NAME
     Apache::ASP - Active Server Pages for Apache with mod_perl 

SYNOPSIS
     SetHandler perl-script
     PerlHandler Apache::ASP
     PerlSetVar Global /tmp 

DESCRIPTION
    This module provides a Active Server Pages port to Apache with perl as
    the host scripting language. Active Server Pages is a web application
    platform that originated with Microsoft's IIS server. Under Apache for
    both Win32 and Unix, it allows a developer to create dynamic web
    applications with session management and perl code embedded in static
    html files.

    This is a portable solution, similar to ActiveWare's PerlScript and
    MKS's PScript implementation of perl for IIS ASP. Work has been done and
    will continue to make ports to and from these other implementations as
    seemless as possible.

    This module works under the Apache HTTP Server with the mod_perl module
    enabled. See http://www.apache.org and http://perl.apache.org for futher
    information.

    For database access, ActiveX, and scripting language issues, please read
    the FAQ at the end of this document.

  INSTALLATION

    Apache::ASP installs easily using the make or nmake commands as shown
    below. Otherwise, just copy ASP.pm to $PERLLIB/site/Apache

     > perl Makefile.PL
     > make 
     > make test
     > make install

     * use nmake for win32

  CONFIG

    Use with Apache. Copy the /eg directory from the ASP installation to
    your Apache document tree and try it out! You have to put

     AllowOverride All

    in your <Directory> config section to let the .htaccess file in the /eg
    installation directory do its work.

    If you want a STARTER config file, just look at the .htaccess file in
    the /eg directory.

    Here is a Location directive that you might (don't) put in a *.conf
    Apache configuration file. It describes the ASP variables that you can
    set. Don't set the optional ones if you don't want, the defaults are
    fine...

     <Location /asp/>    

     ##ASP##PERL##APACHE##UNIX##WINNT##ASP##PERL##APACHE##NOT##IIS##ASP##
     ##
     ## DOCUMENTATION for the config options, only!  DO NOT paste this 
     ## configuration information directly into an Apache *.conf file
     ## unless you know what you are setting with these options.
     ##
     ##ASP##PERL##APACHE##ACTIVE##SERVER##PAGES##SCRIPTING##FREE##PEACE##

     ###########################################################
     ## mandatory 
     ###########################################################

     # Generic apache directives to make asp start ticking.
     SetHandler perl-script
     PerlHandler Apache::ASP

     # Global
     # ------
     # Must be some writeable directory.  Session and Application
     # state files will be stored in this directory, and 
     # as this directory is pushed onto @INC, you will be 
     # able to "use" and "require" files in this directory.
     # Included files may also be in this directory, please see 
     # section on includes for more information.
     PerlSetVar Global /tmp  
            
     ###########################################################
     ## optional flags 
     ###########################################################

     # CookiePath
     # ----------
     # Url root that client responds to by sending the session cookie.
     # If your asp application falls under the server url "/ASP", 
     # then you would set this variable to /ASP.  This then allows
     # you to run different applications on the same server, with
     # different user sessions for each application.
     #
     PerlSetVar CookiePath /   

     # AllowSessionState
     # -----------------
     # Set to 0 for no session tracking, 1 by default
     # If Session tracking is turned off, performance improves,
     # but the $Session object is inaccessible.
     #
     PerlSetVar AllowSessionState 1    

     # SessionTimeout
     # --------------
     # Session timeout in minutes (defaults to 20)
     #
     PerlSetVar SessionTimeout 20 

     # SecureSession
     # -------------
     # default 0, sets the secure tag for the session cookie, so that the cookie
     # will only be transimitted by the browser under https transmissions.
     #
     PerlSetVar SecureSession 1

     # Debug
     # -----
     # 1 for server log debugging, 2 for extra client html output
     # Use 1 for production debugging, use 2 for development.
     # Turn off if you are not debugging.
     #
     PerlSetVar Debug 2     

     # BufferingOn
     # -----------
     # default 1, if true, buffers output through the response object.
     # $Response object will only send results to client browser if
     # a $Response->Flush() is called, or if the asp script ends.  Lots of 
     # output will need to be flushed incrementally.
     # 
     # If false, 0, the output is immediately written to the client,
     # CGI style.
     #
     # I would only turn this off if you have a really robust site,
     # since error handling is poor, if your asp script errors
     # after sending only some text.
     #
     PerlSetVar BufferingOn 1

     # StatINC
     # -------
     # default 0, if true, reloads perl libraries that have changed
     # on disk automatically for ASP scripts.  If false, the www server
     # must be restarted for library changes to take effect.
     #
     # A known bug is that any functions that are exported, e.g. confess 
     # Carp qw(confess), will not be refreshed by StatINC.  To refresh
     # these, you must restart the www server.  
     #
     PerlSetVar StatINC 1

     # SessionSerialize
     # ----------------
     # default 0, if true, locks $Session for duration of script, which
     # serializes requests to the $Session object.  Only one script at
     # a time may run, per user $Session, with sessions allowed.
     # 
     # Serialized requests to the session object is the Microsoft ASP way, 
     # but is dangerous in a production environment, where there is risk
     # of long-running or run-away processes.  If these things happen,
     # a session may be locked for an indefinate period of time.  A user
     # STOP button should safely quit the session however.
     #
     PerlSetVar SessionSerialize 0

     # SoftRedirect
     # ------------
     # default 0, if true, a $Response->Redirect() does not end the 
     # script.  Normally, when a Redirect() is called, the script
     # is ended automatically.  SoftRedirect 1, is a standard
     # way of doing redirects, allowing for html output after the 
     # redirect is specified.
     #
     PerlSetVar SoftRedirect 0

     # NoState
     # -------
     # default 0, if true, neither the $Application nor $Session objects will
     # be created.  Use this for a performance increase.  Please note that 
     # this setting takes precedence over the AllowSessionState setting.
     #
     PerlSetVar NoState 0

