I have been trying to get perl subroutine value and substitution to get the required part of string from randomips subroutine in exim.conf. However when i use string substitution i get error as follow:
Here is what I am trying to achieve
I am trying to split string by colon and get first occurrence as "interface". I'll be using second occurrence as the "helo_data.
exim.pl
sub randomhosts {
#inet = ("x.x.x.1:hostname1.domain.com","x.x.x.2:hostname2.domain.com","x.x.x.3:hostname3.domain.com"
);
return $inet[int rand($#inet+1)];
}
exim.conf
dkim_remote_smtp:
driver = smtp
interface = "${perl{randomhosts}%:*}"
helo_data = "${sender_address_domain}"
Error I get is as follow:
"failed to expand "interface" option for dkim_remote_smtp transport: missing '}' after 'perl'".
Probably the syntax.
Any help?
The code that you are trying to copy was written by someone who doesn't know much about Perl. It includes this line:
return $inet[int rand($#inet+1)];
A Perl programmer would write this as
return $inet[rand #inet];
I think there are a couple of issues here - one with your Exim syntax and one with your Perl syntax.
Exim is giving you this error:
failed to expand "interface" option for dkim_remote_smtp transport: missing '}' after 'perl'
I don't know anything about calling Perl from Exim, but this page mentions a syntax like ${perl{foo}} (which is similar to the one used in the page you are copying from) and one like ${perl{foo}{argument}} for calling a subroutine and passing it an argument. Nowhere does it mention syntax like yours:
${perl{randomhosts}%:*}
I'm not sure where you have got that syntax from, but it seems likely that this is what is causing your first error.
In a comment, you say
I am stying to get first part of string before colon for each random array value for "interface" and part after colon for "helo_data"
It seems to me that Exim doesn't support this requirement. You would need to call the function twice to get the two pieces of information that you require. You might be able to do this in the Perl using something like state variables - but it would be far more complex than the code you currently have there.
Secondly, your Perl code has a syntax error, so even if Exim was able to call your code, it wouldn't work.
The code you're copying sets up #inet like this:
#inet = ("x.x.x.1", "x.x.x.2", "x.x.x.3", "x.x.x.4");
Your equivalent code is this:
#inet = (
"x.x.x.1:hostname1.domain.com",
"x.x.x.2:hostname2.domain.com,
x.x.x.3:hostname3.domain.com
);
I've reformatted it, to make the problems more obvious. You are missing a number of quote marks around the elements of the array. (Note: I see that while I have been writing this answer, you have fixed that.)
Update: Ok, here is some code to put into exim.pl that does what you want.
use feature qw[state];
sub randomhosts {
state $current;
my #inet = (
"x.x.x.1:hostname1.domain.com",
"x.x.x.2:hostname2.domain.com",
"x.x.x.3:hostname3.domain.com"
);
if ($_[0] eq 'generate') {
shift;
#{$current}{qw[ip host]} = split /:/, $inet[rand #inet];
}
return $current->{$_[0]};
}
It generates a new ip/host pair if its first argument is 'generate'. It will then return either the hostname or the ip address from the generated pair. I think you can probably call it from your Exim config file like this:
dkim_remote_smtp:
driver = smtp
interface = "${perl{randomhosts}{generate}{ip}}"
helo_data = "${perl{randomhosts}{host}}"
But I'm no expert in Exim, so that syntax might need tweaking.
First I would like to note I have not worked with exim so I cannot say what exactly you are trying to do and why you have done things exactly so.
In the link you posted, a method called 'randinet' is added to exim.pl and the interface line in exim.conf is replaced by
interface = "${perl{randinet}}"
You have implemented a 'randomhosts' method and replaced the interface line with
interface = "${perl{randomhosts}%:*}"
Now the parser complains about not finding the closing bracket. That is likely due to the symbols you felt free to add but the parser does not have the freedom to ignore.
I suggest you try
interface = "${perl{randomhosts}}"
Related
I wrote a procedure which imports data from an xml-file into a MariaDB using library DBI. The procedure works but I don't understand why the following code gives me the message:
use of uninitialized value $DBI::err in concatenation (.) or string at ...
