| CPAN - query, download and build perl modules from CPAN sites |
CPAN::* Classes: Author, Bundle, Module, Distribution
CPAN - query, download and build perl modules from CPAN sites
Interactive mode:
perl -MCPAN -e shell;
Batch mode:
use CPAN;
autobundle, clean, install, make, recompile, test
This module will eventually be replaced by CPANPLUS. CPANPLUS is kind of a modern rewrite from ground up with greater extensibility and more features but no full compatibility. If you're new to CPAN.pm, you probably should investigate if CPANPLUS is the better choice for you. If you're already used to CPAN.pm you're welcome to continue using it, if you accept that its development is mostly (though not completely) stalled.
The CPAN module is designed to automate the make and install of perl modules and extensions. It includes some primitive searching capabilities and knows how to use Net::FTP or LWP (or lynx or an external ftp client) to fetch the raw data from the net.
Modules are fetched from one or more of the mirrored CPAN (Comprehensive Perl Archive Network) sites and unpacked in a dedicated directory.
The CPAN module also supports the concept of named and versioned bundles of modules. Bundles simplify the handling of sets of related modules. See Bundles below.
The package contains a session manager and a cache manager. There is no status retained between sessions. The session manager keeps track of what has been fetched, built and installed in the current session. The cache manager keeps track of the disk space occupied by the make processes and deletes excess space according to a simple FIFO mechanism.
For extended searching capabilities there's a plugin for CPAN available,
CPAN::WAIT. CPAN::WAIT is a full-text search engine
that indexes all documents available in CPAN authors directories. If
CPAN::WAIT is installed on your system, the interactive shell of
CPAN.pm will enable the wq, wr, wd, wl, and wh commands
which send queries to the WAIT server that has been configured for your
installation.
All other methods provided are accessible in a programmer style and in an interactive shell style.
The interactive mode is entered by running
perl -MCPAN -e shell
which puts you into a readline interface. You will have the most fun if you install Term::ReadKey and Term::ReadLine to enjoy both history and command completion.
Once you are on the command line, type 'h' and the rest should be self-explanatory.
The function call shell takes two optional arguments, one is the
prompt, the second is the default initial command line (the latter
only works if a real ReadLine interface module is installed).
The most common uses of the interactive modes are
a, b, d, and m
for each of the four categories and another, i for any of the
mentioned four. Each of the four entities is implemented as a class
with slightly differing methods for displaying an object.
Arguments you pass to these commands are either strings exactly matching the identification string of an object or regular expressions that are then matched case-insensitively against various attributes of the objects. The parser recognizes a regular expression only if you enclose it between two slashes.
The principle is that the number of found objects influences how an
item is displayed. If the search finds one item, the result is
displayed with the rather verbose method as_string, but if we find
more than one, we display each object with the terse method
<as_glimpse>.
install <distribution_file>
also is run unconditionally. But for
install <module>
CPAN checks if an install is actually needed for it and prints module up to date in the case that the distribution file containing the module doesn't need to be updated.
CPAN also keeps track of what it has done within the current session
and doesn't try to build a package a second time regardless if it
succeeded or not. The force command takes as a first argument the
method to invoke (currently: make, test, or install) and executes the
command from scratch.
Example:
cpan> install OpenGL
OpenGL is up to date.
cpan> force install OpenGL
Running make
OpenGL-0.4/
OpenGL-0.4/COPYRIGHT
[...]
A clean command results in a
make clean
being executed within the distribution file's working directory.
get downloads a distribution file without further action. readme
displays the README file of the associated distribution. Look gets
and untars (if not yet done) the distribution file, changes to the
appropriate directory and opens a subshell process in that directory.
ls lists all distribution files in and below an author's CPAN
directory. Only those files that contain modules are listed and if
there is more than one for any given module, only the most recent one
is listed.
^C anytime and
return to the cpan-shell prompt. A SIGTERM will cause the cpan-shell
to clean up and leave the shell loop. You can emulate the effect of a
SIGTERM by sending two consecutive SIGINTs, which usually means by
pressing ^C twice.
