NAME
swish.cgi -- Example Perl script for searching with the SWISH-E search
engine.
DESCRIPTION
"swish.cgi" is a CGI script for searching with the SWISH-E search
engine version 2.1-dev and above. It returns results a page at a time,
with matching words from the source document highlighted, showing a few
words of content on either side of the highlighted word.
The script is highly configurable. Features include searching multiple
(or selectable) indexes, limiting searches to a subset of documents,
sorting by a number of different properties, and limiting results to a
date range.
On unix type systems the swish.cgi script is installed in the directory
$prefix/lib/swish-e, which is typically /usr/local/lib/swish-e. This
can be overridden by the configure options --prefix or --libexecdir.
The standard configuration (i.e. not using a config file) should work
with most swish index files. Customization of the parameters will be
needed if you are indexing special meta data and want to search and/or
display the meta data. The configuration can be modified by editing
this script directly, or by using a configuration file (.swishcgi.conf
by default). The script’s configuration file is described below.
You are strongly encouraged to get the default configuration working
before making changes. Most problems using this script are the result
of configuration modifications.
The script is modular in design. Both the highlighting code and output
generation is handled by modules, which are included in the
example/modules distribution directory and installed in the
$libexecdir/perl directory. This allows for easy customization of the
output without changing the main CGI script.
Included with the Swish-e distribution is a module to generate standard
HTML output. There’s also modules and template examples to use with
the popular Perl templating systems HTML::Template and Template-
Toolkit. This is very useful if your site already uses one of these
templating systems The HTML::Template and Template-Toolkit packages are
not distributed with Swish-e. They are available from the CPAN
(http://search.cpan.org).
This scipt can also run basically unmodified as a mod_perl handler,
providing much better performance than running as a CGI script. Usage
under mod_perl is described below.
Please read the rest of the documentation. There’s a "DEBUGGING"
section, and a "FAQ" section.
This script should work on Windows, but security may be an issue.
REQUIREMENTS
A reasonably current version of Perl. 5.00503 or above is recommended
(anything older will not be supported).
The Date::Calc module is required to use the date range feature of the
script. The Date::Calc module is also available from CPAN.
INSTALLATION
Here’s an example installation session under Linux. It should be
similar for other operating systems.
For the sake of simplicity in this installation example all files are
placed in web server space, including files such as swish-e index and
configuration files that would normally not be made available via the
web server. Access to these files should be limited once the script is
running. Either move the files to other locations (and adjust the
script’s configuration) or use features of the web server to limit
access (such as with .htaccess).
Please get a simple installation working before modifying the
configuration file. Most problems reported for using this script have
been due to improper configuration.
The script’s default settings are setup for initial testing. By
default the settings expect to find most files and the swish-e binary
in the same directory as the script.
For security reasons, once you have tested the script you will want to
change settings to limit access to some of these files by the web
server (either by moving them out of web space, or using access control
such as .htaccess). An example of using .htaccess on Apache is given
below.
It’s expected that swish-e has already been unpacked and the swish-e
binary has be compiled from source and "make install" has been run. If
swish-e was installed from a vendor package (such as from a RPM or
Debian package) see that pakage’s documentation for where files are
installed.
Example Installation:
1 Symlink or copy the swish.cgi.
Symlink (or copy if your platform or webserver does not allow
symlinks) the swish.cgi script from the installation directory to a
local directory. Typically, this would be the cgi-bin directory or
a location where CGI script are located. In this example a new
directory is created and the script is symlinked.
~$ mkdir swishdir
~$ cd swishdir
~/swishdir$ ln -s /usr/local/lib/swish-e/swish.cgi
The installation directory is set at configure time with the
--prefix or --libexecdir options, but by default is in
/usr/local/lib/swish-e.
2 Create an index
Use an editor and create a simple configuration file for indexing
your files. In this example the Apache documentation is indexed.
Last we run a simple query to test that the index works correctly.
