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using Newtonsoft.Json; | |
using System; | |
using System.Collections.Concurrent; | |
using System.Collections.Generic; | |
using System.ComponentModel.DataAnnotations; | |
using System.Diagnostics.CodeAnalysis; | |
using System.Dynamic; | |
using System.Linq; | |
using System.Linq.Expressions; | |
using System.Net; | |
using System.Net.Http; | |
using System.Reflection; | |
using System.Runtime.Serialization; | |
using System.Web.Http; | |
using System.Web.Http.Controllers; | |
namespace WebAPIPatchDemo.Controllers | |
{ | |
public class SettingsController : ApiController | |
{ | |
static SiteSettings settings = new SiteSettings | |
{ | |
Title = "Test Site", | |
Enabled = true, | |
PageSize = 20, | |
ThemeId = null | |
}; | |
public SiteSettings Get() | |
{ | |
return settings; | |
} | |
public HttpResponseMessage Put(UpdateSiteSettingsCommand command) | |
{ | |
if (!ModelState.IsValid) | |
{ | |
return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState); | |
} | |
Update(settings, command); | |
return Request.CreateResponse(HttpStatusCode.OK); | |
} | |
public void Patch(Delta<UpdateSiteSettingsCommand> patch) | |
{ | |
// probably use automapper for this | |
var command = new UpdateSiteSettingsCommand | |
{ | |
Title = settings.Title, | |
Enabled = settings.Enabled, | |
PageSize =settings.PageSize, | |
ThemeId = settings.ThemeId | |
}; | |
patch.Patch(command); | |
Update(settings, command); | |
} | |
private void Update(SiteSettings settings, UpdateSiteSettingsCommand command) | |
{ | |
settings.Title = command.Title; | |
settings.Enabled = command.Enabled; | |
settings.PageSize = (int)command.PageSize; // because JSON.net deserializes as long instead of int32 | |
settings.ThemeId = (int?)command.ThemeId; | |
} | |
} | |
public class SiteSettings | |
{ | |
public int? ThemeId { get; set; } | |
public string Title { get; set; } | |
public bool Enabled { get; set; } | |
public int PageSize { get; set; } | |
} | |
[DataContract] | |
public class UpdateSiteSettingsCommand | |
{ | |
[Required] | |
[DataMember] | |
public string Title { get; set; } | |
[DataMember(IsRequired = true)] | |
public bool Enabled { get; set; } | |
[DataMember(IsRequired = true)] | |
public long PageSize { get; set; } | |
[DataMember] | |
public long? ThemeId { get; set; } | |
[DataMember] | |
public object Foo { get; set; } | |
} | |
/// <summary> | |
/// <see cref="IDelta" /> allows and tracks changes to an object. | |
/// </summary> | |
public interface IDelta | |
{ | |
/// <summary> | |
/// Returns the Properties that have been modified through this IDelta as an | |
/// enumerable of Property Names | |
/// </summary> | |
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Not appropriate to be a property")] | |
IEnumerable<string> GetChangedPropertyNames(); | |
/// <summary> | |
/// Returns the Properties that have not been modified through this IDelta as an | |
/// enumerable of Property Names | |
/// </summary> | |
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Not appropriate to be a property")] | |
IEnumerable<string> GetUnchangedPropertyNames(); | |
/// <summary> | |
/// Attempts to set the Property called <paramref name="name"/> to the <paramref name="value"/> specified. | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="value">The new value of the Property</param> | |
/// <returns>Returns <c>true</c> if successful and <c>false</c> if not.</returns> | |
bool TrySetPropertyValue(string name, object value); | |
/// <summary> | |
/// Attempts to get the value of the Property called <paramref name="name"/> from the underlying Entity. | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="value">The value of the Property</param> | |
/// <returns>Returns <c>true</c> if the Property was found and <c>false</c> if not.</returns> | |
