//******************************************************************************************************//  HtmlHelper.cs - Gbtc////  Copyright © 2016, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may not use this//  file except in compliance with the License. You may obtain a copy of the License at:////      http://opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  08/04/2016 - J. Ritchie Carroll//       Generated original version of source code.////****************************************************************************************************** using System;using System.IO;using System.Net;using System.Net.Http;using System.Web;using GSF.IO;using GSF.Web.Security;using RazorEngine.Templating;using RazorEngine.Text; namespace GSF.Web.Model{    /// <summary>    /// Defines an HTML helper class for <see cref="IRazorEngine"/> views.    /// </summary>    /// <remarks>    /// This class provides Razor view compatibility functions so that the same view syntax, e.g.,    /// @Html.Raw(""), can be used in both self-hosted and ASP.NET hosted web sites.    /// </remarks>    public class HtmlHelper    {        #region [ Members ]         // Fields        private readonly TemplateBase m_parent;         #endregion         #region [ Constructors ]         // Creates a new HTML helper class associated with parent template        internal HtmlHelper(TemplateBase parent)        {            m_parent = parent;        }         #endregion         #region [ Methods ]         /// <summary>        /// Generates a hidden form field (anti-forgery token) that is validated when the form is submitted.        /// </summary>        /// <returns>The generated form field (anti-forgery token).</returns>        /// <remarks>        /// The anti-forgery token can be used to help protect your application against cross-site request        /// forgery. To use this feature, call the RequestVerificationToken method from a form and add the        /// <see cref="ValidateRequestVerificationTokenAttribute"/> attribute to the action method that you        /// want to protect setting <see cref="ValidateRequestVerificationTokenAttribute.FormValidation"/>        /// to <c>true</c>, for example:        /// <code>        /// [HttpPost]        /// [ValidateRequestVerificationToken(FormValidation = true)]        /// [SuppressMessage("Security", "SG0016", Justification = "CSRF vulnerability handled via ValidateRequestVerificationToken.")]        /// public void ImportData(CancellationToken cancellationToken)        /// {        ///      PostData postData = Request.GetPostData();        ///      string myFieldValue = postData.FormData["MyField"];        /// }        /// </code>        /// </remarks>        public IEncodedString RequestVerificationToken()        {            HttpResponseMessage response = m_parent.ViewBag.Response;             if ((object)response == null)                throw new NullReferenceException("HttpResponseMessage not found in ViewBag.Response, cannot generate anti-forgery token.");             return new RawString(AntiForgery.GetHtml(response));        }         /// <summary>        /// Generates an anti-forgery token that can be manually added to an HTTP request header,        /// e.g., from within an AJAX request.        /// </summary>        /// <returns>Anti-forgery token to be added as an HTTP header value.</returns>        public string RequestVerificationHeaderToken()        {            HttpRequestMessage request = m_parent.ViewBag.Request;             if ((object)request == null)                throw new NullReferenceException("HttpRequestMessage not found in ViewBag.Request, cannot generate anti-forgery header token.");             return request.GenerateRequestVerficationHeaderToken();        }         /// <summary>        /// Returns a string value that is not HTML encoded.        /// </summary>        /// <param name="value">Raw string value to return.</param>        /// <returns>Raw string value that is not HTML encoded.</returns>        public IEncodedString Raw(string value) => new RawString(value);         /// <summary>        /// Includes the template with the specified name.        /// </summary>        /// <param name="name">The name of the template type in cache.</param>        /// <param name="model">The model or NULL if there is no model for the template.</param>        /// <param name="modelType"></param>        /// <returns>The template writer helper.</returns>        public TemplateWriter Partial(string name, object model = null, Type modelType = null)        {            return m_parent.Include(name, model, modelType);        }         /// <summary>        /// Converts relative URL to an absolute URL.        /// </summary>        /// <param name="url">Relative URL.</param>        /// <param name="request">Request message.</param>        /// <returns>Absolute URL.</returns>        /// <remarks>        /// If HttpRequestMessage is not specified, function will attempt to find message in ViewBag.Request.        /// </remarks>        public string ToAbsoluteUrl(string url, HttpRequestMessage request = null)        {            if (string.IsNullOrEmpty(url))                return "";             if ((object)request == null)                request = m_parent.ViewBag.Request;             if ((object)request == null)                throw new ArgumentNullException(nameof(request));             Uri uri = new Uri(request.RequestUri.AbsoluteUri.Replace(request.RequestUri.PathAndQuery, ""));            string port = uri.Port == 80 ? "" : ":" + uri.Port;             return $"{uri.Scheme}://{uri.Host}{port}{VirtualPathUtility.ToAbsolute(url)}";        }         /// <summary>        /// Includes an HTTP resource directly into view page.        /// </summary>        /// <param name="url">URL of resource to include.</param>        /// <returns>Resolved URL resource as an encoded string.</returns>        public IEncodedString IncludeUrl(string url)        {            if (string.IsNullOrEmpty(url))                return new RawString("");             HttpWebRequest request = WebRequest.CreateHttp(url);            request.Credentials = CredentialCache.DefaultCredentials;             using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)            using (Stream stream = response?.GetResponseStream())            {                if ((object)stream == null)                    return new RawString($"<!-- No response from {url} -->");                 using (StreamReader reader = new StreamReader(stream))                    return new RawString(reader.ReadToEnd());            }        }         /// <summary>        /// Includes an embedded resource directly into view page.        /// </summary>        /// <param name="resourceName">Resource to include.</param>        /// <returns>Resource as an encoded string.</returns>        public IEncodedString IncludeResource(string resourceName)        {            if (string.IsNullOrEmpty(resourceName))                return new RawString("");             Stream stream = WebExtensions.OpenEmbeddedResourceStream(resourceName);             if ((object)stream == null)                return new RawString("");             using (StreamReader reader = new StreamReader(stream))                return new RawString(reader.ReadToEnd());        }         /// <summary>        /// Renders a Razor view from an embedded resource.        /// </summary>        /// <param name="resourceName">Embedded resource name.</param>        /// <param name="modelType">Type of model.</param>        /// <param name="model">Model instance.</param>        /// <returns>Rendered resource as an encoded string.</returns>        public IEncodedString RenderResource(string resourceName, Type modelType = null, object model = null)        {            if (FilePath.GetExtension(resourceName).Equals(".vbhtml", StringComparison.OrdinalIgnoreCase))                return new RawString(RazorEngine<VisualBasicEmbeddedResource>.Default.RunCompile(resourceName, modelType, model, m_parent.ViewBag as DynamicViewBag));             return new RawString(RazorEngine<CSharpEmbeddedResource>.Default.RunCompile(resourceName, modelType, model, m_parent.ViewBag as DynamicViewBag));        }         /// <summary>        /// Renders a Razor view from an embedded resource.        /// </summary>        /// <typeparam name="T">Type of model.</typeparam>        /// <param name="resourceName">Embedded resource name.</param>        /// <param name="model">Model instance.</param>        /// <returns>Rendered resource as an encoded string.</returns>        public IEncodedString RenderResource<T>(string resourceName, T model)        {            return RenderResource(resourceName, typeof(T), model);        }         #endregion    }}