~/swishdir$ cat swish.conf
IndexDir /usr/local/apache/htdocs
IndexOnly .html .htm
DefaultContents HTML*
StoreDescription HTML* <body> 200000
MetaNames swishdocpath swishtitle
ReplaceRules remove /usr/local/apache/
If you do not have the Apache docs installed then pick another
directory to index such as /usr/share/doc.
Create the index.
~/swishdir$ swish-e -c swish.conf
Indexing Data Source: "File-System"
Indexing "/usr/local/apache/htdocs"
Removing very common words...
no words removed.
Writing main index...
Sorting words ...
Sorting 7005 words alphabetically
Writing header ...
Writing index entries ...
Writing word text: Complete
Writing word hash: Complete
Writing word data: Complete
7005 unique words indexed.
5 properties sorted.
124 files indexed. 1485844 total bytes. 171704 total words.
Elapsed time: 00:00:02 CPU time: 00:00:02
Indexing done!
Now, verify that the index can be searched:
~/swishdir$ swish-e -w install -m 1
# SWISH format: 2.1-dev-25
# Search words: install
# Number of hits: 14
# Search time: 0.001 seconds
# Run time: 0.040 seconds
1000 htdocs/manual/dso.html "Apache 1.3 Dynamic Shared Object (DSO) support" 17341
.
Let’s see what files we have in our directory now:
~/swishdir$ ls -1
index.swish-e
index.swish-e.prop
swish.cgi
swish.conf
3 Test the CGI script
This is a simple step, but often overlooked. You should test from
the command line instead of jumping ahead and testing with the web
server. See the "DEBUGGING" section below for more information.
~/swishdir$ ./swish.cgi | head
Content-Type: text/html; charset=ISO-8859-1
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>
Search our site
</title>
</head>
<body>
The above shows that the script can be run directly, and generates
a correct HTTP header and HTML.
If you run the above and see something like this:
~/swishdir >./swish.cgi
bash: ./swish.cgi: No such file or directory
then you probably need to edit the script to point to the correct
location of your perl program. Here’s one way to find out where
perl is located (again, on unix):
~/swishdir$ which perl
/usr/local/bin/perl
~/swishdir$ /usr/local/bin/perl -v
This is perl, v5.6.0 built for i586-linux
...
Good! We are using a reasonably current version of perl.
Now that we know perl is at /usr/local/bin/perl we can adjust the
"shebang" line in the perl script (e.g. the first line of the
script):
~/swishdir$ pico swish.cgi
(edit the #! line)
~/swishdir$ head -1 swish.cgi
#!/usr/local/bin/perl -w
4 Test with the web server
How you do this is completely dependent on your web server, and you
may need to talk to your web server admin to get this working.
Often files with the .cgi extension are automatically set up to run
as CGI scripts, but not always. In other words, this step is
really up to you to figure out!
This example shows creating a symlink from the web server space to
the directory used above. This will only work if the web server is
configured to follow symbolic links (the default for Apache).
This operation requires root access:
~/swishdir$ su -c "ln -s $HOME/swishdir /usr/local/apache/htdocs/swishdir"
Password: *********
If your account is on an ISP and your web directory is
~/public_html the you might just move the entire directory:
mv ~/swishdir ~/public_html
Now, let’s make a real HTTP request:
~/swishdir$ GET http://localhost/swishdir/swish.cgi | head -3
#!/usr/local/bin/perl -w
package SwishSearch;
use strict;
Oh, darn. It looks like Apache is not running the script and
instead returning it as a static page. Apache needs to be told
that swish.cgi is a CGI script.
.htaccess comes to the rescue:
~/swishdir$ cat .htaccess
# Deny everything by default
Deny From All
# But allow just CGI script
<files swish.cgi>
Options ExecCGI
Allow From All
SetHandler cgi-script
</files>
That "Deny From All" prevents access to all files (such as config
and index files), and only access is allowed to the swish.cgi
script.
