1File::Fetch(3)        User Contributed Perl Documentation       File::Fetch(3)
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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       "git" 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->file_default
76           The name of the default local file, that $ff->output_file falls
77           back to if it would otherwise return no filename. For example when
78           fetching a URI like http://www.abc.net.au/ the contents retrieved
79           may be from a remote file called 'index.html'. The default value of
80           this attribute is literally 'file_default'.
81
82       $ff->output_file
83           The name of the output file. This is the same as $ff->file, but any
84           query parameters are stripped off. For example:
85
86               http://example.com/index.html?x=y
87
88           would make the output file be "index.html" rather than
89           "index.html?x=y".
90

METHODS

92   $ff = File::Fetch->new( uri => 'http://some.where.com/dir/file.txt' );
93       Parses the uri and creates a corresponding File::Fetch::Item object,
94       that is ready to be "fetch"ed and returns it.
95
96       Returns false on failure.
97
98   $where = $ff->fetch( [to => /my/output/dir/ | \$scalar] )
99       Fetches the file you requested and returns the full path to the file.
100
101       By default it writes to "cwd()", but you can override that by
102       specifying the "to" argument:
103
104           ### file fetch to /tmp, full path to the file in $where
105           $where = $ff->fetch( to => '/tmp' );
106
107           ### file slurped into $scalar, full path to the file in $where
108           ### file is downloaded to a temp directory and cleaned up at exit time
109           $where = $ff->fetch( to => \$scalar );
110
111       Returns the full path to the downloaded file on success, and false on
112       failure.
113
114   $ff->error([BOOL])
115       Returns the last encountered error as string.  Pass it a true value to
116       get the "Carp::longmess()" output instead.
117

HOW IT WORKS

119       File::Fetch is able to fetch a variety of uris, by using several
120       external programs and modules.
121
122       Below is a mapping of what utilities will be used in what order for
123       what schemes, if available:
124
125           file    => LWP, lftp, file
126           http    => LWP, HTTP::Tiny, wget, curl, lftp, fetch, HTTP::Lite, lynx, iosock
127           ftp     => LWP, Net::FTP, wget, curl, lftp, fetch, ncftp, ftp
128           rsync   => rsync
129           git     => git
130
131       If you'd like to disable the use of one or more of these utilities
132       and/or modules, see the $BLACKLIST variable further down.
133
134       If a utility or module isn't available, it will be marked in a cache
135       (see the $METHOD_FAIL variable further down), so it will not be tried
136       again. The "fetch" method will only fail when all options are
137       exhausted, and it was not able to retrieve the file.
138
139       The "fetch" utility is available on FreeBSD. NetBSD and Dragonfly BSD
140       may also have it from "pkgsrc". We only check for "fetch" on those
141       three platforms.
142
143       "iosock" is a very limited IO::Socket::INET based mechanism for
144       retrieving "http" schemed urls. It doesn't follow redirects for
145       instance.
146
147       "git" only supports "git://" style urls.
148
149       A special note about fetching files from an ftp uri:
150
151       By default, all ftp connections are done in passive mode. To change
152       that, see the $FTP_PASSIVE variable further down.
153
154       Furthermore, ftp uris only support anonymous connections, so no named
155       user/password pair can be passed along.
156
157       "/bin/ftp" is blacklisted by default; see the $BLACKLIST variable
158       further down.
159

