Files
Umbraco-CMS/src/Umbraco.Web/PublishedElementExtensions.cs
2019-11-05 14:55:42 +01:00

223 lines
11 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Umbraco.Core;
using Umbraco.Core.Composing;
using Umbraco.Core.Models.PublishedContent;
namespace Umbraco.Web
{
/// <summary>
/// Provides extension methods for <c>IPublishedElement</c>.
/// </summary>
public static class PublishedElementExtensions
{
// lots of debates about accessing dependencies (IPublishedValueFallback) from extension methods, ranging
// from "don't do it" i.e. if an extension method is relying on dependencies, a proper service should be
// created instead, to discussing method injection vs service locator vs other subtleties, see for example
// this post http://marisks.net/2016/12/19/dependency-injection-with-extension-methods/
//
// point is, we do NOT want a service, we DO want to write model.Value<int>("alias", "fr-FR") and hit
// fallback somehow - which pretty much rules out method injection, and basically anything but service
// locator - bah, let's face it, it works
//
// besides, for tests, Current support setting a fallback without even a container
//
private static IPublishedValueFallback PublishedValueFallback => Current.PublishedValueFallback;
#region IsComposedOf
/// <summary>
/// Gets a value indicating whether the content is of a content type composed of the given alias
/// </summary>
/// <param name="content">The content.</param>
/// <param name="alias">The content type alias.</param>
/// <returns>A value indicating whether the content is of a content type composed of a content type identified by the alias.</returns>
public static bool IsComposedOf(this IPublishedElement content, string alias)
{
return content.ContentType.CompositionAliases.InvariantContains(alias);
}
#endregion
#region HasProperty
/// <summary>
/// Gets a value indicating whether the content has a property identified by its alias.
/// </summary>
/// <param name="content">The content.</param>
/// <param name="alias">The property alias.</param>
/// <returns>A value indicating whether the content has the property identified by the alias.</returns>
/// <remarks>The content may have a property, and that property may not have a value.</remarks>
public static bool HasProperty(this IPublishedElement content, string alias)
{
return content.ContentType.GetPropertyType(alias) != null;
}
#endregion
#region HasValue
/// <summary>
/// Gets a value indicating whether the content has a value for a property identified by its alias.
/// </summary>
/// <remarks>Returns true if <c>GetProperty(alias)</c> is not <c>null</c> and <c>GetProperty(alias).HasValue</c> is <c>true</c>.</remarks>
public static bool HasValue(this IPublishedElement content, string alias, string culture = null, string segment = null)
{
var prop = content.GetProperty(alias);
return prop != null && prop.HasValue(culture, segment);
}
#endregion
#region Value
/// <summary>
/// Gets the value of a content's property identified by its alias.
/// </summary>
/// <param name="content">The content.</param>
/// <param name="alias">The property alias.</param>
/// <param name="culture">The variation language.</param>
/// <param name="segment">The variation segment.</param>
/// <param name="fallback">Optional fallback strategy.</param>
/// <param name="defaultValue">The default value.</param>
/// <returns>The value of the content's property identified by the alias, if it exists, otherwise a default value.</returns>
/// <remarks>
/// <para>The value comes from <c>IPublishedProperty</c> field <c>Value</c> ie it is suitable for use when rendering content.</para>
/// <para>If no property with the specified alias exists, or if the property has no value, returns <paramref name="defaultValue"/>.</para>
/// <para>If eg a numeric property wants to default to 0 when value source is empty, this has to be done in the converter.</para>
/// <para>The alias is case-insensitive.</para>
/// </remarks>
public static object Value(this IPublishedElement content, string alias, string culture = null, string segment = null, Fallback fallback = default, object defaultValue = default)
{
var property = content.GetProperty(alias);
// if we have a property, and it has a value, return that value
if (property != null && property.HasValue(culture, segment))
return property.GetValue(culture, segment);
// else let fallback try to get a value
if (PublishedValueFallback.TryGetValue(content, alias, culture, segment, fallback, defaultValue, out var value))
return value;
// else... if we have a property, at least let the converter return its own
// vision of 'no value' (could be an empty enumerable) - otherwise, default
return property?.GetValue(culture, segment);
}
#endregion
#region Value<T>
/// <summary>
/// Gets the value of a content's property identified by its alias, converted to a specified type.
