aspnetcore/src/Microsoft.AspNetCore.Html.Abstractions/HtmlContentBuilderExtensions.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Text.Encodings.Web;

namespace Microsoft.AspNetCore.Html
{
    /// <summary>
    /// Extension methods for <see cref="IHtmlContentBuilder"/>.
    /// </summary>
    public static class HtmlContentBuilderExtensions
    {
        /// <summary>
        /// Appends the specified <paramref name="format"/> to the existing content after replacing each format
        /// item with the HTML encoded <see cref="string"/> representation of the corresponding item in the
        /// <paramref name="args"/> array.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="format">
        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
        /// The format string is assumed to be HTML encoded as-provided, and no further encoding will be performed.
        /// </param>
        /// <param name="args">
        /// The object array to format. Each element in the array will be formatted and then HTML encoded.
        /// </param>
        /// <returns>A reference to this instance after the append operation has completed.</returns>
        public static IHtmlContentBuilder AppendFormat(
            this IHtmlContentBuilder builder,
            string format,
            params object[] args)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            if (format == null)
            {
                throw new ArgumentNullException(nameof(format));
            }

            if (args == null)
            {
                throw new ArgumentNullException(nameof(args));
            }

            builder.AppendHtml(new HtmlFormattableString(format, args));
            return builder;
        }

        /// <summary>
        /// Appends the specified <paramref name="format"/> to the existing content with information from the
        /// <paramref name="formatProvider"/> after replacing each format item with the HTML encoded
        /// <see cref="string"/> representation of the corresponding item in the <paramref name="args"/> array.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="formatProvider">An object that supplies culture-specific formatting information.</param>
        /// <param name="format">
        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
        /// The format string is assumed to be HTML encoded as-provided, and no further encoding will be performed.
        /// </param>
        /// <param name="args">
        /// The object array to format. Each element in the array will be formatted and then HTML encoded.
        /// </param>
        /// <returns>A reference to this instance after the append operation has completed.</returns>
        public static IHtmlContentBuilder AppendFormat(
            this IHtmlContentBuilder builder,
            IFormatProvider formatProvider,
            string format,
            params object[] args)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            if (format == null)
            {
                throw new ArgumentNullException(nameof(format));
            }

            if (args == null)
            {
                throw new ArgumentNullException(nameof(args));
            }

            builder.AppendHtml(new HtmlFormattableString(formatProvider, format, args));
            return builder;
        }

        /// <summary>
        /// Appends an <see cref="Environment.NewLine"/>.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder AppendLine(this IHtmlContentBuilder builder)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.AppendHtml(HtmlString.NewLine);
            return builder;
        }

        /// <summary>
        /// Appends an <see cref="Environment.NewLine"/> after appending the <see cref="string"/> value.
        /// The value is treated as unencoded as-provided, and will be HTML encoded before writing to output.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="unencoded">The <see cref="string"/> to append.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder AppendLine(this IHtmlContentBuilder builder, string unencoded)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.Append(unencoded);
            builder.AppendHtml(HtmlString.NewLine);
            return builder;
        }

        /// <summary>
        /// Appends an <see cref="Environment.NewLine"/> after appending the <see cref="IHtmlContent"/> value.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="content">The <see cref="IHtmlContent"/> to append.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder AppendLine(this IHtmlContentBuilder builder, IHtmlContent content)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.AppendHtml(content);
            builder.AppendHtml(HtmlString.NewLine);
            return builder;
        }

        /// <summary>
        /// Appends an <see cref="Environment.NewLine"/> after appending the <see cref="string"/> value.
        /// The value is treated as HTML encoded as-provided, and no further encoding will be performed.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="encoded">The HTML encoded <see cref="string"/> to append.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder AppendHtmlLine(this IHtmlContentBuilder builder, string encoded)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.AppendHtml(encoded);
            builder.AppendHtml(HtmlString.NewLine);
            return builder;
        }

        /// <summary>
        /// Sets the content to the <see cref="string"/> value. The value is treated as unencoded as-provided,
        /// and will be HTML encoded before writing to output.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="unencoded">The <see cref="string"/> value that replaces the content.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder SetContent(this IHtmlContentBuilder builder, string unencoded)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.Clear();
            builder.Append(unencoded);
            return builder;
        }

        /// <summary>
        /// Sets the content to the <see cref="IHtmlContent"/> value.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="content">The <see cref="IHtmlContent"/> value that replaces the content.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder SetHtmlContent(this IHtmlContentBuilder builder, IHtmlContent content)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.Clear();
            builder.AppendHtml(content);
            return builder;
        }

        /// <summary>
        /// Sets the content to the <see cref="string"/> value. The value is treated as HTML encoded as-provided, and
        /// no further encoding will be performed.
        /// </summary>
        /// <param name="builder">The <see cref="IHtmlContentBuilder"/>.</param>
        /// <param name="encoded">The HTML encoded <see cref="string"/> that replaces the content.</param>
        /// <returns>The <see cref="IHtmlContentBuilder"/>.</returns>
        public static IHtmlContentBuilder SetHtmlContent(this IHtmlContentBuilder builder, string encoded)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.Clear();
            builder.AppendHtml(encoded);
            return builder;
        }
    }
}