     # StateDir
     # --------
     # default $Global/.state.  State files for ASP application go to 
     # this directory.  Where the state files go is the most important
     # determinant in what makes a unique ASP application.  Different
     # configs pointing to the same StateDir are part of the same
     # ASP application.
     # 
     # The default has not changed since implementing this config directive.
     # The reason for this config option is to allow OS's with caching
     # file systems like Solaris to specify a state directory separatly
     # from the Global directory, which contains more permanent files.
     # This way one may point StateDir to /tmp/asp, and make one's ASP
     # application scream with speed.
     #
     PerlSetVar StateDir ./.state

     # StateManager
     # ------------
     # default 10, this number specifies the numbers of times per SessionTimeout
     # that timed out sessions are garbage collected.  The bigger the number,
     # the slower your system, but the more precise Session_OnEnd's will be 
     # run from global.asa, which occur when a timed out session is cleaned up,
     # and the better able to withstand Session guessing hacking attempts.
     # The lower the number, the faster a normal system will run.  
     #
     # The defaults of 20 minutes for SessionTimeout and 10 times for 
     # StateManager, has dead Sessions being cleaned up every 2 minutes.
     #
     PerlSetVar StateManager 10

     # StateDB
     # --------
     # default SDBM_File, this is the internal database used for state
     # objects like $Application and $Session.  Because an %sdbm_file hash has
     # has a limit on the size of a record / key value pair, usually 1024 bytes,
     # you may want to use another tied database like DB_File.  
     #
     # With lightweight $Session and $Application use, you can get 
     # away with SDBM_File, but if you load it up with complex data like
     #   $Session{key} = { # very large complex object }
     # you might max out the 1024 limit.
     # 
     # Currently StateDB can only be: SDBM_File, DB_File
     # Please let me know if you would like to add any more to this list.
     # 
     # If you switch to a new StateDB, you will want to delete the 
     # old StateDir, as there will likely be incompatibilities between
     # the different database formats, including the way garbage collection
     # is handled.
     #
     PerlSetVar StateDB SDBM_File

     # Filter
     # ------
     # On/Off,default Off.  With filtering enabled, you can take advantage of 
     # full server side includes (SSI), implemented through Apache::SSI.  
     # SSI is implemented through this mechanism by using Apache::Filter.  
     # A sample configuration for full SSI with filtering is in the 
     # eg/.htaccess file, with a relevant example script eg/ssi_filter.ssi.
     # 
     # You may only use this option with modperl v1.16 or greater installed
     # and PERL_STACKED_HANDLERS enabled.  Filtering may be used in 
     # conjunction with other handlers that are also "filter aware".
     #
     # With filtering through Apache::SSI, you should expect at least
     # a 20% performance decrease, increasing as your files get bigger, 
     # increasing the work that SSI must do.
     #
     PerlSetVar Filter Off

     # PodComments
     # -----------
     # default 1.  With pod comments turned on, perl pod style comments
     # and documentation are parsed out of scripts at compile time.
     # This make for great documentation and a nice debugging tool,
     # and it lets you comment out perl code and html in blocks.  
     # Specifically text like this:
     # 
     # =pod
     # text or perl code here
     # =cut 
     #
     # will get ripped out of the script before compiling.  The =pod and
     # =cut perl directives must be at the beginning of the line, and must
     # be followed by the end of the line.
     #
     PerlSetVar PodComments 1

     # DynamicIncludes
     # ---------------
     # default 0.  SSI file includes are normally inlined in the calling 
     # script, and the text gets compiled with the script as a whole. 
     # With this option set to TRUE, file includes are compiled as a
     # separate subroutine and called when the script is run.  
     # The advantage of having this turned on is that the code compiled
     # from the include can be shared between scripts, which keeps the 
     # script sizes smaller in memory, and keeps compile times down.
     #
     PerlSetVar DynamicIncludes 0

     </Location>

     ##ASP##PERL##APACHE##UNIX##WINNT##ASP##PERL##APACHE##NOT##IIS##ASP##
     ## END INSERT
     ##ASP##PERL##APACHE##ACTIVE##SERVER##PAGES##SCRIPTING##!#MICROSOFT##

    You can use the same config in .htaccess files without the Location tag.
    I use the <Files ~ (\.asp)> tag in the .htaccess file of the directory
    that I want to run my asp application. This allows me to mix other file
    types in my application, static or otherwise. Again, please see the ./eg
    directory in the installation for some good starter .htaccess configs,
    and see them in action on the example scripts.

ASP Syntax
    ASP embedding syntax allows one to embed code in html in 2 simple ways.
    The first is the <% xxx %> tag in which xxx is any valid perl code. The
    second is <%= xxx %> where xxx is some scalar value that will be
    inserted into the html directly. An easy print.

     A simple asp page would look like:

     <!-- sample here -->
     <html>
     <body>
     For loop incrementing font size: <p>
     <% for(1..5) { %>
            <!-- iterated html text -->
            <font size="<%=$_%>" > Size = <%=$_%> </font> <br>
     <% } %>
     </body>
     </html>
     <!-- end sample here -->

    Notice that your perl code blocks can span any html. The for loop above
    iterates over the html without any special syntax.

The Event Model & global.asa
    The ASP platform allows developers to create Web Applications. In
    fulfillment of real software requirements, ASP allows event-triggered
    actions to be taken, which are defined in a global.asa file. The
    global.asa file resides in the Global directory, defined as a config
    option , and may define the following actions:

            Action                  Event
            ------                  ------
            Script_OnStart *        Beginning of Script execution
            Script_OnEnd *          End of Script execution
            Application_OnStart     Beginning of Application
            Application_OnEnd       End of Application
            Session_OnStart         Beginning of user's Session.
            Session_OnEnd           End of user's Session.

    * These are API extensions that are not portable, but were added because
    they are incredibly useful

    These actions must be defined in the $Global/global.asa file as
    subroutines, for example:

            sub Session_OnStart {
                    $Application->{$Session->SessionID()} = started;
            }

    Sessions are easy to understand. When visiting a page in a web
    application, each user has one unique $Session. This session expires,
    after which the user will have a new $Session upon revisiting.

    A web application starts when the user visits a page in that
    application, and has a new $Session created. Right before the first
    $Session is created, the $Application is created. When the last user
    $Session expires, that $Application expires also.