CPAN.pm ignores a SIGPIPE. If the user sets inactivity_timeout, a
SIGALRM is used during the run of the perl Makefile.PL subprocess.
The commands that are available in the shell interface are methods in the package CPAN::Shell. If you enter the shell command, all your input is split by the Text::ParseWords::shellwords() routine which acts like most shells do. The first word is being interpreted as the method to be called and the rest of the words are treated as arguments to this method. Continuation lines are supported if a line ends with a literal backslash.
autobundle writes a bundle file into the
$CPAN::Config->{cpan_home}/Bundle directory. The file contains
a list of all modules that are both available from CPAN and currently
installed within @INC. The name of the bundle file is based on the
current date and a counter.
recompile() is a very special command in that it takes no argument and
runs the make/test/install cycle with brute force over all installed
dynamically loadable extensions (aka XS modules) with 'force' in
effect. The primary purpose of this command is to finish a network
installation. Imagine, you have a common source tree for two different
architectures. You decide to do a completely independent fresh
installation. You start on one architecture with the help of a Bundle
file produced earlier. CPAN installs the whole Bundle for you, but
when you try to repeat the job on the second architecture, CPAN
responds with a "Foo up to date" message for all modules. So you
invoke CPAN's recompile on the second architecture and you're done.
Another popular use for recompile is to act as a rescue in case your
perl breaks binary compatibility. If one of the modules that CPAN uses
is in turn depending on binary compatibility (so you cannot run CPAN
commands), then you should try the CPAN::Nox module for recovery.
CPAN::* Classes: Author, Bundle, Module, DistributionAlthough it may be considered internal, the class hierarchy does matter for both users and programmer. CPAN.pm deals with above mentioned four classes, and all those classes share a set of methods. A classical single polymorphism is in effect. A metaclass object registers all objects of all kinds and indexes them with a string. The strings referencing objects have a separated namespace (well, not completely separated):
Namespace Class
words containing a "/" (slash) Distribution
words starting with Bundle:: Bundle
everything else Module or Author
Modules know their associated Distribution objects. They always refer to the most recent official release. Developers may mark their releases as unstable development versions (by inserting an underbar into the module version number which will also be reflected in the distribution name when you run 'make dist'), so the really hottest and newest distribution is not always the default. If a module Foo circulates on CPAN in both version 1.23 and 1.23_90, CPAN.pm offers a convenient way to install version 1.23 by saying
install Foo
This would install the complete distribution file (say BAR/Foo-1.23.tar.gz) with all accompanying material. But if you would like to install version 1.23_90, you need to know where the distribution file resides on CPAN relative to the authors/id/ directory. If the author is BAR, this might be BAR/Foo-1.23_90.tar.gz; so you would have to say
install BAR/Foo-1.23_90.tar.gz
The first example will be driven by an object of the class CPAN::Module, the second by an object of class CPAN::Distribution.
If you do not enter the shell, the available shell commands are both
available as methods (CPAN::Shell->install(...)) and as
functions in the calling package (install(...)).
There's currently only one class that has a stable interface -
CPAN::Shell. All commands that are available in the CPAN shell are
methods of the class CPAN::Shell. Each of the commands that produce
listings of modules (r, autobundle, u) also return a list of
the IDs of all modules within the list.
expand($type,@things)CPAN::Shell->expand("Module",@things) method. Expand returns a
list of CPAN::Module objects according to the @things arguments
given. In scalar context it only returns the first element of the
list.
expandany(@things)
# install everything that is outdated on my disk:
perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'
# install my favorite programs if necessary:
for $mod (qw(Net::FTP Digest::MD5 Data::Dumper)){
my $obj = CPAN::Shell->expand('Module',$mod);
$obj->install;
}
# list all modules on my disk that have no VERSION number
for $mod (CPAN::Shell->expand("Module","/./")){
next unless $mod->inst_file;
# MakeMaker convention for undefined $VERSION:
next unless $mod->inst_version eq "undef";
print "No VERSION in ", $mod->id, "\n";
}
# find out which distribution on CPAN contains a module:
print CPAN::Shell->expand("Module","Apache::Constants")->cpan_file
Or if you want to write a cronjob to watch The CPAN, you could list all modules that need updating. First a quick and dirty way:
perl -e 'use CPAN; CPAN::Shell->r;'
If you don't want to get any output in the case that all modules are up to date, you can parse the output of above command for the regular expression //modules are up to date// and decide to mail the output only if it doesn't match. Ick?
