Copyright	(c) Andrew Gibiansky, 2016
License	MIT
Maintainer	andrew.gibiansky@gmail.com
Stability	stable
Portability	POSIX
Safe Haskell	None
Language	Haskell2010

Jupyter.Messages.Internal

Contents

Message Metadata

Description

This module contains type and class definitions pertaining to handling Jupyter messages internally. The types defined here are generally useful for the jupyter library but will not be useful for users of the library.

Synopsis

Message Metadata

data MessageHeader Source

A message header with some metadata.

The metadata has a variety of important information that pertains to the session maintained between the client and the frontend. In addition to metadata, the message headers are used to establish relationships between the messages: in particular, the message parent is used to determine which request a reply corresponds to.

In addition, the message type is sent as a string with the message header.

For more information about the message headers, read the section of the Jupyter messaging protocol about the wire protocol.

Constructors

MessageHeader

Fields

messageIdentifiers :: [ByteString]: The identifiers sent with the message. These identifiers come at the front of the message, and are ZeroMQ routing prefix, which can be zero or more socket identities. These are used, for instance, to know where to send stdin requests (see the messaging spec).
messageParent :: Maybe MessageHeader: The parent header, if present. The parent header is used to establish relationships between request and reply messages and outputs published in response to requests.
messageMetadata :: Object: A free-form dict of metadata.
messageId :: UUID: A unique message UUID.
messageSession :: UUID: A unique session UUID.
messageUsername :: Username: The user who sent this message.
messageType :: MessageType: The type of this message. This is stored as a string, and determines how to parse the content and what to do with the message once it is parsed.

Instances

Eq MessageHeader Source
Show MessageHeader Source

newtype Username Source

A username represented as Text, part of the MessageHeader.

Constructors

Username Text

Instances

Eq Username Source
Ord Username Source
Show Username Source
IsString Username Source
ToJSON Username Source
FromJSON Username Source

newtype MessageType Source

The type of a message, internally stored as a string.

Examples include execute_request, comm_open, and display_data.

Constructors

MessageType
Fields messageTypeText :: Text

Instances

Eq MessageType Source
Ord MessageType Source
Show MessageType Source
IsString MessageType Source
ToJSON MessageType Source
FromJSON MessageType Source

class ToJSON v => IsMessage v where Source

Jupyter messages are represented as a variety of datatypes, depending on where in the messaging protocol the message is used (for instance, ClientRequest or Comm).

Given any message, however, you need to be able to get a MessageType for it, so that when encoding the message onto the wire you can include the message type in the header. The IsMessage typeclass provides a single method, getMessageType, which gets the message type of any Jupyter message.

Methods

getMessageType :: v -> MessageType Source

Get the message type for a Jupyter message.

parseMessageContent :: MessageType -> Maybe (Object -> Parser v) Source

Get a parser for this message type.

If this message type does not correspond to one of the constructors for the data type v, then return Nothing. Otherwise, return a parser that parses the message body into the given datatype.

This is a slightly unusual but necessary interface, because the message type and the message body come in separate bytestrings, as they are separate blobs sent on the communication sockets. Thus, we must look first at the message type, and choose the JSON parser based on the message type.

Instances

IsMessage Comm Source
IsMessage KernelOutput Source
IsMessage ClientReply Source
IsMessage KernelRequest Source
IsMessage KernelReply Source
IsMessage ClientRequest Source
(IsMessage v1, IsMessage v2) => IsMessage (Either v1 v2) Source	Provide an `IsMessage` instance for the sum of two types which have `IsMessage` instances. This is particularly useful for dealing with the shell and iopub socket, where kernels and clients can receive different types of messages on one socket (kernels can receive `Comm` and `ClientRequest` messages on the shell socket, while clients can receive `KernelOutput` and `Comm` messages on the iopub socket).