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## Rook::Utils$parse() has a few problems: 1. it adds an extra \r\n to the file
## uploaded; 2. if there are multiple files uploaded, only the info about the
## last file is recorded. Besides, I did not escape non-file data, nor did I
## unescape the filenames. The former is not important to me at the moment,
## since the primary purpose of this function is for shiny IE8/9 file uploading;
## the latter is probably not important, either, since the users normally only
## want the content of the file(s) instead of the name(s).
#' Parse multipart form data
#'
#' This function parses the HTML form data from a Rook environment (an HTTP POST
#' request).
#' @param env the HTTP request environment
#' @return A named list containing the values of the form data, and the files
#' uploaded are saved to temporary files (the temporary filenames are
#' returned). It may also be \code{NULL} if there is anything unexpected in
#' the form data, or the form is empty.
#' @references This function was borrowed from
#' \url{https://github.com/jeffreyhorner/Rook/} with slight modifications.
#' @export
#' @useDynLib mime, .registration = TRUE
parse_multipart = function(env) {
ctype = env$CONTENT_TYPE
if (length(grep('^multipart', ctype)) == 0L) return()
EOL = '\r\n'
params = list()
input = env$rook.input; input$rewind()
content_length = as.integer(env$CONTENT_LENGTH)
# some constants regarding boundaries
boundary = gsub('^multipart/.*boundary="?([^";,]+)"?', '--\\1', ctype)
bytesize = function(x) nchar(x, type = 'bytes')
EOL_size = bytesize(EOL)
EOL_raw = charToRaw(EOL)
boundary_size = bytesize(boundary)
boundaryEOL = paste(boundary, EOL, sep = '')
boundaryEOL_size = boundary_size + bytesize(EOL)
boundaryEOL_raw = charToRaw(boundaryEOL)
EOLEOL = paste(EOL, EOL, sep = '')
EOLEOL_size = bytesize(EOLEOL)
EOLEOL_raw = charToRaw(EOLEOL)
buf = new.env(parent = emptyenv())
buf$bufsize = 16384L # never read more than bufsize bytes (16K)
buf$read_buffer = input$read(boundaryEOL_size)
buf$read_buffer_len = length(buf$read_buffer)
buf$unread = content_length - boundary_size
if (!identical(boundaryEOL_raw, buf$read_buffer)) {
warning('bad content body')
input$rewind()
return()
}
# read the smaller one of the unread content and the next chunk
fill_buffer = function() {
x = input$read(min(buf$bufsize, buf$unread))
n = length(x)
if (n == 0L) return()
buf$read_buffer = c(buf$read_buffer, x)
buf$read_buffer_len = length(buf$read_buffer)
buf$unread = buf$unread - n
}
# slices off the beginning part of read_buffer, e.g. i is the position of
# EOLEOL, and size is EOLEOL_size, and read_buffer is [......EOLEOL+++], then
# slice_buffer returns the the beginning [......], and turns read_buffer to
# the remaining [+++]
slice_buffer = function(i, size) {
slice = buf$read_buffer[if (i > 1) 1:(i - 1) else 1]
buf$read_buffer = if ((i+size) <= buf$read_buffer_len)
buf$read_buffer[(i + size):buf$read_buffer_len] else raw()
buf$read_buffer_len = length(buf$read_buffer)
slice
}
# prime the read_buffer
buf$read_buffer = raw()
fill_buffer()
# find the position of the raw vector x1 in x2
raw_match = function(x1, x2) {
if (is.character(x1)) x1 = charToRaw(x1)
.Call('rawmatch', x1, x2, PACKAGE = 'mime')
}
unescape = function(x) {
unlist(lapply(x, function(s) utils::URLdecode(chartr('+', ' ', s))))
}
while (TRUE) {
head = value = NULL
filename = content_type = name = NULL
while (is.null(head)) {
i = raw_match(EOLEOL_raw, buf$read_buffer)
if (length(i)) {
head = slice_buffer(i, EOLEOL_size)
break
} else if (buf$unread) {
fill_buffer()
} else {
break # we've read everything and still haven't seen a valid head
}
}
if (is.null(head)) {
warning('Bad post payload: searching for a header')
input$rewind()
return()
}
# cat('Head:',rawToChar(head),'\n') they're 8bit clean
head = rawToChar(head)