Here the code (abbreviated):
my $insert_art = $dbh->prepare(
"INSERT INTO odbb_articles (creation_dt,ref_data,comp_no)".
"VALUES (?,?,?)"
);
....
my $comp_no = $xpc->findvalue('./sr:ARTCOMP/sr:COMPNO',$node1);
....
$insert_art->execute($creation_dt,$ref_data,$comp_no)
or die "Fehler bei der Ausfuehrung: ".
"$DBI::err -> $DBI::errstr (odbb_articles $DBI::state)\n";
If I insert the code
if ($comp_no eq "") { $comp_no = undef; }
just before $insert_art->execute the procedure works. This error happens when there is no entry in the xml-file for element COMPNO. I can avoid it if I define it as undef. I just wonder
why $comp_no cause this problem and
is there another solution than to control if $comp_no is "" and define it as undef?
The reason for the second question is to avoid the if statement if there are a lot of variables/columns which may have empty entries.
Thanks for help.
use of uninitialized value $DBI::err in concatenation (.) or string at ...
The error message you are seeing is Perl telling you that $DBI::err is undef. That is not because of the value of your $comp_no. It's just a result of what your program is doing.
So when you pass an empty string to the comp_no column, the database doesn't like that. It throws an error. DBI catches that error and passes it on. The $insert_art->execute returns a false value and the right-hand-side of the or gets called. That's your die.
Now in the string that you pass to die you put three variables:
$DBI::err
$DBI::errstr
$DBI::state
According to the DBI documentation, those are equivalent to the functions $h->err, $h->errstr and $h->state with $h being the last handle used. Let's look at the docs for those.
$h->err
Returns the native database engine error code from the last driver method called. The code is typically an integer but you should not assume that.
The DBI resets $h->err to undef before almost all DBI method calls, so the value only has a short lifespan. Also, for most drivers, the statement handles share the same error variable as the parent database handle, so calling a method on one handle may reset the error on the related handles. [...]
This does not explain when it can be undef.
$h->errstr
Returns the native database engine error message from the last DBI method called. This has the same lifespan issues as the "err" method described above.
The returned string may contain multiple messages separated by newline characters.
The errstr() method should not be used to test for errors, use err() for that, because drivers may return 'success with information' or warning messages via errstr() for methods that have not 'failed'.
Ok, so this is text. Don't use it to test for specific errors. You're not doing that. You just want to give debug output when the program fails.
$h->state
Returns a state code in the standard SQLSTATE five character format. Note that the specific success code 00000 is translated to any empty string (false). If the driver does not support SQLSTATE (and most don't), then state() will return S1000 (General Error) for all errors.
The driver is free to return any value via state, e.g., warning codes, even if it has not declared an error by returning a true value via the "err" method described above.
The state() method should not be used to test for errors, use err() for that, because drivers may return a 'success with information' or warning state code via state() for methods that have not 'failed'.
Again, this is not very clear about how useful it is.
My advice is to get rid of $DBI::err and $DBI::state. You don't need those to figure out what the problem is. Just output $DBI::errstr.
$insert_art->execute($creation_dt,$ref_data,$comp_no)
or die "Fehler bei der Ausfuehrung: " . $dbh->errstr;
Now your program will still fail, but at least you will have a meaningful error message that will explain what your database didn't like about the statement. That's better than being told how there is a bug in your error handling code.
Afterwards, the other answers will probably apply to fix the reason this is happening in the first case.
On another note, a word on die: If you provide a \n at the end of your arguments, it will not print your current script, line number and input handle line number. But those might be useful in your case. You can include them.
In a SQL database an empty string is very different to null.
If comp_no has a foreign key pointing to a record in another table, then the value "" is an accettable one only if there is a record with "" as primary key, very improbable.
