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diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod index d00d918deb2..b42755efe0a 100644 --- a/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod +++ b/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod @@ -1,355 +1,207 @@ =head1 NAME -perlfaq9 - Networking +perlfaq9 - Web, Email and Networking =head1 DESCRIPTION -This section deals with questions related to networking, the internet, -and a few on the web. +This section deals with questions related to running web sites, +sending and receiving email as well as general networking. -=head2 What is the correct form of response from a CGI script? +=head2 Should I use a web framework? -(Alan Flavell <flavell+www@a5.ph.gla.ac.uk> answers...) +Yes. If you are building a web site with any level of interactivity +(forms / users / databases), you +will want to use a framework to make handling requests +and responses easier. -The Common Gateway Interface (CGI) specifies a software interface between -a program ("CGI script") and a web server (HTTPD). It is not specific -to Perl, and has its own FAQs and tutorials, and usenet group, -comp.infosystems.www.authoring.cgi +If there is no interactivity then you may still want +to look at using something like L<Template Toolkit|https://metacpan.org/module/Template> +or L<Plack::Middleware::TemplateToolkit> +so maintenance of your HTML files (and other assets) is easier. -The CGI specification is outlined in an informational RFC: -http://www.ietf.org/rfc/rfc3875 +=head2 Which web framework should I use? +X<framework> X<CGI.pm> X<CGI> X<Catalyst> X<Dancer> -These Perl FAQs very selectively cover some CGI issues. However, Perl -programmers are strongly advised to use the C<CGI.pm> module, to take care -of the details for them. +There is no simple answer to this question. Perl frameworks can run everything +from basic file servers and small scale intranets to massive multinational +multilingual websites that are the core to international businesses. -The similarity between CGI response headers (defined in the CGI -specification) and HTTP response headers (defined in the HTTP -specification, RFC2616) is intentional, but can sometimes be confusing. +Below is a list of a few frameworks with comments which might help you in +making a decision, depending on your specific requirements. Start by reading +the docs, then ask questions on the relevant mailing list or IRC channel. -The CGI specification defines two kinds of script: the "Parsed Header" -script, and the "Non Parsed Header" (NPH) script. Check your server -documentation to see what it supports. "Parsed Header" scripts are -simpler in various respects. The CGI specification allows any of the -usual newline representations in the CGI response (it's the server's -job to create an accurate HTTP response based on it). So "\n" written in -text mode is technically correct, and recommended. NPH scripts are more -tricky: they must put out a complete and accurate set of HTTP -transaction response headers; the HTTP specification calls for records -to be terminated with carriage-return and line-feed; i.e., ASCII \015\012 -written in binary mode. +=over 4 -Using C<CGI.pm> gives excellent platform independence, including EBCDIC -systems. C<CGI.pm> selects an appropriate newline representation -(C<$CGI::CRLF>) and sets binmode as appropriate. +=item L<Catalyst> -=head2 My CGI script runs from the command line but not the browser. (500 Server Error) +Strongly object-oriented and fully-featured with a long development history and +a large community and addon ecosystem. It is excellent for large and complex +applications, where you have full control over the server. -(contributed by brian d foy) - -There are many things that might be wrong with your CGI program, and only -some of them might be related to Perl. Try going through the troubleshooting -guide on Perlmonks: - - http://www.perlmonks.org/?node_id=380424 - -=head2 How can I get better error messages from a CGI program? - -Use the C<CGI::Carp> module. It replaces C<warn> and C<die>, plus the -normal C<Carp> module's C<carp>, C<croak>, and C<confess> functions with -more verbose and safer versions. It still sends them to the normal -server error log. - - use CGI::Carp; - warn "This is a complaint"; - die "But this one is serious"; - -The following use of C<CGI::Carp> also redirects errors to a file of your choice, -placed in a C<BEGIN> block to catch compile-time warnings as well: - - BEGIN { - use CGI::Carp qw(carpout); - open(LOG, ">>/var/local/cgi-logs/mycgi-log") - or die "Unable to append to mycgi-log: $!