If you prefer to do it more in a programmer style in one single process, maybe something like this suits you better:
# list all modules on my disk that have newer versions on CPAN
for $mod (CPAN::Shell->expand("Module","/./")){
next unless $mod->inst_file;
next if $mod->uptodate;
printf "Module %s is installed as %s, could be updated to %s from CPAN\n",
$mod->id, $mod->inst_version, $mod->cpan_version;
}
If that gives you too much output every day, you maybe only want to watch for three modules. You can write
for $mod (CPAN::Shell->expand("Module","/Apache|LWP|CGI/")){
as the first line instead. Or you can combine some of the above tricks:
# watch only for a new mod_perl module
$mod = CPAN::Shell->expand("Module","mod_perl");
exit if $mod->uptodate;
# new mod_perl arrived, let me know all update recommendations
CPAN::Shell->r;
The programming interface for the classes CPAN::Module, CPAN::Distribution, CPAN::Bundle, and CPAN::Author is still considered beta and partially even alpha. In the following paragraphs only those methods are documented that have proven useful over a longer time and thus are unlikely to change.
clean method on all items contained in the bundle.
force is passed recursively to
all contained objects.
get method on all items contained in the bundle
$CPAN::Config-{cpan_home}>. Note that this is different from
CPAN::Module::inst_file.
install method on all items contained in the bundle
make method on all items contained in the bundle
readme method on all items contained in the bundle
test method on all items contained in the bundle
make clean there.
cvs -d $cvs_root import -m $cvs_log $cvs_dir $userid v$version
there.
make install there. If make has not
yet been run, it will be run first. A make test will be issued in
any case and if this fails, the install will be canceled. The
cancellation can be avoided by letting force run the install for
you.
get method to make sure the distribution is
downloaded and unpacked. Changes to the directory where the
distribution has been unpacked and runs the external commands perl
Makefile.PL and make there.
make the distribution. Returns undef
otherwise.
$CPAN::Config-{pager}>.
make test there.
$CPAN::Config-{index_expire}> days.
install on the distribution associated with this module.
make on the distribution associated with this module.
readme on the distribution associated with this module.
test on the distribution associated with this module.
Currently the cache manager only keeps track of the build directory
($CPAN::Config->{build_dir}). It is a simple FIFO mechanism that
deletes complete directories below build_dir as soon as the size of
all directories there gets bigger than $CPAN::Config->{build_cache}
(in MB). The contents of this cache may be used for later
re-installations that you intend to do manually, but will never be
trusted by CPAN itself. This is due to the fact that the user might
use these directories for building modules on different architectures.
There is another directory ($CPAN::Config->{keep_source_where}) where the original distribution files are kept. This directory is not covered by the cache manager and must be controlled by the user. If you choose to have the same directory as build_dir and as keep_source_where directory, then your sources will be deleted with the same fifo mechanism.
A bundle is just a perl module in the namespace Bundle:: that does not define any functions or methods. It usually only contains documentation.
It starts like a perl module with a package declaration and a $VERSION variable. After that the pod section looks like any other pod with the only difference being that one special pod section exists starting with (verbatim):
=head1 CONTENTS
In this pod section each line obeys the format
Module_Name [Version_String] [- optional text]
The only required part is the first field, the name of a module (e.g. Foo::Bar, ie. not the name of the distribution file). The rest of the line is optional. The comment part is delimited by a dash just as in the man page header.
The distribution of a bundle should follow the same convention as other distributions.
