Handler Function — logic.handlerFunction

Declares a named Express request handler with fixed req, res, next parameters. Routes attach to a Handler Function instead of embedding a handler inline — this is the node every route needs at least one of.

• Inputs: in — "Attach" (exec) — wire a Route's "Handler" output here
• Outputs: out — "Next" (exec) — wire to another Handler Function to chain them
• Config fields:

Key	Type	Default	Notes
name	text	handler	Must be a valid JS identifier — the function name Express will call.
body	code	""	Only used in "code" mode. Available: req, res, next. Call res.json(...)/res.send(...) to respond, next() to continue.
mode	select	code	"code" uses the Function Body field above; "blueprint" compiles this handler from a nested node graph instead — see Function Graphs & Blueprint Mode.
isAsync	boolean	false	Enable to use await inside this handler's body.
npmDependencies	text	""	Comma-separated npm packages (code mode only), e.g. "axios, lodash@^4.17.0".

function handler(req, res, next) {
  res.status(200).json({ message: "Hello World" });
}

app.get("/hello", handler);

Chaining multiple handlers on one route

Wire a Handler Function's "Next" output into another Handler Function's "Attach" input to register both on the same route — every handler but the last must call next() in its body to reach the next one:

app.get("/orders", requireAuth, listOrders);

The same Handler Function node can also be reused across multiple routes; it just appears more than once as app.METHOD(path, handlerName).

Blueprint mode and variable access

In "blueprint" mode, a Handler Function's body is a nested visual graph, same as a Function's — see Function Graphs & Blueprint Mode. Inside that graph, a Send JSON node is the way to respond, and variable.get/variable.set nodes can read and write both the graph's own local variables and the main canvas's module-level variables (visible and editable from the graph's Module Variables panel).