// from a <see cref="JsonElement"/> error element
+        /// </summary>
+        /// <param name="el">An error element that represens the error</param>
+        public O2ErrorResponseMessage(ref JsonElement el)
+        {
+            if(el.TryGetProperty("error_code", out JsonElement code))
+            {
+                this.ErrorCode = code.GetString();
+            }
+            if (el.TryGetProperty("error_code", out JsonElement description))
+            {
+                this.ErrorDescription = description.GetString();
+            }
+        }
+    }
+}
diff --git a/lib/Net.Rest.Client/src/OAuth2/OAuth2AuthenticationException.cs b/lib/Net.Rest.Client/src/OAuth2/OAuth2AuthenticationException.cs
new file mode 100644
index 0000000..7176093
--- /dev/null
+++ b/lib/Net.Rest.Client/src/OAuth2/OAuth2AuthenticationException.cs
@@ -0,0 +1,77 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: OAuth2AuthenticationException.cs 
+*
+* OAuth2AuthenticationException.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+using System.Net;
+using System.Security.Authentication;
+
+using RestSharp;
+
+namespace VNLib.Net.Rest.Client.OAuth2
+{
+    /// <summary>
+    /// Raised when a token request made to the authorization endpoint 
+    /// fails. Inner exceptions may be set if the response succeeds but
+    /// returned invalid data
+    /// </summary>
+    public class OAuth2AuthenticationException : AuthenticationException
+    {
+        /// <summary>
+        /// The status code returned from the request
+        /// </summary>
+        public HttpStatusCode StatusCode => ErrorResponse?.StatusCode ?? 0;
+        /// <summary>
+        /// The string representation of the response that was received by the token request
+        /// </summary>
+        public RestResponse ErrorResponse { get; }
+        ///<inheritdoc/>
+        public OAuth2AuthenticationException()
+        { }
+        ///<inheritdoc/>
+        public OAuth2AuthenticationException(string message) : base(message)
+        { }
+        ///<inheritdoc/>
+        public OAuth2AuthenticationException(string message, Exception innerException) : base(message, innerException)
+        { }
+        /// <summary>
+        /// Initializes a new <see cref="OAuth2AuthenticationException"/> with the 
+        /// specified server response
+        /// </summary>
+        /// <param name="response">The response containing the error result</param>
+        public OAuth2AuthenticationException(RestResponse response) : base()
+        {
+            ErrorResponse = response;
+        }
+        /// <summary>
+        /// Initializes a new <see cref="OAuth2AuthenticationException"/> with the 
+        /// specified server response
+        /// </summary>
+        /// <param name="response">The response containing the error result</param>
+        /// <param name="innerException">An inner excepion that caused the authentication to fail</param>
+        public OAuth2AuthenticationException(RestResponse response, Exception innerException) : base(null, innerException)
+        {
+            ErrorResponse = response;
+        }
+    }
+}
diff --git a/lib/Net.Rest.Client/src/OAuth2/OAuth2Authenticator.cs b/lib/Net.Rest.Client/src/OAuth2/OAuth2Authenticator.cs
new file mode 100644
index 0000000..b978404
--- /dev/null
+++ b/lib/Net.Rest.Client/src/OAuth2/OAuth2Authenticator.cs
@@ -0,0 +1,137 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Net.Rest.Client
+* File: OAuth2Authenticator.cs 
+*
+* OAuth2Authenticator.cs is part of VNLib.Net.Rest.Client which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Net.Rest.Client is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Net.Rest.Client is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Net.Rest.Client. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+using System.Net;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+using RestSharp;
+using RestSharp.Authenticators;
+
+using VNLib.Utils;
+using VNLib.Utils.Extensions;
+
+#nullable enable
+
+namespace VNLib.Net.Rest.Client.OAuth2
+{
+    /// <summary>
+    /// A self-contained OAuth2 RestSharp authenticator. Contains resources
+    /// that should be disposed, when no longer in use. Represents a single 
+    /// session on the remote server
+    /// </summary>
+    public class OAuth2Authenticator : VnDisposeable, IAuthenticator
+    {
+        private string? AccessToken;
+        private DateTime Expires;
+
+        private uint _counter;
+
+        private readonly RestClient _client;
+        private readonly Func<Credential> CredFunc;
+        private readonly string TokenAuthPath;
+        private readonly SemaphoreSlim _tokenLock;
+
+        /// <summary>
+        /// Initializes a new <see cref="OAuth2Authenticator"/> to be used for 
+        /// authorizing requests to a remote server
+        /// </summary>