Bundles are treated specially in the CPAN package. If you say 'install
Bundle::Tkkit' (assuming such a bundle exists), CPAN will install all
the modules in the CONTENTS section of the pod. You can install your
own Bundles locally by placing a conformant Bundle file somewhere into
your @INC path. The autobundle() command which is available in the
shell interface does that for you by including all currently installed
modules in a snapshot bundle file.
If you have a local mirror of CPAN and can access all files with
``file:'' URLs, then you only need a perl better than perl5.003 to run
this module. Otherwise Net::FTP is strongly recommended. LWP may be
required for non-UNIX systems or if your nearest CPAN site is
associated with a URL that is not ftp:.
If you have neither Net::FTP nor LWP, there is a fallback mechanism implemented for an external ftp command or for an external lynx command.
This module presumes that all packages on CPAN
perl -MExtUtils::MakeMaker -le \
'print MM->parse_version(shift)' filename
If you are author of a package and wonder if your $VERSION can be parsed, please try the above method.
come as compressed or gzipped tarfiles or as zip files and contain a Makefile.PL (well, we try to handle a bit more, but without much enthusiasm).
The debugging of this module is a bit complex, because we have interferences of the software producing the indices on CPAN, of the mirroring process on CPAN, of packaging, of configuration, of synchronicity, and of bugs within CPAN.pm.
For code debugging in interactive mode you can try ``o debug'' which will list options for debugging the various parts of the code. You should know that ``o debug'' has built-in completion support.
For data debugging there is the dump command which takes the same
arguments as make/test/install and outputs the object's Data::Dumper
dump.
CPAN.pm works nicely without network too. If you maintain machines that are not networked at all, you should consider working with file: URLs. Of course, you have to collect your modules somewhere first. So you might use CPAN.pm to put together all you need on a networked machine. Then copy the $CPAN::Config->{keep_source_where} (but not $CPAN::Config->{build_dir}) directory on a floppy. This floppy is kind of a personal CPAN. CPAN.pm on the non-networked machines works nicely with this floppy. See also below the paragraph about CD-ROM support.
When the CPAN module is used for the first time, a configuration
dialog tries to determine a couple of site specific options. The
result of the dialog is stored in a hash reference $CPAN::Config
in a file CPAN/Config.pm.
The default values defined in the CPAN/Config.pm file can be
overridden in a user specific file: CPAN/MyConfig.pm. Such a file is
best placed in $HOME/.cpan/CPAN/MyConfig.pm, because $HOME/.cpan is
added to the search path of the CPAN module before the use() or
require() statements.
The configuration dialog can be started any time later again by
issueing the command o conf init in the CPAN shell.
Currently the following keys in the hash reference $CPAN::Config are defined:
build_cache size of cache for directories to build modules
build_dir locally accessible directory to build modules
index_expire after this many days refetch index files
cache_metadata use serializer to cache metadata
cpan_home local directory reserved for this package
dontload_hash anonymous hash: modules in the keys will not be
loaded by the CPAN::has_inst() routine
gzip location of external program gzip
histfile file to maintain history between sessions
histsize maximum number of lines to keep in histfile
inactivity_timeout breaks interactive Makefile.PLs after this
many seconds inactivity. Set to 0 to never break.
inhibit_startup_message
if true, does not print the startup message
keep_source_where directory in which to keep the source (if we do)
make location of external make program
make_arg arguments that should always be passed to 'make'
make_install_arg same as make_arg for 'make install'
makepl_arg arguments passed to 'perl Makefile.PL'
pager location of external program more (or any pager)
prerequisites_policy
what to do if you are missing module prerequisites
('follow' automatically, 'ask' me, or 'ignore')
proxy_user username for accessing an authenticating proxy
proxy_pass password for accessing an authenticating proxy
scan_cache controls scanning of cache ('atstart' or 'never')
tar location of external program tar
term_is_latin if true internal UTF-8 is translated to ISO-8859-1
(and nonsense for characters outside latin range)
unzip location of external program unzip
urllist arrayref to nearby CPAN sites (or equivalent locations)
wait_list arrayref to a wait server to try (See CPAN::WAIT)
ftp_proxy, } the three usual variables for configuring
http_proxy, } proxy requests. Both as CPAN::Config variables
no_proxy } and as environment variables configurable.
