/// <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)
{
object valueAtFromLocation = null;
// get path result
var pathResult = PropertyHelpers.GetActualPropertyPath(
operation.from,
objectToApplyTo,
operation,
true);
var positionAsInteger = pathResult.NumericEnd;
var actualPathToFromProperty = pathResult.PathToProperty;
PropertyInfo fromProperty = PropertyHelpers
.FindProperty(objectToApplyTo, actualPathToFromProperty);
// does property at from exist?
if (fromProperty == null)
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operation,
string.Format("Patch failed: property at location from: {0} does not exist", operation.from))
, 422);
}
// 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 (fromProperty.PropertyType.IsNonStringList())
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(fromProperty.PropertyType);
if (!fromProperty.CanRead)
{
// cannot get the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operation,
string.Format("Patch failed: cannot get property value at location from: {0}. Possible cause: the property doesn't have an accessible getter.", operation.from)),
422);
}
// get value (it can be cast, we just checked that)
var array = PropertyHelpers.GetValue(fromProperty, objectToApplyTo, actualPathToFromProperty) as IList;
if (array.Count <= positionAsInteger)
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operation,
string.Format("Patch failed: provided from path is invalid for array property type at location from: {0}: invalid position",
operation.from))
, 422);
}
valueAtFromLocation = array[positionAsInteger];
}
else
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operation,
string.Format("Patch failed: provided from path is invalid for array property type at location from: {0}: expected array",
operation.from))
, 422);
}
}
else
{
if (!fromProperty.CanRead)
{
// cannot get the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operation,
string.Format("Patch failed: cannot get property value at location from: {0}. Possible cause: the property doesn't have an accessible getter.", operation.from)),
422);
}
// no list, just get the value
valueAtFromLocation = PropertyHelpers.GetValue(fromProperty, objectToApplyTo, actualPathToFromProperty);
}
// add operation to target location with that value.
Add(operation.path, valueAtFromLocation, 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.
// get path result
var pathResult = PropertyHelpers.GetActualPropertyPath(
path,
objectToApplyTo,
operationToReport,
true);
var appendList = pathResult.ExecuteAtEnd;
var positionAsInteger = pathResult.NumericEnd;
var actualPathToProperty = pathResult.PathToProperty;
var pathProperty = PropertyHelpers
.FindProperty(objectToApplyTo, actualPathToProperty);
// does property at path exist?
if (pathProperty == null)
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: property at location path: {0} does not exist", path))
, 422);
}
// 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 (pathProperty.PropertyType.IsNonStringList())
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(pathProperty.PropertyType);
var conversionResult = PropertyHelpers.ConvertToActualType(genericTypeOfArray, value);
if (!conversionResult.CanBeConverted)
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided value is invalid for array property type at location path: {0}", path))
, 422);
}
if (!pathProperty.CanRead)
{
// cannot get the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: cannot get property value at location from: {0}. Possible cause: the property doesn't have an accessible getter.", path)),
422);
}
// get value (it can be cast, we just checked that)
var array = PropertyHelpers.GetValue(pathProperty, objectToApplyTo, actualPathToProperty) as IList;
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(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location path: {0}: position larger than array size", path))
, 422);
}
}
}
else
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location path: {0}: expected array", path))
, 422);
}
}
else
{
var conversionResultTuple = PropertyHelpers.ConvertToActualType(pathProperty.PropertyType, value);
// conversion successful
if (conversionResultTuple.CanBeConverted)
{
if (!pathProperty.CanWrite)
{
// cannot set the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: cannot set property value at path {0}. Possible cause: the property doesn't have an accessible setter.", path)),
422);
}
PropertyHelpers.SetValue(pathProperty, objectToApplyTo, actualPathToProperty,
conversionResultTuple.ConvertedInstance);
}
else
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided value is invalid for property type at location path: {0}", path))
, 422);
}
}
}
/// <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)
{
// get path result
var pathResult = PropertyHelpers.GetActualPropertyPath(
path,
objectToApplyTo,
operationToReport,
false);
var removeFromList = pathResult.ExecuteAtEnd;
var positionAsInteger = pathResult.NumericEnd;
var actualPathToProperty = pathResult.PathToProperty;
var pathProperty = PropertyHelpers
.FindProperty(objectToApplyTo, actualPathToProperty);
// does the target location exist?
if (pathProperty == null)
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: property at location path: {0} does not exist", path))
, 422);
}
// 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 (pathProperty.PropertyType.IsNonStringList())
{
// now, get the generic type of the enumerable
var genericTypeOfArray = PropertyHelpers.GetEnumerableType(pathProperty.PropertyType);
if (!pathProperty.CanRead)
{
// cannot get the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: cannot get property value at path: {0}. Possible cause: the property doesn't have an accessible getter.", path)),
422);
}
// get value (it can be cast, we just checked that)
var array = PropertyHelpers.GetValue(pathProperty, objectToApplyTo, actualPathToProperty) as IList;
if (removeFromList)
{
if (array.Count == 0)
{
// if the array is empty, we should throw an error
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location path: {0}: position larger than array size", path))
, 422);
}
array.RemoveAt(array.Count - 1);
}
else
{
if (positionAsInteger < array.Count)
{
array.RemoveAt(positionAsInteger);
}
else
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location path: {0}: position larger than array size",
path))
, 422);
}
}
}
else
{
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: provided path is invalid for array property type at location path: {0}: expected array",
path))
, 422);
}
}
else
{
if (!pathProperty.CanWrite)
{
// cannot set the property
throw new JsonPatchException(
new JsonPatchError(
objectToApplyTo,
operationToReport,
string.Format("Patch failed: cannot set property value at path {0}. Possible cause: the property doesn't have an accessible setter.", path)),
422);
}
// setting the value to "null" will use the default value in case of value types, and
// null in case of reference types
PropertyHelpers.SetValue(pathProperty, objectToApplyTo, actualPathToProperty, null);
}
}