答复: why can't I get data from DBM in mod_perl

[silent <si...@gmail.com>]

Thanks all, after I chown it to apache user and group it works!
And I also made operator precedences mistake in my script.


Thanks! 

-----邮件原件-----
发件人: tomas@tuxteam.de [mailto:tomas@tuxteam.de] 
发送时间: Friday, November 24, 2006 6:27 PM
收件人: silent
抄送: modperl@perl.apache.org
主题: Re: why can't I get data from DBM in mod_perl

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On Fri, Nov 24, 2006 at 04:47:21PM +0800, silent wrote:
> Hi all,
> I need help with mod_perl:
> My ENV is redhat ES4 + apache2.0.59 + mod_perl2.
> 
> I wrote a small script:
> ####################
> package myconf;
> 
> use strict;
> use warnings;
> use DB_File;
[...]
> warn "data count:$#title\n";  ### but in error_log  it is -1
[..]

Seems the tie didn't work and now your hash is empty.

This ain't a modperl question :-)

You'll get exactly this behaviour when you can't write to the file
(because of permissions -- or just because the file is not there).

Watch this:

 | tomas@herr-turtur:~$ perl
 | use DB_File;
 | 
 | tie my %dbh, 'DB_File', "foobar" || die "Argh: $@";
 | $dbh{'one'}=1;
 | $dbh{'two'}=2;

Now foobar has some stuff in it.

 | tomas@herr-turtur:~$ sudo chown root.root foobar
 | tomas@herr-turtur:~$ ls -l foobar
 | -rw-r--r-- 1 root root 12288 2006-11-24 11:05 foobar

and now I can read (but not write) to foobar

 | tomas@herr-turtur:~$ perl
 | use DB_File;
 | 
 | tie my %dbh, 'DB_File', "foobar" || die "Argh: $@";
 | print join("\n", map("$_=>" . $dbh{$_}, sort(keys(%dbh)))), "\n";
 | 

Noting... %dbh is empty!

 | tomas@herr-turtur:~$ sudo chown tomas.users foobar

Now I can open foobar r/w

 | tomas@herr-turtur:~$ perl
 | use DB_File;
 | 
 | tie my %dbh, 'DB_File', "foobar" || die "Argh: $@";
 | print join("\n", map("$_=>" . $dbh{$_}, sort(keys(%dbh)))), "\n";
 | one=>1
 | two=>2

It works!

You can fine-tune the behaviour using some flags, like O_RDONLY and so
on.

HTH
- -- tomás
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