"error: missing value where TRUE/FALSE needed" -- request$get_header() parses dates wrong?

[greg-minshall]

hi. in routr's ressource_route() function, there is a line

m_since <- request$get_header('If-Modified-Since')

it appears get_header returns a vector of length 2, the first being day-name, which is separated by a comma from the second element (day, month, year, ...).

when in the subsequent if statement, m_since is fed to from_http_date(), i'm guessing two NAs result. which, it appears, results in the subject error message.

i took a quick look in the code in request.R, but didn't immediately see where the headers are set (maybe not even in reqres? in fiery? httpuv?).

a hack in routr would be something like

diff --git a/R/ressource_route.R b/R/ressource_route.R
index 02021fe..cb990a9 100644
--- a/R/ressource_route.R
+++ b/R/ressource_route.R
@@ -143,6 +143,10 @@ ressource_route <- function(..., default_file = 'index.html', default_ext = 'htm
       m_time <- file.mtime(real_file)
       etag <- request$get_header('If-None-Match')
       new_tag <- digest(m_time)
+      if (!is.null(m_since)) {
+          m_since <- paste(m_since, collapse=", ")
+      }
       if ((!is.null(m_since) && from_http_date(m_since) < m_time) ||
           (!is.null(etag) && etag == new_tag)) {
         response$status_with_text(304L)

cheers.

[greg-minshall]

ah. i see the headers are being set in request.R by Request$private$get_headers(), where there is a strsplit() of concern.

i guess one possibility (hack) would be to avoid the strsplit if passing the pre-split string to from_http_date() returns non-NA? seems a bit precarious. a simple search restricted to developer.mozilla.org makes it seem as if there are only a handful of headers that have day-name, such as

• Date
• Last-Modified
• If-Modified-Since
• If-Range

so, one could except those from the strsplit(), i guess. (i don't know enough HTTP to know which headers want to be split.)