World widget

WIT interface for the interaction between the host application and widgets Inspired by work-in-progress WASI Preview 2 WIT definitions (https://github.com/bytecodealliance/preview2-prototyping/tree/main/wit)

• Imports:
  • interface widget:widget/http
  • interface widget:widget/random
  • interface widget:widget/types
  • interface widget:widget/clocks
  • interface widget:widget/logging
  • type widget-context
  • type widget-result
• Exports:
  • function get-name
  • function get-version
  • function get-config-schema
  • function get-run-update-cycle-seconds
  • function run

Import interface widget:widget/http

HTTP interface for widgets. Allows them to make HTTP/HTTPS requests.

Types

type status

u16

#### `variant method`

Variant Cases

• get
• head
• post
• put
• delete

record response

Record Fields

• status: status

  HTTP status code

• content-length: option<u64>

  content-length, if known

• bytes: list<u8>

  response body as raw bytes

Functions

request: func

Params

• method: method
• url: string
• body: option<list<u8>>

Return values

• result<response>

Import interface widget:widget/random

Functions

get-random: func

Returns a random number generated by a cryptographically secure pseudorandom number generator (CSPRNG)

Return values

• u64

Import interface widget:widget/types

Types

record datetime

Record Fields

• seconds: u64

  Seconds since epoch

• nanoseconds: u32

record widget-context

Configuration that the widget receives from the host.

Record Fields

• last-invocation: datetime

  Timestamp of the last widget invocation.

• config: string

  Widget specific configuration serialized as JSON Must comply with the widget's config schema obtained by get-config-schema

record widget-result

The result of a widget invocation.

Record Fields

• data: string

  Formatted string Can also be an error explaining what went wrong for the user

Import interface widget:widget/clocks

Types

type datetime

datetime

----

Functions

now: func

Return values

• datetime

Import interface widget:widget/logging

Allows widgets to write logs to the host

Types

enum level

Enum Cases

• debug
• info
• warn
• error

Functions

log: func

Params

• level: level
• context: string
• message: string

Exported types from world widget

Types

type widget-context

widget-context

#### `type widget-result` [`widget-result`](#widget_result)

## Exported functions from world `widget`

get-name: func

Return the name of the widget

Return values

• string

get-version: func

Return the semantic version of the widget

Return values

• string

get-config-schema: func

Return the config JSON schema string

Return values

• string

get-run-update-cycle-seconds: func

Returns the run update cycle in seconds. With this, widgets can control how frequently they shall be updated.

Return values

• u32

run: func

Invoke the widget with the given context

Params

• context: widget-context

Return values

• widget-result