  Script_OnStart & Script_OnEnd

    The script events are used to run any code for all scripts in an
    application defined by a global.asa. Often, you would like to run the
    same code for every script, which you would otherwise have to add by
    hand, or add with a file include, but with these events, just add your
    code to the global.asa, and it will be run.

    There is one caveat. Code in Script_OnEnd is not gauranteed to be run
    when the user hits a STOP button, since the program execution ends
    immediately at this event. To always run critical code, use the $Server-
    >RegisterCleanup() method.

  Application_OnStart

    This event marks the beginning of an ASP application, and is run just
    before the Session_OnStart of the first Session of an application. This
    event is useful to load up $Application with data that will be used in
    all user sessions.

  Application_OnEnd

    The end of the application is marked by this event, which is run after
    the last user session has timed out for a given ASP application.

  Session_OnStart

    Triggered by the beginning of a user's session, Session_OnStart get's
    run before the user's executing script, and if the same session recently
    timed out, after the session's triggered Session_OnEnd.

    The Session_OnStart is particularly useful for caching database data,
    and avoids having the caching handled by clumsy code inserted into each
    script being executed.

  Session_OnEnd

    Triggered by a user's session ending, Session_OnEnd can be useful for
    cleaning up and analyzing user data accumulated during a session.

    Sessions end when the session timeout expires, and the StateManager
    performs session cleanup. The timing of the Session_OnEnd does not occur
    immediately after the session times out, but when the first script runs
    after the session expires, and the StateManager allows for that session
    to be cleaned up.

    So on a busy site with default SessionTimeout (20 minutes) and
    StateManager (10 times) settings, the Session_OnEnd for a particular
    session should be run near 22 minutes past the last activity that
    Session saw. A site infrequently visited will only have the
    Session_OnEnd run when a subsequent visit occurs, and theoretically the
    last session of an application ever run will never have its
    Session_OnEnd run.

    Thus I would not put anything mission-critical in the Session_OnEnd,
    just stuff that would be nice to run whenever it gets run.

The Object Model
    The beauty of the ASP Object Model is that it takes the burden of CGI
    and Session Management off the developer, and puts them in objects
    accessible from any ASP script & include. For the perl programmer, treat
    these objects as globals accesible from anywhere in your ASP
    application.

     Currently the Apache::ASP object model supports the following:

     Object         --      Function
     ------                 --------
     $Session       --      session state
     $Response      --      output
     $Request       --      input
     $Application   --      application state
     $Server        --      OLE support + misc

    These objects, and their methods are further defined in the following
    sections.

  $Session Object

    The $Session object keeps track of user + web client state, in a
    persistent manner, making it relatively easy to develop web
    applications. The $Session state is stored accross HTTP connections, in
    SDBM_Files in the Global directory, and will persist across server
    restarts.

    The user's session is referenced by a 32-byte md5-hashed cookie, and can
    be considered secure from session_id guessing, or session hijacking.
    When a hacker fails to guess a session, the system times out for a
    second, and with 2**128 (3.4e38) keys to guess, a hacker won't be
    guessing an id any time soon. Compare the 32-byte key with Miscrosoft
    ASP implementation which is only 16 bytes.

    If an incoming cookie matches a timed out or non-existent session, a new
    session is created with the incoming id. If the id matches a currently
    active session, the session is tied to it and returned. This is also
    similar to Microsoft's ASP implementation.

    The $Session ref is a hash ref, and can be used as such to store data as
    in:

     $Session->{count}++;   # increment count by one
     %{$Session} = ();      # clear $Session data

    The $Session object state is implemented through MLDBM, and a user
    should be aware of the limitations of MLDBM. Basically, you can read
    complex structures, but not write them, directly:

     $data = $Session->{complex}{data};      # Read ok.
     $Session->{complex}{data} = $data;      # Write NOT ok.
     $Session->{complex} = {data => $data};  # Write ok, all at once.

    Please see MLDBM for more information on this topic. $Session can also
    be used for the following methods and properties:

    $Session->{CodePage}
        Not implemented. May never be until someone explains what its
        supposed to do.

    $Session->{LCID}
        Not implemented. May never be until someone explains what its
        supposed to do.

    $Session->{SessionID}
        SessionID property, returns the id for the current session, which is
        exchanged between the client and the server as a cookie.

    $Session->{Timeout} [= $minutes]
        Timeout property, if minutes is being assigned, sets this default
        timeout for the user session, else returns the current session
        timeout.

        If a user session is inactive for the full timeout, the session is
        destroyed by the system. No one can access the session after it
        times out, and the system garbage collects it eventually.

    $Session->Abandon()
        The abandon method times out the session immediately. All Session
        data is cleared in the process, just as when any session times out.

  $Response Object

    This object manages the output from the ASP Application and the client
    web browser. It does store state information like the $Session object
    but does have a wide array of methods to call.

    $Response->{Buffer}
        Default 1, when TRUE sends output from script to client only at the
        end of processing the script. When 0, response is not buffered, and
        client is sent output as output is generated by the script.

    $Response->{CacheControl}
        Default "private", when set to public allows proxy servers to cache
        the content. This setting controls the value set in the HTTP header
        Cache-Control

    $Response->{Charset}
        This member when set appends itself to the value of the Content-
        Length HTTP header. If $Response->{Charset} = 'ISO-LATIN-1' is set,
        the corresponding header would look like:

          Content-Type:text/html; charset=ISO-LATIN-1

    $Response->{ContentType} = "text/html"
        Sets the MIME type for the current response being sent to the
        client. Sent as an HTTP header.

    $Response->{Expires} = $time
        Sends a response header to the client indicating the $time in
        SECONDS in which the document should expire. A time of 0 means
        immediate expiration. The header generated is a standard HTTP date
        like: "Wed, 09 Feb 1994 22:23:32 GMT".

    $Response->{ExpiresAbsolute} = $date
        Sends a response header to the client with $date being an absolute
        time to expire. Formats accepted are all those accepted by
        HTTP::Date::str2time(), e.g.

