Trait Loader 

pub trait Loader: Sync {
    type Error: Error + Send + Sync + 'static;

    // Required method
    fn load(
        &self,
        url: Iri<&str>,
    ) -> impl Future<Output = Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>> + Send;
}

Document loader.

A document loader is required by most processing functions to fetch remote documents identified by an IRI. In particular, the loader is in charge of fetching all the remote contexts imported in a @context entry.

This library provides a few default loader implementations:

• NoLoader dummy loader that always fail. Perfect if you are certain that the processing will not require any loading.
• Standard HashMap and BTreeMap mapping IRIs to pre-loaded documents. This way no network calls are performed and the loaded content can be trusted.
• FsLoader that redirecting registered IRI prefixes to a local directory on the file system. This also avoids network calls. The loaded content can be trusted as long as the file system is trusted.
• ReqwestLoader actually downloading the remote documents using the reqwest library. This requires the reqwest feature to be enabled.

A loader is Sync and its Loader::load future is Send, so that the algorithms, which hold the loader by reference across .awaits, can run on a multi-threaded executor.

Required Associated Types

type Error: Error + Send + Sync + 'static

Loader-specific error type.

Required Methods

fn load( &self, url: Iri<&str>, ) -> impl Future<Output = Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>> + Send

Loads the document behind the given IRI.

The future is Send, so that an async fn generic over its loader, and the algorithms that invoke it, are Send whenever their other inputs are. An implementation written as an async fn meets this when what it holds across an .await is Send.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl Loader for BTreeMap<IriBuf, RemoteDocument>

type Error = EntryNotFound

async fn load( &self, url: Iri<&str>, ) -> Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>

impl<L: Loader> Loader for &L

type Error = <L as Loader>::Error

async fn load( &self, url: Iri<&str>, ) -> Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>

impl<L: Loader> Loader for &mut L

type Error = <L as Loader>::Error

async fn load( &self, url: Iri<&str>, ) -> Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>

impl<S: BuildHasher + Send + Sync> Loader for HashMap<IriBuf, RemoteDocument, S>

type Error = EntryNotFound

async fn load( &self, url: Iri<&str>, ) -> Result<RemoteDocument<IriBuf>, LoadError<Self::Error>>

Implementors

impl Loader for FsLoader

type Error = Error

impl Loader for NoLoader

type Error = CannotLoad

impl Loader for ReqwestLoader

Available on crate feature reqwest only.

type Error = Error

impl<L1, L2> Loader for ChainLoader<L1, L2>

where L1: Loader, L2: Loader,

type Error = ChainError<<L1 as Loader>::Error, <L2 as Loader>::Error>