embedded_figure_protocol.md

Embedded figure protocol (v1)

The figURL is of the form

https://figurl.org/f?v=<view_uri>&d=&label=<label>&s=<url_state_string>&zone=<zone>

The figure is embedded in an iframe in one of two ways

Method 1:

<iframe src={`${srcUrl}?parentOrigin=${parentOrigin}>&figureId=${figureId}&s=<url_state_string>`}>

where

const srcUrl = '<obtained-from-view-uri>'
const parentOrigin = window.location.protocol + '//' + window.location.host
const figureId = '<random-figure-id>'

Method 2:

<iframe sandbox="allow-scripts" srcdoc="<html_source>">

where the html source is obtained from downloading the content at the view URI. Note the sandbox attribute should be used for security reasons, giving minimal permissions to the child window. For example, we don't want the child window to access the parent's DOM or the parent's local storage.

For method 2, a message is posted immediately after iframe.onload to the iframe as follows:

const msg = {
    type: 'initializeFigure',
    parentOrigin: '*',
    figureId: '<figure_id>',
    s?: <url_state_string>
}
iframe.postMessage(msg, '*')

The child posts messages to the parent as follows:

const request: FigurlRequest = ... // defined below
const msgToParent = {
    type: 'figurlRequest',
    figureId: '<figure_id>',
    requestId: '<random_request_id>',
    request: request
}
window.parent.postMessage(msgToParent, '<parent_origin>')

The parent sends messages to the child as follows:

const msgToChild: FigurlResponseMessage | FileDownloadProgressMessage | SetCurrentUserMessage = ... // defined below

// For method 1, origin is origin of <src_url>
// For method 2, origin is *
iframe.postMessage(msgToChild, origin)

// request message to parent

type FigurlRequest =
    GetFigureDataRequest |
    GetFileDataRequest |
    GetFileDataUrlRequest |
    StoreFileRequest |
    StoreGithubFileRequest |
    SetUrlStateRequest

type GetFigureDataRequest = {
    type: 'getFigureData'
}

type GetFileDataRequest = {
    type: 'getFileData'
    uri: string
    responseType?: string // 'text', 'json', 'json-deserialized': default is 'json-deserialized'
}

type GetFileDataUrlRequest = {
    type: 'getFileDataUrl'
    uri: string
}

type StoreFileRequest = {
    type: 'storeFile'
    fileData: string
}

type StoreGithubFileRequest = {
    type: 'storeGithubFile'
    fileData: string
    uri: string
}

type SetUrlStateRequest = {
    type: 'setUrlState'
    state: {[key: string]: any}
}

// response message to child

type FigurlResponseMessage = {
    type: 'figurlResponse',
    requestId: string,
    response: FigurlResponse
}

type FigurlResponse =
    GetFigureDataResponse |
    GetFileDataResponse |
    GetFileDataUrlResponse |
    StoreFileResponse |
    StoreGithubFileResponse |
    SetUrlStateResponse

type GetFigureDataResponse = {
    type: 'getFigureData'
    figureData: any
}

type GetFileDataResponse = {
    type: 'getFileData'
    fileData?: any
    errorMessage?: string
}

type GetFileDataUrlResponse = {
    type: 'getFileDataUrl'
    fileDataUrl?: string
    errorMessage?: string
}

type StoreFileResponse = {
    type: 'storeFile'
    uri?: string
    error?: string
}

type StoreGithubFileResponse = {
    type: 'storeGithubFile'
    success: boolean
    error?: string
}

type SetUrlStateResponse = {
    type: 'setUrlState'
}

// other messages to child

type FileDownloadProgressMessage = {
    type: 'fileDownloadProgress'
    uri: string
    loaded: number
    total: number
}

type SetCurrentUserMessage = {
    type: 'setCurrentUser',
    userId: string
}