         "Wed, 09 Feb 1994 22:23:32 GMT"       -- HTTP format
         "Tuesday, 08-Feb-94 14:15:29 GMT"     -- old rfc850 HTTP format

         "08-Feb-94"         -- old rfc850 HTTP format    (no weekday, no time)
         "09 Feb 1994"       -- proposed new HTTP format  (no weekday, no time)

         "Feb  3  1994"      -- Unix 'ls -l' format
         "Feb  3 17:03"      -- Unix 'ls -l' format

    $Response->{IsClientConnected}
        Not implemented. May never be. When a client connection drops, the
        currently running code is aborted, so there is not any relevant time
        that you would use this property.

    $Response->{PICS}
        If this property has been set, a PICS-Label HTTP header will be sent
        with its value. For those that do not know, PICS is a header that is
        useful in rating the internet. It stands for Platform for Internet
        Content Selection, and you can find more info about it at:
        http://www.w3.org

    $Response->{Status} = $status
        Sets the status code returned by the server. Can be used to set
        messages like 500, internal server error

    $Response->AddHeader($name, $value)
        Adds a custom header to a web page. Headers are sent only before any
        text from the main page is sent, so if you want to set a header
        after some text on a page, you must turn BufferingOn.

    $Response->AppendToLog($message)
        Adds $message to the server log. Useful for debugging.

    $Response->BinaryWrite($data)
        Writes binary data to the client. The only difference from
        $Response->Write() is that $Response->Flush() is called internally
        first, so the data cannot be parsed as an html header. Flushing
        flushes the header if has not already been written.

        If you have set the $Reponse->{ContentType} to something other than
        text/html, cgi header parsing (see CGI notes), will be automatically
        be turned off, so you will not necessarily need to use BinaryWrite
        for writing binary data.

        For an example of BinaryWrite, see the gif.htm example in
        ./eg/gif.htm

        Please note that if you are on Win32, you will need to call binmode
        on a file handle before reading, if its data is binary.

    $Response->Clear()
        Erases buffered ASP output.

    $Response->Cookies($name,$value)
    $Response->Cookies($name,$key,$value)
    $Response->Cookies($name,$attribute,$value)
        Sets the key or attribute of cookie with name $name to the value
        $value. If $key is not defined, the Value of the cookie is set. ASP
        CookiePath is assumed to be / in these examples.

         $Response->Cookies('name', 'value'); 
         #-->   Set-Cookie: name=value; path=/

         $Response->Cookies("Test", "data1", "test value");     
         $Response->Cookies("Test", "data2", "more test");      
         $Response->Cookies("Test", "Expires", &HTTP::Date::time2str(time() + 86400)); 
         $Response->Cookies("Test", "Secure", 1);               
         $Response->Cookies("Test", "Path", "/");
         $Response->Cookies("Test", "Domain", "host.com");
         #-->   Set-Cookie:Test=data1=test%20value&data2=more%20test;   \
         #              expires=Fri, 23 Apr 1999 07:19:52 GMT;          \
         #              path=/; domain=host.com; secure

        The latter use of $key in the cookies not only sets cookie
        attributes such as Expires, but also treats the cookie as a hash of
        key value pairs which can later be accesses by

         $Request->Cookies('Test', 'data1');
         $Request->Cookies('Test', 'data2');

        Because this is perl, you can (NOT PORTABLE) reference the cookies
        directly through hash notation. The same 5 commands above could be
        compressed to:

         $Response->{Cookies}{Test} = 
                { 
                        Secure  => 1, 
                        Value   => {data1 => 'test value', data2 => 'more test'},
                        Expires => 86400, # not portable shortcut, see above for proper use
                        Domain  => 'host.com',
                        Path    => '/'
                };

        and the first command would be:

         # you don't need to use hash notation when you are only setting 
         # a simple value
         $Response->{Cookies}{'Test Name'} = 'Test Value'; 

        I prefer the hash notation for cookies, as this looks nice, and is
        quite perlish. It is here to stay. The Cookie() routine is very
        complex and does its best to allow access to the underlying hash
        structure of the data. This is the best emulation I could write
        trying to match the Collections functionality of cookies in IIS ASP.

        For more information on Cookies, please go to the source at:
        http://home.netscape.com/newsref/std/cookie_spec.html

    $Response->Debug(@args)
        API Extension. If the Debug config option is set greater than 0,
        this routine will write @args out to server error log. refs in @args
        will be expanded one level deep, so data in simple data structures
        like one-level hash refs and array refs will be displayed. CODE refs
        like

         $Response->Debug(sub { "some value" });

        will be executed and their output added to the debug output. This
        extension allows the user to tie directly into the debugging
        capabilities of this module.

        While developing an app on a production server, it is often useful
        to have a separate error log for the application to catch debuging
        output separately. One way of implementing this is to use the Apache
        ErrorLog configuration directive to create a separate error log for
        a virtual host.

        If you want further debugging support, like stack traces in your
        code, consider doing things like:

         $Response->Debug( sub { Carp::longmess('debug trace') };
         $SIG{__WARN__} = \&Carp::cluck; # then warn() will stack trace

        The only way at present to see exactly where in your script an error
        occured is to set the Debug config directive to 2, and match the
        error line number to perl script generated from your ASP script.

        If you would like to see the HTML preceeding an error while
        developing, consider setting the BufferingOn config directive to 0.

    $Response->End()
        Sends result to client, and immediately exits script. Automatically
        called at end of script, if not already called.

    $Response->Flush()
        Sends buffered output to client and clears buffer.

    $Response->Include($filename, @args)
        This API extension calls the routine compiled from asp script in
        $filename with the args @args. This is a direct translation of the
        SSI tag <!--#include file=$filename args=@args-->

        Please see the SSI section for more on SSI in general.

        This API extension was created to allow greater modularization of
        code by allowing includes to be called with runtime arguments. Files
        included are compiled once, and the anonymous coderef from that
        compilation is cached, thus including a file in this manner is just
        like calling a perl subroutine.

    $Response->Redirect($url)
        Sends the client a command to go to a different url $url. Script
        immediately ends.

    $Response->Write($data)
        Write output to the HTML page. <%=$data%> syntax is shorthand for a
        $Response->Write($data). All final output to the client must at some
        point go through this method.

