Image.Components.Signing (image_components v0.1.1)

Copy Markdown View Source

Client-side HMAC signing for URLs emitted by Image.Components.URL.

Functionally equivalent to Image.Plug.Signing on the back-end: HMAC-SHA256 over the path-and-query (with the sig parameter removed), hex-encoded, appended as ?sig=<hex>. Sign-only — the back-end verifies. Use this when your Image.Plug deployment is configured with :signing and you need the component to emit authentic URLs.

Self-contained — does not depend on image_plug. Both packages share the wire format, not the code.

Examples

iex> path = "/cdn-cgi/image/width=200/photo.jpg"
iex> signed = Image.Components.Signing.sign(path, ["secret"])
iex> String.starts_with?(signed, path <> "?sig=")
true

Summary

Functions

sign(path, list, options \\ [])

Signs path with the first key in keys.

Functions

sign(path, list, options \\ [])

@spec sign(String.t(), [String.t(), ...], keyword()) :: String.t()

Signs path with the first key in keys.

Arguments

  • path is the request path (with or without an existing query string).

  • keys is a non-empty list of secret-key strings. The first key is used.

Options

  • :expires_at — DateTime or unix-seconds integer. When set, appends ?exp=<unix-seconds> and signs the result.

Returns

  • The path with ?sig=<hex> (and optional ?exp=…) appended.

Examples

iex> Image.Components.Signing.sign("/foo.jpg", ["secret"])
...> |> String.starts_with?("/foo.jpg?sig=")
true

iex> Image.Components.Signing.sign("/foo.jpg?other=1", ["secret"])
...> =~ "?other=1&sig="
true