phpman > perldoc > HTML::Mason::CGIHandler(3pm)

NAME
    HTML::Mason::CGIHandler - Use Mason in a CGI environment

SYNOPSIS
    In httpd.conf or .htaccess:

        <LocationMatch "\.html$">
            Action html-mason /cgi-bin/mason_handler.cgi
            AddHandler html-mason .html
        </LocationMatch>
        <LocationMatch "^/cgi-bin/">
            RemoveHandler .html
        </LocationMatch>
        <FilesMatch "(autohandler|dhandler)$">
            Order allow,deny
            Deny from all
        </FilesMatch>

    A script at /cgi-bin/mason_handler.pl :

       #!/usr/bin/perl
       use HTML::Mason::CGIHandler;

       my $h = HTML::Mason::CGIHandler->new
        (
         data_dir  => '/home/jethro/code/mason_data',
         allow_globals => [qw(%session $u)],
        );

       $h->handle_request;

    A .html component somewhere in the web server's document root:

       <%args>
        $mood => 'satisfied'
       </%args>
       % $r->err_header_out(Location => "http://blahblahblah.com/moodring/$mood.html");
       ...

DESCRIPTION
    This module lets you execute Mason components in a CGI environment. It lets you keep your
    top-level components in the web server's document root, using regular component syntax and
    without worrying about the particular details of invoking Mason on each request.

    If you want to use Mason components from *within* a regular CGI script (or any other Perl
    program, for that matter), then you don't need this module. You can simply follow the directions
    in the Using Mason from a standalone script section of the administrator's manual.

    This module also provides an $r request object for use inside components, similar to the Apache
    request object under "HTML::Mason::ApacheHandler", but limited in functionality. Please note
    that we aim to replicate the "mod_perl" functionality as closely as possible - if you find
    differences, do *not* depend on them to stay different. We may fix them in a future release.
    Also, if you need some missing functionality in $r, let us know, we might be able to provide it.

    Finally, this module alters the "HTML::Mason::Request" object $m to provide direct access to the
    CGI query, should such access be necessary.

  "HTML::Mason::CGIHandler" Methods
    *   new()

        Creates a new handler. Accepts any parameter that the Interpreter accepts.

        If no "comp_root" parameter is passed to "new()", the component root will be
        $ENV{DOCUMENT_ROOT}.

    *   handle_request()

        Handles the current request, reading input from $ENV{QUERY_STRING} or "STDIN" and sending
        headers and component output to "STDOUT". This method doesn't accept any parameters. The
        initial component will be the one specified in $ENV{PATH_INFO}.

    *   handle_comp()

        Like "handle_request()", but the first (only) parameter is a component path or component
        object. This is useful within a traditional CGI environment, in which you're essentially
        using Mason as a templating language but not an application server.

        "handle_component()" will create a CGI query object, parse the query parameters, and send
        the HTTP header and component output to STDOUT. If you want to handle those parts yourself,
        see the Using Mason from a standalone script section of the administrator's manual.

    *   handle_cgi_object()

        Also like "handle_request()", but this method takes only a CGI object as its parameter. This
        can be quite useful if you want to use this module with CGI::Fast.

        The component path will be the value of the CGI object's "path_info()" method.

    *   request_args()

        Given an "HTML::Mason::FakeApache" object, this method is expected to return a hash
        containing the arguments to be passed to the component. It is a separate method in order to
        make it easily overrideable in a subclass.

    *   interp()

        Returns the Mason Interpreter associated with this handler. The Interpreter lasts for the
        entire lifetime of the handler.

  $r Methods
    *   headers_in()

        This works much like the "Apache" method of the same name. In an array context, it will
        return a %hash of response headers. In a scalar context, it will return a reference to the
        case-insensitive hash blessed into the "HTML::Mason::FakeTable" class. The values initially
        populated in this hash are extracted from the CGI environment variables as best as possible.
        The pattern is to merely reverse the conversion from HTTP headers to CGI variables as
        documented here: <http://cgi-spec.golux.com/draft-coar-cgi-v11-03-clean.html#6.1>.

    *   header_in()

        This works much like the "Apache" method of the same name. When passed the name of a header,
        returns the value of the given incoming header. When passed a name and a value, sets the
        value of the header. Setting the header to "undef" will actually *unset* the header (instead
        of setting its value to "undef"), removing it from the table of headers returned from future
        calls to "headers_in()" or "header_in()".

    *   headers_out()

        This works much like the "Apache" method of the same name. In an array context, it will
        return a %hash of response headers. In a scalar context, it will return a reference to the
        case-insensitive hash blessed into the "HTML::Mason::FakeTable" class. Changes made to this
        hash will be made to the headers that will eventually be passed to the "CGI" module's
        "header()" method.

    *   header_out()

        This works much like the "Apache" method of the same name. When passed the name of a header,
        returns the value of the given outgoing header. When passed a name and a value, sets the
        value of the header. Setting the header to "undef" will actually *unset* the header (instead
        of setting its value to "undef"), removing it from the table of headers that will be sent to
        the client.

        The headers are eventually passed to the "CGI" module's "header()" method.

    *   err_headers_out()

        This works much like the "Apache" method of the same name. In an array context, it will
        return a %hash of error response headers. In a scalar context, it will return a reference to
        the case-insensitive hash blessed into the "HTML::Mason::FakeTable" class. Changes made to
        this hash will be made to the error headers that will eventually be passed to the "CGI"
        module's "header()" method.

