Using JSON payloads

A very common design pattern, especially when developing REST APIs, is to accept JSON payloads sent as application/json data over POST requests. Genie efficiently handles this use case through the utility function Requests.jsonpayload. Under the cover, Genie will process the POST request and will attempt to parse the JSON text payload. If this fails, we can still access the raw data (the text payload not converted to JSON) by using the Requests.rawpayload method.


using Genie, Genie.Requests, Genie.Renderer.Json

route("/jsonpayload", method = POST) do
  @show jsonpayload()
  @show rawpayload()

  json("Hello $(jsonpayload()["name"])")


Next we make a POST request using the HTTP package:

using HTTP

HTTP.request("POST", "http://localhost:8000/jsonpayload", [("Content-Type", "application/json")], """{"name":"Adrian"}""")

We will get the following output:

jsonpayload() = Dict{String,Any}("name"=>"Adrian")
rawpayload() = "{\"name\":\"Adrian\"}"

INFO:Main: /jsonpayload 200

HTTP/1.1 200 OK
Content-Type: application/json
Transfer-Encoding: chunked

"Hello Adrian""""

First, for the two @show calls, notice how jsonpayload had successfully converted the POST data to a Dict. While the rawpayload returns the POST data as a String, exactly as received. Finally, our route handler returns a JSON response, greeting the user by extracting the name from within the jsonpayload Dict.