Support user-defined redaction in req_headers()

[gvelasq]

The Google Cloud APIs use the x-goog-api-key header to pass API keys. Currently, only the Authorization header is automatically redacted by req_headers(), as implemented in the internal function headers_redact(). x-goog-api-key is therefore not redacted:

library(httr2)

req_google <-
  request("https://www.googleapis.com") %>%
  req_url_path_append("youtube/v3") %>%
  req_headers("x-goog-api-key" = "ABC123XYZ")

req_google
#> <httr2_request>
#> GET https://www.googleapis.com/youtube/v3
#> Headers:
#> • x-goog-api-key: 'ABC123XYZ'
#> Body: empty

^{Created on 2023-06-29 with reprex v2.0.2}

I recently added support for YouTube Data API key authentication in gojiplus/tuber#126, and it would be great to be able to redact the x-goog-api-key header used here for use in continuous integration. More broadly, a .redact = TRUE argument to req_headers() would permit users to redact any header. The desired behavior would look like the code block below:

library(httr2)

req_google <-
  request("https://www.googleapis.com") %>%
  req_url_path_append("youtube/v3") %>%
  req_headers("x-goog-api-key" = "ABC123XYZ", .redact = TRUE)

req_google
#> <httr2_request>
#> GET https://www.googleapis.com/youtube/v3
#> Headers:
#> • x-goog-api-key: '<REDACTED>'
#> Body: empty

[gvelasq]

Thank you, @mgirlich!

[mgirlich]

Happy to help 😄