    *   err_header_out()

        This works much like the "Apache" method of the same name. When passed the name of a header,
        returns the value of the given outgoing error header. When passed a name and a value, sets
        the value of the error header. Setting the header to "undef" will actually *unset* the
        header (instead of setting its value to "undef"), removing it from the table of headers that
        will be sent to the client.

        The headers are eventually passed to the "CGI" module's "header()" method.

        One header currently gets special treatment - if you set a "Location" header, you'll cause
        the "CGI" module's "redirect()" method to be used instead of the "header()" method. This
        means that in order to do a redirect, all you need to do is:

         $r->err_header_out(Location => 'http://redirect.to/here');

        You may be happier using the "$m->redirect" method, though, because it hides most of the
        complexities of sending headers and getting the status code right.

    *   content_type()

        When passed an argument, sets the content type of the current request to the value of the
        argument. Use this method instead of setting a "Content-Type" header directly with
        "header_out()". Like "header_out()", setting the content type to "undef" will remove any
        content type set previously.

        When called without arguments, returns the value set by a previous call to "content_type()".
        The behavior when "content_type()" hasn't already been set is undefined - currently it
        returns "undef".

        If no content type is set during the request, the default MIME type "text/html" will be
        used.

    *   method()

        Returns the request method used for the current request, e.g., "GET", "POST", etc.

    *   http_header()

        This method returns the outgoing headers as a string, suitable for sending to the client.

    *   send_http_header()

        Sends the outgoing headers to the client.

    *   notes()

        This works much like the "Apache" method of the same name. When passed a $key argument, it
        returns the value of the note for that key. When passed a $value argument, it stores that
        value under the key. Keys are case-insensitive, and both the key and the value must be
        strings. When called in a scalar context with no $key argument, it returns a hash reference
        blessed into the "HTML::Mason::FakeTable" class.

    *   pnotes()

        Like "notes()", but takes any scalar as an value, and stores the values in a case-sensitive
        hash.

    *   subprocess_env()

        Works like the "Apache" method of the same name, but is simply populated with the current
        values of the environment. Still, it's useful, because values can be changed and then seen
        by later components, but the environment itself remains unchanged. Like the "Apache" method,
        it will reset all of its values to the current environment again if it's called without a
        $key argument.

    *   params()

        This method returns a hash containing the parameters sent by the client. Multiple parameters
        of the same name are represented by array references. If both POST and query string
        arguments were submitted, these will be merged together.

  Added $m methods
    The $m object provided in components has all the functionality of the regular
    "HTML::Mason::Request" object $m, and the following:

    *   cgi_object()

        Returns the current "CGI" request object. This is handy for processing cookies or perhaps
        even doing HTML generation (but is that *really* what you want to do?). If you pass an
        argument to this method, you can set the request object to the argument passed. Use this
        with care, as it may affect components called after the current one (they may check the
        content length of the request, for example).

        Note that the ApacheHandler class (for using Mason under mod_perl) also provides a
        "cgi_object()" method that does the same thing as this one. This makes it easier to write
        components that function equally well under CGIHandler and ApacheHandler.

    *   cgi_request()

        Returns the object that is used to emulate Apache's request object. In other words, this is
        the object that $r is set to when you use this class.

  "HTML::Mason::FakeTable" Methods
    This class emulates the behavior of the "Apache::Table" class, and is used to store manage the
    tables of values for the following attributes of <$r>:

    headers_in
    headers_out
    err_headers_out
    notes
    subprocess_env

    "HTML::Mason::FakeTable" is designed to behave exactly like "Apache::Table", and differs in only
    one respect. When a given key has multiple values in an "Apache::Table" object, one can fetch
    each of the values for that key using Perl's "each" operator:

      while (my ($k, $v) = each %{$r->headers_out}) {
          push @cookies, $v if lc $k eq 'set-cookie';
      }

    If anyone knows how Apache::Table does this, let us know! In the meantime, use "get()" or "do()"
    to get at all of the values for a given key ("get()" is much more efficient, anyway).

    Since the methods named for these attributes return an "HTML::Mason::FakeTable" object hash in a
    scalar reference, it seemed only fair to document its interface.

    *   new()

        Returns a new "HTML::Mason::FakeTable" object. Any parameters passed to "new()" will be
        added to the table as initial values.

    *   add()

        Adds a new value to the table. If the value did not previously exist under the given key, it
        will be created. Otherwise, it will be added as a new value to the key.

    *   clear()

        Clears the table of all values.

    *   do()

        Pass a code reference to this method to have it iterate over all of the key/value pairs in
        the table. Keys will multiple values will trigger the execution of the code reference
        multiple times for each value. The code reference should expect two arguments: a key and a
        value. Iteration terminates when the code reference returns false, to be sure to have it
        return a true value if you wan it to iterate over every value in the table.

    *   get()

        Gets the value stored for a given key in the table. If a key has multiple values, all will
        be returned when "get()" is called in an array context, and only the first value when it is
        called in a scalar context.

    *   merge()

        Merges a new value with an existing value by concatenating the new value onto the existing.
        The result is a comma-separated list of all of the values merged for a given key.

    *   set()

        Takes key and value arguments and sets the value for that key. Previous values for that key
        will be discarded. The value must be a string, or "set()" will turn it into one. A value of
        "undef" will have the same behavior as "unset()".

    *   unset()

        Takes a single key argument and deletes that key from the table, so that none of its values
        will be in the table any longer.