Let’s try the request one more time:
~/swishdir >GET http://localhost/swishdir/swish.cgi | head
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>
Search our site
</title>
</head>
<body>
<h2>
<a href="http://swish-e.org">
That looks better! Now use your web browser to test.
Now, you may note that the links are not valid on the search
results page. The swish config file contained the line:
ReplaceRules remove /usr/local/apache/
To make those links works (and assuming your web server will follow
symbolic links):
~/swishtest$ ln -s /usr/local/apache/htdocs
BTW - "GET" used above is a program included with Perl’s LWP
library. If you do no have this you might try something like:
wget -O - http://localhost/swishdir/swish.cgi | head
and if nothing else, you can always telnet to the web server and
make a basic request.
~/swishtest$ telnet localhost 80
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
GET /swishtest/swish.cgi http/1.0
HTTP/1.1 200 OK
Date: Wed, 13 Feb 2002 20:14:31 GMT
Server: Apache/1.3.20 (Unix) mod_perl/1.25_01
Connection: close
Content-Type: text/html; charset=ISO-8859-1
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>
Search our site
</title>
</head>
<body>
This may seem like a lot of work compared to using a browser, but
browsers are a poor tool for basic CGI debugging.
If you have problems check the "DEBUGGING" section below.
CONFIGURATION
If you want to change the location of the swish-e binary or the index
file, use multiple indexes, add additional metanames and properties,
change the default highlighting behavior, etc., you will need to adjust
the script’s configuration settings.
Again, please get a test setup working with the default parameters
before making changes to any configuration settings. Better to debug
one thing at a time...
In general, you will need to adjust the script’s settings to match the
index file you are searching. For example, if you are indexing a
hypermail list archive you may want to make the script use
metanames/properties of Subject, Author, and, Email address. Or you
may wish to provide a way to limit searches to subsets of documents
(e.g. parts of your directory tree).
To make things somewhat "simple", the configuration parameters are
included near the top of the swish.cgi program. That is the only place
that the individual parameters are defined and explained, so you will
need to open up the swish.cgi script in an editor to view the options.
Further questions about individual settings should be referred to the
swish-e discussion list.
The parameters are all part of a perl "hash" structure, and the
comments at the top of the program should get you going. The perl hash
structure may seem a bit confusing, but it makes it easy to create
nested and complex parameters. Syntax is important, so cut-n-paste
should be your best defense if you are not a perl programmer.
By the way, Perl has a number of quote operators. For example, to
quote a string you might write:
title => 'Search My Site',
Some options take more than one parameter, where each parameter must be
quoted. For example:
metanames => [ 'swishdefault', 'swishtitle', 'swishdocpath' ],
which assigns an array ( [...] ) of three strings to the "metanames"
variable. Lists of quoted strings are so common in perl that there’s a
special operator called "qw" (quote word) to save typing all those
quotes:
metanames => [ qw/ swishdefault swishtitle swishdocpath / ],
or to use the parenthesis as the quote character (you can pick any):
metanames => [ qw( swishdefault swishtitle swishdocpath ) ],
There are two options for changing the configuration settings from
their default values: One way is to edit the script directly, or the
other was is to use a separate configuration file. In either case, the
configuration settings are a basic perl hash reference.
Using a configuration file is described below, but contains the same
hash structure.
There are many configuration settings, and some of them are commented
out either by using a "#" symbol, or by simply renaming the
configuration directive (e.g. by adding an "x" to the parameter name).
A very basic configuration setup might look like:
return {
title => 'Search the Swish-e list', # Title of your choice.
swish_binary => 'swish-e', # Location of swish-e binary
swish_index => 'index.swish-e', # Location of your index file
};
Or if searching more than one index:
return {
title => 'Search the Swish-e list',
swish_binary => 'swish-e',
swish_index => ['index.swish-e', 'index2'],
};
Both of these examples return a reference to a perl hash ( "return
{...}" ). In the second example, the multiple index files are set as
an array reference.
Note that in the example above the swish-e binary file is relative to
the current directory. If running under mod_perl you will need to use
absolute paths.