GLOBAL VARIABLES

161       The behaviour of File::Fetch can be altered by changing the following
162       global variables:
163
164   $File::Fetch::FROM_EMAIL
165       This is the email address that will be sent as your anonymous ftp
166       password.
167
168       Default is "File-Fetch@example.com".
169
170   $File::Fetch::USER_AGENT
171       This is the useragent as "LWP" will report it.
172
173       Default is "File::Fetch/$VERSION".
174
175   $File::Fetch::FTP_PASSIVE
176       This variable controls whether the environment variable "FTP_PASSIVE"
177       and any passive switches to commandline tools will be set to true.
178
179       Default value is 1.
180
181       Note: When $FTP_PASSIVE is true, "ncftp" will not be used to fetch
182       files, since passive mode can only be set interactively for this binary
183
184   $File::Fetch::TIMEOUT
185       When set, controls the network timeout (counted in seconds).
186
187       Default value is 0.
188
189   $File::Fetch::WARN
190       This variable controls whether errors encountered internally by
191       "File::Fetch" should be "carp"'d or not.
192
193       Set to false to silence warnings. Inspect the output of the "error()"
194       method manually to see what went wrong.
195
196       Defaults to "true".
197
198   $File::Fetch::DEBUG
199       This enables debugging output when calling commandline utilities to
200       fetch files.  This also enables "Carp::longmess" errors, instead of the
201       regular "carp" errors.
202
203       Good for tracking down why things don't work with your particular
204       setup.
205
206       Default is 0.
207
208   $File::Fetch::BLACKLIST
209       This is an array ref holding blacklisted modules/utilities for fetching
210       files with.
211
212       To disallow the use of, for example, "LWP" and "Net::FTP", you could
213       set $File::Fetch::BLACKLIST to:
214
215           $File::Fetch::BLACKLIST = [qw|lwp netftp|]
216
217       The default blacklist is [qw|ftp|], as "/bin/ftp" is rather unreliable.
218
219       See the note on "MAPPING" below.
220
221   $File::Fetch::METHOD_FAIL
222       This is a hashref registering what modules/utilities were known to fail
223       for fetching files (mostly because they weren't installed).
224
225       You can reset this cache by assigning an empty hashref to it, or
226       individually remove keys.
227
228       See the note on "MAPPING" below.
229

MAPPING

231       Here's a quick mapping for the utilities/modules, and their names for
232       the $BLACKLIST, $METHOD_FAIL and other internal functions.
233
234           LWP         => lwp
235           HTTP::Lite  => httplite
236           HTTP::Tiny  => httptiny
237           Net::FTP    => netftp
238           wget        => wget
239           lynx        => lynx
240           ncftp       => ncftp
241           ftp         => ftp
242           curl        => curl
243           rsync       => rsync
244           lftp        => lftp
245           fetch       => fetch
246           IO::Socket  => iosock
247

FREQUENTLY ASKED QUESTIONS

249   So how do I use a proxy with File::Fetch?
250       "File::Fetch" currently only supports proxies with LWP::UserAgent.  You
251       will need to set your environment variables accordingly. For example,
252       to use an ftp proxy:
253
254           $ENV{ftp_proxy} = 'foo.com';
255
256       Refer to the LWP::UserAgent manpage for more details.
257
258   I used 'lynx' to fetch a file, but its contents is all wrong!
259       "lynx" can only fetch remote files by dumping its contents to "STDOUT",
260       which we in turn capture. If that content is a 'custom' error file
261       (like, say, a "404 handler"), you will get that contents instead.
262
263       Sadly, "lynx" doesn't support any options to return a different exit
264       code on non-"200 OK" status, giving us no way to tell the difference
265       between a 'successful' fetch and a custom error page.
266
267       Therefor, we recommend to only use "lynx" as a last resort. This is why
268       it is at the back of our list of methods to try as well.
269
270   Files I'm trying to fetch have reserved characters or non-ASCII characters
271       in them. What do I do?
272       "File::Fetch" is relatively smart about things. When trying to write a
273       file to disk, it removes the "query parameters" (see the "output_file"
274       method for details) from the file name before creating it. In most
275       cases this suffices.
276
277       If you have any other characters you need to escape, please install the
278       "URI::Escape" module from CPAN, and pre-encode your URI before passing
279       it to "File::Fetch". You can read about the details of URIs and URI
280       encoding here:
281
282       <https://datatracker.ietf.org/doc/html/rfc2396>
283

TODO

285       Implement $PREFER_BIN
286           To indicate to rather use commandline tools than modules
287

BUG REPORTS

289       Please report bugs or other issues to <bug-file-fetch@rt.cpan.org<gt>.
290

AUTHOR

292       This module by Jos Boumans <kane@cpan.org>.
293
295       This library is free software; you may redistribute and/or modify it
296       under the same terms as Perl itself.
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300perl v5.34.0                      2022-01-20                    File::Fetch(3)
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