\n"; - carpout(*LOG); - } - -You can even arrange for fatal errors to go back to the client browser, -which is nice for your own debugging, but might confuse the end user. +=item L<Dancer> - use CGI::Carp qw(fatalsToBrowser); - die "Bad error here"; +Young and free of legacy weight, providing a lightweight and easy to learn API. +Has a growing addon ecosystem. It is best used for smaller projects and +very easy to learn for beginners. -Even if the error happens before you get the HTTP header out, the module -will try to take care of this to avoid the dreaded server 500 errors. -Normal warnings still go out to the server error log (or wherever -you've sent them with C<carpout>) with the application name and date -stamp prepended. +=item L<Mojolicious> -=head2 How do I remove HTML from a string? - -The most correct way (albeit not the fastest) is to use C<HTML::Parser> -from CPAN. Another mostly correct -way is to use C<HTML::FormatText> which not only removes HTML but also -attempts to do a little simple formatting of the resulting plain text. - -Many folks attempt a simple-minded regular expression approach, like -C<< s/<.*?>//g >>, but that fails in many cases because the tags -may continue over line breaks, they may contain quoted angle-brackets, -or HTML comments may be present. Plus, folks forget to convert -entities--like C<<> for example. - -Here's one "simple-minded" approach, that works for most files: - - #!/usr/bin/perl -p0777 - s/<(?:[^>'"]*|(['"]).*?\g1)*>//gs +Fairly young with a focus on HTML5 and real-time web technologies such as +WebSockets. -If you want a more complete solution, see the 3-stage striphtml -program in -http://www.cpan.org/authors/Tom_Christiansen/scripts/striphtml.gz -. +=item L<Web::Simple> -Here are some tricky cases that you should think about when picking -a solution: +Currently experimental, strongly object-oriented, built for speed and intended +as a toolkit for building micro web apps, custom frameworks or for tieing +together existing Plack-compatible web applications with one central dispatcher. - <IMG SRC = "foo.gif" ALT = "A > B"> +=back - <IMG SRC = "foo.gif" - ALT = "A > B"> +All of these interact with or use L<Plack> which is worth understanding +the basics of when building a website in Perl (there is a lot of useful +L<Plack::Middleware|https://metacpan.org/search?q=plack%3A%3Amiddleware>). - <!-- <A comment> --> +=head2 What is Plack and PSGI? - <script>if (a<b && a>c)</script> +L<PSGI> is the Perl Web Server Gateway Interface Specification, it is +a standard that many Perl web frameworks use, you should not need to +understand it to build a web site, the part you might want to use is L<Plack>. - <# Just data #> +L<Plack> is a set of tools for using the PSGI stack. It contains +L<middleware|https://metacpan.org/search?q=plack%3A%3Amiddleware> +components, a reference server and utilities for Web application frameworks. +Plack is like Ruby's Rack or Python's Paste for WSGI. - <![INCLUDE CDATA [ >>>>>>>>>>>> ]]> +You could build a web site using L<Plack> and your own code, +but for anything other than a very basic web site, using a web framework +(that uses L<Plack>) is a better option. -If HTML comments include other tags, those solutions would also break -on text like this: +=head2 How do I remove HTML from a string? - <!-- This section commented out. - <B>You can't see me!</B> - --> +Use L<HTML::Strip>, or L<HTML::FormatText> which not only removes HTML +but also attempts to do a little simple formatting of the resulting +plain text. =head2 How do I extract URLs? -You can easily extract all sorts of URLs from HTML with -C<HTML::SimpleLinkExtor> which handles anchors, images, objects, -frames, and many other tags that can contain a URL. If you need -anything more complex, you can create your own subclass of -C<HTML::LinkExtor> or C<HTML::Parser>. You might even use -C<HTML::SimpleLinkExtor> as an example for something specifically +L<HTML::SimpleLinkExtor> will extract URLs from HTML, it handles anchors, +images, objects, frames, and many other tags that can contain a URL. +If you need anything more complex, you can create your own subclass of +L<HTML::LinkExtor> or L<HTML::Parser>. You might even use +L<HTML::SimpleLinkExtor> as an example for something specifically suited to your needs. -You can use C<URI::Find> to extract URLs from an arbitrary text document. - -Less complete solutions involving regular expressions can save -you a lot of processing time if you know that the input is simple. One -solution from Tom Christiansen runs 100 times faster than most -module-based approaches but only extracts URLs from anchors where the first -attribute is HREF and there are no other attributes. - - #!