The script can also use the SWISH::API perl module (included with the
swish-e distribution in the perl directory) to access the swish-e
index. The "use_library" option is used to enable the use of the
SWISH::API module:
return {
title => 'Search the Swish-e list',
swish_index => ['index.swish-e', 'index2'],
use_library => 1, # enable use of the SWISH::API module
};
The module must be available via the @INC array, like all Perl modules.
Using the SWISH::API module avoids the need to fork and execute a the
swish-e program. Under mod_perl you will may see a significant
performance improvement when using the SWISH::API module. Under normal
CGI usage you will probably not see any speed improvements.
Using A Configuration File
As mentioned above, configuration settings can be either set in the
swish.cgi script, or set in a separate configuration file. Settings in
a configuration file will override the settings in the script.
By default, the swish.cgi script will attempt to read settings from the
file .swishcgi.conf. For example, you might only wish to change the
title used in the script. Simply create a file called .swishcgi.conf
in the same directory as the CGI script:
> cat .swishcgi.conf
# Example swish.cgi configuration script.
return {
title => 'Search Our Mailing List Archive',
};
The settings you use will depend on the index you create with swish:
return {
title => 'Search the Apache documentation',
swish_binary => 'swish-e',
swish_index => 'index.swish-e',
metanames => [qw/swishdefault swishdocpath swishtitle/],
display_props => [qw/swishtitle swishlastmodified swishdocsize swishdocpath/],
title_property => 'swishdocpath',
prepend_path => 'http://myhost/apachedocs',
name_labels => {
swishdefault => 'Search All',
swishtitle => 'Title',
swishrank => 'Rank',
swishlastmodified => 'Last Modified Date',
swishdocpath => 'Document Path',
swishdocsize => 'Document Size',
},
};
The above configuration defines metanames to use on the form. Searches
can be limited to these metanames.
"display_props" tells the script to display the property
"swishlastmodified" (the last modified date of the file), the document
size, and path with the search results.
The parameter "name_labels" is a hash (reference) that is used to give
friendly names to the metanames.
Here’s another example. Say you want to search either (or both) the
Apache 1.3 documentation and the Apache 2.0 documentation indexed
seperately.
return {
title => 'Search the Apache Documentation',
date_ranges => 0,
swish_index => [ qw/ index.apache index.apache2 / ],
select_indexes => {
method => 'checkbox_group',
labels => [ '1.3.23 docs', '2.0 docs' ], # Must match up one-to-one to swish_index
description => 'Select: ',
},
};
Now you can select either or both sets of documentation while
searching.
All the possible settings are included in the default configuration
located near the top of the swish.cgi script. Open the swish.cgi
script with an editor to look at the various settings. Contact the
Swish-e Discussion list for help in configuring the script.
DEBUGGING
Most problems with using this script have been a result of improper
configuration. Please get the script working with default settings
before adjusting the configuration settings.
The key to debugging CGI scripts is to run them from the command line,
not with a browser.
First, make sure the program compiles correctly:
$ perl -c swish.cgi
swish.cgi syntax OK
Next, simply try running the program:
$ ./swish.cgi | head
Content-Type: text/html; charset=ISO-8859-1
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>
Search our site
</title>
</head>
<body>
Under Windows you will need to run the script as:
C:\wwwroot\swishtest> perl swish.cgi
Now, you know that the program compiles and will run from the command
line. Next, try accessing the script from a web browser.
If you see the contents of the CGI script instead of its output then
your web server is not configured to run the script. With Apache look
at settings like ScriptAlias, SetHandler, and Options.
If an error is reported (such as Internal Server Error or Forbidden)
you need to locate your web server’s error_log file and carefully read
what the problem is. Contact your web administrator for help locating
the web server’s error log.
If you don’t have access to the web server’s error_log file, you can
modify the script to report errors to the browser screen. Open the
script and search for "CGI::Carp". (Author’s suggestion is to debug
from the command line -- adding the browser and web server into the
equation only complicates debugging.)