[SuppressMessage("Microsoft.Design", "CA1007:UseGenericsWhereAppropriate", Justification = "Generics not appropriate here")] | |
[SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters", MessageId = "1#", Justification = "Out param is appropriate here")] | |
bool TryGetPropertyValue(string name, out object value); | |
/// <summary> | |
/// Attempts to get the <see cref="Type"/> of the Property called <paramref name="name"/> from the underlying Entity. | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="type">The type of the Property</param> | |
/// <returns>Returns <c>true</c> if the Property was found and <c>false</c> if not.</returns> | |
bool TryGetPropertyType(string name, out Type type); | |
/// <summary> | |
/// Clears the <see cref="IDelta" />. | |
/// </summary> | |
void Clear(); | |
} | |
/// <summary> | |
/// An attribute to disable WebApi model validation for a particular type. | |
/// </summary> | |
[AttributeUsage(AttributeTargets.Class, Inherited = true, AllowMultiple = false)] | |
internal sealed class NonValidatingParameterBindingAttribute : ParameterBindingAttribute | |
{ | |
public override HttpParameterBinding GetBinding(HttpParameterDescriptor parameter) | |
{ | |
return parameter.BindWithFormatter(parameter.Configuration.Formatters, bodyModelValidator: null); | |
} | |
} | |
/// <summary> | |
/// A class the tracks changes (i.e. the Delta) for a particular <typeparamref name="TEntityType"/>. | |
/// </summary> | |
/// <typeparam name="TEntityType">TEntityType is the base type of entity this delta tracks changes for.</typeparam> | |
[NonValidatingParameterBinding] | |
public class Delta<TEntityType> : DynamicObject, IDelta where TEntityType : class | |
{ | |
// cache property accessors for this type and all its derived types. | |
private static ConcurrentDictionary<Type, Dictionary<string, PropertyAccessor<TEntityType>>> _propertyCache = new ConcurrentDictionary<Type, Dictionary<string, PropertyAccessor<TEntityType>>>(); | |
private Dictionary<string, PropertyAccessor<TEntityType>> _propertiesThatExist; | |
private HashSet<string> _changedProperties; | |
private TEntityType _entity; | |
private Type _entityType; | |
/// <summary> | |
/// Initializes a new instance of <see cref="Delta{TEntityType}"/>. | |
/// </summary> | |
public Delta() | |
: this(typeof(TEntityType)) | |
{ | |
} | |
/// <summary> | |
/// Initializes a new instance of <see cref="Delta{TEntityType}"/>. | |
/// </summary> | |
/// <param name="entityType">The derived entity type for which the changes would be tracked. | |
/// <paramref name="entityType"/> should be assignable to instances of <typeparamref name="TEntityType"/>.</param> | |
public Delta(Type entityType) | |
{ | |
Initialize(entityType); | |
} | |
/// <summary> | |
/// The actual type of the entity for which the changes are tracked. | |
/// </summary> | |
public Type EntityType | |
{ | |
get | |
{ | |
return _entityType; | |
} | |
} | |
/// <summary> | |
/// Clears the Delta and resets the underlying Entity. | |
/// </summary> | |
public void Clear() | |
{ | |
Initialize(_entityType); | |
} | |
/// <summary> | |
/// Attempts to set the Property called <paramref name="name"/> to the <paramref name="value"/> specified. | |
/// <remarks> | |
/// Only properties that exist on <see cref="EntityType"/> can be set. | |
/// If there is a type mismatch the request will fail. | |
/// </remarks> | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="value">The new value of the Property</param> | |
/// <returns>True if successful</returns> | |
public bool TrySetPropertyValue(string name, object value) | |
{ | |
if (name == null) | |
{ | |
throw new ArgumentNullException("name"); | |
} | |
if (!_propertiesThatExist.ContainsKey(name)) // BF - this is case sensitive, probably shouldn't be if working with json | |
