Trait Deserializer 

pub trait Deserializer<T>:
    Send
    + Sync
    + 'static {
    // Required method
    fn deserialize<'a>(
        &'a self,
        topic: &'a str,
        data: &'a [u8],
    ) -> impl Future<Output = Result<T, Error>> + Send + 'a;

    // Provided methods
    fn deserialize_with_headers<'a>(
        &'a self,
        topic: &'a str,
        headers: &'a mut RecordHeaders,
        data: &'a [u8],
    ) -> impl Future<Output = Result<T, Error>> + Send + 'a { ... }
    fn deserialize_with_headers_bytes<'a>(
        &'a self,
        topic: &'a str,
        headers: &'a mut RecordHeaders,
        data: &'a Bytes,
    ) -> impl Future<Output = Result<T, Error>> + Send + 'a { ... }
    fn configure<'a>(
        &'a mut self,
        configs: &'a HashMap<String, String>,
        is_key: bool,
    ) -> impl Future<Output = Result<(), Error>> + Send + 'a { ... }
    fn close(&mut self) -> impl Future<Output = Result<(), Error>> + Send { ... }
}

An interface for converting bytes to objects.

This interface can be combined with ClusterResourceListener to receive cluster metadata once it’s available, as well as Monitorable to enable the deserializer to register metrics. For the latter, the following tags are automatically added to all metrics registered: config set to either key.deserializer or value.deserializer, and class set to the deserializer class name.

Type Parameters

• T - Type to be deserialized into.

Translation notes

WARNING: combining with ClusterResourceListener or Monitorable has no effect: no client registers either.

Methods return a Send future, which the consumer stores inline: a deserializer awaiting a large operation only on a cache miss should Box::pin it alone.

A poll() cancelled mid-record deserializes that record again on the next poll().

Required Methods

fn deserialize<'a>( &'a self, topic: &'a str, data: &'a [u8], ) -> impl Future<Output = Result<T, Error>> + Send + 'a

Deserialize a record value from a byte array into a value or object.

Arguments

• topic - topic associated with the data
• data - serialized bytes

Returns

The deserialized typed object.

Errors

Whatever error the deserializer reports; the consumer returns it from poll.

Translation notes

The consumer skips the call for a null key or value, so data and the result are never None.

Provided Methods

fn deserialize_with_headers<'a>( &'a self, topic: &'a str, headers: &'a mut RecordHeaders, data: &'a [u8], ) -> impl Future<Output = Result<T, Error>> + Send + 'a

Deserialize a record value from a byte array into a value or object.

Note that the passed in headers may be empty. The implementation is allowed to modify the passed in headers, as a side effect of deserialization. It is considered best practice to not delete or modify existing headers, but rather only add new ones.

Arguments

• topic - topic associated with the data
• headers - headers associated with the record
• data - serialized bytes

Returns

The deserialized typed object.

Errors

As deserialize.

Translation notes

The default implementation ignores the headers and delegates to deserialize. The consumer skips the call for a null key or value.

fn deserialize_with_headers_bytes<'a>( &'a self, topic: &'a str, headers: &'a mut RecordHeaders, data: &'a Bytes, ) -> impl Future<Output = Result<T, Error>> + Send + 'a

Deserialize a record value from a [Bytes] buffer into a value or object.

If this method is overridden, the implementation cannot make any assumptions about the passed in buffer.

Note that the passed in headers may be empty. The implementation is allowed to modify the passed in headers, as a side effect of deserialization. It is considered best practice to not delete or modify existing headers, but rather only add new ones.

Arguments

• topic - topic associated with the data
• headers - headers associated with the record
• data - serialized bytes

Returns

The deserialized typed object.

Errors

As deserialize.

Translation notes

The consumer calls this overload. data is a refcounted slice of the fetched bytes, so a deserializer may keep it without copying. The default delegates to deserialize_with_headers with &data[..], copying nothing. The consumer skips the call for a null key or value.

fn configure<'a>( &'a mut self, configs: &'a HashMap<String, String>, is_key: bool, ) -> impl Future<Output = Result<(), Error>> + Send + 'a

Configure this class. The default implementation is a no-op.

Arguments

• configs - configs in key/value pairs
• is_key - whether the deserializer is used for the key or the value

Errors

Whatever error the deserializer reports.

fn close(&mut self) -> impl Future<Output = Result<(), Error>> + Send

Close this deserializer.

This method must be idempotent as it may be called multiple times.

Errors

Whatever error the deserializer reports; the consumer still closes the other deserializer, then returns it as the source of its own.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Deserializer<String> for StringDeserializer

impl Deserializer<Vec<u8>> for ByteArrayDeserializer

impl Deserializer<Bytes> for BytesDeserializer