cors: Allow Cross-Origin-Requests

In beakr: A Minimalist Web Framework for R

Description

Allow Cross-Origin Resource Sharing headers as described in MDN Web Docs. Cross-origin resource sharing is a mechanism that allows restricted resources on a web page to be requested from another domain(origin) outside the domain from which the first resource was served.

Usage

cors(
  beakr,
  path = NULL,
  methods = c("GET", "POST", "PUT", "DELETE", "OPTIONS", "PATCH"),
  origin = "*",
  credentials = NULL,
  headers = NULL,
  maxAge = NULL,
  expose = NULL
)

Arguments

beakr	Beakr instance object.
path	String representing a path for which to specify a CORS policy. Default NULL applies a single policy for all URL routes.
methods	A vector of the request methods to allow. i.e Access-Control-Allow-Methods parameter, e.g GET, POST.
origin	A vector of the request origin(s) for which resource sharing is enabled. i.e Access-Control-Allow-Origin response header parameter.
credentials	A boolean to enable/disable credentialed requests. i.e Access-Control-Allow-Credentials response header parameter.
headers	A vector of the allowed headers. i.e Access-Control-Allow-Headers response header parameter.
maxAge	The max age, in seconds. i.e Access-Control-Max-Age response header parameter.
expose	The headers to expose. i.e Access-Control-Expose-Headers response header parameter.

Value

A Beakr instance with CORS enabled

Note

You can verify that CORS is enabled by using the Chrome browser and opening up the Developer Tools. The "Network" tab allows you to inspect response headers and see where the Cross-Origin policy is specified.

If you run the example in the console, be sure to stopServer(bekar) when you are done.

See Also

Request, Response, Error

Examples

library(beakr)

# Create an new beakr instance
beakr <- newBeakr()

# beakr pipeline
beakr %>%

  # Enable CORS
  cors() %>%

  # Respond to GET requests at the "/hi" route
  httpGET(path = "/hi", function(req, res, err) {
    print("Hello, World!")
  }) %>%

  # Respond to GET requests at the "/bye" route
  httpGET(path = "/bye", function(req, res, err) {
    print("Farewell, my friends.")
  }) %>%

  # Start the server on port 25118
  listen(host = "127.0.0.1", port = 25118, daemon = TRUE)

# ------------------------------------------------------------
# POINT YOUR BROWSER AT:
# * http://127.0.0.1:25118/hi
# * http://127.0.0.1:25118/bye
#
# THEN, STOP THE SERVER WITH stopServer(beakr)
# ------------------------------------------------------------

# Stop the beakr instance server
stopServer(beakr)

beakr documentation built on April 7, 2021, 1:06 a.m.