/// </summary>
/// <typeparam name="T">The target property type.</typeparam>
/// <param name="content">The content.</param>
/// <param name="alias">The property alias.</param>
/// <param name="culture">The variation language.</param>
/// <param name="segment">The variation segment.</param>
/// <param name="fallback">Optional fallback strategy.</param>
/// <param name="defaultValue">The default value.</param>
/// <returns>The value of the content's property identified by the alias, converted to the specified type.</returns>
/// <remarks>
/// <para>The value comes from <c>IPublishedProperty</c> field <c>Value</c> ie it is suitable for use when rendering content.</para>
/// <para>If no property with the specified alias exists, or if the property has no value, or if it could not be converted, returns <c>default(T)</c>.</para>
/// <para>If eg a numeric property wants to default to 0 when value source is empty, this has to be done in the converter.</para>
/// <para>The alias is case-insensitive.</para>
/// </remarks>
public static T Value<T>(this IPublishedElement content, string alias, string culture = null, string segment = null, Fallback fallback = default, T defaultValue = default)
{
var property = content.GetProperty(alias);
// if we have a property, and it has a value, return that value
if (property != null && property.HasValue(culture, segment))
return property.Value<T>(culture, segment);
// else let fallback try to get a value
if (PublishedValueFallback.TryGetValue(content, alias, culture, segment, fallback, defaultValue, out var value))
return value;
// else... if we have a property, at least let the converter return its own
// vision of 'no value' (could be an empty enumerable) - otherwise, default
return property == null ? default : property.Value<T>(culture, segment);
}
#endregion
#region ToIndexedArray
public static IndexedArrayItem<TContent>[] ToIndexedArray<TContent>(this IEnumerable<TContent> source)
where TContent : class, IPublishedElement
{
var set = source.Select((content, index) => new IndexedArrayItem<TContent>(content, index)).ToArray();
foreach (var setItem in set) setItem.TotalCount = set.Length;
return set;
}
#endregion
#region OfTypes
// the .OfType<T>() filter is nice when there's only one type
// this is to support filtering with multiple types
public static IEnumerable<T> OfTypes<T>(this IEnumerable<T> contents, params string[] types)
where T : IPublishedElement
{
if (types == null || types.Length == 0) return Enumerable.Empty<T>();
return contents.Where(x => types.InvariantContains(x.ContentType.Alias));
}
#endregion
#region IsSomething
/// <summary>
/// Gets a value indicating whether the content is visible.
/// </summary>
/// <param name="content">The content.</param>
/// <returns>A value indicating whether the content is visible.</returns>
/// <remarks>A content is not visible if it has an umbracoNaviHide property with a value of "1". Otherwise,
/// the content is visible.</remarks>
public static bool IsVisible(this IPublishedElement content)
{
// rely on the property converter - will return default bool value, ie false, if property
// is not defined, or has no value, else will return its value.
return content.Value<bool>(Constants.Conventions.Content.NaviHide) == false;
}
#endregion
#region MediaUrl
/// <summary>
/// Gets the url for a media.
/// </summary>
/// <param name="content">The content item.</param>
/// <param name="culture">The culture (use current culture by default).</param>
/// <param name="mode">The url mode (use site configuration by default).</param>
/// <param name="propertyAlias">The alias of the property (use 'umbracoFile' by default).</param>
/// <returns>The url for the media.</returns>
/// <remarks>
/// <para>The value of this property is contextual. It depends on the 'current' request uri,
/// if any. In addition, when the content type is multi-lingual, this is the url for the
/// specified culture. Otherwise, it is the invariant url.</para>
/// </remarks>
public static string MediaUrl(this IPublishedContent content, string culture = null, UrlMode mode = UrlMode.Default, string propertyAlias = Constants.Conventions.Media.File)
{
var umbracoContext = Composing.Current.UmbracoContext;
if (umbracoContext == null)
throw new InvalidOperationException("Cannot resolve a Url when Current.UmbracoContext is null.");
if (umbracoContext.UrlProvider == null)
throw new InvalidOperationException("Cannot resolve a Url when Current.UmbracoContext.UrlProvider is null.");
return umbracoContext.UrlProvider.GetMediaUrl(content, mode, culture, propertyAlias);
}
#endregion
}
}