/usr/bin/perl -n00 - # qxurl - tchrist@perl.com - print "$2\n" while m{ - < \s* - A \s+ HREF \s* = \s* (["']) (.*?) \g1 - \s* > - }gsix; - -=head2 How do I download a file from the user's machine? How do I open a file on another machine? - -In this case, download means to use the file upload feature of HTML -forms. You allow the web surfer to specify a file to send to your web -server. To you it looks like a download, and to the user it looks -like an upload. No matter what you call it, you do it with what's -known as B<multipart/form-data> encoding. The C<CGI.pm> module (which -comes with Perl as part of the Standard Library) supports this in the -C<start_multipart_form()> method, which isn't the same as the C<startform()> -method. - -See the section in the C<CGI.pm> documentation on file uploads for code -examples and details. - -=head2 How do I make an HTML pop-up menu with Perl? - -(contributed by brian d foy) - -The C<CGI.pm> module (which comes with Perl) has functions to create -the HTML form widgets. See the C<CGI.pm> documentation for more -examples. - - use CGI qw/:standard/; - print header, - start_html('Favorite Animals'), - - start_form, - "What's your favorite animal? ", - popup_menu( - -name => 'animal', - -values => [ qw( Llama Alpaca Camel Ram ) ] - ), - submit, - - end_form, - end_html; +You can use L<URI::Find> to extract URLs from an arbitrary text document. =head2 How do I fetch an HTML file? (contributed by brian d foy) -Use the libwww-perl distribution. The C<LWP::Simple> module can fetch web +Use the libwww-perl distribution. The L<LWP::Simple> module can fetch web resources and give their content back to you as a string: - use LWP::Simple qw(get); + use LWP::Simple qw(get); - my $html = get( "http://www.example.com/index.html" ); + my $html = get( "http://www.example.com/index.html" ); It can also store the resource directly in a file: - use LWP::Simple qw(getstore); + use LWP::Simple qw(getstore); - getstore( "http://www.example.com/index.html", "foo.html" ); + getstore( "http://www.example.com/index.html", "foo.html" ); If you need to do something more complicated, you can use -C<LWP::UserAgent> module to create your own user-agent (e.g. browser) +L<LWP::UserAgent> module to create your own user-agent (e.g. browser) to get the job done. If you want to simulate an interactive web -browser, you can use the C<WWW::Mechanize> module. +browser, you can use the L<WWW::Mechanize> module. =head2 How do I automate an HTML form submission? If you are doing something complex, such as moving through many pages -and forms or a web site, you can use C<WWW::Mechanize>. See its +and forms or a web site, you can use L<WWW::Mechanize>. See its documentation for all the details. If you're submitting values using the GET method, create a URL and encode the form using the C<query_form> method: - use LWP::Simple; - use URI::URL; + use LWP::Simple; + use URI::URL; - my $url = url('http://www.perl.com/cgi-bin/cpan_mod'); - $url->query_form(module => 'DB_File', readme => 1); - $content = get($url); + my $url = url('L<http://www.perl.com/cgi-bin/cpan_mod')>; + $url->query_form(module => 'DB_File', readme => 1); + $content = get($url); If you're using the POST method, create your own user agent and encode the content appropriately. - use HTTP::Request::Common qw(POST); - use LWP::UserAgent; + use HTTP::Request::Common qw(POST); + use LWP::UserAgent; - $ua = LWP::UserAgent->new(); - my $req = POST 'http://www.perl.com/cgi-bin/cpan_mod', - [ module => 'DB_File', readme => 1 ]; - $content = $ua->request($req)->as_string; + my $ua = LWP::UserAgent->new(); + my $req = POST 'L<http://www.perl.com/cgi-bin/cpan_mod'>, + [ module => 'DB_File', readme => 1 ]; + my $content = $ua->request($req)->as_string; =head2 How do I decode or create those %-encodings on the web? -X<URI> X<CGI.pm> X<CGI> X<URI::Escape> X<RFC 2396> +X<URI> X<URI::Escape> X<RFC 2396> -(contributed by brian d foy) - -Those C<%> encodings handle reserved characters in URIs, as described -in RFC 2396, Section 2. This encoding replaces the reserved character -with the hexadecimal representation of the character's number from -the US-ASCII table. For instance, a colon, C<:>, becomes C<%3A>. - -In CGI scripts, you don't have to worry about decoding URIs if you are -using C<CGI.pm>. You shouldn't have to process the URI yourself, -either