The script does offer some basic debugging options that allow debugging
from the command line. The debugging options are enabled by setting an
environment variable "SWISH_DEBUG". How that is set depends on your
operating system and the shell you are using. These examples are using
the "bash" shell syntax.
Note: You can also use the "debug_options" configuration setting, but
the recommended method is to set the environment variable.
You can list the available debugging options like this:
$ SWISH_DEBUG=help ./swish.cgi >outfile
Unknown debug option 'help'. Must be one of:
basic: Basic debugging
command: Show command used to run swish
headers: Show headers returned from swish
output: Show output from swish
summary: Show summary of results
dump: Show all data available to templates
Debugging options may be combined:
$ SWISH_DEBUG=command,headers,summary ./swish.cgi >outfile
You will be asked for an input query and the max number of results to
return. You can use the defaults in most cases. It’s a good idea to
redirect output to a file. Any error messages are sent to stderr, so
those will still be displayed (unless you redirect stderr, too).
Here are some examples:
~/swishtest$ SWISH_DEBUG=basic ./swish.cgi >outfile
Debug level set to: 1
Enter a query [all]:
Using 'not asdfghjklzxcv' to match all records
Enter max results to display [1]:
------ Can't use DateRanges feature ------------
Script will run, but you can't use the date range feature
Can't locate Date/Calc.pm in @INC (@INC contains: modules /usr/local/lib/perl5/5.6.0/i586-linux /usr/local/lib/perl5/5.6.0 /usr/local/lib/perl5/site_perl/5.6.0/i586-linux /usr/local/lib/perl5/site_perl/5.6.0 /usr/local/lib/perl5/site_perl/5.005/i586-linux /usr/local/lib/perl5/site_perl/5.005 /usr/local/lib/perl5/site_perl .) at modules/DateRanges.pm line 107, <STDIN> line 2.
BEGIN failed--compilation aborted at modules/DateRanges.pm line 107, <STDIN> line 2.
Compilation failed in require at ./swish.cgi line 971, <STDIN> line 2.
--------------
Can't exec "./swish-e": No such file or directory at ./swish.cgi line 1245, <STDIN> line 2.
Child process Failed to exec './swish-e' Error: No such file or directory at ./swish.cgi line 1246, <STDIN> line 2.
Failed to find any results
The above indicates two problems. First problem is that the Date::Calc
module is not installed. The Date::Calc module is needed to use the
date limiting feature of the script.
The second problem is a bit more serious. It’s saying that the script
can’t find the swish-e binary file. In this example it’s specified as
being in the current directory. Either correct the path to the swish-e
binary, or make a local copy or symlink to the swish-e binary.
~/swishtest$ cat .swishcgi.conf
return {
title => 'Search the Apache Documentation',
swish_binary => '/usr/local/bin/swish-e',
date_ranges => 0,
};
Now, let’s try again:
~/swishtest$ SWISH_DEBUG=basic ./swish.cgi >outfile
Debug level set to: 1
---------- Read config parameters from '.swishcgi.conf' ------
$VAR1 = {
'date_ranges' => 0,
'title' => 'Search the Apache Documentation'
};
-------------------------
Enter a query [all]:
Using 'not asdfghjklzxcv' to match all records
Enter max results to display [1]:
Found 1 results
Can't locate SWISH::TemplateDefault.pm in @INC (@INC contains: modules /usr/local/lib/perl5/5.6.0/i586-linux /usr/local/lib/perl5/5.6.0 /usr/local/lib/perl5/site_perl/5.6.0/i586-linux /usr/local/lib/perl5/site_perl/5.6.0 /usr/local/lib/perl5/site_perl/5.005/i586-linux /usr/local/lib/perl5/site_perl/5.005 /usr/local/lib/perl5/site_perl .) at ./swish.cgi line 608.
