


ncgi(n)                    CGI Support                    ncgi(n)


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NAME
       ncgi - Procedures to manipulate CGI values.

SYNOPSIS
       package require Tcl  8.2

       package require ncgi  ?1.3?

       ::ncgi::cookie cookie

       ::ncgi::decode str

       ::ncgi::empty name

       ::ncgi::exists name

       ::ncgi::encode string

       ::ncgi::header ?type? args

       ::ncgi::import cginame ?tclname?

       ::ncgi::importAll args

       ::ncgi::importFile cmd cginame ?filename?

       ::ncgi::input ?fakeinput? ?fakecookie?

       ::ncgi::multipart type query

       ::ncgi::nvlist

       ::ncgi::names

       ::ncgi::parse

       ::ncgi::parseMimeValue value

       ::ncgi::query

       ::ncgi::redirect url

       ::ncgi::reset query type

       ::ncgi::setCookie args

       ::ncgi::setDefaultValue key defvalue

       ::ncgi::setDefaultValueList key defvaluelist

       ::ncgi::setValue key value




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ncgi(n)                    CGI Support                    ncgi(n)


       ::ncgi::setValueList key valuelist

       ::ncgi::type

       ::ncgi::urlStub ?url?

       ::ncgi::value key ?default?

       ::ncgi::valueList key ?default?

_________________________________________________________________

DESCRIPTION
       The  ncgi  package provides commands that manipulate CGI values.  These
       are values that come from Web forms and are  processed  either  by  CGI
       scripts  or  web pages with embedded Tcl code.  Use the ncgi package to
       query these values, set and get cookies, and encode and decode www-url-
       encoded values.

       In  the  simplest case, a CGI script first calls ::ncgi::parse and then
       calls ::ncgi::value to get different form values.  If a  CGI  value  is
       repeated,  you  should  use  ::ncgi::valueList to get back the complete
       list of values.

       An alternative to ::ncgi::parse is ::ncgi::input, which  has  semantics
       similar  to  Don  Libes'  cgi_input procedure.  ::ncgi::input restricts
       repeated CGI values to have names that end with "List".  In this  case,
       ::ncgi::value   will   return   the   complete   list  of  values,  and
       ::ncgi::input will raise errors if it find repeated form elements with-
       out the right name.

       The  ::ncgi::reset procedure can be used in test suites and Web servers
       to initialize the source of the CGI values.  Otherwise the  values  are
       read in from the CGI environment.

       The complete set of procedures is described below.

       ::ncgi::cookie cookie
              Return a list of values for cookie, if any.  It is possible that
              more than one cookie with the same name can be present, so  this
              procedure returns a list.

       ::ncgi::decode str
              Decode  strings  in  www-url-encoding,  which represents special
              characters with a %xx sequence, where xx is the  character  code
              in hex.

       ::ncgi::empty name
              Returns  1  if  the  CGI variable name is not present or has the
              empty string as its value.

       ::ncgi::exists name
              The return value is a boolean. It returns 0 if the CGI  variable
              name is not present, and 1 otherwise.



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ncgi(n)                    CGI Support                    ncgi(n)


       ::ncgi::encode string
              Encode string into www-url-encoded format.

       ::ncgi::header ?type? args
              Output the CGI header to standard output.  This emits a Content-
              Type: header and additional headers based on args,  which  is  a
              list  of  header  names  and header values. The type defaults to
              "text/html".

       ::ncgi::import cginame ?tclname?
              This creates a variable in the current scope with the  value  of
              the  CGI variable cginame.  The name of the variable is tclname,
              or cginame if tclname is empty (default).

       ::ncgi::importAll args
              This imports several CGI variables as Tcl variables.  If args is
              empty,  then  every  CGI  value is imported.  Otherwise each CGI
              variable listed in args is imported.

       ::ncgi::importFile cmd cginame ?filename?
              This provides information about an uploaded  file  from  a  form
              input  field  of type file with name cginame.  cmd can be one of
              -server -client, -type or -data.

              -client cginame
                     returns the filename as sent by the client.

              -type cginame
                     returns the mime type of the uploaded file.

              -data cginame
                     returns the contents of the file.

              -server cginame filename
                     writes the file contents to a local  temporary  file  (or
                     filename  if  supplied) and returns the name of the file.
                     The caller is responsible for deleting  this  file  after
                     use.

       ::ncgi::input ?fakeinput? ?fakecookie?
              This  reads and decodes the CGI values from the environment.  It
              restricts repeated form values to  have  a  trailing  "List"  in
              their  name.   The  CGI  values  are  obtained  later  with  the
              ::ncgi::value procedure.

       ::ncgi::multipart type query
              This procedure parses a multipart/form-data query.  This is used
              by  ::ncgi::nvlist and not normally called directly.  It returns
              an alternating list of names and structured values.  Each struc-
              ture value is in turn a list of two elements.  The first element
              is meta-data from the multipart/form-data structure.  The second
              element  is  the  form value.  If you use ::ncgi::value you just
              get the form value.  If you use ::ncgi::valueList  you  get  the
              structured value with meta data and the value.



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ncgi(n)                    CGI Support                    ncgi(n)


              The  type  is  the  whole Content-Type, including the parameters
              like boundary.  This returns a list of  names  and  values  that
              describe  the  multipart  data.   The  values  are a nested list
              structure that has some descriptive information first,  and  the
              actual  form  value second.  The descriptive information is list
              of header names and values that describe the content.