{ | |
return false; | |
} | |
PropertyAccessor<TEntityType> cacheHit = _propertiesThatExist[name]; | |
if (value == null && !IsNullable(cacheHit.Property.PropertyType)) | |
{ | |
return false; | |
} | |
// BF - Issue here is that a nullable int is passed as a long | |
if (value != null && !cacheHit.Property.PropertyType.IsAssignableFrom(value.GetType())) | |
{ | |
return false; | |
} | |
//.Setter.Invoke(_entity, new object[] { value }); | |
cacheHit.SetValue(_entity, value); | |
_changedProperties.Add(name); | |
return true; | |
} | |
/// <summary> | |
/// Attempts to get the value of the Property called <paramref name="name"/> from the underlying Entity. | |
/// <remarks> | |
/// Only properties that exist on <see cref="EntityType"/> can be retrieved. | |
/// Both modified and unmodified properties can be retrieved. | |
/// </remarks> | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="value">The value of the Property</param> | |
/// <returns>True if the Property was found</returns> | |
public bool TryGetPropertyValue(string name, out object value) | |
{ | |
if (name == null) | |
{ | |
throw new ArgumentNullException("name"); | |
} | |
if (_propertiesThatExist.ContainsKey(name)) | |
{ | |
PropertyAccessor<TEntityType> cacheHit = _propertiesThatExist[name]; | |
value = cacheHit.GetValue(_entity); | |
return true; | |
} | |
else | |
{ | |
value = null; | |
return false; | |
} | |
} | |
/// <summary> | |
/// Attempts to get the <see cref="Type"/> of the Property called <paramref name="name"/> from the underlying Entity. | |
/// <remarks> | |
/// Only properties that exist on <see cref="EntityType"/> can be retrieved. | |
/// Both modified and unmodified properties can be retrieved. | |
/// </remarks> | |
/// </summary> | |
/// <param name="name">The name of the Property</param> | |
/// <param name="type">The type of the Property</param> | |
/// <returns>Returns <c>true</c> if the Property was found and <c>false</c> if not.</returns> | |
public bool TryGetPropertyType(string name, out Type type) | |
{ | |
if (name == null) | |
{ | |
throw new ArgumentNullException("name"); | |
} | |
PropertyAccessor<TEntityType> value; | |
if (_propertiesThatExist.TryGetValue(name, out value)) | |
{ | |
type = value.Property.PropertyType; | |
return true; | |
} | |
else | |
{ | |
type = null; | |
return false; | |
} | |
} | |
/// <summary> | |
/// Overrides the DynamicObject TrySetMember method, so that only the properties | |
/// of <see cref="EntityType"/> can be set. | |
/// </summary> | |
public override bool TrySetMember(SetMemberBinder binder, object value) | |
{ | |
if (binder == null) | |
{ | |
throw new ArgumentNullException("binder"); | |
} | |
return TrySetPropertyValue(binder.Name, value); | |
} | |
/// <summary> | |
/// Overrides the DynamicObject TryGetMember method, so that only the properties | |
/// of <see cref="EntityType"/> can be got. | |
/// </summary> | |
public override bool TryGetMember(GetMemberBinder binder, out object result) | |
{ | |
if (binder == null) | |
{ | |
throw new ArgumentNullException("binder"); | |
} | |
return TryGetPropertyValue(binder.Name, out result); | |
} | |
/// <summary> | |
/// Returns the <see cref="EntityType"/> instance | |
/// that holds all the changes (and original values) being tracked by this Delta. | |
/// </summary> | |
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Not appropriate to be a property")] | |
public TEntityType GetEntity() | |
{ | |
return _entity; | |
} | |
/// <summary> | |
/// Returns the Properties that have been modified through this Delta as an | |
/// enumeration of Property Names | |
/// </summary> | |
public IEnumerable<string> GetChangedPropertyNames() | |
{ | |
return _changedProperties; | |
} | |
/// <summary> | |
/// Returns the Properties that have not been modified through this Delta as an | |