This means that the swish.cgi script could not locate a required
module. To correct this locate where the SWISH::Template module is
installed and add a "use lib" line to your configuration file (or to
the swish.cgi script):
~/swishtest$ cat .swishcgi.conf
use lib '/home/bill/local/lib/perl';
return {
title => 'Search the Apache Documentation',
date_ranges => 0,
};
~/swishtest$ SWISH_DEBUG=basic ./swish.cgi >outfile
Debug level set to: 1
---------- Read config parameters from '.swishcgi.conf' ------
$VAR1 = {
'date_ranges' => 0,
'title' => 'Search the Apache Documentation'
};
-------------------------
Enter a query [all]:
Using 'not asdfghjklzxcv' to match all records
Enter max results to display [1]:
Found 1 results
That is much better!
The "use lib" statement tells Perl where to look for modules by adding
the path supplied to an array called @INC.
Note that most modules are in the SWISH namespace. For example, the
default output module is called SWISH::TemplateDefault. When Perl is
looking for that module it is looking for the file
SWISH/TemplateDefault.pm. If the "use lib" statement is set as:
use lib '/home/bill/local/lib/perl';
then Perl will look (among other places) for the file
/home/bill/local/lib/perl/SWISH/TemplateDefault.pm
when attempting to load the SWISH::TemplateDefault module. Relative
paths may also be used.
use lib 'modules';
will cause Perl to look for the file:
./modules/SWISH/TemplateDefault.pm
relative to where the swish.cgi script is running. (This is not true
when running under mod_perl).
Here’s another common problem. Everything checks out, but when you run
the script you see the message:
Swish returned unknown output
Ok, let’s find out what output it is returning:
~/swishtest$ SWISH_DEBUG=headers,output ./swish.cgi >outfile
Debug level set to: 13
---------- Read config parameters from '.swishcgi.conf' ------
$VAR1 = {
'swish_binary' => '/usr/local/bin/swish-e',
'date_ranges' => 0,
'title' => 'Search the Apache Documentation'
};
-------------------------
Enter a query [all]:
Using 'not asdfghjklzxcv' to match all records
Enter max results to display [1]:
usage: swish [-i dir file ... ] [-S system] [-c file] [-f file] [-l] [-v (num)]
...
version: 2.0
docs: http://sunsite.berkeley.edu/SWISH-E/
*** 9872 Failed to run swish: 'Swish returned unknown output' ***
Failed to find any results
Oh, looks like /usr/local/bin/swish-e is version 2.0 of swish. We need
2.1-dev and above!
Frequently Asked Questions
Here’s some common questions and answers.
How do I change the way the output looks?
The script uses a module to generate output. By default it uses the
SWISH::TemplateDefault.pm module. The module used is selected in the
swish.cgi configuration file. Modules are located in the
example/modules/SWISH directory in the distribution, but are installed
in the $prefix/lib/swish-e/perl/SWISH/ directory.
To make simple changes you can edit the installed SWISH::TemplatDefault
module directly, otherwise make a copy of the module and modify its
package name. For example, change directories to the location of the
installed module and copy the module to a new name:
$ cp TemplateDefault.pm MyTemplateDefault.pm
Then at the top of the module adjust the "package" line to:
package SWISH::MyTemplateDefault;
To use this modules you need to adjust the configuration settings
(either at the top of swish.cgi or in a configuration file:
template => {
package => 'SWISH::MyTemplateDefault',
},
The module does not need to be in the SWISH namespace, and can be
stored in any location as long as the module can be found via the @INC
array (i.e. modify the "use lib" statement in swish.cgi if needed).
How do I use a templating system with swish.cgi?
In addition to the TemplateDefault.pm module, the swish-e distribution
includes two other Perl modules for generating output using the
templating systems HTML::Template and Template-Toolkit.
Templating systems use template files to generate the HTML, and make
maintaining the look of a large (or small) site much easier.
HTML::Template and Template-Toolkit are separate packages and can be
downloaded from the CPAN. See http://search.cpan.org.