You can set and query each of these options interactively in the cpan
shell with the command set defined within the o conf command:
o conf <scalar option>o conf <scalar option> <value>o conf <list option>o conf <list option> [shift|pop]o conf <list option> [unshift|push|splice] <list>
urllist parameters are URLs according to RFC 1738. We do a little guessing if your URL is not compliant, but if you have problems with file URLs, please try the correct format. Either:
file://localhost/whatever/ftp/pub/CPAN/
or
file:///home/ftp/pub/CPAN/
The urllist parameter of the configuration table contains a list of
URLs that are to be used for downloading. If the list contains any
file URLs, CPAN always tries to get files from there first. This
feature is disabled for index files. So the recommendation for the
owner of a CD-ROM with CPAN contents is: include your local, possibly
outdated CD-ROM as a file URL at the end of urllist, e.g.
o conf urllist push file://localhost/CDROM/CPAN
CPAN.pm will then fetch the index files from one of the CPAN sites that come at the beginning of urllist. It will later check for each module if there is a local copy of the most recent version.
Another peculiarity of urllist is that the site that we could successfully fetch the last file from automatically gets a preference token and is tried as the first site for the next request. So if you add a new site at runtime it may happen that the previously preferred site will be tried another time. This means that if you want to disallow a site for the next transfer, it must be explicitly removed from urllist.
There's no strong security layer in CPAN.pm. CPAN.pm helps you to install foreign, unmasked, unsigned code on your machine. We compare to a checksum that comes from the net just as the distribution file itself. If somebody has managed to tamper with the distribution file, they may have as well tampered with the CHECKSUMS file. Future development will go towards strong authentication.
Most functions in package CPAN are exported per default. The reason for this is that the primary use is intended for the cpan shell or for one-liners.
Populating a freshly installed perl with my favorite modules is pretty easy if you maintain a private bundle definition file. To get a useful blueprint of a bundle definition file, the command autobundle can be used on the CPAN shell command line. This command writes a bundle definition file for all modules that are installed for the currently running perl interpreter. It's recommended to run this command only once and from then on maintain the file manually under a private name, say Bundle/my_bundle.pm. With a clever bundle file you can then simply say
cpan> install Bundle::my_bundle
then answer a few questions and then go out for a coffee.
Maintaining a bundle definition file means keeping track of two things: dependencies and interactivity. CPAN.pm sometimes fails on calculating dependencies because not all modules define all MakeMaker attributes correctly, so a bundle definition file should specify prerequisites as early as possible. On the other hand, it's a bit annoying that many distributions need some interactive configuring. So what I try to accomplish in my private bundle file is to have the packages that need to be configured early in the file and the gentle ones later, so I can go out after a few minutes and leave CPAN.pm untended.
Thanks to Graham Barr for contributing the following paragraphs about the interaction between perl, and various firewall configurations. For further informations on firewalls, it is recommended to consult the documentation that comes with the ncftp program. If you are unable to go through the firewall with a simple Perl setup, it is very likely that you can configure ncftp so that it works for your firewall.
Firewalls can be categorized into three basic types.
To access servers outside these types of firewalls with perl (even for ftp) you will need to use LWP.
To access servers outside these type of firewalls with perl you will need to use Net::FTP.
There are two that I can think off.
For accessing ftp servers behind such firewalls you may need to set
the environment variable FTP_PASSIVE to a true value, e.g.
env FTP_PASSIVE=1 perl -MCPAN -eshell
or
perl -MCPAN -e '$ENV{FTP_PASSIVE} = 1; shell'
If you can go through your firewall with e.g. lynx, presumably with a command such as
/usr/local/bin/lynx -pscott:tiger
then you would configure CPAN.pm with the command
o conf lynx "/usr/local/bin/lynx -pscott:tiger"
That's all. Similarly for ncftp or ftp, you would configure something like
o conf ncftp "/usr/bin/ncftp -f /home/scott/ncftplogin.cfg"
Your mileage may vary...