/// enumeration of Property Names | |
/// </summary> | |
public IEnumerable<string> GetUnchangedPropertyNames() | |
{ | |
return _propertiesThatExist.Keys.Except(GetChangedPropertyNames()); | |
} | |
/// <summary> | |
/// Copies the changed property values from the underlying entity (accessible via <see cref="GetEntity()" />) | |
/// to the <paramref name="original"/> entity. | |
/// </summary> | |
/// <param name="original">The entity to be updated.</param> | |
public void CopyChangedValues(TEntityType original) | |
{ | |
if (original == null) | |
{ | |
throw new ArgumentNullException("original"); | |
} | |
if (!_entityType.IsAssignableFrom(original.GetType())) | |
{ | |
throw new InvalidOperationException(string.Format("Cannot use Delta of type '{0}' on an entity of type '{1}'.", _entityType, original.GetType())); | |
} | |
PropertyAccessor<TEntityType>[] propertiesToCopy = GetChangedPropertyNames().Select(s => _propertiesThatExist[s]).ToArray(); | |
foreach (PropertyAccessor<TEntityType> propertyToCopy in propertiesToCopy) | |
{ | |
propertyToCopy.Copy(_entity, original); | |
} | |
} | |
/// <summary> | |
/// Copies the unchanged property values from the underlying entity (accessible via <see cref="GetEntity()" />) | |
/// to the <paramref name="original"/> entity. | |
/// </summary> | |
/// <param name="original">The entity to be updated.</param> | |
public void CopyUnchangedValues(TEntityType original) | |
{ | |
if (original == null) | |
{ | |
throw new ArgumentNullException("original"); | |
} | |
if (!_entityType.IsAssignableFrom(original.GetType())) | |
{ | |
throw new InvalidOperationException(string.Format("Cannot use Delta of type '{0}' on an entity of type '{1}'.", _entityType, original.GetType())); | |
} | |
PropertyAccessor<TEntityType>[] propertiesToCopy = GetUnchangedPropertyNames().Select(s => _propertiesThatExist[s]).ToArray(); | |
foreach (PropertyAccessor<TEntityType> propertyToCopy in propertiesToCopy) | |
{ | |
propertyToCopy.Copy(_entity, original); | |
} | |
} | |
/// <summary> | |
/// Overwrites the <paramref name="original"/> entity with the changes tracked by this Delta. | |
/// <remarks>The semantics of this operation are equivalent to a HTTP PATCH operation, hence the name.</remarks> | |
/// </summary> | |
/// <param name="original">The entity to be updated.</param> | |
public void Patch(TEntityType original) | |
{ | |
CopyChangedValues(original); | |
} | |
/// <summary> | |
/// Overwrites the <paramref name="original"/> entity with the values stored in this Delta. | |
/// <remarks>The semantics of this operation are equivalent to a HTTP PUT operation, hence the name.</remarks> | |
/// </summary> | |
/// <param name="original">The entity to be updated.</param> | |
public void Put(TEntityType original) | |
{ | |
CopyChangedValues(original); | |
CopyUnchangedValues(original); | |
} | |
private void Initialize(Type entityType) | |
{ | |
if (entityType == null) | |
{ | |
throw new ArgumentNullException("entityType"); | |
} | |
if (!typeof(TEntityType).IsAssignableFrom(entityType)) | |
{ | |
throw new InvalidOperationException(string.Format("The entity type '{0}' is not assignable to the Delta type '{1}'.", entityType, typeof(TEntityType))); | |
} | |
_entity = Activator.CreateInstance(entityType) as TEntityType; | |
_changedProperties = new HashSet<string>(); | |
_entityType = entityType; | |
_propertiesThatExist = InitializePropertiesThatExist(); | |
} | |
private Dictionary<string, PropertyAccessor<TEntityType>> InitializePropertiesThatExist() | |
{ | |
return _propertyCache.GetOrAdd( | |
_entityType, | |
(backingType) => backingType | |
.GetProperties() | |
.Where(p => p.GetSetMethod() != null && p.GetGetMethod() != null) | |
.Select<PropertyInfo, PropertyAccessor<TEntityType>>(p => new CompiledPropertyAccessor<TEntityType>(p)) | |
