aspnetcore/src/Microsoft.AspNet.JsonPatch/Adapters/ObjectAdapter.cs

670 lines
29 KiB
C#

// Copyright (c) Microsoft Open Technologies, Inc. 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.Collections;
using System.Reflection;
using Microsoft.AspNet.JsonPatch.Exceptions;
using Microsoft.AspNet.JsonPatch.Helpers;
using Microsoft.AspNet.JsonPatch.Operations;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
namespace Microsoft.AspNet.JsonPatch.Adapters
{
public class ObjectAdapter<T> : IObjectAdapter<T> where T : class
{
public IContractResolver ContractResolver { get; set; }
public ObjectAdapter(IContractResolver contractResolver)
{
ContractResolver = contractResolver;
}
/// <summary>
/// The "add" operation performs one of the following functions,
/// depending upon what the target location references:
///
/// o If the target location specifies an array index, a new value is
/// inserted into the array at the specified index.
///
/// o If the target location specifies an object member that does not
/// already exist, a new member is added to the object.
///
/// o If the target location specifies an object member that does exist,
/// that member's value is replaced.
///
/// The operation object MUST contain a "value" member whose content
/// specifies the value to be added.
///
/// For example:
///
/// { "op": "add", "path": "/a/b/c", "value": [ "foo", "bar" ] }
///
/// When the operation is applied, the target location MUST reference one
/// of:
///
/// o The root of the target document - whereupon the specified value
/// becomes the entire content of the target document.
///
/// o A member to add to an existing object - whereupon the supplied
/// value is added to that object at the indicated location. If the
/// member already exists, it is replaced by the specified value.
///
/// o An element to add to an existing array - whereupon the supplied
/// value is added to the array at the indicated location. Any
/// elements at or above the specified index are shifted one position
/// to the right. The specified index MUST NOT be greater than the
/// number of elements in the array. If the "-" character is used to
/// index the end of the array (see [RFC6901]), this has the effect of
/// appending the value to the array.
///
/// Because this operation is designed to add to existing objects and
/// arrays, its target location will often not exist. Although the
/// pointer's error handling algorithm will thus be invoked, this
/// specification defines the error handling behavior for "add" pointers
/// to ignore that error and add the value as specified.
///
/// However, the object itself or an array containing it does need to
/// exist, and it remains an error for that not to be the case. For
/// example, an "add" with a target location of "/a/b" starting with this
/// document:
///
/// { "a": { "foo": 1 } }
///
/// is not an error, because "a" exists, and "b" will be added to its
/// value. It is an error in this document:
///
/// { "q": { "bar": 2 } }
///
/// because "a" does not exist.
/// </summary>
/// <param name="operation">The add operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Add(Operation<T> operation, T objectToApplyTo)
{
Add(operation.path, operation.value, objectToApplyTo, operation);
}
/// <summary>
/// Add is used by various operations (eg: add, copy, ...), yet through different operations;
/// This method allows code reuse yet reporting the correct operation on error
/// </summary>
private void Add(string path, object value, T objectToApplyTo, Operation<T> operationToReport)
{
// add, in this implementation, does not just "add" properties - that's
// technically impossible; It can however be used to add items to arrays,
// or to replace values.
// first up: if the path ends in a numeric value, we're inserting in a list and
// that value represents the position; if the path ends in "-", we're appending
// to the list.
var appendList = false;
var positionAsInteger = -1;
var actualPathToProperty = path;
if (path.EndsWith("/-"))
{
appendList = true;
actualPathToProperty = path.Substring(0, path.Length - 2);
}
else
{
positionAsInteger = PropertyHelpers.GetNumericEnd(path);
if (positionAsInteger > -1)
{
actualPathToProperty = path.Substring(0,
path.IndexOf('/' + positionAsInteger.ToString()));
}
}
var patchProperty = PropertyHelpers
.FindPropertyAndParent(objectToApplyTo, actualPathToProperty, ContractResolver);
// does property at path exist?
CheckIfPropertyExists(patchProperty, objectToApplyTo, operationToReport, path);
// it exists. If it' an array, add to that array. If it's not, we replace.