  $Request Object

    The request object manages the input from the client brower, like posts,
    query strings, cookies, etc. Normal return results are values if an
    index is specified, or a collection / perl hash ref if no index is
    specified. WARNING, the latter property is not supported in Activeware
    PerlScript, so if you use the hashes returned by such a technique, it
    will not be portable.

     # A normal use of this feature would be to iterate through the 
     # form variables in the form hash...

     $form = $Request->Form();
     for(keys %{$form}) {
            $Response->Write("$_: $form->{$_}<br>\n");
     }

     # Please see the eg/server_variables.htm asp file for this 
     # method in action.

    $Request->{TotalBytes}
        The amount of data sent by the client in the body of the request,
        usually the length of the form data. This is the same value as
        $Request->ServerVariables('CONTENT_LENGTH')

    $Request->BinaryRead($length)
        Returns a scalar whose contents are the first $length bytes of the
        form data, or body, sent by the client request. This data is the raw
        data sent by the client, without any parsing done on it by
        Apache::ASP.

    $Request->ClientCertificate()
        Not implemented.

    $Request->Cookies($name)
    $Request->Cookies($name,$key)
        Returns the value of the Cookie with name $name. If a $key is
        specified, then a lookup will be done on the cookie as if it were a
        query string. So, a cookie set by:

         Set-Cookie: test=data1=1&data2=2

        would have a value of 2 returned by $Request-
        >Cookies('test','data2').

        If no name is specified, a hash will be returned of cookie names as
        keys and cookie values as values. If the cookie value is a query
        string, it will automatically be parsed, and the value will be a
        hash reference to these values.

        When in doubt, try it out. Remember that unless you set the Expires
        attribute of a cookie with $Response->Cookies('cookie', 'Expires',
        $xyz), the cookies that you set will only last until you close your
        browser, so you may find your self opening & closing your browser a
        lot when debugging cookies.

        For more information on cookies in ASP, please read $Response-
        >Cookies()

    $Request->Form($name)
        Returns the value of the input of name $name used in a form with
        POST method. If $name is not specified, returns a ref to a hash of
        all the form data.

        File upload data will be loaded into $Request->Form('file_field'),
        where the value is the actual file name of the file uploaded, and
        the contents of the file can be found by reading from the file name
        as a file handle as in:

         while(read($Request->Form('file_field_name'), $data, 1024)) {};

        For more information, please see the CGI / File Upload section, as
        file uploads are implemented via the CGI.pm module. An example can
        be found in the installation samples ./eg/file_upload.asp

    $Request->QueryString($name)
        Returns the value of the input of name $name used in a form with GET
        method, or passed by appending a query string to the end of a url as
        in http://someurl.com/?data=value. If $name is not specified,
        returns a ref to a hash of all the query string data.

    $Request->ServerVariables($name)
        Returns the value of the server variable / environment variable with
        name $name. If $name is not specified, returns a ref to a hash of
        all the server / environment variables data. The following would be
        a common use of this method:

         $env = $Request->ServerVariables();
         # %{$env} here would be equivalent to the cgi %ENV in perl.

  $Application Object

    Like the $Session object, you may use the $Application object to store
    data across the entire life of the application. Every page in the ASP
    application always has access to this object. So if you wanted to keep
    track of how many visitors there where to the application during its
    lifetime, you might have a line like this:

     $Application->{num_users}++

    The Lock and Unlock methods are used to prevent simultaneous access to
    the $Application object.

    $Application->Lock()
        Locks the Application object for the life of the script, or until
        UnLock() unlocks it, whichever comes first. When $Application is
        locked, this gaurantees that data being read and written to it will
        not suddenly change on you between the reads and the writes.

        This and the $Session object both lock automatically upon every read
        and every write to ensure data integrity. This lock is useful for
        concurrent access control purposes.

        Be careful to not be too liberal with this, as you can quickly
        create application bottlenecks with its improper use.

    $Application->UnLock()
        Unlocks the $Application object. If already unlocked, does nothing.

    $Application->SessionCount()
        This NON-PORTABLE method returns the current number of active
        sessions, in the application. This method is not implemented as part
        of the ASP object model, but is implemented here because it is
        useful. In particular, when accessing databases with license
        requirements, one can monitor usage effectively through accessing
        this value.

        This is a new feature as of v.06, and if run on a site with previous
        versions of Apache::ASP, the count may take a while to synch up. To
        ensure a correct count, you must delete all the current state files
        associated with an application, usually in the $Global/.state
        directory.

  $Server Object

    The server object is that object that handles everything the other
    objects do not. The best part of the server object for Win32 users is
    the CreateObject method which allows developers to create instances of
    ActiveX components, like the ADO component.

    $Server->{ScriptTimeout} = $seconds
        Not implemented. May never be. Please see the Apache Timeout
        configuration option, normally in httpd.conf.

    $Server->CreateObject($program_id)
        Allows use of ActiveX objects on Win32. This routine returns a
        reference to an Win32::OLE object upon success, and nothing upon
        failure. It is through this mechanism that a developer can utilize
        ADO. The equivalent syntax in VBScript is

         Set object = Server.CreateObject(program_id)

        For further information, try 'perldoc Win32::OLE' from your favorite
        command line.

    $Server->HTMLEncode($string)
        Returns an HTML escapes version of $string. &, ", >, <, are each
        escapes with their HTML equivalents. Strings encoded in this nature
        should be raw text displayed to an end user, as HTML tags become
        escaped with this method. "

    $Server->MapPath($url);
        Given the url $url, absolute, or relative to the current executing
        script, this method returns the equivalent filename that the server
        would translate the request to, regardless or whether the request
        would be valid.

        Only a $url that is relative to the host is valid. Urls like "." and
        "/" are fine arguments to MapPath, but "http://localhost" would not
        be.

        To see this method call in action, check out the sample
        ./eg/server.htm script.

    $Server->URLEncode($string)
        Returns the URL-escaped version of the string $string. +'s are
        substituted in for spaces and special characters are escaped to the
        ascii equivalents. Strings encoded in this manner are safe to put in
        url's... they are especially useful for encoding data used in a
        query string as in:

         $data = $Server->URLEncode("test data");
         $url = "http://localhost?data=$data";

         $url evaluates to http://localhost?data=test+data, and is a 
         valid URL for use in anchor <a> tags and redirects, etc.