+        /// <param name="clientOps">The RestClient options for the client used to authenticate with the OAuth2 server</param>
+        /// <param name="credFunc">The credential factory function</param>
+        /// <param name="tokenPath">The path within the remote OAuth2 server to authenticate against</param>
+        public OAuth2Authenticator(RestClientOptions clientOps, Func<Credential> credFunc, string tokenPath)
+        {
+            //Default to expired
+            Expires = DateTime.MinValue;
+            _client = new(clientOps);
+            CredFunc = credFunc;
+            TokenAuthPath = tokenPath;
+            _tokenLock = new(1, 1);
+        }
+
+        async ValueTask IAuthenticator.Authenticate(RestClient client, RestRequest request)
+        {
+            //Wait for access to the token incase another thread is updating it
+            using SemSlimReleaser releaser = await _tokenLock.GetReleaserAsync(CancellationToken.None);
+            //Check expiration
+            if (Expires < DateTime.UtcNow)
+            {
+                //We need to refresh the token
+                await RefreshTokenAsync();
+            }
+            //Add bearer token to the request
+            request.AddOrUpdateHeader("Authorization", AccessToken!);
+            //Inc counter
+            _counter++;
+        }
+
+        private async Task RefreshTokenAsync()
+        {
+            using Credential creds = CredFunc();
+            //Build request to the authentication endpoint
+            RestRequest tokenRequest = new(TokenAuthPath, Method.Post);
+            //Setup grant-type paramter
+            tokenRequest.AddParameter("grant_type", "client_credentials", ParameterType.GetOrPost);
+            //Add client id
+            tokenRequest.AddParameter("client_id", creds.UserName, ParameterType.GetOrPost);
+            //Add secret
+            tokenRequest.AddParameter("client_secret", creds.Password, ParameterType.GetOrPost);
+            //exec get token
+            RestResponse tokenResponse = await _client.ExecuteAsync(tokenRequest);
+            if (!tokenResponse.IsSuccessful)
+            {
+                throw new OAuth2AuthenticationException(tokenResponse, tokenResponse.ErrorException);
+            }
+            try
+            {
+                //Get a json doc for the response data
+                using JsonDocument response = JsonDocument.Parse(tokenResponse.RawBytes);
+                //Get expiration
+                int expiresSec = response.RootElement.GetProperty("expires_in").GetInt32();
+                //get access token
+                string? accessToken = response.RootElement.GetProperty("access_token").GetString();
+                string? tokenType = response.RootElement.GetProperty("token_type").GetString();
+
+                //Store token variables, expire a few minutes before the server to allow for time disparity
+                Expires = DateTime.UtcNow.AddSeconds(expiresSec).Subtract(TimeSpan.FromMinutes(2));
+                //compile auth header value
+                AccessToken = $"{tokenType} {accessToken}";
+                //Reset counter
+                _counter = 0;
+            }
+            catch (Exception ex)
+            {
+                throw new OAuth2AuthenticationException(tokenResponse, ex);
+            }
+        }
+
+        protected override void Free()
+        {
+            _tokenLock.Dispose();
+            _client.Dispose();
+        }
+    }
+}
diff --git a/lib/Net.Rest.Client/src/VNLib.Net.Rest.Client.csproj b/lib/Net.Rest.Client/src/VNLib.Net.Rest.Client.csproj
new file mode 100644
index 0000000..1324192
--- /dev/null
+++ b/lib/Net.Rest.Client/src/VNLib.Net.Rest.Client.csproj
@@ -0,0 +1,44 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <Copyright>Copyright © 2022 Vaughn Nugent</Copyright>
+    <Authors>Vaughn Nugent</Authors>
+    <Version>1.0.1.1</Version>
+    <Description>An Oauth2 rest client connection pool for OAuth2 authenticated services</Description>
+    <PackageProjectUrl>https://www.vaughnnugent.com/resources</PackageProjectUrl>    
+    <AssemblyName>VNLib.Net.Rest.Client</AssemblyName>
+    <RootNamespace>VNLib.Net.Rest.Client</RootNamespace>
+    <GenerateDocumentationFile>True</GenerateDocumentationFile>
+    <AnalysisLevel>latest-all</AnalysisLevel>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
+    <Deterministic>False</Deterministic>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <Deterministic>False</Deterministic>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="ErrorProne.NET.CoreAnalyzers" Version="0.1.2">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="ErrorProne.NET.Structs" Version="0.1.2">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="RestSharp" Version="108.0.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\VNLib\Utils\src\VNLib.Utils.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Folder Include="Exceptions\" />
+  </ItemGroup>
+
+</Project>