Falcon App Server: Request Body Cannot Be Rewound for Multiple Reads

[franciscojmc]

Description

When using the Falcon app server (which uses protocol-rack internally), request bodies cannot be properly rewound for subsequent reads. After the first read, subsequent reads return an empty string even after calling rewind.

Steps to Reproduce

1. Create a simple Rack application that reads a request body twice
2. Run it with Falcon server
3. POST data to the endpoint
4. Observe that the second read returns an empty string

Test

# typed: true
# frozen_string_literal: true

require "rack"

class BodyTestApp
  def call(env)
    # Get the request body
    body = env["rack.input"]

    # First read
    body.rewind
    first_read = body.read

    # Second read
    body.rewind
    second_read = body.read

    # Response showing both reads
    response_body = "First read: #{first_read.inspect}\n\nSecond read: #{second_read.inspect}"

    [200, { "Content-Type" => "text/plain" }, [response_body]]
  end
end

Output

➜ curl -X POST -d "This is test data" http://localhost:9292
First read: "This is test data"

Second read: ""

Expected Behavior

Both reads should return the same data after calling rewind.

[ioquatix]

Fixed by #24.