How to upload a file using CGI.pm

1
How to upload a file using CGI.pm

• http//www.perlfect.com/articles/upload.shtml
• ACTION"/cgi-bin/upload.pl" METHOD"POST"
• Please choose directory to upload to
  
  images/OPTION
• sounds
• Please select a file to upload
  
  
• ENCTYPE is a parameter to the form.

2
The CGI script

• !/usr/bin/perl
• use CGI
• my cgi new CGI
• my dir cgi-param('dir')
• my file cgi-param('file')

3
After that

• filem/.(\\\/)(.)/ strip the remote
  path and keep the filename
• my name 2
• open(LOCAL, "dir/name") or die !
• while()
• print LOCAL _
• print cgi-header()
• print "file has been successfully uploaded...
  thank you.\n"

4
Preprocessing URL-encoded CGI input

• Read the following
• http//www.perlfect.com/articles/url_decoding.shtm
  l

5

• GET The input of a GET request is stored in a
  special environmental variable (if you don't know
  what that is, don't worry) called QUERY_STRING To
  access an environmental variable from your
  script, you have to use the ENV hash that perl
  nicely provides. All you need to say is
• my_input ENVQUERY_STRING
• and the form's data will be put to my_input.
• POST The POST method does not put your input in
  some variable. Instead, the web server, upon
  executing your script will pass the CGI input to
  the script from STDIN. (the standard input) So,
  all you have to do is to read from the STDIN
  filehandle to get your input. The only tricky
  thing is that, an EOF (end-of-file) is not
  guaranteed at the end of the string. So how do
  you figure out how much you need to read? Not
  coincidentally, the server puts the length of the
  input string into an environmental variable,
  CONTENT_LENGTH. So you have to read
  CONTENT_LENGTH bytes from STDIN. The line that
  does this is
• read(STDIN, my_input, ENVCONTENT_LENGTH)

6
How to decode it?

• The general form is the following
• field1value1field2value2...fieldnvaluen
• First of all you'll have to separate each
  field-value pair from the rest. We use the split
  function to do that.
• _at_fv_pairs split /\/ , my_input

7
to space, and hexacodes into special characters

• foreach pair (_at_fv_pairs) if(pairm/()(.
  )/)
• field 1
• value 2
• value s/\/ /g value
  s/(\dA-Fa-f2)/pack("C", hex(1))/eg
  INPUTfieldvalue