// is the path an array (but not a string (= char[]))? In this case,
// the path must end with "/position" or "/-", which we already determined before.
if (appendList || positionAsInteger > -1)
{
// what if it's an array but there's no position??
if (IsNonStringArray(patchProperty))
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(
patchProperty.Property.PropertyType);
var conversionResult = PropertyHelpers.ConvertToActualType(genericTypeOfArray, value);
CheckIfPropertyCanBeSet(conversionResult, objectToApplyTo, operationToReport, path);
// get value (it can be cast, we just checked that)
var array = (IList)patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
if (appendList)
{
array.Add(conversionResult.ConvertedInstance);
}
else
{
// specified index must not be greater than the amount of items in the array
if (positionAsInteger <= array.Count)
{
array.Insert(positionAsInteger, conversionResult.ConvertedInstance);
}
else
{
throw new JsonPatchException<T>(operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at " +
"location path: {0}: position larger than array size",
path, 422),
objectToApplyTo);
}
}
}
else
{
throw new JsonPatchException<T>(operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location " +
"path: {0}: expected array",
path),
objectToApplyTo, 422);
}
}
else
{
var conversionResultTuple = PropertyHelpers.ConvertToActualType(
patchProperty.Property.PropertyType,
value);
// Is conversion successful
CheckIfPropertyCanBeSet(conversionResultTuple, objectToApplyTo, operationToReport, path);
patchProperty.Property.ValueProvider.SetValue(
patchProperty.Parent,
conversionResultTuple.ConvertedInstance);
}
}
/// <summary>
/// The "move" operation removes the value at a specified location and
/// adds it to the target location.
///
/// The operation object MUST contain a "from" member, which is a string
/// containing a JSON Pointer value that references the location in the
/// target document to move the value from.
///
/// The "from" location MUST exist for the operation to be successful.
///
/// For example:
///
/// { "op": "move", "from": "/a/b/c", "path": "/a/b/d" }
///
/// This operation is functionally identical to a "remove" operation on
/// the "from" location, followed immediately by an "add" operation at
/// the target location with the value that was just removed.
///
/// The "from" location MUST NOT be a proper prefix of the "path"
/// location; i.e., a location cannot be moved into one of its children.
/// </summary>
/// <param name="operation">The move operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Move(Operation<T> operation, T objectToApplyTo)
{
// get value at from location
object valueAtFromLocation = null;
var positionAsInteger = -1;
var actualFromProperty = operation.from;
positionAsInteger = PropertyHelpers.GetNumericEnd(operation.from);
if (positionAsInteger > -1)
{
actualFromProperty = operation.from.Substring(0,
operation.from.IndexOf('/' + positionAsInteger.ToString()));
}
var patchProperty = PropertyHelpers
.FindPropertyAndParent(objectToApplyTo, actualFromProperty, ContractResolver);
// does property at from exist?
CheckIfPropertyExists(patchProperty, objectToApplyTo, operation, operation.from);
// is the path an array (but not a string (= char[]))? In this case,
// the path must end with "/position" or "/-", which we already determined before.
if (positionAsInteger > -1)
{
if (IsNonStringArray(patchProperty))
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(patchProperty.Property.PropertyType);
// get value (it can be cast, we just checked that)
var array = (IList)patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
if (array.Count <= positionAsInteger)
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location from: {0}: invalid position",
operation.from),
objectToApplyTo, 422);
}
valueAtFromLocation = array[positionAsInteger];
}
else
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location from: {0}: expected array",
operation.from),
objectToApplyTo, 422);
}
}
else
{
// no list, just get the value
// set the new value
valueAtFromLocation = patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
}
// remove that value
Remove(operation.from, objectToApplyTo, operation);
// add that value to the path location
Add(operation.path, valueAtFromLocation, objectToApplyTo, operation);
}
/// <summary>
/// The "remove" operation removes the value at the target location.
///
/// The target location MUST exist for the operation to be successful.
///
/// For example:
///
/// { "op": "remove", "path": "/a/b/c" }
///
/// If removing an element from an array, any elements above the
/// specified index are shifted one position to the left.
/// </summary>
/// <param name="operation">The remove operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Remove(Operation<T> operation, T objectToApplyTo)
{
Remove(operation.path, objectToApplyTo, operation);
}
/// <summary>
/// Remove is used by various operations (eg: remove, move, ...), yet through different operations;
/// This method allows code reuse yet reporting the correct operation on error
/// </summary>
private void Remove(string path, T objectToApplyTo, Operation<T> operationToReport)
{
var removeFromList = false;
var positionAsInteger = -1;
var actualPathToProperty = path;
if (path.EndsWith("/-"))
{
removeFromList = true;
actualPathToProperty = path.Substring(0, path.Length - 2);
}
else
{
positionAsInteger = PropertyHelpers.GetNumericEnd(path);
if (positionAsInteger > -1)
{
actualPathToProperty = path.Substring(0,
path.IndexOf('/' + positionAsInteger.ToString()));
}
}
var patchProperty = PropertyHelpers
.FindPropertyAndParent(objectToApplyTo, actualPathToProperty, ContractResolver);
// does the target location exist?
