specifying output path for knit2html - r

Question

I'm having trouble specifying an output path for the html generated by knit2html or its dependent functions. I would like to specify 'outfile' in the the call to knit2html(), but I get the error,
Error in knit2html(input = "test.Rmd", output = "test-abcd.html") :
object 'outfile' not found
'output' is a parameter of markdownToHTML which should work I'd think. I can't find anywhere in the source where 'outfile' is used.
This should reproduce my experience.
library(knitr)
library(markdown)
# a minimal example
writeLines(c("```{r hello-random, echo=TRUE}", "rnorm(5)", "```"),
"test.Rmd")
# this works and outputs to test.html
knit2html(input = "test.Rmd")
# this generates the above error
knit2html(input = "test.Rmd",
output = "test-abcd.html")
# breaking it down into two steps works in this simple case,
# but not in my application. trying to diagnose that difference currently
knit("test.Rmd")
markdownToHTML("test.md",
output="test-abcd.html")
relevant version info might be useful?
sessionInfo()
R version 3.0.0 (2013-04-03)
Platform: x86_64-pc-linux-gnu (64-bit)
other attached packages:
[1] plyr_1.8 knitr_1.2 digest_0.6.3 markdown_0.5.4 xtable_1.7-1 reshape2_1.2.2 scales_0.2.3 ggplot2_0.9.3.1 data.table_1.8.8

Answer 1

First, thanks for the very clear and reproducible question. If you take a look at the knit2html function source code, you can understand what the problem is :
R> knit2html
function (input, ..., envir = parent.frame(), text = NULL, quiet = FALSE,
encoding = getOption("encoding"))
{
if (is.null(text)) {
out = knit(input, envir = envir, encoding = encoding,
quiet = quiet)
markdown::markdownToHTML(out, outfile <- sub_ext(out,
"html"), ...)
invisible(outfile)
}
else {
out = knit(text = text, envir = envir, encoding = encoding,
quiet = quiet)
markdown::markdownToHTML(text = out, ...)
}
}
<environment: namespace:knitr>
If the text argument is NULL (ie, if you provide a file as input instead of a character vector), then the given file is passed to the knit function, and the markdownToHTML function is called the following way :
markdown::markdownToHTML(out, outfile <- sub_ext(out, "html"), ...)
So in this case the output file name is generated by substituting the existing file name extension with html, and you can't provide your own output filename as an argument.