token = '[^\\s()<>,;:\\"\\/\\[\\]?=]+'
condisp = sprintf('Content-Disposition:\\s*%s\\s*', token)
dispparm = sprintf(';\\s*(%s)=("(?:\\"|[^"])*"|%s)*', token, token)
rfc2183 = sprintf('(?m)^%s(%s)+$', condisp, dispparm)
broken_quoted = sprintf(
'(?m)^%s.*;\\sfilename="(.*?)"(?:\\s*$|\\s*;\\s*%s=)', condisp, token
)
broken_unquoted = sprintf('(?m)^%s.*;\\sfilename=(%s)', condisp, token)
if (length(grep(rfc2183, head, perl = TRUE))) {
first_line = sub(condisp, '', strsplit(head, EOL)[[1L]][1], perl = TRUE)
pairs = strsplit(first_line, ';', fixed = TRUE)[[1L]]
fnmatch = '\\s*filename=(.*)\\s*'
if (any(grepl(fnmatch, pairs, perl = TRUE))) {
filename = pairs[grepl(fnmatch, pairs, perl = TRUE)][1]
filename = gsub('"', '', sub(fnmatch, '\\1', filename, perl = TRUE))
}
} else if (length(grep(broken_quoted, head, perl = TRUE))) {
filename = sub(
broken_quoted, '\\1', strsplit(head, '\r\n')[[1L]][1], perl = TRUE
)
} else if (length(grep(broken_unquoted, head, perl = TRUE))) {
filename = sub(
broken_unquoted, '\\1', strsplit(head, '\r\n')[[1L]][1], perl = TRUE
)
}
# TODO: decoding filenames seems to be a mess here; skip it for now
# if (!is.null(filename) && filename != '') {
# filename = unescape(filename)
# }
headlines = strsplit(head, EOL, fixed = TRUE)[[1L]]
content_type_re = '(?mi)Content-Type: (.*)'
content_types = grep(content_type_re, headlines, perl = TRUE, value = TRUE)
if (length(content_types)) {
content_type = sub(content_type_re, '\\1', content_types[1], perl = TRUE)
}
name = sub(
'(?si)Content-Disposition:.*\\s+name="?([^\";]*).*"?', '\\1', head,
perl = TRUE
)
while (TRUE) {
i = raw_match(boundary, buf$read_buffer)
if (length(i)) {
value = slice_buffer(i, boundary_size)
# strip off the extra EOL before the boundary
if (identical(tail(value, EOL_size), EOL_raw))
value = head(value, -EOL_size)
if (length(value)) {
# drop EOL only values
if (identical(value, EOL_raw)) break
if (!is.null(filename) || !is.null(content_type)) {
data = list()
data$name = if (is.null(filename)) NA_character_ else filename
data$size = length(value)
data$type = if (is.null(content_type)) NA_character_ else content_type
data$datapath = tempfile()
con = file(data$datapath, open = 'wb')
tryCatch(writeBin(value, con), finally = close(con))
params[[name]] = rbind(params[[name]], as.data.frame(data, stringsAsFactors = FALSE))
} else {
len = length(value)
# trim trailing EOL
if (len > 2 && length(raw_match(EOL, value[(len - 1):len])))
len = len - 2
# handle array parameters (TODO: why Utils$escape?)
paramValue = rawToChar(value[1:len])
paramSet = FALSE
if (grepl('\\[\\]$', name)) {
name = sub('\\[\\]$', '', name)
if (name %in% names(params)) {
params[[name]] = c(params[[name]], paramValue)
paramSet = TRUE
}
}
if (!paramSet) params[[name]] = paramValue
}
}
break
} else if (buf$unread) {
fill_buffer()
} else {
break # we've read everything and still haven't seen a valid value
}
}
if (is.null(value)) {
# bad post payload
input$rewind()
warning('Bad post payload: searching for a body part')
return(NULL)
}
# now search for ending markers or the beginning of another part
while (buf$read_buffer_len < 2 && buf$unread) fill_buffer()
if (buf$read_buffer_len < 2 && buf$unread == 0) {
# bad stuff at the end; just return what we've got and presume everything
# is okay
input$rewind()
return(params)
}
# valid ending
if (length(raw_match('--', buf$read_buffer[1:2]))) {
input$rewind()
return(params)
}
# skip past the EOL.
if (length(raw_match(EOL, buf$read_buffer[1:EOL_size]))) {
slice_buffer(1, EOL_size)
} else {
warning('Bad post body: EOL not present')
input$rewind()
return(params)
}
# another sanity check before we try to parse another part
if ((buf$read_buffer_len + buf$unread) < boundary_size) {
warning('Bad post body: unknown trailing bytes')
input$rewind()
return(params)
}
}
}
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