JSON Patch
draft-pbryan-json-patch-02

Abstract

JSON Patch defines the media type "application/json-patch", a JSON document structure for expressing a sequence of partial modifications to a JSON document.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on April 25, 2012.

Copyright Notice

Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

Table of Contents

• 1. Introduction
• 2. Conventions
• 3. Document Structure
• 4. Operations
• 4.1. add
• 4.2. remove
• 4.3. replace
• 5. Error Handling
• 6. Acknowledgements
• 7. IANA Considerations
• 8. Security Considerations
• 9. References
• 9.1. Normative References
• 9.2. Informative References
• Appendix A. Examples
• Appendix A.1. Adding an Object Member
• Appendix A.2. Adding an Array Element
• Appendix A.3. Removing an Object Member
• Appendix A.4. Removing an Array Element
• Appendix A.5. Replacing a Value
• Author's Address

1. Introduction

JavaScript Object Notation (JSON) [RFC4627] is a common format for the exchange and storage of structured data. HTTP PATCH [RFC5789] extends HTTP [RFC2616] with a method to perform partial modifications to resources.

The JSON Patch media type "application/json-patch" is a JSON document structure for expressing a sequence of partial modifications to a JSON document, suitable for use with the HTTP PATCH method.

2. Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

3. Document Structure

A JSON Patch document contains a JSON array of objects. Each object contains an operation to apply to the target JSON document.

A sample JSON Patch document:

[
    { "remove": "/a/b/c" },
    { "add": "/a/b/c", "value": "foo" },
    { "replace": "/a/b/c", "value": "bar" }
]
         

Evaluation of a JSON Patch document begins with a target JSON document to modify. Operations are applied sequentially in the order they appear in the array. Each operation in the sequence is applied to the target document. The resulting modified document becomes the target for the next operation. The process repeats until all operations are successfully applied.

4. Operations

The operation to perform is expressed in the name of a member in the operation object, with that member's value holding a string containing the [JSON Pointer], which references the value to modify. It is an error condition if an operation object contains more than one operation member.

4.1. add

The "add" operation adds a new value into an object or array. The value to be added is specified in the operation object's "value" member.

If adding to an object, it is an error condition if the member to be added in the object already exists.

If adding to an array, all elements at or above the specified index are shifted one position to the right. It is an error condition if the specified index is greater than the number of elements in the existing array.

4.2. remove

The "remove" operation removes a value from an object or array.

If removing an element from an array, all elements above the specified index are shifted one position to the left.

It is an error condition if the value to be removed does not exist.

4.3. replace

The "replace" operation replaces an existing value with a new value. This operation is equivalent to expressing a "remove" operation for a value, followed immediately by an "add" operation for the same value. The value to be replaced is specified in the operation object's "value" member.

It is an error condition if the value to be replaced does not exist.

5. Error Handling

In the event of an error condition, evaluation of the JSON Patch document terminates and modification of the target document fails to complete.

6. Acknowledgements

The structure of a JSON Patch document was informed by the XML Patch document [RFC5261] specification.

7. IANA Considerations

The Internet media type for a JSON Patch document is application/json-patch.

Type name:

application

Subtype name:

json-patch

Required parameters:

none

Optional parameters:

none

Encoding considerations:

Per JSON [RFC4627]: 8bit if UTF-8; binary if UTF-16 or UTF-32.

Security considerations:

See Security Considerations in section 8.

Interoperability considerations:

N/A

Published specification:

draft-pbryan-json-patch-02

Applications that use this media type:

HTTP clients and servers.

Additional information:

• N/A
• .json-patch
• TEXT

Person & email address to contact for further information:

Paul C. Bryan <paul.bryan@forgerock.com>

Intended usage:

COMMON

Restrictions on usage:

none

Author:

Paul C. Bryan <paul.bryan@forgerock.com>

Change controller:

Paul C. Bryan <paul.bryan@forgerock.com>

8. Security Considerations

This specification has the same security considerations as JSON [RFC4627] and JSON Pointer [JSON Pointer].

9. References

9.1. Normative References

9.2. Informative References

Appendix A. Examples

Appendix A.1. Adding an Object Member

An example target JSON document:

{
    "foo": "bar"
}
                 

A JSON Patch document:

[
    { "add": "/baz", "value": "qux" }
]
                 

The resulting JSON document:

{
    "baz": "qux",
    "foo": "bar"
}
                 

Appendix A.2. Adding an Array Element

An example target JSON document:

{
    "foo": [ "bar", "baz" ]
}
                 

A JSON Patch document:

[
    { "add": "/foo/1", "value": "qux" }
]
                 

The resulting JSON document:

{
    "foo": [ "bar", "qux", "baz" ]
}
                 

Appendix A.3. Removing an Object Member

An example target JSON document:

{
    "baz": "qux",
    "foo": "bar"
}
                 

A JSON Patch document:

[
    { "remove": "/baz" }
]
                 

The resulting JSON document:

{
    "foo": "bar"
}
                 

Appendix A.4. Removing an Array Element

An example target JSON document:

{
    "foo": [ "bar", "qux", "baz" ]
}
                 

A JSON Patch document:

[
    { "remove": "/foo/1" }
]
                 

The resulting JSON document:

{
    "foo": ["bar", "baz"]
}
                 

Appendix A.5. Replacing a Value

An example target JSON document:

{
    "baz": "qux",
    "foo": "bar"
}
                 

A JSON Patch document:

[
      { "replace": "/baz", "value": "boo" }
]
                 

The resulting JSON document:

{
    "baz": "boo",
    "foo": "bar"
}
                 

Author's Address