Trait NodeProcessor 

pub trait NodeProcessor {
    // Required methods
    fn name(&self) -> &str;
    fn process(
        &self,
        input: NodeInput,
        progress: &ProgressReporter,
        ctx: &dyn ProcessContext,
    ) -> Result<NodeOutput, BntoError>;

    // Provided methods
    fn validate(&self, _params: &Map<String, Value>) -> Vec<String> { ... }
    fn process_batch(
        &self,
        input: BatchInput,
        progress: &ProgressReporter,
        ctx: &dyn ProcessContext,
    ) -> Result<NodeOutput, BntoError> { ... }
    fn metadata(&self) -> NodeMetadata { ... }
}

The contract that every node type must implement.

Currently synchronous – async is handled at the Web Worker level. wasm-bindgen doesn’t support async trait methods across the WASM boundary.

Required Methods

fn name(&self) -> &str

The unique name of this node type (e.g., “compress-images”). Used for logging and progress reporting.

fn process( &self, input: NodeInput, progress: &ProgressReporter, ctx: &dyn ProcessContext, ) -> Result<NodeOutput, BntoError>

Process a single input file and produce output.

Arguments:

• &self — reference to the node processor instance
• input — the file data, filename, MIME type, and config params
• progress — callback to report progress to the UI (0-100%)
• ctx — system access boundary (commands, temp files, env vars)

Returns:

• Ok(NodeOutput) — processing succeeded, here are the results
• Err(BntoError) — processing failed, here’s what went wrong

Provided Methods

fn validate(&self, _params: &Map<String, Value>) -> Vec<String>

Validate the input parameters before processing.

This is called BEFORE process() to catch configuration errors early (missing required params, invalid values, etc.) without doing any expensive file processing.

Returns a list of validation errors (empty = valid).

Default implementation passes validation. Override in specific node types to add parameter validation.

fn process_batch( &self, input: BatchInput, progress: &ProgressReporter, ctx: &dyn ProcessContext, ) -> Result<NodeOutput, BntoError>

Process a batch of files together, producing combined output.

Override this for processors with InputCardinality::Batch (merge, zip, concat). The default falls back to calling process() per file and concatenating results — suitable for PerFile processors.

fn metadata(&self) -> NodeMetadata

Return the processor’s self-describing metadata.

This tells consumers everything about this processor: what it’s called, what category it belongs to, what parameters it accepts, what files it handles, and whether it runs in the browser.

Every concrete processor SHOULD override this with its real metadata. The default returns a placeholder “unknown” metadata — useful for tests and mocks that don’t need real metadata.

Implementors