1File::Fetch(3pm)       Perl Programmers Reference Guide       File::Fetch(3pm)
2
3
4

NAME

6       File::Fetch - A generic file fetching mechanism
7

SYNOPSIS

9           use File::Fetch;
10
11           ### build a File::Fetch object ###
12           my $ff = File::Fetch->new(uri => 'http://some.where.com/dir/a.txt');
13
14           ### fetch the uri to cwd() ###
15           my $where = $ff->fetch() or die $ff->error;
16
17           ### fetch the uri to /tmp ###
18           my $where = $ff->fetch( to => '/tmp' );
19
20           ### parsed bits from the uri ###
21           $ff->uri;
22           $ff->scheme;
23           $ff->host;
24           $ff->path;
25           $ff->file;
26

DESCRIPTION

28       File::Fetch is a generic file fetching mechanism.
29
30       It allows you to fetch any file pointed to by a "ftp", "http", "file",
31       or "rsync" uri by a number of different means.
32
33       See the "HOW IT WORKS" section further down for details.
34

ACCESSORS

36       A "File::Fetch" object has the following accessors
37
38       $ff->uri
39           The uri you passed to the constructor
40
41       $ff->scheme
42           The scheme from the uri (like 'file', 'http', etc)
43
44       $ff->host
45           The hostname in the uri.  Will be empty if host was originally
46           'localhost' for a 'file://' url.
47
48       $ff->vol
49           On operating systems with the concept of a volume the second
50           element of a file:// is considered to the be volume specification
51           for the file.  Thus on Win32 this routine returns the volume, on
52           other operating systems this returns nothing.
53
54           On Windows this value may be empty if the uri is to a network
55           share, in which case the 'share' property will be defined.
56           Additionally, volume specifications that use '|' as ':' will be
57           converted on read to use ':'.
58
59           On VMS, which has a volume concept, this field will be empty
60           because VMS file specifications are converted to absolute UNIX
61           format and the volume information is transparently included.
62
63       $ff->share
64           On systems with the concept of a network share (currently only
65           Windows) returns the sharename from a file://// url.  On other
66           operating systems returns empty.
67
68       $ff->path
69           The path from the uri, will be at least a single '/'.
70
71       $ff->file
72           The name of the remote file. For the local file name, the result of
73           $ff->output_file will be used.
74
75       $ff->output_file
76           The name of the output file. This is the same as $ff->file, but any
77           query parameters are stripped off. For example:
78
79               http://example.com/index.html?x=y
80
81           would make the output file be "index.html" rather than
82           "index.html?x=y".
83

METHODS

85   $ff = File::Fetch->new( uri => 'http://some.where.com/dir/file.txt' );
86       Parses the uri and creates a corresponding File::Fetch::Item object,
87       that is ready to be "fetch"ed and returns it.
88
89       Returns false on failure.
90
91   $where = $ff->fetch( [to => /my/output/dir/ | \$scalar] )
92       Fetches the file you requested and returns the full path to the file.
93
94       By default it writes to "cwd()", but you can override that by
95       specifying the "to" argument:
96
97           ### file fetch to /tmp, full path to the file in $where
98           $where = $ff->fetch( to => '/tmp' );
99
100           ### file slurped into $scalar, full path to the file in $where
101           ### file is downloaded to a temp directory and cleaned up at exit time
102           $where = $ff->fetch( to => \$scalar );
103
104       Returns the full path to the downloaded file on success, and false on
105       failure.
106
107   $ff->error([BOOL])
108       Returns the last encountered error as string.  Pass it a true value to
109       get the "Carp::longmess()" output instead.
110

HOW IT WORKS

112       File::Fetch is able to fetch a variety of uris, by using several
113       external programs and modules.
114
115       Below is a mapping of what utilities will be used in what order for
116       what schemes, if available:
117
118           file    => LWP, lftp, file
119           http    => LWP, wget, curl, lftp, lynx, iosock
120           ftp     => LWP, Net::FTP, wget, curl, lftp, ncftp, ftp
121           rsync   => rsync
122
123       If you'd like to disable the use of one or more of these utilities
124       and/or modules, see the $BLACKLIST variable further down.
125
126       If a utility or module isn't available, it will be marked in a cache
127       (see the $METHOD_FAIL variable further down), so it will not be tried
128       again. The "fetch" method will only fail when all options are
129       exhausted, and it was not able to retrieve the file.
130
131       "iosock" is a very limited IO::Socket::INET based mechanism for
132       retrieving "http" schemed urls. It doesn't follow redirects for
133       instance.
134
135       A special note about fetching files from an ftp uri:
136
137       By default, all ftp connections are done in passive mode. To change
138       that, see the $FTP_PASSIVE variable further down.
139
140       Furthermore, ftp uris only support anonymous connections, so no named
141       user/password pair can be passed along.
142
143       "/bin/ftp" is blacklisted by default; see the $BLACKLIST variable
144       further down.
145

