Struct SignedWatermarkParams 

#[non_exhaustive]
pub struct SignedWatermarkParams {
    pub url: String,
    pub position: Option<String>,
    pub opacity: Option<u8>,
    pub margin: Option<u32>,
}

Builds a signed public transform URL for the server adapter.

The resulting URL targets either GET /images/by-path or GET /images/by-url depending on source. base_url must be an absolute http or https URL that points at the externally visible server origin. The helper applies the same canonical query and HMAC-SHA256 signature scheme that the server adapter verifies at request time.

The helper serializes only explicitly requested transform options and omits fields that would resolve to the documented defaults on the server side.

Errors

Returns an error string when base_url is not an absolute http or https URL, when the visible authority cannot be determined, or when the HMAC state cannot be initialized.

Examples

use truss::{sign_public_url, SignedUrlSource};
use truss::{MediaType, TransformOptions};

let mut options = TransformOptions::default();
options.format = Some(MediaType::Jpeg);

let url = sign_public_url(
    "https://cdn.example.com",
    SignedUrlSource::Path {
        path: "/image.png".to_string(),
        version: None,
    },
    &options,
    "public-dev",
    "secret-value",
    4_102_444_800,
    None,
    None,
)
.unwrap();

assert!(url.starts_with("https://cdn.example.com/images/by-path?"));
assert!(url.contains("keyId=public-dev"));
assert!(url.contains("signature="));

Optional watermark parameters for signed URL generation.

Each field other than the URL is None when the caller does not name it, and the server then applies the same default it applies to a watermark from any other adapter.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

url: String

The URL the watermark image is fetched from.

position: Option<String>

Where to place the watermark, as the name the vocabulary uses.

opacity: Option<u8>

Opacity of the watermark, 1 to 100.

margin: Option<u32>

Margin in pixels from the nearest edge.

Implementations

impl SignedWatermarkParams

pub fn new(url: impl Into<String>) -> Self

Names the watermark image and leaves every other parameter to the server’s default.

A caller assigns the rest afterwards. The struct is #[non_exhaustive], so a parameter the watermark vocabulary gains later is a minor change rather than a breaking one.

Trait Implementations

impl Debug for SignedWatermarkParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SignedWatermarkParams

fn default() -> SignedWatermarkParams

Returns the “default value” for a type.