on the way in or the way out. +Most of the time you should not need to do this as +your web framework, or if you are making a request, +the L<LWP> or other module would handle it for you. -If you have to encode a string yourself, remember that you should -never try to encode an already-composed URI. You need to escape the -components separately then put them together. To encode a string, you -can use the C<URI::Escape> module. The C<uri_escape> function -returns the escaped string: +To encode a string yourself, use the L<URI::Escape> module. The C<uri_escape> +function returns the escaped string: - my $original = "Colon : Hash # Percent %"; + my $original = "Colon : Hash # Percent %"; - my $escaped = uri_escape( $original ); + my $escaped = uri_escape( $original ); - print "$escaped\n"; # 'Colon%20%3A%20Hash%20%23%20Percent%20%25' + print "$escaped\n"; # 'Colon%20%3A%20Hash%20%23%20Percent%20%25' To decode the string, use the C<uri_unescape> function: - my $unescaped = uri_unescape( $escaped ); - - print $unescaped; # back to original - -If you wanted to do it yourself, you simply need to replace the -reserved characters with their encodings. A global substitution -is one way to do it: + my $unescaped = uri_unescape( $escaped ); - # encode - $string =~ s/([^^A-Za-z0-9\-_.!~*'()])/ sprintf "%%%0x", ord $1 /eg; + print $unescaped; # back to original - #decode - $string =~ s/%([A-Fa-f\d]{2})/chr hex $1/eg; +Remember not to encode a full URI, you need to escape each +component separately and then join them together. =head2 How do I redirect to another page? -Specify the complete URL of the destination (even if it is on the same -server). This is one of the two different kinds of CGI "Location:" -responses which are defined in the CGI specification for a Parsed Headers -script. The other kind (an absolute URLpath) is resolved internally to -the server without any HTTP redirection. The CGI specifications do not -allow relative URLs in either case. - -Use of C<CGI.pm> is strongly recommended. This example shows redirection -with a complete URL. This redirection is handled by the web browser. - - use CGI qw/:standard/; - - my $url = 'http://www.cpan.org/'; - print redirect($url); - -This example shows a redirection with an absolute URLpath. This -redirection is handled by the local web server. +Most Perl Web Frameworks will have a mechanism for doing this, +using the L<Catalyst> framework it would be: - my $url = '/CPAN/index.html'; - print redirect($url); + $c->res->redirect($url); + $c->detach(); -But if coded directly, it could be as follows (the final "\n" is -shown separately, for clarity), using either a complete URL or -an absolute URLpath. - - print "Location: $url\n"; # CGI response header - print "\n"; # end of headers +If you are using Plack (which most frameworks do), then +L<Plack::Middleware::Rewrite> is worth looking at if you +are migrating from Apache or have URL's you want to always +redirect. =head2 How do I put a password on my web pages? -To enable authentication for your web server, you need to configure -your web server. The configuration is different for different sorts -of web servers--apache does it differently from iPlanet which does -it differently from IIS. Check your web server documentation for -the details for your particular server. - -=head2 How do I edit my .htpasswd and .htgroup files with Perl? - -The C<HTTPD::UserAdmin> and C<HTTPD::GroupAdmin> modules provide a -consistent OO interface to these files, regardless of how they're -stored. Databases may be text, dbm, Berkeley DB or any database with -a DBI compatible driver. C<HTTPD::UserAdmin> supports files used by the -"Basic" and "Digest" authentication schemes. Here's an example: +See if the web framework you are using has an +authentication system and if that fits your needs. - use HTTPD::UserAdmin (); - HTTPD::UserAdmin - ->new(DB => "/foo/.htpasswd") - ->add($username => $password); +Alternativly look at L<Plack::Middleware::Auth::Basic>, +or one of the other L<Plack authentication|https://metacpan.org/search?q=plack+auth> +options. -=head2 How do I make sure users can't enter values into a form that cause my CGI script to do bad things? +=head2 How do I make sure users can't enter values into a form that causes my CGI script to do bad things? (contributed by brian d foy) You can't prevent people from sending your script bad data. Even if you add some client-side checks, people may disable them or bypass them completely. For instance, someone might use a module such as -C<LWP> to access your CGI program. If