Two basic templates are provided as examples for generating output
using these templating systems. The example templates are located in
the example directory. The module SWISH::TemplateHTMLTemplate uses the
file swish.tmpl to generate its output, while the module
SWISH::TemplateToolkit uses the swish.tt file. (Note: swish.tt was
renamed from search.tt Jun 03, 2004.)
To use either of these modules you will need to adjust the "template"
configuration setting. Examples for both templating systems are
provided in the configuration settings near the top of the swish.cgi
program.
Use of these modules is an advanced usage of swish.cgi and are provided
as examples only.
All of the output generation modules are passed a hash with the results
from the search, plus other data use to create the output page. You
can see this hash by using the debugging option "dump" or by using the
included SWISH::TemplateDumper module:
~/swishtest >cat .swishcgi.conf
return {
title => 'Search the Apache Documentation',
template => {
package => 'SWISH::TemplateDumper',
},
};
And run a query. For example:
http://localhost/swishtest/swish.cgi?query=install
Why are there three different highlighting modules?
Three are three highlighting modules included with the swish-e
distribution. Each is a trade-off of speed vs. accuracy:
SWISH::DefaultHighlight - reasonably fast, but does not highlight phrases
SWISH::PhraseHighlight - reasonably slow, but is reasonably accurate
SWISH::SimpleHighlight - fast, some phrases, but least accurate
Eh, the default is actually "PhraseHighlight". Oh well.
All of the highlighting modules slow down the script. Optimizations to
these modules are welcome!
My ISP doesn’t provide access to the web server logs
There are a number of options. One way it to use the CGI::Carp module.
Search in the swish.cgi script for:
use Carp;
# Or use this instead -- PLEASE see perldoc CGI::Carp for details
# use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
And change it to look like:
#use Carp;
# Or use this instead -- PLEASE see perldoc CGI::Carp for details
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
This should be only for debugging purposes, as if used in production
you may end up sending quite ugly and confusing messages to your
browsers.
Why does the output show (NULL)?
Swish-e displays (NULL) when attempting to display a property that does
not exist in the index.
The most common reason for this message is that you did not use
StoreDescription in your config file while indexing.
StoreDescription HTML* <body> 200000
That tells swish to store the first 200,000 characters of text
extracted from the body of each document parsed by the HTML parser.
The text is stored as property "swishdescription".
The index must be recreated after changing the swish-e configuration.
Running:
~/swishtest > ./swish-e -T index_metanames
will display the properties defined in your index file.
This can happen with other properties, too. For example, this will
happen when you are asking for a property to display that is not
defined in swish.
~/swishtest > ./swish-e -w install -m 1 -p foo
# SWISH format: 2.1-dev-25
# Search words: install
err: Unknown Display property name "foo"
.
~/swishtest > ./swish-e -w install -m 1 -x 'Property foo=<foo>\n'
# SWISH format: 2.1-dev-25
# Search words: install
# Number of hits: 14
# Search time: 0.000 seconds
# Run time: 0.038 seconds
Property foo=(NULL)
.
To check that a property exists in your index you can run:
~/swishtest > ./swish-e -w not dkdk -T index_metanames | grep foo
foo : id=10 type=70 META_PROP:STRING(case:ignore) *presorted*
Ok, in this case we see that "foo" is really defined as a property.
Now let’s make sure swish.cgi is asking for "foo" (sorry for the long
lines):
~/swishtest > SWISH_DEBUG=command ./swish.cgi > /dev/null
Debug level set to: 3
Enter a query [all]:
Using 'not asdfghjklzxcv' to match all records
Enter max results to display [1]:
---- Running swish with the following command and parameters ----
./swish-e \
-w \
'swishdefault=(not asdfghjklzxcv)' \
-b \
1 \
-m \
1 \
-f \
index.swish-e \
-s \
swishrank \
desc \
swishlastmodified \
desc \
-x \
'<swishreccount>\t<swishtitle>\t<swishdescription>\t<swishlastmodified>\t<swishdocsize>\t<swishdocpath>\t<fos>\t<swishrank>\t<swishdocpath>\n' \
-H \
9
If you look carefully you will see that the -x parameter has "fos"
instead of "foo", so there’s our problem.
