=head1 NAME
-perlfaq9 - Networking ($Revision: 1.20 $, $Date: 1998/06/22 18:31:09 $)
+perlfaq9 - Networking ($Revision: 1.26 $, $Date: 1999/05/23 16:08:30 $)
=head1 DESCRIPTION
http://www.webthing.com/page.cgi/cgifaq
Web FAQ
- http://www.boutell.com/faq/
+ http://www.boutell.com/faq/
WWW Security FAQ
http://www.w3.org/Security/Faq/
=head2 How do I remove HTML from a string?
-The most correct way (albeit not the fastest) is to use HTML::Parse
-from CPAN (part of the libwww-perl distribution, which is a must-have
-module for all web hackers).
+The most correct way (albeit not the fastest) is to use HTML::Parser
+from CPAN (part of the HTML-Tree package on CPAN).
Many folks attempt a simple-minded regular expression approach, like
C<s/E<lt>.*?E<gt>//g>, but that fails in many cases because the tags
<IMG SRC = "foo.gif" ALT = "A > B">
- <IMG SRC = "foo.gif"
+ <IMG SRC = "foo.gif"
ALT = "A > B">
<!-- <A comment> -->
}gsix;
This version does not adjust relative URLs, understand alternate
-bases, deal with HTML comments, deal with HREF and NAME attributes in
-the same tag, or accept URLs themselves as arguments. It also runs
-about 100x faster than a more "complete" solution using the LWP suite
-of modules, such as the
-http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/xurl.gz
-program.
+bases, deal with HTML comments, deal with HREF and NAME attributes
+in the same tag, understand extra qualifiers like TARGET, or accept
+URLs themselves as arguments. It also runs about 100x faster than a
+more "complete" solution using the LWP suite of modules, such as the
+http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/xurl.gz program.
=head2 How do I download a file from the user's machine? How do I open a file on another machine?
$html_code = `lynx -source $url`;
$text_data = `lynx -dump $url`;
-The libwww-perl (LWP) modules from CPAN provide a more powerful way to
-do this. They work through proxies, and don't require lynx:
+The libwww-perl (LWP) modules from CPAN provide a more powerful way
+to do this. They don't require lynx, but like lynx, can still work
+through proxies:
# simplest version
use LWP::Simple;
getprint "http://www.sn.no/libwww-perl/";
# or print ASCII from HTML from a URL
+ # also need HTML-Tree package from CPAN
use LWP::Simple;
- use HTML::Parse;
+ use HTML::Parser;
use HTML::FormatText;
my ($html, $ascii);
$html = get("http://www.perl.com/");
print "Location: $url\n\n";
exit;
-To be correct to the spec, each of those C<"\n">
-should really each be C<"\015\012">, but unless you're
-stuck on MacOS, you probably won't notice.
+To target a particular frame in a frameset, include the "Window-target:"
+in the header.
+
+ print <<EOF;
+ Location: http://www.domain.com/newpage
+ Window-target: <FrameName>
+
+ EOF
+
+To be correct to the spec, each of those virtual newlines should really be
+physical C<"\015\012"> sequences by the time you hit the client browser.
+Except for NPH scripts, though, that local newline should get translated
+by your server into standard form, so you shouldn't have a problem
+here, even if you are stuck on MacOS. Everybody else probably won't
+even notice.
=head2 How do I put a password on my web pages?
tempted to reinvent the wheel. Instead, use the CGI.pm or CGI_Lite.pm
(available from CPAN), or if you're trapped in the module-free land
of perl1 .. perl4, you might look into cgi-lib.pl (available from
-http://www.bio.cam.ac.uk/web/form.html).
+http://cgi-lib.stanford.edu/cgi-lib/ ).
Make sure you know whether to use a GET or a POST in your form.
GETs should only be used for something that doesn't update the server.
deliverable which are compliant.
Many are tempted to try to eliminate many frequently-invalid
-mail addresses with a simple regexp, such as
+mail addresses with a simple regex, such as
C</^[\w.-]+\@([\w.-]\.)+\w+$/>. It's a very bad idea. However,
this also throws out many valid ones, and says nothing about
potential deliverability, so is not suggested. Instead, see
To: Final Destination <you\@otherhost>
Subject: A relevant subject line
- Body of the message goes here, in as many lines as you like.
+ Body of the message goes here after the blank line
+ in as many lines as you like.
EOF
close(SENDMAIL) or warn "sendmail didn't close nicely";
be immediately delivered, so leave it out if you want immediate
delivery.
-Or use the CPAN module Mail::Mailer:
+Alternate, less convenient approaches include calling mail (sometimes
+called mailx) directly or simply opening up port 25 have having an
+intimate conversation between just you and the remote SMTP daemon,
+probably sendmail.
+
+Or you might be able use the CPAN module Mail::Mailer:
use Mail::Mailer;
The Mail::Internet module uses Net::SMTP which is less Unix-centric than
Mail::Mailer, but less reliable. Avoid raw SMTP commands. There
-are many reasons to use a mail transport agent like sendmail. These
+are many reasons to use a mail transport agent like sendmail. These
include queueing, MX records, and security.
=head2 How do I read mail?
-Use the Mail::Folder module from CPAN
-(part of the MailFolder package) or the Mail::Internet module from
-CPAN (also part of the MailTools package).
-
- # sending mail
- use Mail::Internet;
- use Mail::Header;
- # say which mail host to use
- $ENV{SMTPHOSTS} = 'mail.frii.com';
- # create headers
- $header = new Mail::Header;
- $header->add('From', 'gnat@frii.com');
- $header->add('Subject', 'Testing');
- $header->add('To', 'gnat@frii.com');
- # create body
- $body = 'This is a test, ignore';
- # create mail object
- $mail = new Mail::Internet(undef, Header => $header, Body => \[$body]);
- # send it
- $mail->smtpsend or die;
-
-Often a module is overkill, though. Here's a mail sorter.
-
- #!/usr/bin/perl
+While you could use the Mail::Folder module from CPAN (part of the
+MailFolder package) or the Mail::Internet module from CPAN (also part
+of the MailTools package), often a module is overkill, though. Here's a
+mail sorter.
+
+ #!/usr/bin/perl
# bysub1 - simple sort by subject
my(@msgs, @sub);
my $msgno = -1;
$sub[++$msgno] = lc($1) || '';
}
$msgs[$msgno] .= $_;
- }
+ }
for my $i (sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msgs)) {
print $msgs[$i];
}
-Or more succinctly,
+Or more succinctly,
#!/usr/bin/perl -n00
# bysub2 - awkish sort-by-subject
use Socket;
use Sys::Hostname;
my $host = hostname();
- my $addr = inet_ntoa(scalar(gethostbyname($name)) || 'localhost');
+ my $addr = inet_ntoa(scalar gethostbyname($host || 'localhost'));
Probably the simplest way to learn your DNS domain name is to grok
it out of /etc/resolv.conf, at least under Unix. Of course, this
A DCE::RPC module is being developed (but is not yet available), and
will be released as part of the DCE-Perl package (available from
-CPAN). No ONC::RPC module is known.
+CPAN). The rpcgen suite, available from CPAN/authors/id/JAKE/, is
+an RPC stub generator and includes an RPC::ONC module.
=head1 AUTHOR AND COPYRIGHT
-Copyright (c) 1997, 1998 Tom Christiansen and Nathan Torkington.
+Copyright (c) 1997-1999 Tom Christiansen and Nathan Torkington.
All rights reserved.
When included as part of the Standard Version of Perl, or as part of
https://perl5.git.perl.org / perl5.git / blobdiff