    $Server->RegisterCleanup($sub_reference)
         non-portable extension

        Sets a subroutine reference to be executed after the script ends,
        whether normally or abnormally, the latter occuring possibly by the
        user hitting the STOP button, or the web server being killed. This
        subroutine must be a code reference created like:

         $Server->RegisterCleanup(sub { $main::Session->{served}++; });
           or
         sub served { $main::Session->{served}++; }
         $Server->RegisterCleanup(\&served);

        The reference to the subroutine passed in will be executed. Though
        the subroutine will be executed in anonymous context, instead of the
        script, all objects will still be defined in main::*, that you would
        reference normally in your script. Output written to $main::Response
        will have no affect at this stage, as the request to the www client
        has already completed.

        Check out the eg/register_cleanup.asp script for an example of this
        routine's use.

Server Side Includes (SSI) & Code Sharing
    SSI is great! One of the main features of SSI is to include other files
    in the script being requested. In Apache::ASP, this is implemented in a
    couple ways, the most crucial of which is implemented in the file
    include. Formatted as

     <!--#include file=filename.inc-->

    ,the .inc being merely a convention, text from the included file will be
    inserted directly into the script being executed and the script will be
    compiled as a whole. Whenever the script or any of its includes change,
    the script will be recompiled.

    Includes go a great length to promote good decomposition and code
    sharing in ASP scripts, but they are still fairly static. As of version
    .09, includes may have dynamic runtime execution, as subroutines
    compiled into the global.asa namespace. The first way to invoke includes
    dynamically is

     <!--#include file=filename.inc args=@args-->

    If @args is specified, Apache::ASP knows to execute the include at
    runtime instead of inlining it directly into the compiled code of the
    script. It does this by compiling the script at runtime as a subroutine,
    and caching it for future invocations. Then the compiled subroutine is
    executed and has @args passed into its as arguments.

    This is still might be too static for some, as @args is still hardcoded
    into the ASP script, so finally, one may execute an include at runtime
    by utilizing this API extension

     $Response->Include("filename.inc", @args);

    , which is a direct transalation of the dynamic include above.

    Although inline includes should be a little faster, runtime dynamic
    includes represent great potential savings in httpd memory, as includes
    are shared between scripts keeping the size of each script to a minimum.
    This can often be significant saving if much of the formatting occurs in
    an included header of a www page.

    By default, all includes will be inlined unless called with an args
    parameter. However, if you want all your includes to be compiled as subs
    and dynamically executed at runtime, turn the DynamicIncludes config
    option on as documented above.

    That is not all! SSI is full featured. One of the things missing above
    is the

     <!--#include virtual=filename.cgi-->

    tag. This and many other SSI code extensions are available by filtering
    Apache::ASP output through Apache::SSI via the Apache::Filter and the
    Filter config options. For more information on how to wire Apache::ASP
    and Apache::SSI together, please see the Filter config option documented
    above. Also please see Apache::SSI for further information on the
    capabilities it offers.

EXAMPLES
    Use with Apache. Copy the ./eg directory from the ASP installation to
    your Apache document tree and try it out! You have to put

     AllowOverride All

    in your <Directory> config section to let the .htaccess file in the /eg
    installation directory do its work.

    IMPORTANT (FAQ): Make sure that the web server has write access to that
    directory. Usually a

     chmod -R 0777 eg

    will do the trick :)

COMPATIBILITY
  CGI

    CGI has been the standard way of deploying web applications long before
    ASP came along. CGI.pm is a very useful module that aids developers in
    the building of these applications, and Apache::ASP has been made to be
    compatible with function calls in CGI.pm. Please see cgi.htm in the ./eg
    directory for a sample ASP script written almost entirely in CGI.

    As of version 0.09, use of CGI.pm for both input and output is seemless
    when working under Apache::ASP. Thus if you would like to port existing
    CGI scripts over to Apache::ASP, all you need to do is wrap <% %> around
    the script to get going. This functionality has been implemented so that
    developers may have the best of both worlds when building their web
    applications.

    Following are some special notes with respect to compatibility with CGI.
    Use of CGI.pm in any of these ways was made possible through a great
    amount of work, and is not gauranteed to be portable with other perl ASP
    implementations, as other ASP implementations will likely be more
    limited.

    Query Object Initialization
        You may create a CGI $query object like so:

                use CGI;
                my $query = new CGI;

        As of Apache::ASP version 0.09, form input may be read in by CGI
        upon initialization. Before, Apache::ASP would consume the form
        input when reading into $Request->Form(), but now form input is
        cached, and may be used by CGI input routines.

    CGI headers
        Not only can you use the CGI $query->header() method to put out
        headers, but you can also print "Header: value\n", and add similar
        lines to the top of your script, like:

         Some-Header: Value
         Some-Other: OtherValue

         <html><body> Script body starts here.

        Once there are no longer any cgi sytle headers, or the there is a
        newline, the body of the script begins. So if you just had an asp
        script like:

            print join(":", %{$Request->QueryString});

        You would likely end up with no output, as that line is interpreted
        as a header because of the semicolon. When doing basic debugging, as
        long as you start the page with <html> you will avoid this problem.

    print()ing CGI
        CGI is notorious for its print() statements, and the functions in
        CGI.pm usually return strings to print(). You can do this under
        Apache::ASP, since print just aliases to $Response->Write(). Note
        that $| has no affect.

                print $query->header();
                print $query->start_form();

    File Upload
        CGI.pm is used for implementing reading the input from file upload.
        You may create the file upload form however you wish, and then the
        data may be recovered from the file upload by using $Request-
        >Form(). Data from a file upload gets written to a filehandle, that
        may in turn be read from. The original file name that was uploaded
        is the name of the file handle.

                my $filehandle = $Request->Form('file_upload_field_name');
                print $filehandle; # will get you the file name
                my $data;
                while(read($filehandle, $data, 1024)) {
                        # data from the uploaded file read into $data
                };

        Please see the docs on CGI.pm (try perldoc CGI) for more information
        on this topic, and ./eg/file_upload.asp for an example of its use.

