Server block handler

Building

In order for the Ziggy server to pick up on changes in your code, your plugin needs to be rebuilt. You should use one of the package.json scripts. With dev, it will build on any changes.

The Ziggy server will pick up on changes in real-time. If you do not see changes in the Ziggy UI, then reload the browser.

If you have added new blocks, then you should run ziggy plugin register.

The code

my-block.v1.server.ts contains the code that executes on the server when your Flow runs.

Basic Block

export async function executeMyBlockBlockV1(props: BlockExecutionProps): Promise<void> {
  const { blockToExecute: block } = props

  if (!block) {
    throw new Error('Block to execute is not defined')
  }

  const config = block.data.config as MyBlockBlockV1Config
  const startTime = new Date()

  try {
    logMessage(props, block, `Executing My Block block: ${config.name}`)

    // Wait for all incoming edges to be populated
    // Note that safeWaitForInputEdgeData() let's you wait for just one specific edge
    const inputEdges = await safeWaitForAllInputEdgeData(props, block)
    if (!inputEdges) throw new Error('No input edges for this block')

    // Get the actual payload data
    const inputData = inputEdges.map(edge => edge.payload)

    // Get the data from the first input edge, if you're interested in it
    const firstEdgeData = inputData[0]

    // TODO: Implement your block logic here
    const outputData = {
      name: config.name,
      timestamp: new Date().toISOString(),
      // Anything else you might want to output to the outgoing edge
    }

    block.data.executionTime = new Date().getTime() - startTime.getTime()
    const outEdges = outgoingEdgeAssignment(props, block, 0, inputEdges, outputData)

    props.logTime(props, block, inputData ? [inputData] : [], outEdges, block.data.executionTime)
  } catch (error: any) {
    formulateFatalError(props, block, error.stack || error.message)
  }
}

Waiting for input edge data

When a Ziggy server block is called, it should (almost) always wait for data to arrive before anything else.

    const inputEdges = await safeWaitForAllInputEdgeData(props, block)

This function does just that. It will wait until all incoming edges are populated with data before executing.

There is an alternative function safeWaitForInputEdgeData() that lets you wait for a specific edge (usually i0) before executing. You would only needs this in special cases.

    const inputData = inputEdges.map(edge => edge.payload)

This line extracts the edge data from the edge. If you are only interested in the first edge (a common case) then you would access inputData[0].

Outputting data to an edge

Once your code has got some data (in the above example, it has hard-coded outputData) then you use the following function to output it to the outgoing edge.

    const outEdges = outgoingEdgeAssignment(props, block, 0, inputEdges, outputData)

Note that the 3rd parameter allows you to specify which edge you are populating, which is usually 0. If your function is doing somewhere more complex involving multiple output edges, then you would make multiple outgoingEdgeAssignment() calls.

Log timing

The following function is responsible for passing timing information to the client block, where it is rendered in the top right of the block.

    props.logTime(props, block, inputData ? [inputData] : [], outEdges, block.data.executionTime)

Error handling

So any errors are output to the UI log and server logs, throw an error in the code, which will be caught and managed by formulateFatalError().