GLOBAL VARIABLES

147       The behaviour of File::Fetch can be altered by changing the following
148       global variables:
149
150   $File::Fetch::FROM_EMAIL
151       This is the email address that will be sent as your anonymous ftp
152       password.
153
154       Default is "File-Fetch@example.com".
155
156   $File::Fetch::USER_AGENT
157       This is the useragent as "LWP" will report it.
158
159       Default is "File::Fetch/$VERSION".
160
161   $File::Fetch::FTP_PASSIVE
162       This variable controls whether the environment variable "FTP_PASSIVE"
163       and any passive switches to commandline tools will be set to true.
164
165       Default value is 1.
166
167       Note: When $FTP_PASSIVE is true, "ncftp" will not be used to fetch
168       files, since passive mode can only be set interactively for this binary
169
170   $File::Fetch::TIMEOUT
171       When set, controls the network timeout (counted in seconds).
172
173       Default value is 0.
174
175   $File::Fetch::WARN
176       This variable controls whether errors encountered internally by
177       "File::Fetch" should be "carp"'d or not.
178
179       Set to false to silence warnings. Inspect the output of the "error()"
180       method manually to see what went wrong.
181
182       Defaults to "true".
183
184   $File::Fetch::DEBUG
185       This enables debugging output when calling commandline utilities to
186       fetch files.  This also enables "Carp::longmess" errors, instead of the
187       regular "carp" errors.
188
189       Good for tracking down why things don't work with your particular
190       setup.
191
192       Default is 0.
193
194   $File::Fetch::BLACKLIST
195       This is an array ref holding blacklisted modules/utilities for fetching
196       files with.
197
198       To disallow the use of, for example, "LWP" and "Net::FTP", you could
199       set $File::Fetch::BLACKLIST to:
200
201           $File::Fetch::BLACKLIST = [qw|lwp netftp|]
202
203       The default blacklist is [qw|ftp|], as "/bin/ftp" is rather unreliable.
204
205       See the note on "MAPPING" below.
206
207   $File::Fetch::METHOD_FAIL
208       This is a hashref registering what modules/utilities were known to fail
209       for fetching files (mostly because they weren't installed).
210
211       You can reset this cache by assigning an empty hashref to it, or
212       individually remove keys.
213
214       See the note on "MAPPING" below.
215

MAPPING

217       Here's a quick mapping for the utilities/modules, and their names for
218       the $BLACKLIST, $METHOD_FAIL and other internal functions.
219
220           LWP         => lwp
221           Net::FTP    => netftp
222           wget        => wget
223           lynx        => lynx
224           ncftp       => ncftp
225           ftp         => ftp
226           curl        => curl
227           rsync       => rsync
228           lftp        => lftp
229           IO::Socket  => iosock
230

FREQUENTLY ASKED QUESTIONS

232   So how do I use a proxy with File::Fetch?
233       "File::Fetch" currently only supports proxies with LWP::UserAgent.  You
234       will need to set your environment variables accordingly. For example,
235       to use an ftp proxy:
236
237           $ENV{ftp_proxy} = 'foo.com';
238
239       Refer to the LWP::UserAgent manpage for more details.
240
241   I used 'lynx' to fetch a file, but its contents is all wrong!
242       "lynx" can only fetch remote files by dumping its contents to "STDOUT",
243       which we in turn capture. If that content is a 'custom' error file
244       (like, say, a "404 handler"), you will get that contents instead.
245
246       Sadly, "lynx" doesn't support any options to return a different exit
247       code on non-"200 OK" status, giving us no way to tell the difference
248       between a 'successfull' fetch and a custom error page.
249
250       Therefor, we recommend to only use "lynx" as a last resort. This is why
251       it is at the back of our list of methods to try as well.
252
253   Files I'm trying to fetch have reserved characters or non-ASCII characters
254       in them. What do I do?
255       "File::Fetch" is relatively smart about things. When trying to write a
256       file to disk, it removes the "query parameters" (see the "output_file"
257       method for details) from the file name before creating it. In most
258       cases this suffices.
259
260       If you have any other characters you need to escape, please install the
261       "URI::Escape" module from CPAN, and pre-encode your URI before passing
262       it to "File::Fetch". You can read about the details of URIs and URI
263       encoding here:
264
265         http://www.faqs.org/rfcs/rfc2396.html
266

TODO

268       Implement $PREFER_BIN
269           To indicate to rather use commandline tools than modules
270

BUG REPORTS

272       Please report bugs or other issues to <bug-file-fetch@rt.cpan.org<gt>.
273

AUTHOR

275       This module by Jos Boumans <kane@cpan.org>.
276
278       This library is free software; you may redistribute and/or modify it
279       under the same terms as Perl itself.
280
281
282
283perl v5.12.4                      2011-06-07                  File::Fetch(3pm)
Impressum