Struct c2pa::Builder

pub struct Builder {
    pub definition: ManifestDefinition,
    pub remote_url: Option<String>,
    pub no_embed: bool,
    /* private fields */
}

Available on crate feature unstable_api only.

A Builder is used to add a signed manifest to an asset.

Example: Building and signing a manifest

use std::path::PathBuf;

use c2pa::{create_signer, Builder, SigningAlg};
use serde::Serialize;
use serde_json::json;
use tempfile::tempdir;

#[derive(Serialize)]
struct Test {
    my_tag: usize,
}

let manifest_json = json!({
   "claim_generator_info": [
      {
          "name": "c2pa_test",
          "version": "1.0.0"
      }
   ],
   "title": "Test_Manifest"
}).to_string();

let mut builder = Builder::from_json(&manifest_json)?;
builder.add_assertion("org.contentauth.test", &Test { my_tag: 42 })?;

let source = PathBuf::from("tests/fixtures/C.jpg");
let dir = tempdir()?;
let dest = dir.path().join("test_file.jpg");

// Create a ps256 signer using certs and key files
let signcert_path = "tests/fixtures/certs/ps256.pub";
let pkey_path = "tests/fixtures/certs/ps256.pem";
let signer = create_signer::from_files(signcert_path, pkey_path, SigningAlg::Ps256, None)?;

// embed a manifest using the signer
builder.sign(
    signer.as_ref(),
    "image/jpeg",
    &mut std::fs::File::open(&source)?,
    &mut std::fs::File::create(&dest)?,
)?;

Fields

definition: ManifestDefinition

remote_url: Option<String>

Optional remote URL for the manifest

no_embed: bool

Implementations

impl Builder

pub fn from_json(json: &str) -> Result<Self>

Creates a new builder from a JSON ManifestDefinition string.

Arguments

• json - A JSON string representing the ManifestDefinition.

Returns

• A new Builder.

pub fn set_format(&mut self, format: &str) -> &mut Self

Sets the MIME format for this Builder.

Arguments

• format - The format of the asset associated with this Builder.

Returns

• A mutable reference to the Builder.

pub fn set_thumbnail<R>( &mut self, format: &str, stream: &mut R ) -> Result<&mut Self>

where R: Read + Seek + ?Sized,

Sets a thumbnail for the Builder.

The thumbnail should represent the associated asset for this Builder.

Arguments

• format - The format of the thumbnail.
• stream - A stream to read the thumbnail from.

Returns

• A mutable reference to the Builder.

Errors

• If the thumbnail is not valid.

pub fn add_assertion<S, T>(&mut self, label: S, data: &T) -> Result<&mut Self>

where S: Into<String>, T: Serialize,

Adds a CBOR assertion to the manifest.

Arguments

• label - A label for the assertion.
• data - The data for the assertion. The data is any Serde Serializable type.

Returns

• A mutable reference to the Builder.

Errors

• If the assertion is not valid.

pub fn add_assertion_json<S, T>( &mut self, label: S, data: &T ) -> Result<&mut Self>

where S: Into<String>, T: Serialize,

Adds a Json assertion to the manifest.

Arguments

• label - A label for the assertion.
• data - The data for the assertion. The data is any Serde Serializable type.

Returns

• A mutable reference to the Builder.

Errors

• If the assertion is not valid.

pub fn add_ingredient<'a, T, R>( &'a mut self, ingredient_json: T, format: &str, stream: &mut R ) -> Result<&'a mut Ingredient>

where T: Into<String>, R: Read + Seek + Send,

Adds an Ingredient to the manifest

Arguments

• ingredient_json - A JSON string representing the Ingredient.
• format - The format of the Ingredient.
• stream - A stream to read the Ingredient from.

Returns

• A mutable reference to the Ingredient.

Errors

• If the Ingredient is not valid

pub fn add_resource( &mut self, id: &str, stream: impl Read + Seek + Send ) -> Result<&mut Self>

Adds a resource to the manifest. The id should match up with an identifier in the manifest.

Arguments

• id - The identifier for the resource.
• stream - A stream to read the resource from.

Returns

• A mutable reference to the builder.

Errors

• If the resource is not valid.

pub fn to_archive(&mut self, stream: impl Write + Seek) -> Result<()>

Convert the Builder into a archive formatted stream.

The archive is a zip formatted stream containing the manifest.json, resources, and ingredients.

Arguments

• stream - A stream to write the zip into.

Errors

• If the archive cannot be written.

pub fn from_archive(stream: impl Read + Seek) -> Result<Self>

Unpacks an archive stream into a Builder.

Arguments

• stream - A stream to read the archive from.

Returns

• A new Builder.

Errors

• If the archive cannot be read.

pub fn sign<R, W>( &mut self, signer: &dyn Signer, format: &str, source: &mut R, dest: &mut W ) -> Result<Vec<u8>>

where R: Read + Seek + Send, W: Write + Read + Seek + Send,

Embed a signed manifest into a stream using a supplied signer.

Arguments

• format - The format of the stream
• source - The stream to read from
• dest - The stream to write to
• signer - The signer to use

Returns

• The bytes of c2pa_manifest that was embedded.

Errors

• If the manifest cannot be signed.

pub async fn sign_async<R, W>( &mut self, signer: &dyn AsyncSigner, format: &str, source: &mut R, dest: &mut W ) -> Result<Vec<u8>>

where R: Read + Seek + Send, W: Write + Read + Seek + Send,

Embed a signed manifest into a stream using a supplied signer.

Arguments

• format - The format of the stream
• source - The stream to read from
• dest - The stream to write to
• signer - The signer to use

Returns

• The bytes of c2pa_manifest that was embedded.

Errors

• If the manifest cannot be signed.

pub fn sign_file<S, D>( &mut self, signer: &dyn Signer, source: S, dest: D ) -> Result<Vec<u8>>

where S: AsRef<Path>, D: AsRef<Path>,

Available on crate feature file_io only.

Sign a file using a supplied signer.

Arguments

• source - The path to the file to read from.
• dest - The path to the file to write to (this must not already exist).
• signer - The signer to use.

Returns

• The bytes of c2pa_manifest that was created.

Errors

• If the manifest cannot be signed.

Trait Implementations

impl AsRef<Builder> for Builder

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Debug for Builder

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

Formats the value using the given formatter.

impl Default for Builder

fn default() -> Builder

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Builder

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for Builder

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.