Post form data to a flow

Problem

You want to post form data to a flow.

Solution

Use the HTTP In node to listen for POST requests that have their Content-Type set to application/x-www-form-urlencoded and access the form data as properties of msg.payload.

Example

[{"id":"5b98a8ac.a46758","type":"http in","z":"3045204d.cfbae","name":"","url":"/hello-form","method":"post","swaggerDoc":"","x":120,"y":820,"wires":[["bba61009.4459f"]]},{"id":"bba61009.4459f","type":"template","z":"3045204d.cfbae","name":"page","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"<html>\n    <head></head>\n    <body>\n        <h1>Hello {{ payload.name }}!</h1>\n    </body>\n</html>","x":290,"y":820,"wires":[["6ceb930a.93146c"]]},{"id":"6ceb930a.93146c","type":"http response","z":"3045204d.cfbae","name":"","x":430,"y":820,"wires":[]}]
[~]$ curl -X POST -d "name=Nick" http://localhost:1880/hello-form
<html>
    <head></head>
    <body>
        <h1>Hello Nick!</h1>
    </body>
</html>

Discussion

HTML Forms can be used to send data from the browser back to a server. If configured to POST the data, the browser will encode the data held in the <form> using a content-type of application/x-www-form-urlencoded.

For example, when a form that looks like this is submitted:

<form action="http://localhost:1880/hello-form" method="post">
  <input name="name" value="Nick">
  <button>Say hello</button>
</form>

it results in the request:

POST / HTTP/1.1
Host: localhost:1880
Content-Type: application/x-www-form-urlencoded
Content-Length: 9

name=Nick

When the HTTP In node receives such a request, it parses the body of the request and makes the form data available under msg.payload:

var name = msg.payload.name;