you want to prevent data that +L<LWP> to submit to your web site. If you want to prevent data that try to use SQL injection or other sorts of attacks (and you should want to), you have to not trust any data that enter your program. The L<perlsec> documentation has general advice about data security. -If you are using the C<DBI> module, use placeholder to fill in data. +If you are using the L<DBI> module, use placeholder to fill in data. If you are running external programs with C<system> or C<exec>, use the list forms. There are many other precautions that you should take, too many to list here, and most of them fall under the category of not @@ -357,62 +209,29 @@ using any data that you don't intend to use. Trust no one. =head2 How do I parse a mail header? -For a quick-and-dirty solution, try this solution derived -from L<perlfunc/split>: - - $/ = ''; - $header = <MSG>; - $header =~ s/\n\s+/ /g; # merge continuation lines - %head = ( UNIX_FROM_LINE, split /^([-\w]+):\s*/m, $header ); - -That solution doesn't do well if, for example, you're trying to -maintain all the Received lines. A more complete approach is to use -the C<Mail::Header> module from CPAN (part of the C<MailTools> package). - -=head2 How do I decode a CGI form? - -(contributed by brian d foy) - -Use the C<CGI.pm> module that comes with Perl. It's quick, -it's easy, and it actually does quite a bit of work to -ensure things happen correctly. It handles GET, POST, and -HEAD requests, multipart forms, multivalued fields, query -string and message body combinations, and many other things -you probably don't want to think about. +Use the L<Email::MIME> module. It's well-tested and supports all the +craziness that you'll see in the real world (comment-folding whitespace, +encodings, comments, etc.). -It doesn't get much easier: the C<CGI.pm> module automatically -parses the input and makes each value available through the -C<param()> function. + use Email::MIME; - use CGI qw(:standard); + my $message = Email::MIME->new($rfc2822); + my $subject = $message->header('Subject'); + my $from = $message->header('From'); - my $total = param( 'price' ) + param( 'shipping' ); +If you've already got some other kind of email object, consider passing +it to L<Email::Abstract> and then using its cast method to get an +L<Email::MIME> object: - my @items = param( 'item' ); # multiple values, same field name - -If you want an object-oriented approach, C<CGI.pm> can do that too. - - use CGI; - - my $cgi = CGI->new(); - - my $total = $cgi->param( 'price' ) + $cgi->param( 'shipping' ); - - my @items = $cgi->param( 'item' ); - -You might also try C<CGI::Minimal> which is a lightweight version -of the same thing. Other CGI::* modules on CPAN might work better -for you, too. - -Many people try to write their own decoder (or copy one from -another program) and then run into one of the many "gotchas" -of the task. It's much easier and less hassle to use C<CGI.pm>. + my $mail_message_object = read_message(); + my $abstract = Email::Abstract->new($mail_message_object); + my $email_mime_object = $abstract->cast('Email::MIME'); =head2 How do I check a valid mail address? (partly contributed by Aaron Sherman) -This isn't as simple a question as it sounds. There are two parts: +This isn't as simple a question as it sounds. There are two parts: a) How do I verify that an email address is correctly formatted? @@ -420,32 +239,8 @@ b) How do I verify that an email address targets a valid recipient? Without sending mail to the address and seeing whether there's a human on the other end to answer you, you cannot fully answer part I<b>, but -either the C<Email::Valid> or the C<RFC::RFC822::Address> module will do -both part I<a> and part I<b> as far as you can in real-time. - -If you want to just check part I<a> to see that the address is valid -according to the mail header standard with a simple regular expression, -you can have problems, because there are deliverable addresses that -aren't RFC-2822 (the latest mail header standard) compliant, and -addresses that aren't deliverable which, are compliant. However, the -following will match valid RFC-2822 addresses that do not have comments, -folding whitespace, or any other obsolete or non-essential elements. -This I<just> matches the address itself: - - my $atom = qr{[a-zA-Z0-9_!#\$\%&'*+/=?\^`{}~|\-]+}; - my $dot_atom = qr{$atom(?:\.