Temporarily mock requests — with_mocked

Mocking allows you to selectively and temporarily replace the response you would typically receive from a request with your own code. These functions are low-level and we don't recommend using them directly. Instead use package that uses these functions under the hood, like httptest2 or vcr.

Usage

with_mocked_responses(mock, code)

local_mocked_responses(mock, env = caller_env())

Arguments

mock

A function, a list, or NULL.

NULL disables mocking and returns httr2 to regular operation.
A list of responses will be returned in sequence. After all responses have been used up, will return 503 server errors.
For maximum flexibility, you can supply a function that that takes a single argument, req, and returns either NULL (if it doesn't want to handle the request) or a response (if it does).

code

Code to execute in the temporary environment.

env

Environment to use for scoping changes.

Value

with_mocked_responses() returns the result of evaluating code.

Examples

# This function should perform a response against google.com:
google <- function() {
  request("http://google.com") |>
    req_perform()
}

# But I can use a mock to instead return my own made up response:
my_mock <- function(req) {
  response(status_code = 403)
}
try(with_mocked_responses(my_mock, google()))
#> Error in req_perform(request("http://google.com")) : 
#>   HTTP 403 Forbidden.