Interfaces and Core Nodes
A workflow is built from three kinds of node.
Source → Transform → Destination
The node palette
In the Workflow Builder, the palette groups node types under three headings. Drag one onto the canvas to add it.
| Group | Node | Triggered by | Script |
|---|---|---|---|
| Source | HTTP | An inbound HTTP request on a route | Required |
| Source | LLP | An inbound HL7 v2 message over MLLP | Only for a custom ACK |
| Source | File/FTP | A timer, polling a directory or FTP/FTPS/SFTP server | Not used |
| Source | Custom | A timer | Required |
| Transform | Custom | An inbound message from an upstream node | Required |
| Destination | File/FTP | An inbound message from an upstream node | Not used |
| Destination | LLP | An inbound message from an upstream node | Not used |
Transport nodes are configured with fields, not code. You write Lua only where the work is genuinely yours: HTTP handling, transformation, and generated or fetched messages.
:::note How this documentation names nodes The palette shows a group heading and a short name. In running text, naming a node type needs both, so this documentation writes them together — "Source HTTP", "Destination File/FTP". In the Studio you will see HTTP under Source. :::
Your project's own node templates appear in the same palette, under the group matching their type.
:::caution Destination Custom The palette also offers Custom under Destination. It has no runtime implementation in this release — a workflow containing one will not run it. Use Transform Custom for script-driven delivery instead: a transform node that calls out and never pushes is a destination in every practical sense. See Custom Scripting Nodes. :::
Choosing a source
| You need to receive | Use |
|---|---|
| HL7 v2 over an MLLP socket | Source LLP |
| An HTTP or REST call | Source HTTP |
| Files from a directory | Source File/FTP |
| Files from an FTP, FTPS, or SFTP server | Source File/FTP with Use FTP enabled |
| Data you fetch or generate yourself on a schedule | Source Custom |
Choosing a destination
| You need to deliver | Use |
|---|---|
| HL7 v2 over MLLP, with ACK handling | Destination LLP |
| Files to a directory | Destination File/FTP |
| Files to an FTP, FTPS, or SFTP server | Destination File/FTP with Upload to FTP enabled |
| An outbound HTTP call | Transform Custom, calling linkiir.link.web.post |
Transform Custom, calling linkiir.link.mail.send | |
| A database write | Transform Custom, calling linkiir.store |
The last three are transform nodes rather than dedicated destination types: you make the outbound call from a script. See Linkiir Scripting API.
Required fields and when they are checked
Node configuration forms do not mark fields as required, and they let you save an incomplete node. Validation happens when the node starts: a missing or invalid value stops the start and names the field.
missing required field: Route Path
invalid required field: Interval (must be > 0)
missing required field: FTP Server (required when Use FTP is enabled)
The reference pages below mark the fields each node type needs to start. Everything else has a working default.
This is why Run Test followed by starting a single node is the right order when building: the test catches script errors, the start catches configuration errors.
Fields you can add yourself
Beyond the fields a node type defines, you can add your own to a node's configuration and read them from your script. Useful for values you want configurable without editing code.
Nodes created from a Linkiir-supplied template have their built-in fields locked: you can change a value, but not a label, type, or option list, and you cannot remove one. Fields you add yourself remain fully editable.
Reference pages
:::note Conditional fields Many fields appear only once the setting they depend on is enabled. The FTP fields on a File/FTP node appear after you turn Use FTP on; the TLS fields appear after Use SSL. If a field in these pages is not visible, check the setting it depends on. :::