CheckIfPropertyExists(patchProperty, objectToApplyTo, operationToReport, path);
// get the property, and remove it - in this case, for DTO's, that means setting
// it to null or its default value; in case of an array, remove at provided index
// or at the end.
if (removeFromList || positionAsInteger > -1)
{
// what if it's an array but there's no position??
if (IsNonStringArray(patchProperty))
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(patchProperty.Property.PropertyType);
// get value (it can be cast, we just checked that)
var array = (IList)patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
if (removeFromList)
{
array.RemoveAt(array.Count - 1);
}
else
{
if (positionAsInteger < array.Count)
{
array.RemoveAt(positionAsInteger);
}
else
{
throw new JsonPatchException<T>(operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at " +
"location path: {0}: position larger than array size",
path),
objectToApplyTo, 422);
}
}
}
else
{
throw new JsonPatchException<T>(operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at " +
"location path: {0}: expected array",
path),
objectToApplyTo, 422);
}
}
else
{
// setting the value to "null" will use the default value in case of value types, and
// null in case of reference types
object value = null;
if (patchProperty.Property.PropertyType.GetTypeInfo().IsValueType
&& Nullable.GetUnderlyingType(patchProperty.Property.PropertyType) == null)
{
value = Activator.CreateInstance(patchProperty.Property.PropertyType);
}
patchProperty.Property.ValueProvider.SetValue(patchProperty.Parent, value);
}
}
/// <summary>
/// The "test" operation tests that a value at the target location is
/// equal to a specified value.
///
/// The operation object MUST contain a "value" member that conveys the
/// value to be compared to the target location's value.
///
/// The target location MUST be equal to the "value" value for the
/// operation to be considered successful.
///
/// Here, "equal" means that the value at the target location and the
/// value conveyed by "value" are of the same JSON type, and that they
/// are considered equal by the following rules for that type:
///
/// o strings: are considered equal if they contain the same number of
/// Unicode characters and their code points are byte-by-byte equal.
///
/// o numbers: are considered equal if their values are numerically
/// equal.
///
/// o arrays: are considered equal if they contain the same number of
/// values, and if each value can be considered equal to the value at
/// the corresponding position in the other array, using this list of
/// type-specific rules.
///
/// o objects: are considered equal if they contain the same number of
/// members, and if each member can be considered equal to a member in
/// the other object, by comparing their keys (as strings) and their
/// values (using this list of type-specific rules).
///
/// o literals (false, true, and null): are considered equal if they are
/// the same.
///
/// Note that the comparison that is done is a logical comparison; e.g.,
/// whitespace between the member values of an array is not significant.
///
/// Also, note that ordering of the serialization of object members is
/// not significant.
///
/// Note that we divert from the rules here - we use .NET's comparison,
/// not the one above. In a future version, a "strict" setting might
/// be added (configurable), that takes into account above rules.
///
/// For example:
///
/// { "op": "test", "path": "/a/b/c", "value": "foo" }
/// </summary>
/// <param name="operation">The test operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Test(Operation<T> operation, T objectToApplyTo)
{
// get value at path location
object valueAtPathLocation = null;
var positionInPathAsInteger = -1;
var actualPathProperty = operation.path;
positionInPathAsInteger = PropertyHelpers.GetNumericEnd(operation.path);
if (positionInPathAsInteger > -1)
{
actualPathProperty = operation.path.Substring(0,
operation.path.IndexOf('/' + positionInPathAsInteger.ToString()));
}
var patchProperty = PropertyHelpers
.FindPropertyAndParent(objectToApplyTo, actualPathProperty, ContractResolver);
// does property at path exist?
CheckIfPropertyExists(patchProperty, objectToApplyTo, operation, operation.path);
// get the property path
Type typeOfFinalPropertyAtPathLocation;
// is the path an array (but not a string (= char[]))? In this case,
// the path must end with "/position" or "/-", which we already determined before.
if (positionInPathAsInteger > -1)
{
if (IsNonStringArray(patchProperty))
{
// now, get the generic type of the enumerable
typeOfFinalPropertyAtPathLocation = PropertyHelpers
.GetEnumerableType(patchProperty.Property.PropertyType);
// get value (it can be cast, we just checked that)
var array = (IList)patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
if (array.Count <= positionInPathAsInteger)
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location path: {0}: invalid position",
operation.path),
objectToApplyTo, 422);
}
valueAtPathLocation = array[positionInPathAsInteger];
}
else
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location path: {0}: expected array",
operation.path),
objectToApplyTo, 422);
}
}
else
{
// no list, just get the value
valueAtPathLocation = patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
typeOfFinalPropertyAtPathLocation = patchProperty.Property.PropertyType;
}
var conversionResultTuple = PropertyHelpers.ConvertToActualType(
typeOfFinalPropertyAtPathLocation,
operation.value);
// Is conversion successful
CheckIfPropertyCanBeSet(conversionResultTuple, objectToApplyTo, operation, operation.path);
//Compare
}
/// <summary>
/// The "replace" operation replaces the value at the target location
/// with a new value. The operation object MUST contain a "value" member
/// whose content specifies the replacement value.