Yu can fix this converting empty values to undef:
for ($creation_dt,$ref_data,$comp_no ){
defined $_ and $_ eq '' and $_ = undef;
}
$insert_art->execute($creation_dt,$ref_data,$comp_no);
or also
$insert_art->execute(map {defined($_) && length($_) ? $_ : undef} ($creation_dt,$ref_data,$comp_no));
This is a possible shortcut:
$comp_no ||= undef;
With the caveat that this will work in any case where $comp_no evaluates as false, meaning a value of 0 will actually cause the result to go undef also, which may or may not matter to you. If your field is numeric, I'd say it matters a lot.
I feel like I must be missing something obvious. I know the XPath to a WebElement and I want to compare the text in that element to some string.
Say the XPath for the element is /html/body/div/a/strong and I want to compare it to $str.
So it shows up in source like ...<strong>find this string</strong>
So I say
use strict;
use warnings;
use Selenium::Remote::Driver;
# Fire up a Selenium object, get to the page, etc..
Test::More::ok($sel->find_element("/html/body/div/a") eq $str, "Text matched");
When I run this the test fails when it should pass. When I try to print the value of find_element($xpath) I get some hash reference. I've googled around some and find examples telling me to try find_element($xpath)->get_text() but get_text() isn't even a method in the original package. Is it an obsolete method that used to actually work?
Most of the examples online for this module say "It's easy!" then show me how to get_title() but not how to check the text at an XPath. I might be going crazy.
Following up on our comment thread, I'm posting this as an answer:
Selenium::Remote::WebDriver definitely has a method named find_element(), and Selenium::Remote::WebElement definitely has a method named get_text().
Something like this...
my $text = $sel->find_element(...)->get_text();
...works fine on my end, though it looks like it'll error out if the element isn't found.
I'm new to using Perl XML::SAX and I encountered a problem with the characters event that is triggered. I'm trying to parse a very large XML file using perl.
My goal is to get the content of each tag (I do not know the tag names - given any xml file, I should be able to crack the record pattern and return every record with its data and tag like Tag:Data).
While working with small files, everything is ok. But when running on a large file, the characters{} event does partial reading of the content. There is no specific pattern in the way it cuts down the reading. Sometimes its the starting few characters of data and sometimes its last few characters and sometimes its just one letter from the actual data.
The Sax Parser is:
$myhandler = MyFilter->new();
$parser = XML::SAX::ParserFactory->parser(Handler => $myhandler);
$parser->parse_file($filename);
And, I have written my own Handler called MyFilter and overridding the character method of the parser.
sub characters {
my ($self, $element) = #_;
$globalvar = $element->{Data};
print "content is: $globalvar \n";
}
Even this print statement, reads the values partially at times.
I also tried loading the Parsesr Package before calling the $parser->parse() as:
$XML::SAX::ParserPackage = "XML::SAX::ExpatXS";
Stil doesn't work. Could anyone help me out here? Thanks in advance!
Sounds like you need XML::Filter::BufferText.
http://search.cpan.org/dist/XML-Filter-BufferText/BufferText.pm
From the description "One common cause of grief (and programmer error) is that XML parsers aren't required to provide character events in one chunk. They can, but are not forced to, and most don't. This filter does the trivial but oft-repeated task of putting all characters into a single event."
It's very easy to use once you have it installed and will solve your partial character data problem.
It seems to me that there simply has to be a better way of doing this, but i still haven't found one. And i'm sure i'm not the only one who could use a way to do this: Run an SQL query that only produces one field in one row, then assign that field to a scalar. (In my case, if the query results in more than one field/row, then i have bigger things to worry about than the script breaking).
For example, to get the timestamp from the SQL server, one could use:
my $timestamp;
my $cmd = $dbh->prepare('SELECT cast(now() AS timestamp);') or die $!;
$cmd->execute();
while (my #asd = $cmd->fetchrow_array) { $timestamp = $asd[0] }
Dirty, but it works. But using 4 lines seem a bit much for a simple assignment, especially considering how well perl and postgresql can communicate with eachother via DBI. Sure, i could write a subroutine for it, but isn't there something native that allows me to fetch data as easily as i submit data with $dbh->do() ?
