The images of a canvas (Hakushi.Kits.Images), checked on the server
before they become nodes, and kept in the app's store with
Storehouse.
The browser's content type is a claim. Storehouse reads the bytes of
the file (Storehouse.Check): a PNG, JPEG, GIF or WebP image, from its
signature, with its width and height from its header (a JPEG's turned
as its EXIF orientation says, as browsers draw it). Any other file is
refused, an SVG too (it may hold a script), and an image whose header
has no size.
store/2 checks a file and stores it under a new key, in the store of
config :storehouse, adapter: ... (the local disk, S3, or one of the
app's); fetch/2 downloads an image from an address of the hosts an
app allows, then stores it, so an image pasted by its address, or added
by an agent, is the app's own file as an upload is.
Summary
Types
A stored image: a Storehouse.File, with its key and url in the
store, the client's name, its checked content_type, bytes,
width, height and checksum, and the URL of a smaller copy
(preview), or nil.
Functions
The content type of an image's file extension (".png"), or nil for
another.
The file extensions of the images a canvas takes, as an upload's accept.
Downloads the image at url, from a host of :hosts, then checks and
stores it as store/2 does (Storehouse.fetch/2).
Whether url is an address that fetch/2 takes with hosts (https
only).
Whether url is an address an image node may show: http or https,
or a path of the app (/uploads/…).
Checks the image at path and stores it under a new key, with
Storehouse.store/2. The file at path is left where it is.
The content types of the images a canvas takes.
Types
@type image() :: Storehouse.File.t()
A stored image: a Storehouse.File, with its key and url in the
store, the client's name, its checked content_type, bytes,
width, height and checksum, and the URL of a smaller copy
(preview), or nil.
Functions
The content type of an image's file extension (".png"), or nil for
another.
@spec extensions() :: [String.t()]
The file extensions of the images a canvas takes, as an upload's accept.
Downloads the image at url, from a host of :hosts, then checks and
stores it as store/2 does (Storehouse.fetch/2).
Only https addresses (and http, with http: true) of the hosts the
app allows are fetched, and a redirect only to one of them: the server
never fetches an address a person or an agent chose freely, which could
be one of the app's own network. A host is a name ("images.example.com")
or a name with a leading *. for its subdomains ("*.example.com").
Options
:hosts- the hosts it fetches from (required).:http- whetherhttpaddresses are fetched. The default isfalse.:timeout- in milliseconds, for the whole download. The default is 10 seconds.- the options of
store/2.
Whether url is an address that fetch/2 takes with hosts (https
only).
iex> Hakushi.Images.fetchable?("https://images.example.com/a.png", ["*.example.com"])
true
iex> Hakushi.Images.fetchable?("https://example.org/a.png", ["*.example.com"])
falseWhether url is an address an image node may show: http or https,
or a path of the app (/uploads/…).
Checks the image at path and stores it under a new key, with
Storehouse.store/2. The file at path is left where it is.
A file that is not an image a canvas takes gives
{:error, :not_an_image}; one over a limit, {:error, :too_large}.
Options
:name- the file's name, for its key and its node. The default is the base name ofpath.:adapter- the store. The default isStorehouse.adapter/0.:thumbnail- a function of the stored image (aStorehouse.File) andpaththat gives the URL of a smaller copy, ornil: the app makes and stores it (withimageorvix, say). The canvas shows it when it is zoomed out. An exception, or a result that is not a URL, gives none.:max_bytes- the largest file. The default is 10 MB.:max_pixels- the most pixels (width × height). The default is 50 million.
@spec types() :: [String.t()]
The content types of the images a canvas takes.