V6 DECODE64 not working properly

It turns out that after all these years, V6's built-in DECODE64 and ENCODE64 actually do not work properly with some binary data.

proc COMPARE_BASE64 {} {
 set code  {2lIU1ZNw5BYvKi79j4L/+GGmjAQK7uiBQG7elDdKZcE=}
 set vgn_result [DECODE64 $code];         #VGN built-in function
 set tcl_result [::base64::decode $code]; #TclLib tcl-only implementation 
 return [join [list \\
   [BIN2HEX $vgn_result] \\
   [BIN2HEX $tcl_result] \\
   [string compare $vgn_result $tcl_result ] \\
  ] "\\r\\n"]
}
proc BIN2HEX { text }  { binary scan $text H* result; return $result }
COMPARE_BASE64

--- result ----
da52145370e4162f2a2efd8f82fff861a68c040aeee881406e94374a65c1
da5214d59370e4162f2a2efd8f82fff861a68c040aeee881406ede94374a65c1
1

If you need to encode/decode base64 for use in non-vignette systems make sure you use tcllib's base64.

This was tested on Vignette's V6 but I am sure it's true for Storyserver 4.2 and V5 as well.

Save binary file in Tcl under V6

This issue pops up every couple of years. It's nothing new, but still worth documenting.

The Challenge: To save a posted file to a file system, not using SUBMIT_STATIC_FILE.

The Problem: Vignette V6 pre-process the form submitted data so that any <input type="file"> are encoded as an hex string. If you ERROR_TRACE the variable for the file, you will see a string that looks like 0x1D00ABADD1D9....

The Solution: binary format to the rescue. and with a bit of trimming, you get it all in a few lines:

proc save_files { } {
#FileData,FileExtention,Field1 are posted from the <form>

set filename [generate_filename]
set bin_filename "${filename}.[SHOW FileExtention]"
set xml_filename "${filename}.xml"

### This will save a binary file.
set file [open $bin_filename "w"]
fconfigure $file -translation binary
puts -nonewline $file [binary format H* [string range [SHOW FileData] 2 end-1]]
close $file

### This will save a utf-8 xml (text) file
set file [open $xml_filename "w"]
fconfigure $file -encoding "utf-8"
puts $file "<?xml version='1.0' encoding='utf-8' ?>"
puts $file "<formdata>"
puts $file "<Field1>[HTML_ESCAPE [SHOW Field1]]</Field1>"
#...more fields...
$puts $file "<Attachment>$bin_filename</Attachment>"
puts $file "</formdata>"
close $file
}

* Remember to use H* and not h*.
* The example above also saves a text file in utf-8 with extra data from the form
* Make sure your form is enctype=multipart/form-data
* This will not work in Storyserver 4.2.