///
/// The target location MUST exist for the operation to be successful.
///
/// For example:
///
/// { "op": "replace", "path": "/a/b/c", "value": 42 }
///
/// This operation is functionally identical to a "remove" operation for
/// a value, followed immediately by an "add" operation at the same
/// location with the replacement value.
///
/// Note: even though it's the same functionally, we do not call remove + add
/// for performance reasons (multiple checks of same requirements).
/// </summary>
/// <param name="operation">The replace operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Replace(Operation<T> operation, T objectToApplyTo)
{
Remove(operation.path, objectToApplyTo, operation);
Add(operation.path, operation.value, objectToApplyTo, operation);
}
/// <summary>
/// The "copy" operation copies the value at a specified location to the
/// target location.
///
/// The operation object MUST contain a "from" member, which is a string
/// containing a JSON Pointer value that references the location in the
/// target document to copy the value from.
///
/// The "from" location MUST exist for the operation to be successful.
///
/// For example:
///
/// { "op": "copy", "from": "/a/b/c", "path": "/a/b/e" }
///
/// This operation is functionally identical to an "add" operation at the
/// target location using the value specified in the "from" member.
///
/// Note: even though it's the same functionally, we do not call add with
/// the value specified in from for performance reasons (multiple checks of same requirements).
/// </summary>
/// <param name="operation">The copy operation</param>
/// <param name="objectApplyTo">Object to apply the operation to</param>
public void Copy(Operation<T> operation, T objectToApplyTo)
{
// get value at from location
object valueAtFromLocation = null;
var positionAsInteger = -1;
var actualFromProperty = operation.from;
positionAsInteger = PropertyHelpers.GetNumericEnd(operation.from);
if (positionAsInteger > -1)
{
actualFromProperty = operation.from.Substring(0,
operation.from.IndexOf('/' + positionAsInteger.ToString()));
}
var patchProperty = PropertyHelpers
.FindPropertyAndParent(objectToApplyTo, actualFromProperty, ContractResolver);
// does property at from exist?
CheckIfPropertyExists(patchProperty, objectToApplyTo, operation, operation.from);
// get the property path
// is the path an array (but not a string (= char[]))? In this case,
// the path must end with "/position" or "/-", which we already determined before.
if (positionAsInteger > -1)
{
if (IsNonStringArray(patchProperty))
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(patchProperty.Property.PropertyType);
// get value (it can be cast, we just checked that)
var array = (IList)patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
if (array.Count <= positionAsInteger)
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location from: {0}: invalid position",
operation.from),
objectToApplyTo, 422);
}
valueAtFromLocation = array[positionAsInteger];
}
else
{
throw new JsonPatchException<T>(operation,
string.Format("Patch failed: provided from path is invalid for array property type at " +
"location from: {0}: expected array",
operation.from),
objectToApplyTo, 422);
}
}
else
{
// no list, just get the value
// set the new value
valueAtFromLocation = patchProperty.Property.ValueProvider.GetValue(patchProperty.Parent);
}
// add operation to target location with that value.
Add(operation.path, valueAtFromLocation, objectToApplyTo, operation);
}
private void CheckIfPropertyExists(
JsonPatchProperty patchProperty,
T objectToApplyTo,
Operation<T> operation,
string propertyPath)
{
if (patchProperty == null)
{
throw new JsonPatchException<T>(
operation,
string.Format("Patch failed: property at location {0} does not exist", propertyPath),
objectToApplyTo, 422);
}
if (patchProperty.Property.Ignored)
{
throw new JsonPatchException<T>(
operation,
string.Format("Patch failed: cannot update property at location {0}", propertyPath),
objectToApplyTo, 422);
}
}
private bool IsNonStringArray(JsonPatchProperty patchProperty)
{
return !(patchProperty.Property.PropertyType == typeof(string))
&& typeof(IList).GetTypeInfo().IsAssignableFrom(
patchProperty.Property.PropertyType.GetTypeInfo());
}
private void CheckIfPropertyCanBeSet(
ConversionResult result,
T objectToApplyTo,
Operation<T> operation,
string path)
{
var errorMessage = "Patch failed: provided value is invalid for property type at location path: ";
if (!result.CanBeConverted)
{
throw new JsonPatchException<T>(operation, string.Format(errorMessage + "{0}", path), objectToApplyTo, 422);
}
}
}
}