  PerlScript

    Much work has been done to bring compatibility with ASP applications
    written in PerlScript under IIS. Most of that work revolved around
    bringing a Win32::OLE Collection interface to many of the objects in
    Apache::ASP, which are natively written as perl hashes.

    The following objects in Apache::ASP respond as Collections:

            $Application
            $Session
            $Request->Form
            $Request->QueryString
            $Request->Cookies
            $Response->Cookies
            $Response->Cookies('Any Cookie')

    And as such may be used with the following syntax, as compared with the
    Apache::ASP native calls. Please note the native Apache::ASP interface
    is compatible with the deprecated PerlScript interface.

            C = PerlScript Compatibility    N = Native Apache::ASP 
            
            ## Collection->Contents($name) 
            [C] $Application->Contents('XYZ')               
            [N] $Application->{XYZ}

            ## Collection->SetProperty($property, $name, $value)
            [C] $Application->Contents->SetProperty('Item', 'XYZ', "Fred");
            [N] $Application->{XYZ} = "Fred"

            ## Collection->GetProperty($property, $name)
            [C] $Application->Contents->GetProperty('Item', 'XYZ')          
            [N] $Application->{XYZ}

            ## Collection->Item($name)
            [C] print $Request->QueryString->Item('message'), "<br>\n\n";
            [N] print $Request->{QueryString}{'message'}, "<br>\n\n";               

            ## Working with Cookies
            [C] $Response->SetProperty('Cookies', 'Testing', 'Extra');
            [C] $Response->SetProperty('Cookies', 'Testing', {'Path' => '/'});
            [C] print $Request->Cookies(Testing) . "<br>\n";
            [N] $Response->{Cookies}{Testing} = {Value => Extra, Path => '/'};
            [N] print $Request->{Cookies}{Testing} . "<br>\n";

    Several incompatibilities exist between PerlScript and Apache::ASP:

     > Collection->{Count} property has not been implemented.
     > VBScript dates may not be used for Expires property of cookies.
     > Win32::OLE::in may not be used.  Use keys() to iterate over Collections.
     > The ->{Item} property is parsed automatically out of scripts, use ->Item().

FAQ
    What is the best way to debug an ASP application ?
        There are lots of perl-ish tricks to make your life developing and
        debugging an ASP application easier. For starters, you will find
        some helpful hints by reading the $Response->Debug() API extension,
        and the Debug configuration directive.

    Apache errors on the PerlHandler directive ?
        You do not have mod_perl correctly installed for Apache. The
        PerlHandler directive in Apache *.conf files is an extension enabled
        by mod_perl and will not work if mod_perl is not correctly
        installed.

        Common user errors are not doing a 'make install' for mod_perl,
        which installs the perl side of mod_perl, and not starting the right
        httpd after building it. The latter often occurs when you have an
        old apache server without mod_perl, and you have built a new one
        without copying over to its proper location.

        To get mod_perl, go to http://perl.apache.org

    How are file uploads handled?
        Please see the CGI section above. File uploads are implemented
        through CGI.pm which is loaded at runtime only for this purpose.
        This is the only time that CGI.pm will be loaded by Apache::ASP,
        which implements all other cgi-ish functionality natively. The
        rationale for not implementing file uploads natively is that the
        extra 100K in mem for CGI.pm shouldn't be a big deal if you are
        working with bulky file uploads.

    How is database connectivity handled?
        Database connectivity is handled through perl's DBI & DBD
        interfaces. Please see
        http://www.hermetica.com/technologia/perl/DBI/ for more information.
        In the UNIX world, it seems most databases have cross platform
        support in perl.

        DBD::ODBC is often your ticket on Win32. On UNIX, commercial vendors
        like OpenLink Software (http://www.openlinksw.com/) provide the nuts
        and bolts for ODBC.

    Do I have access to ActiveX objects?
        Only under Win32 will developers have access to ActiveX objects
        through the perl Win32::OLE interface. This will remain true until
        there are free COM ports to the UNIX world. At this time, there is
        no ActiveX for the UNIX world.

    Can I script in VBScript or JScript ?
        Yes, but not with this perl module. For ASP with other scripting
        languages besides perl, you will need to go with a commercial vendor
        in the UNIX world. ChiliSoft (http://www.chilisoft.com/) has one
        such solution. Of course on NT, you get this for free with IIS.

    How do I get things I want done?!
        If you find a problem with the module, or would like a feature
        added, please mail support, as listed below, and your needs will be
        promptly and seriously considered, then implemented.

    What is the state of Apache::ASP?  Can I publish a web site on it?
        Apache::ASP has been production ready since v.02. Work being done on
        the module is on a per-need basis, with the goal being to eventually
        have the ASP API completed, with full portability to ActiveState
        PerlScript and MKS PScript. If you can suggest any changes to
        facilitate these goals, your comments are welcome.

    I am getting a tie or MLDBM / state error message, what do I do?
        Make sure the web server or you have write access to the eg
        directory, or to the directory specified as Global in the config you
        are using. Default for Global is the directory the script is in
        (e.g. '.'), but should be set to some directory not under the www
        server document root, for security reasons, on a production site.

        Usually a

         chmod -R -0777 eg

        will take care of the write access issue for initial testing
        purposes.

        Failing write access being the problem, try upgrading your version
        of Data::Dumper and MLDBM, which are the modules used to write the
        state files.

    How do I access the ASP Objects in general?
        All the ASP objects can be referenced through the main package with
        the following notation:

         $main::Response->Write("html output");

        This notation can be used from anywhere in perl, including routines
        defined in your global.asa, and registered with $Server-
        >RegisterCleanup().