.ToDictionary(p => p.Property.Name)); | |
} | |
private static bool IsNullable(Type type) | |
{ | |
return !type.IsValueType || Nullable.GetUnderlyingType(type) != null; | |
} | |
} | |
/// <summary> | |
/// Represents a strategy for Getting and Setting a PropertyInfo on <typeparamref name="TEntityType"/> | |
/// </summary> | |
/// <typeparam name="TEntityType">The type that contains the PropertyInfo</typeparam> | |
internal abstract class PropertyAccessor<TEntityType> where TEntityType : class | |
{ | |
protected PropertyAccessor(PropertyInfo property) | |
{ | |
if (property == null) | |
{ | |
throw new ArgumentNullException("property"); | |
} | |
Property = property; | |
if (Property.GetGetMethod() == null || Property.GetSetMethod() == null) | |
{ | |
throw new ArgumentException("The PropertyInfo provided must have public 'get' and 'set' accessor methods.", "property"); | |
} | |
} | |
public PropertyInfo Property | |
{ | |
get; | |
private set; | |
} | |
public void Copy(TEntityType from, TEntityType to) | |
{ | |
if (from == null) | |
{ | |
throw new ArgumentNullException("from"); | |
} | |
if (to == null) | |
{ | |
throw new ArgumentNullException("to"); | |
} | |
SetValue(to, GetValue(from)); | |
} | |
public abstract object GetValue(TEntityType entity); | |
public abstract void SetValue(TEntityType entity, object value); | |
} | |
/// <summary> | |
/// CompiledPropertyAccessor is a <see cref="PropertyAccessor{TEntityType}"/> that pre-compiles (using expression) | |
/// a Getter and Setter for the PropertyInfo of TEntityType provided via the constructor. | |
/// </summary> | |
/// <typeparam name="TEntityType">The type on which the PropertyInfo exists</typeparam> | |
internal class CompiledPropertyAccessor<TEntityType> : PropertyAccessor<TEntityType> where TEntityType : class | |
{ | |
private Action<TEntityType, object> _setter; | |
private Func<TEntityType, object> _getter; | |
public CompiledPropertyAccessor(PropertyInfo property) | |
: base(property) | |
{ | |
_setter = MakeSetter(Property); | |
_getter = MakeGetter(Property); | |
} | |
public override object GetValue(TEntityType entity) | |
{ | |
if (entity == null) | |
{ | |
throw new ArgumentNullException("entity"); | |
} | |
return _getter(entity); | |
} | |
public override void SetValue(TEntityType entity, object value) | |
{ | |
if (entity == null) | |
{ | |
throw new ArgumentNullException("entity"); | |
} | |
_setter(entity, value); | |
} | |
private static Action<TEntityType, object> MakeSetter(PropertyInfo property) | |
{ | |
Type type = typeof(TEntityType); | |
ParameterExpression entityParameter = Expression.Parameter(type); | |
ParameterExpression objectParameter = Expression.Parameter(typeof(object)); | |
MemberExpression toProperty = Expression.Property(Expression.TypeAs(entityParameter, property.DeclaringType), property); | |
UnaryExpression fromValue = Expression.Convert(objectParameter, property.PropertyType); | |
BinaryExpression assignment = Expression.Assign(toProperty, fromValue); | |
Expression<Action<TEntityType, object>> lambda = Expression.Lambda<Action<TEntityType, object>>(assignment, entityParameter, objectParameter); | |
return lambda.Compile(); | |
} | |
private static Func<TEntityType, object> MakeGetter(PropertyInfo property) | |
{ | |
Type type = typeof(TEntityType); | |
ParameterExpression entityParameter = Expression.Parameter(type); | |
MemberExpression fromProperty = Expression.Property(Expression.TypeAs(entityParameter, property.DeclaringType), property); | |
UnaryExpression convert = Expression.Convert(fromProperty, typeof(Object)); | |
Expression<Func<TEntityType, object>> lambda = Expression.Lambda<Func<TEntityType, object>>(convert, entityParameter); | |
return lambda.Compile(); | |
} | |
} | |
} |
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