$atom)*}; - my $quoted = qr{"(?:\\[^\r\n]|[^\\"])*"}; - my $local = qr{(?:$dot_atom|$quoted)}; - my $quotedpair = qr{\\[\x00-\x09\x0B-\x0c\x0e-\x7e]}; - my $domain_lit = qr{\[(?:$quotedpair|[\x21-\x5a\x5e-\x7e])*\]}; - my $domain = qr{(?:$dot_atom|$domain_lit)}; - my $addr_spec = qr{$local\@$domain}; - -Just match an address against C</^${addr_spec}$/> to see if it follows -the RFC2822 specification. However, because it is impossible to be -sure that such a correctly formed address is actually the correct way -to reach a particular person or even has a mailbox associated with it, -you must be very careful about how you use this. +the L<Email::Valid> module will do both part I<a> and part I<b> as far +as you can in real-time. Our best advice for verifying a person's mail address is to have them enter their address twice, just as you normally do to change a @@ -455,165 +250,117 @@ back and they've followed your directions, you can be reasonably assured that it's real. A related strategy that's less open to forgery is to give them a PIN -(personal ID number). Record the address and PIN (best that it be a -random one) for later processing. In the mail you send, ask them to -include the PIN in their reply. But if it bounces, or the message is -included via a "vacation" script, it'll be there anyway. So it's -best to ask them to mail back a slight alteration of the PIN, such as -with the characters reversed, one added or subtracted to each digit, etc. +(personal ID number). Record the address and PIN (best that it be a +random one) for later processing. In the mail you send, include a link to +your site with the PIN included. If the mail bounces, you know it's not +valid. If they don't click on the link, either they forged the address or +(assuming they got the message) following through wasn't important so you +don't need to worry about it. =head2 How do I decode a MIME/BASE64 string? -The C<MIME-Base64> package (available from CPAN) handles this as well as -the MIME/QP encoding. Decoding BASE64 becomes as simple as: +The L<MIME::Base64> package handles this as well as the MIME/QP encoding. +Decoding base 64 becomes as simple as: + + use MIME::Base64; + my $decoded = decode_base64($encoded); + +The L<Email::MIME> module can decode base 64-encoded email message parts +transparently so the developer doesn't need to worry about it. - use MIME::Base64; - $decoded = decode_base64($encoded); +=head2 How do I find the user's mail address? -The C<MIME-Tools> package (available from CPAN) supports extraction with -decoding of BASE64 encoded attachments and content directly from email -messages. +Ask them for it. There are so many email providers available that it's +unlikely the local system has any idea how to determine a user's email address. -If the string to decode is short (less than 84 bytes long) -a more direct approach is to use the C<unpack()> function's "u" -format after minor transliterations: +The exception is for organization-specific email (e.g. foo@yourcompany.com) +where policy can be codified in your program. In that case, you could look at +$ENV{USER}, $ENV{LOGNAME}, and getpwuid($<) in scalar context, like so: - tr#A-Za-z0-9+/##cd; # remove non-base64 chars - tr#A-Za-z0-9+/# -_#; # convert to uuencoded format - $len = pack("c", 32 + 0.75*length); # compute length byte - print unpack("u", $len . $_); # uudecode and print + my $user_name = getpwuid($<) -=head2 How do I return the user's mail address? +But you still cannot make assumptions about whether this is correct, unless +your policy says it is. You really are best off asking the user. -On systems that support getpwuid, the C<< $< >> variable, and the -C<Sys::Hostname> module (which is part of the standard perl distribution), -you can probably try using something like this: +=head2 How do I send email? - use Sys::Hostname; - $address = sprintf('%s@%s', scalar getpwuid($<), hostname); +Use the L<Email::MIME> and L<Email::Sender::Simple> modules, like so: -Company policies on mail address can mean that this generates addresses -that the company's mail system will not accept, so you should ask for -users' mail addresses when this matters. Furthermore, not all systems -on which Perl runs are so forthcoming with this information as is Unix. + # first, create your message + my $message = Email::MIME->create( + header_str => [ + From => 'you@example.com', + To => 'friend@example.com', + Subject => 'Happy birthday!', + ], + attributes => { + encoding => 'quoted-printable', + charset => 'ISO-8859-1', + }, + body_str => "Happy birthday to you!