req_dry_run: Perform a dry run

In r-lib/httr2: Perform HTTP Requests and Process the Responses

Perform a dry run

Description

This shows you exactly what httr2 will send to the server, without actually sending anything. It requires the httpuv package because it works by sending the real HTTP request to a local webserver, thanks to the magic of curl::curl_echo().

Usage

req_dry_run(
  req,
  quiet = FALSE,
  redact_headers = TRUE,
  testing_headers = is_testing(),
  pretty_json = getOption("httr2_pretty_json", TRUE)
)

Arguments

req	A httr2 request object.
quiet	If TRUE doesn't print anything.
redact_headers	Redact confidential data in the headers? Currently redacts the contents of the Authorization header to prevent you from accidentally leaking credentials when debugging/reprexing.
testing_headers	If TRUE, removes headers that httr2 would otherwise be automatically added, which are likely to change across test runs. This currently includes: The default User-Agent, which varies based on libcurl, curl, and httr2 versions. The 'Host“ header, which is often set to a testing server. The Content-Length header, which will often vary by platform because of varying newline encodings. (And is also not correct if you have pretty_json = TRUE.) The Accept-Encoding header, which varies based on how libcurl was built.
pretty_json	If TRUE, automatically prettify JSON bodies.

Details

Limitations

• The Host header is not respected.

• The HTTP version is always HTTP/1.1 (since you can't determine what it will actually be without connecting to the real server).

Value

Invisibly, a list containing information about the request, including method, path, and headers.

Examples

# httr2 adds default User-Agent, Accept, and Accept-Encoding headers
request("http://example.com") |> req_dry_run()

# the Authorization header is automatically redacted to avoid leaking
# credentials on the console
req <- request("http://example.com") |> req_auth_basic("user", "password")
req |> req_dry_run()

# if you need to see it, use redact_headers = FALSE
req |> req_dry_run(redact_headers = FALSE)

r-lib/httr2 documentation built on Feb. 18, 2025, 8:45 p.m.