Most probably you do have the old version installed. This can
happen if a module installs itself into a different directory in the
@INC path than it was previously installed. This is not really a
CPAN.pm problem, you would have the same problem when installing the
module manually. The easiest way to prevent this behaviour is to add
the argument UNINST=1 to the make install call, and that is why
many people add this argument permanently by configuring
o conf make_install_arg UNINST=1
Because there are people who have their precise expectations about who
may install where in the @INC path and who uses which @INC array. In
fine tuned environments UNINST=1 can cause damage.
Run the autobundle command for your old perl and optionally rename the resulting bundle file (e.g. Bundle/mybundle.pm), install the new perl with the Configure option prefix, e.g.
./Configure -Dprefix=/usr/local/perl-5.6.78.9
Install the bundle file you produced in the first step with something like
cpan> install Bundle::mybundle
and you're done.
You may want to configure something like
o conf make_arg "| tee -ai /root/.cpan/logs/make.out" o conf make_install_arg "| tee -ai /root/.cpan/logs/make_install.out"
so that STDOUT is captured in a file for later inspection.
You will most probably like something like this:
o conf makepl_arg "LIB=~/myperl/lib \
INSTALLMAN1DIR=~/myperl/man/man1 \
INSTALLMAN3DIR=~/myperl/man/man3"
install Sybase::Sybperl
You can make this setting permanent like all o conf settings with
o conf commit.
You will have to add ~/myperl/man to the MANPATH environment variable and also tell your perl programs to look into ~/myperl/lib, e.g. by including
use lib "$ENV{HOME}/myperl/lib";
or setting the PERL5LIB environment variable.
Another thing you should bear in mind is that the UNINST parameter should never be set if you are not root.
look Sybase::Sybperl
The reason for this is that CPAN does not know the dependencies of all modules when it starts out. To decide about the additional items to install, it just uses data found in the generated Makefile. An undetected missing piece breaks the process. But it may well be that your Bundle installs some prerequisite later than some depending item and thus your second try is able to resolve everything. Please note, CPAN.pm does not know the dependency tree in advance and cannot sort the queue of things to install in a topologically correct order. It resolves perfectly well IFF all modules declare the prerequisites correctly with the PREREQ_PM attribute to MakeMaker. For bundles which fail and you need to install often, it is recommended sort the Bundle definition file manually. It is planned to improve the metadata situation for dependencies on CPAN in general, but this will still take some time.
Have a look at the CPAN::Site module.
Some versions of readline are picky about capitalization in the
/etc/inputrc file and specifically RedHat 6.2 comes with a
/etc/inputrc that contains the word on in lowercase. Change the
occurrences of on to On and the bug should disappear.
Internally CPAN.pm uses the UTF-8 charset. If your terminal is expecting ISO-8859-1 charset, a converter can be activated by setting term_is_latin to a true value in your config file. One way of doing so would be
cpan> ! $CPAN::Config->{term_is_latin}=1
Extended support for converters will be made available as soon as perl becomes stable with regard to charset issues.
We should give coverage for all of the CPAN and not just the PAUSE part, right? In this discussion CPAN and PAUSE have become equal -- but they are not. PAUSE is authors/, modules/ and scripts/. CPAN is PAUSE plus the clpa/, doc/, misc/, ports/, and src/.
Future development should be directed towards a better integration of the other parts.
If a Makefile.PL requires special customization of libraries, prompts the user for special input, etc. then you may find CPAN is not able to build the distribution. In that case, you should attempt the traditional method of building a Perl module package from a shell.
Andreas Koenig <andreas.koenig@anima.de>
Kawai,Takanori provides a Japanese translation of this manpage at http://member.nifty.ne.jp/hippo2000/perltips/CPAN.htm
perl(1), CPAN::Nox(3)
| CPAN - query, download and build perl modules from CPAN sites |