Serialization

Throughout the REST API, content needs to be serialized and deserialized to and from JSON representations.

In general, the format used for serializing content when reading from the API is the same as is used to submit content to the API for writing.

Basic Types

Basic Python data types that have a corresponding type in JSON, like integers or strings, will simply be translated between the Python type and the respective JSON type.

Dates and Times

Since JSON doesn’t have native support for dates/times, the Python/Zope datetime types will be serialized to an ISO 8601 datestring.

Python JSON
time(19, 45, 55) '19:45:55'
date(2015, 11, 23) '2015-11-23'
datetime(2015, 11, 23, 19, 45, 55) '2015-11-23T19:45:55'
DateTime('2015/11/23 19:45:55') '2015-11-23T19:45:55'

RichText fields

RichText fields will be serialized as follows:

A RichTextValue like

RichTextValue(u'<p>Hallöchen</p>',
              mimeType='text/html',
              outputMimeType='text/html')

will be serialized to

{
  "data": "<p>Hall\u00f6chen</p>",
  "content-type": "text/html",
  "encoding": "utf-8"
}

File / Image Fields

Download (serialization)

For download, a file field will be serialized to a mapping that contains the file’s most basic metadata, and a hyperlink that the client can follow to download the file:

{
  "...": "",
  "@type": "File",
  "title": "My file",
  "file": {
    "content-type": "application/pdf",
    "download": "http://localhost:55001/plone/file/@@download/file",
    "filename": "file.pdf",
    "size": 74429
  }
}

That URL in the download property points to the regular Plone download view. The client can send a GET request to that URL with an Accept header containing the MIME type indicated in the content-type property, and will get a response containing the file.

Image fields are serialized in the same way, except that their serialization contains their width and height, and an additional property scales that contains a mapping with the available image scales. Image URLs are created using the UID-based URL that changes each time the image is modified, so these URLs can be properly cached:

{
  "icon": {
    "download": "http://localhost:55001/plone/image/@@images/8eed3f80-5e1f-4115-85b8-650a10a6ca84.png",
    "height": 32,
    "width": 24
  },
  "large": {
    "download": "http://localhost:55001/plone/image/@@images/0d1824d1-2672-4b62-9277-aeb220d3bf15.png",
    "height": 768,
    "width": 576
  },
  "..." : {}
}

Upload (deserialization)

For file or image fields, the client must provide the file’s data as a mapping containg the file data and some additional metadata:

  • data - the base64 encoded contents of the file
  • encoding - the encoding you used to encode the data, so usually base64
  • content-type - the MIME type of the file
  • filename - the name of the file, including extension
{
  "...": "",
  "@type": "File",
  "title": "My file",
  "file": {
      "data": "TG9yZW0gSXBzdW0uCg==",
      "encoding": "base64",
      "filename": "lorem.txt",
      "content-type": "text/plain"}
}

Relations

Serialization

A RelationValue will be serialized to a short summary representation of the referenced object:

{
  "@id": "http://nohost/plone/doc1",
  "@type": "DXTestDocument",
  "title": "Document 1",
  "description": "Description"
}

The RelationList containing that reference will be represended as a list in JSON.

Deserialization

In order to set a relation when creating or updating content, you can use one of several ways to specify relations:

Type Example
UID '9b6a4eadb9074dde97d86171bb332ae9'
IntId 123456
Path '/plone/doc1'
URL 'http://localhost:8080/plone/doc1'