\n", + ); -The C<Mail::Util> module from CPAN (part of the C<MailTools> package) provides a -C<mailaddress()> function that tries to guess the mail address of the user. -It makes a more intelligent guess than the code above, using information -given when the module was installed, but it could still be incorrect. -Again, the best way is often just to ask the user. + use Email::Sender::Simple qw(sendmail); + sendmail($message); -=head2 How do I send mail? +By default, L<Email::Sender::Simple> will try `sendmail` first, if it exists +in your $PATH. This generally isn't the case. If there's a remote mail +server you use to send mail, consider investigating one of the Transport +classes. At time of writing, the available transports include: -Use the C<sendmail> program directly: +=over 4 - open(SENDMAIL, "|/usr/lib/sendmail -oi -t -odq") - or die "Can't fork for sendmail: $!\n"; - print SENDMAIL <<"EOF"; - From: User Originating Mail <me\@host> - To: Final Destination <you\@otherhost> - Subject: A relevant subject line +=item L<Email::Sender::Transport::Sendmail> - 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"; +This is the default. If you can use the L<mail(1)> or L<mailx(1)> +program to send mail from the machine where your code runs, you should +be able to use this. -The B<-oi> option prevents C<sendmail> from interpreting a line consisting -of a single dot as "end of message". The B<-t> option says to use the -headers to decide who to send the message to, and B<-odq> says to put -the message into the queue. This last option means your message won't -be immediately delivered, so leave it out if you want immediate -delivery. +=item L<Email::Sender::Transport::SMTP> -Alternate, less convenient approaches include calling C<mail> (sometimes -called C<mailx>) directly or simply opening up port 25 have having an -intimate conversation between just you and the remote SMTP daemon, -probably C<sendmail>. +This transport contacts a remote SMTP server over TCP. It optionally +uses SSL and can authenticate to the server via SASL. -Or you might be able use the CPAN module C<Mail::Mailer>: +=item L<Email::Sender::Transport::SMTP::TLS> - use Mail::Mailer; +This is like the SMTP transport, but uses TLS security. You can +authenticate with this module as well, using any mechanisms your server +supports after STARTTLS. - $mailer = Mail::Mailer->new(); - $mailer->open({ From => $from_address, - To => $to_address, - Subject => $subject, - }) - or die "Can't open: $!\n"; - print $mailer $body; - $mailer->close(); +=back -The C<Mail::Internet> module uses C<Net::SMTP> which is less Unix-centric than -C<Mail::Mailer>, but less reliable. Avoid raw SMTP commands. There -are many reasons to use a mail transport agent like C<sendmail>. These -include queuing, MX records, and security. +Telling L<Email::Sender::Simple> to use your transport is straightforward. + + sendmail( + $message, + { + transport => $email_sender_transport_object, + } + ); =head2 How do I use MIME to make an attachment to a mail message? -This answer is extracted directly from the C<MIME::Lite> documentation. -Create a multipart message (i.e., one with attachments). - - use MIME::Lite; - - ### Create a new multipart message: - $msg = MIME::Lite->new( - From =>'me@myhost.com', - To =>'you@yourhost.com', - Cc =>'some@other.com, some@more.com', - Subject =>'A message with 2 parts...', - Type =>'multipart/mixed' - ); - - ### Add parts (each "attach" has same arguments as "new"): - $msg->attach(Type =>'TEXT', - Data =>"Here's the GIF file you wanted" - ); - $msg->attach(Type =>'image/gif', - Path =>'aaa000123.gif', - Filename =>'logo.gif' - ); - - $text = $msg->as_string; - -C<MIME::Lite> also includes a method for sending these things. - - $msg->send; - -This defaults to using L<sendmail> but can be customized to use -SMTP via L<Net::SMTP>. - -=head2 How do I read mail? - -While you could use the C<Mail::Folder> module from CPAN (part of the -C<MailFolder> package) or the C<Mail::Internet> module from CPAN (part -of the C<MailTools> package), often a module is overkill. Here's a -mail sorter. - - #!/usr/bin/perl - - my(@msgs, @sub); - my $msgno = -1; - $/ = ''; # paragraph reads - while (<>) { - if (/^From /m) { - /^Subject:\s*(?:Re:\s*)*(.*)/mi; - $sub[++$msgno] = lc($1) || ''; - } - $msgs[$msgno] .= $_; - } - for my $i (sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msgs)) { - print $msgs[$i]; - } - -Or more succinctly, - - #!/usr/bin/perl -n00 - # bysub2 - awkish sort-by-subject - BEGIN { $msgno = -1 } - $sub[++$msgno] = (/^Subject:\s*(?:Re:\s*)*(.*)/mi)[0] if /^From/m; - $msg[$msgno] .