And yes, i did try google.
Usually I write:
$value = $dbh->selectall_arrayref($sql)->[0]->[0];
There's always selectrow_array:
selectrow_array
#row_ary = $dbh->selectrow_array($statement);
#row_ary = $dbh->selectrow_array($statement, \%attr);
#row_ary = $dbh->selectrow_array($statement, \%attr, #bind_values);
This utility method combines prepare, execute and fetchrow_array into a single call.
So something like this:
my $timestamp = $dbh->selectrow_array('select cast(now() as timestamp)');
There's also selectrow_arrayref and selectrow_hashref for similar situations.
From perldoc DBI:
"selectrow_arrayref"
$ary_ref = $dbh->selectrow_arrayref($statement);
$ary_ref = $dbh->selectrow_arrayref($statement, \%attr);
$ary_ref = $dbh->selectrow_arrayref($statement, \%attr, #bind_values);
This utility method combines "prepare", "execute" and
"fetchrow_arrayref" into a single call. It returns the first row of
data from the statement. The $statement parameter can be a previously
prepared statement handle, in which case the "prepare" is skipped.
If any method fails, and "RaiseError" is not set, "selectrow_array"
will return undef.
That will get you most of the way. You still need to do some error checking, but you would be doing that anyway.
Wouldn't fetchrow_array actually only return a scalar as you're only asking for one column?
I'm in a web scripting class, and honestly and unfortunately, it has come second to my networking and design and analysis classes. Because of this I find I encounter problems that may be mundane but can't find the solution to it easily.
I am writing a CGI form that is supposed to work with a MySQL DB. I can insert and delete into the DB just fine. My problem comes when querying the DB.
My code compiles fine and I don't get errors when trying to "display" the info in the DB through the browser but the data and text doesn't in fact display. The code in question is here:
print br, 'test';
my $dbh = DBI->connect("DBI:mysql:austinc4", "*******", "*******", {RaiseError => 1} );
my $usersstatement = "select * from users";
my $projstatment = "select * from projects";
# Get the handle
my $userinfo = $dbh->query($usersstatement);
my $projinfo = $dbh->query($projstatement);
# Fetch rows
while (#userrow = $userinfo->fetchrow()) {
print $userrow[0], br;
}
print 'end';
This code is in an if statement that is surrounded by the print header, start_html, form, /form, end_html. I was just trying to debug and find out what was happening and printed the statements test and end. It prints out test but doesn't print out end. It also doesn't print out the data in my DB, which happens to come before I print out end.
What I believe I am doing is:
Connecting to my DB
Forming a string the contains the command/request to the DB
Getting a handle for my query I perform on the DB
Fetching a row from my handle
Printing the first field in the row I fetched from my table
But I don't see why my data wouldn't print out as well as the end text. I looked in DB and it does in fact contain data in the DB and the table that I am trying to get data from.
This one has got me stumped, so I appreciate any help. Thanks again. =)
Solution:
I was using a that wasn't supported by the modules I was including. This leads me to another question. How can I detect errors like this? My program does in fact compile correctly and the webpage doesn't "break". Aside from me double checking that all the methods I do use are valid, do I just see something like text not being displayed and assume that an error like this occurred?
Upon reading the comments, the reason your program is broken is because query() does not execute an SQL query. Therefore you are probably calling an undefined subroutine unless this is a wrapper you have defined elsewhere.
Here is my original posting of helpful hints, which still apply:
I hope you have use CGI, use DBI, etc... and use CGI::Carp and use strict;
Look in /var/log/apache2/access.log or error.log for the bugs
Realize that the first thing a CGI script prints MUST be a valid header or the web server and browser become unhappy and often nothing else displays.
Because of #3 print the header first BEFORE you do anything, especially before you connect to the database where the script may die or print something else because otherwise the errors or other messages will be emitted before the header.
If you still don't see an error go back to #2.
CGIs that use CGI.pm can be run from a command line in a terminal session without going through the webserver. This is also a good way to debug.