Convert multipart form into JSON

Webhook Relay detects multipart/formdata requests and automatically parses them so your function can use it. Parsed form data can be accessed through r.RequestFormData variable. You can use Webhook Relay to receive a form and convert it into any kind of JSON that can be sent to another API.

For example if the payload fragment looks like this:

...
  --------------------------5683f7544dff7b07
  Content-Disposition: form-data; name="username"
  
  John
  --------------------------5683f7544dff7b07
  ...

Then to get username value (which is John) you will need to:

-- import "json" package when working with JSON
  local json = require("json")
  
  -- values can be accessed through 'r.RequestFormData' object. Since 
  -- there can be multiple values for each key, you also need to 
  -- specify that it's the first element of the list:
  local username = r.RequestFormData.username[1]
  local first_name = r.RequestFormData.first_name[1]
  
  -- transforming form data into JSON
  local json_payload = {
    username = username,
    first_name = first_name
  }
  
  local encoded_payload, err = json.encode(json_payload)
  if err then error(err) end
  
  r:SetRequestBody(encoded_payload)

For the decoding to work, Webhook Relay expects a header Content-Type that includes multipart/form-data and the boundary.