= $_; - END { print @msg[ sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msg) ] } +L<Email::MIME> directly supports multipart messages. L<Email::MIME> +objects themselves are parts and can be attached to other L<Email::MIME> +objects. Consult the L<Email::MIME> documentation for more information, +including all of the supported methods and examples of their use. + +=head2 How do I read email? + +Use the L<Email::Folder> module, like so: + + use Email::Folder; + + my $folder = Email::Folder->new('/path/to/email/folder'); + while(my $message = $folder->next_message) { + # next_message returns Email::Simple objects, but we want + # Email::MIME objects as they're more robust + my $mime = Email::MIME->new($message->as_string); + } + +There are different classes in the L<Email::Folder> namespace for +supporting various mailbox types. Note that these modules are generally +rather limited and only support B<reading> rather than writing. =head2 How do I find out my hostname, domainname, or IP address? X<hostname, domainname, IP address, host, domain, hostfqdn, inet_ntoa, @@ -621,62 +368,48 @@ gethostbyname, Socket, Net::Domain, Sys::Hostname> (contributed by brian d foy) -The C<Net::Domain> module, which is part of the standard distribution starting -in perl5.7.3, can get you the fully qualified domain name (FQDN), the host +The L<Net::Domain> module, which is part of the Standard Library starting +in Perl 5.7.3, can get you the fully qualified domain name (FQDN), the host name, or the domain name. - use Net::Domain qw(hostname hostfqdn hostdomain); - - my $host = hostfqdn(); - -The C<Sys::Hostname> module, included in the standard distribution since -perl5.6, can also get the hostname. - - use Sys::Hostname; + use Net::Domain qw(hostname hostfqdn hostdomain); - $host = hostname(); + my $host = hostfqdn(); -To get the IP address, you can use the C<gethostbyname> built-in function -to turn the name into a number. To turn that number into the dotted octet -form (a.b.c.d) that most people expect, use the C<inet_ntoa> function -from the C<Socket> module, which also comes with perl. +The L<Sys::Hostname> module, part of the Standard Library, can also get the +hostname: - use Socket; + use Sys::Hostname; - my $address = inet_ntoa( - scalar gethostbyname( $host || 'localhost' ) - ); + $host = hostname(); -=head2 How do I fetch a news article or the active newsgroups? -Use the C<Net::NNTP> or C<News::NNTPClient> modules, both available from CPAN. -This can make tasks like fetching the newsgroup list as simple as +The L<Sys::Hostname::Long> module takes a different approach and tries +harder to return the fully qualified hostname: - perl -MNews::NNTPClient - -e 'print News::NNTPClient->new->list("newsgroups")' + use Sys::Hostname::Long 'hostname_long'; -=head2 How do I fetch/put an FTP file? + my $hostname = hostname_long(); -(contributed by brian d foy) +To get the IP address, you can use the C<gethostbyname> built-in function +to turn the name into a number. To turn that number into the dotted octet +form (a.b.c.d) that most people expect, use the C<inet_ntoa> function +from the L<Socket> module, which also comes with perl. -The C<LWP> family of modules (available on CPAN as the libwww-perl distribution) -can work with FTP just like it can with many other protocols. C<LWP::Simple> -makes it quite easy to fetch a file: + use Socket; - use LWP::Simple; + my $address = inet_ntoa( + scalar gethostbyname( $host || 'localhost' ) + ); - my $data = get( 'ftp://some.ftp.site/some/file.txt' ); +=head2 How do I fetch/put an (S)FTP file? -If you want more direct or low-level control of the FTP process, you can use -the C<Net::FTP> module (in the Standard Library since Perl 5.8). It's -documentation has examples showing you just how to do that. +L<Net::FTP>, and L<Net::SFTP> allow you to interact with FTP and SFTP (Secure +FTP) servers. =head2 How can I do RPC in Perl? -(contributed by brian d foy) - -Use one of the RPC modules you can find on CPAN ( -http://search.cpan.org/search?query=RPC&mode=all ). +Use one of the RPC modules( L<https://metacpan.org/search?q=RPC> ). =head1 AUTHOR AND COPYRIGHT @@ -687,7 +420,7 @@ This documentation is free; you can redistribute it and/or modify it under the same terms as Perl itself. Irrespective of its distribution, all code examples in this file -are hereby placed into the public domain. You are permitted and +are hereby placed into the public domain. You are permitted and encouraged to use this code in your own programs for fun -or for profit as you see fit. A simple comment in the code giving +or for profit as you see fit. A simple comment in the code giving credit would be courteous but is not required. |