使用梅森模板执行Perl脚本

Question

I have installed Mason module from cpan. Now i am executing my first program using mason template.

first_mason.mc

% my $name = "Mason";
    Hello world! Welcome to <% $name %>. 

first_mason.pl

#!/usr/local/bin/perl
use Mason;
my $mason = Mason->new(comp_root => '...');
print $mason->run('first_mason.mc')->output;

This throws an error as follows

first_mason.mc is not an absolute path at C:/Perl/site/lib/Mason/Request.pm line 256**

Note

I am placing both files in the path where mason is installed(to find an installation path ,i used perldoc -l Mason ) and executed a program using perl first_mason.pl

Answer 1

There is no need to put your files in the directory where Mason is installed:

• Perl should know where to find Mason when you import it with use (assuming your perl installation is correct).
• Mason will know where to find the .mc file via the comp_root argument.
• The component name needs to be specified as a path relative to comp_root , always beginning with / .
• You need to leave out the .mc from the component name.

So, if you place the 2 files in your home directory, then the script should look like this:

#!/usr/local/bin/perl
use Mason;
my $mason = Mason->new(comp_root => $HOME_DIR); # where $HOME_DIR is `C:\User\your_name`
print $mason->run('/first_mason')->output;

From the documentation :

The component root and component paths

When you use Mason, you specify a component root that all component files live under. Thereafter, any component will be referred to by its virtual path relative to the root, rather than its full filename.

For example, if the component root is '/opt/web/comps', then the component path '/foo/bar.mc' refers to the file '/opt/web/comps/foo/bar.mc'.

Answer 2

@stevenl fully answers your question. Simply don't blindly copy the Synopsis from the Mason docs, need read the docs too. :) Eg in the example code:

#!/usr/local/bin/perl
use Mason;
my $mason = Mason->new(comp_root => '...');
print $mason->run('/foo')->output;

you need replace

• and the shebang line #!/usr/local/bin/perl with the real path to your perl interpreter
• the '...' with the real path in the filesystem, where your component are, eg

comp_root => '/some/real/path/here/where/my/component/root/is'

---

However, I wrote this answer mainly with a reason: if you want use the Mason for the web-app development, check the Poet module too. It GREATLY simplifies the whole process, and you will not need care about many-many things. Eg after installing the Poet you can simply:

poet new MyApp
myapp/bin/run.pl

and you will immediately get ( without any configuration) an WORKING web-app, and you could access it in your browser at http://localhost:5000 . Your component_root will be inside of the myapp directory as myapp/comps .