       ::ncgi::nvlist
              This returns all the query data as a name, value list.   In  the
              case  of  multipart/form-data,  the  values  are  structured  as
              described in ::ncgi::multipart.

       ::ncgi::names
              This returns all names found in  the  query  data,  as  a  list.
              ::ncgi::multipart.

       ::ncgi::parse
              This reads and decodes the CGI values from the environment.  The
              CGI values are obtained later with the ::ncgi::value  procedure.
              IF  a  CGI  value  is repeated, then you should use ::ncgi::val-
              ueList to get the complete list of values.

       ::ncgi::parseMimeValue value
              This decodes the Content-Type and other MIME headers  that  have
              the form of "primary value; param=val; p2=v2" It returns a list,
              where the first element is the primary  value,  and  the  second
              element is a list of parameter names and values.

       ::ncgi::query
              This returns the raw query data.

       ::ncgi::redirect url
              Generate  a  response  that  causes  a  302  redirect by the Web
              server.  The url is the new URL that is the target of the  redi-
              rect.   The  URL  will  be qualified with the current server and
              current directory, if necessary, to convert it into a full  URL.

       ::ncgi::reset query type
              Set the query data and Content-Type for the current CGI session.
              This is used by the test suite and by Web servers to  initialize
              the ncgi module so it does not try to read standard input or use
              environment variables to get its data.  If neither query or type
              are  specified,  then  the ncgi module will look in the standard
              CGI environment for its data.

       ::ncgi::setCookie args
              Set a cookie value that will be returned as part of  the  reply.
              This  must  be done before ::ncgi::header or ::ncgi::redirect is
              called in order for the cookie to  be  returned  properly.   The
              args are a set of flags and values:

              -name name





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ncgi(n)                    CGI Support                    ncgi(n)


              -value value

              -expires date

              -path path restriction

              -domain domain restriction

       ::ncgi::setDefaultValue key defvalue
              Set  a  CGI  value  if it does not already exists.  This affects
              future  calls  to  ::ncgi::value  (but  not  future   calls   to
              ::ncgi::nvlist).  If the CGI value already is present, then this
              procedure has no side effects.

       ::ncgi::setDefaultValueList key defvaluelist
              Like ::ncgi::setDefaultValue except that the value  already  has
              list  structure  to  represent  multiple  checkboxes or a multi-
              selection.

       ::ncgi::setValue key value
              Set a CGI value, overriding whatever  was  present  in  the  CGI
              environment already.  This affects future calls to ::ncgi::value
              (but not future calls to ::ncgi::nvlist).

       ::ncgi::setValueList key valuelist
              Like ::ncgi::setValue except that the  value  already  has  list
              structure to represent multiple checkboxes or a multi-selection.

       ::ncgi::type
              Returns the Content-Type of the current CGI values.

       ::ncgi::urlStub ?url?
              Returns the current URL, but without the protocol,  server,  and
              port.  If url is specified, then it defines the URL for the cur-
              rent session.  That value will be returned by  future  calls  to
              ::ncgi::urlStub

       ::ncgi::value key ?default?
              Return the CGI value identified by key.  If the CGI value is not
              present, then the default value is returned instead. This  value
              defaults to the empty string.

              If  the form value key is repeated, then there are two cases: if
              ::ncgi::parse was called, then ::ncgi::value  only  returns  the
              first  value  associated with key.  If ::ncgi::input was called,
              then ::ncgi::value returns a Tcl list value and key must end  in
              "List"  (e.g.,  "skuList").  In the case of multipart/form-data,
              this procedure just returns the value of the form  element.   If
              you want the meta-data associated with each form value, then use
              ::ncgi::valueList.

       ::ncgi::valueList key ?default?
              Like ::ncgi::value, but this always returns  a  list  of  values
              (even   if   there   is   only  one  value).   In  the  case  of



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ncgi(n)                    CGI Support                    ncgi(n)


              multipart/form-data, this procedure returns a list of  two  ele-
              ments.   The first element is meta-data in the form of a parame-
              ter, value list.  The second element is the form value.


EXAMPLES
       Uploading a file

       HTML:
       <html>
       <form action="/cgi-bin/upload.cgi" method="POST" enctype="multipart/form-data">
       Path: <input type="file" name="filedata"><br>
       Name: <input type="text" name="filedesc"><br>
       <input type="submit">
       </form>
       </html>

       TCL: upload.cgi
       #!/usr/local/bin/tclsh

       ::ncgi::parse
       set filedata [::ncgi::value filedata]
       set filedesc [::ncgi::value filedesc]

       puts "<html> File uploaded at <a href=\"/images/$filedesc\">$filedesc</a> </html>"

       set filename /www/images/$filedesc

       set fh [open $filename w]
       puts -nonewline $fh $filedata
       close $fh



BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will  undoubtedly  contain
       bugs  and  other  problems.  Please report such in the category ncgi of
       the         Tcllib         SF         Trackers          [http://source-
       forge.net/tracker/?group_id=12883].   Please  also report any ideas for
       enhancements you may have for either package and/or documentation.

SEE ALSO
       html

KEYWORDS
       CGI, cookie, form, html

CATEGORY
       CGI programming








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