api/utils/render

Module rendering views as images

Description:

  • Module rendering views as images

Source:

Methods

(static) renderView(options, cb) → {void}

Description:

  • Function to render views as images

Source:
Parameters:
Name Type Description
options object

options required for rendering

Properties
Name Type Description
host string

the hostname
token string

the login token value
view string

the view to open
id string

the id of the block to capture screenshot of
savePath string

path where to save the screenshot
cbFn function

function called after opening the view
beforeScrnCbFn function

function called just before capturing the screenshot
dimensions object

the dimensions of the screenshot

Properties
Name Type Description
width number

the width of the screenshot
height number

the height of the screenshot
padding number

the padding value to subtract from the height of the screenshot
scale number

the scale(ppi) value of the screenshot
cb function

callback function called with the error value or the image data
Returns:

void

Type
void

(inner) cdnOrigin() → {string|null}

Description:

  • Origin of the configured CDN, when one is configured as an absolute url

    cdn belongs to the dashboard's config rather than the api's. In the standard layout both live in the same tree and this finds it with no operator action; where the api is deployed without the dashboard the file is absent, and the origin is named in countlyConfig.render.allowedOrigins instead.

Source:
Returns:

the CDN origin, or null when there is none to allow

Type
string | null

(inner) fetchChromeExecutablePath() → {Promise}

Description:

  • Function to fetch Chrome executable

Source:
Returns:

Promise

Type
Promise

(inner) originOf(url) → {string|null}

Description:

  • Origin of a url, or null when it has none to speak of

    A relative cdn ("" or "/assets/") has no origin and returns null here, which is correct: it is already served from the dashboard origin and needs no entry.

Source:
Parameters:
Name Type Description
url string

absolute url, or anything at all
Returns:

the serialised origin, or null when there is not a real one

Type
string | null

(inner) renderAssetOrigins(host) → {Array.<string>}

Description:

  • Origins the renderer may fetch subresources from

    The dashboard's own origin, the configured CDN, the map tile provider the shipped dashboard uses, and anything the operator adds in countlyConfig.render.allowedOrigins (entries may be a bare origin or any url on it). Everything else is aborted.

Source:
Parameters:
Name Type Description
host string

dashboard origin plus the configured path
Returns:

origins to allow, empty when the host itself cannot be parsed

Type
Array.<string>

(inner) sameOriginView(host, view) → {string|null}

Description:

  • Check that a view stays on the dashboard, and return the url to navigate to

    The view can come from a request (/o/render passes params.qstring.view through), and the url is built by concatenation. With the default countlyConfig.path of "" the prefix is exactly "http://localhost", so a view that does not begin with "/" rewrites the host instead of the path:

    "@169.254.169.254/latest/meta-data/" -> host 169.254.169.254 ":8500/v1/kv/?recurse" -> host localhost:8500 ".internal.example/x" -> host localhost.internal.example

    Parsing the concatenated url and comparing origins settles all of those at once, rather than trying to enumerate them. It also agrees with what Chromium will do with the same string, since both use the WHATWG url parser. Note that a private range denylist would be the wrong control here: the intended target is loopback.

    The returned url is the concatenation itself, unchanged, so a configured countlyConfig.path keeps working exactly as before.

Source:
Parameters:
Name Type Description
host string

dashboard origin plus the configured path
view string

view to render, expected to be a path on that dashboard
Returns:

url to navigate to, or null when it leaves the dashboard origin

Type
string | null

(inner) saveScreenshot(image, path, source) → {Promise}

Description:

  • Function to save screenshots

Source:
Parameters:
Name Type Description
image Buffer

image data to store
path String

path where image should be stored
source String

who provided image
Returns:

Promise

Type
Promise

(inner) timeout(ms) → {Promise}

Description:

  • Function to set a timeout

Source:
Parameters:
Name Type Description
ms number

Total milliseconds
Returns:

Promise

Type
Promise