        Only in your main ASP script and includes, can you use the normal
        notation:

         $Response->Write("html output");

    Can I print() in ASP?
        Yes. You can print() from anywhere in an ASP script as it aliases to
        the $Response->Write() method. However, this method is not portable
        (unless you can tell me otherwise :)

PERFORMANCE
  BENCHMARKS

     Hits/Sec       Processor       OS      Static  ASP     State   DBI     Logic
     --------       ---------       --      ------  ---     -----   ---     -----
     25             PII 300         WinNT   Y       -       -       -       -
     16             PII 300         WinNT   -       Y       -       -       -
     11             PII 300         WinNT   -       Y       Y       -       -
     10             PII 300         WinNT   -       Y       -       -       Y
     7              PII 300         WinNT   -       Y       Y       Oracle  Y

     * all benchmarks run with clients and server on same machine
     ** please mail me some of your results if you conduct your own benchmark

     Static -       Static html content, the fastest, included for control purposes.
     ASP    -       ASP script, as opposed to static content.
     State  -       Defined $Application and $Session objects.
     DBI     -      Persistent Database connection part of script, with Apache::DBI.
     Logic  -       Real web application logic, extra modules, etc.  A "Real Site".

  HINTS

     1) Use NoState 1 setting if you don't need the $Application or $Session objects.
        State objects such as these tie to files on disk and will incur a performace
        penalty.

     2) If you need the state objects $Application and $Session, and if 
        running an OS that caches files in memory, set your "StateDir" 
        directory to a cached file system.  On WinNT, all files 
        may be cached, and you have no control of this.  On Solaris, /tmp is cached
        and would be a good place to set the "StateDir" config setting to.  
        When cached file systems are used there is little performance penalty 
        for using state files.

     3) Don't use .htaccess files or the StatINC setting in a production system
        as there are many more files touched per request using these features.  I've
        seen performance slow down by half because of using these.  For eliminating
        the .htaccess file, move settings into *.conf Apache files.

     4) Set your max requests per child thread or process (in httpd.conf) high, 
        so that ASP scripts have a better chance being cached, which happens after 
        they are first compiled.  You will also avoid the process fork penalty on 
        UNIX systems.  Somewhere between 100 - 1000 is probably pretty good.

     5) If you have a lot of scripts, and limited memory, set NoCache to 1,
        so that compiled scripts are not cached in memory.  You lose about
        10-15% in speed for small scripts, but save about 10K per cached
        script.  These numbers are very rough.  If you use includes, you
        can instead try setting DynamicIncludes to 1, which will share compiled
        code for includes between scripts.

     6) Turn debugging off by setting Debug to 0.  Having the debug config option
        on slows things down immensely.

     7) Precompile your scripts by using the Apache::ASP->Loader() routine
        documented below.  This will at least save the first user hitting 
        a script from suffering compile time lag.  On UNIX, precompiling scripts
        upon server startup allows this code to be shared with forked child
        www servers, so you reduce overall memory usage, and use less CPU 
        compiling scripts for each separate www server process.  These 
        savings could be significant.  On my PII300, it takes a couple seconds
        to compile 28 scripts upon server startup, and this savings is passed
        on to the child servers.

     8) For more tips and tricks for general Apache and mod_perl performance
        tuning, please reference the docs at http://perl.apache.org

  PRECOMPILING SCRIPTS

    Apache::ASP->Loader() can be called to precompile scripts and even
    entire ASP applications at server startup. The reasons why you would do
    this are described in the HINTS section. Note also that in modperl, you
    can precompile modules with the PerlModule config directive, which is
    highly recommended.

     Apache::ASP->Loader($path, $pattern, %config)

    This routine takes a file or directory as its first arg. If a file, that
    file will be compiled. If a directory, that directory will be recursed,
    and all files in it whose file name matches $pattern will be compiled.
    $pattern defaults to .*, which says that all scripts in a directory will
    be compiled by default. The %config args, are the config options that
    you want set that affect compilation. These options include Global &
    DynamicIncludes. If your scripts are later run with different config
    options, your scripts may have to be recompiled.

    Here is an example of use in a *.conf file:

     <Perl> 
            Apache::ASP->Loader(
                    'c:/proj/site', "(asp|htm)\$", 
                    Debug => 1,
                    Global => '/proj/perllib'
                    ); 
     </Perl>

    This config section tells the server to compile all scripts in
    c:/proj/site that end in asp or htm, and print debugging output so you
    can see it work. It also sets the Global directory to be /proj/perllib,
    which needs to be the same as your real config since scripts are cached
    uniquely by their Global directory. You will probably want to use this
    on a production server, unless you cannot afford the extra startup time.

    To see precompiling in action, set Debug to 1 for the Loader() and for
    your application in general and watch your error_log for messages
    indicating scripts being cached.

SEE ALSO
    perl(1), mod_perl(3), Apache(3), MLDBM(3), HTTP::Date(3), CGI(3),
    Win32::OLE(3)

NOTES
    Many thanks to those who helped me make this module a reality. ASP +
    Apache, web development could not be better! Kudos go out to:

     :) Doug MacEachern, for moral support and of course mod_perl
     :) Ryan Whelan, for boldly testing on Unix in the early infancy of ASP
     :) Lupe Christoph, for his immaculate and stubborn testing skills
     :) Bryan Murphy, for being a PerlScript wiz
     :) Francesco Pasqualini, for bringing ASP to CGI
     :) Michael Rothwell, for his love of Session hacking
     :) Lincoln Stein, for his blessed CGI module
     :) Alan Sparks, for knowing when size is more important than speed
     :) Jeff Groves, who put a STOP to user stop button woes
     :) Matt Sergeant, for his excellect tutorial on PerlScript
     :) Ken Williams, for great teamwork bringing full SSI to the table
     :) Darren Gibbons, the biggest cookie-monster I have ever known.
     :) Doug Silver, for finding most of the bugs.
     :) Marc Spencer, who brainstormed dynamic includes.
     :) Greg Stark, for endless enthusiasm, pushing the module to its limits.
     :) Richard Rossi, for his need for speed & bravely testing dynamic includes

SUPPORT
    Please send any questions or comments to the Apache modperl mailing list
    at modperl@apache.org or to me at chamas@alumni.stanford.org.

COPYRIGHT
    Copyright (c) 1998-1999, Joshua Chamas.

    All rights reserved. This program is free software; you can redistribute
    it and/or modify it under the same terms as Perl itself.