How do I use the SWISH::API perl module with swish.cgi?
Use the "use_library" configuration directive:
use_library => 1,
This will only provide improved performance when running under mod_perl
or other persistent environments.
Why does the "Run time" differ when using the SWISH::API module
When using the SWISH::API module the run (and search) times are
calculated within the script. When using the swish-e binary the swish-
e program reports the times. The "Run time" may include the time
required to load and compile the SWISH::API module.
MOD_PERL
This script can be run under mod_perl (see http://perl.apache.org).
This will improve the response time of the script compared to running
under CGI by loading the swish.cgi script into the Apache web server.
You must have a mod_perl enabled Apache server to run this script under
mod_perl.
Configuration is simple. In your httpd.conf or your startup.pl file
you need to load the script. For example, in httpd.conf you can use a
perl section:
<perl>
use lib '/usr/local/apache/cgi-bin'; # location of the swish.cgi file
use lib '/home/yourname/swish-e/example/modules'; # modules required by swish.cgi
require "swish.cgi";
</perl>
Again, note that the paths used will depend on where you installed the
script and the modules. When running under mod_perl the swish.cgi
script becomes a perl module, and therefore the script does not need to
be installed in the cgi-bin directory. (But, you can actually use the
same script as both a CGI script and a mod_perl module at the same
time, read from the same location.)
The above loads the script into mod_perl. Then to configure the script
to run add this to your httpd.conf configuration file:
<location /search>
PerlSetVar Swish_Conf_File /home/yourname/swish-e/myconfig.pl
allow from all
SetHandler perl-script
PerlHandler SwishSearch
</location>
Note that you use the "Swish_Conf_File" setting in httpd.conf to tell
the script which config file to use. This means you can use the same
script (and loaded modules) for different search sites (running on the
same Apache server). You can just specify differnt config files for
each Location and they can search different indexes and have a
completely different look for each site, but all share the same code.
Note that the config files are cached in the swish.cgi script. Changes
to the config file will require restarting the Apache server before
they will be reloaded into the swish.cgi script. This avoids calling
stat() for every request.
Unlike CGI, mod_perl does not change the current directory to the
location of the script, so your settings for the swish binary and the
path to your index files must be absolute paths (or relative to the
server root).
Using the SWISH::API module with mod_perl will provide the most
performance improvements. Use of the SWISH::API module can be enabled
by the configuration setting "use_library":
use_library => 1,
Without highlighting code enabled, using the SWISH::API module resulted
in about 20 requests per second, where running the swish-e binary
slowed the script down to about 8 requests per second.
Note that the highlighting code is slow. For the best search
performance turn off highlighting. In your config file you can add:
highlighting => 0, # disable highlighting
and the script will show the first 500 chars of the description (or
whatever you set for "max_chars"). Without highlight one test was
processing about 20 request per second. With The "PhraseHighlight"
module that dropped to a little better than two requests per second,
"DefaultHighlight" was about 2.3 request per second, and
"SimpleHighlight" was about 6 request per second.
Experiement with different highlighting options when testing
performance.
Please post to the swish-e discussion list if you have any questions
about running this script under mod_perl.
Here’s some general request/second on an Athlon XP 1800+ with 1/2GB
RAM, Linux 2.4.20.
Highlighting Mode
None Phrase Default Simple
Using SWISH::API 45 1.5 2 12
----------------------------------------------------------------------------
Using swish-e 12 1.3 1.8 7.5
binary
As you can see the highlighting code is a limiting factor.
SpeedyCGI
SpeedyCGI (also called PersistentPerl) is another way to run Perl
scripts persistently. SpeedyCGI is good if you do not have mod_perl
available or do not have root access. SpeedyCGI works on Unix systems
by loading the script into a "back end" process and keeping it in
memory between requests. New requests are passed to the back end
processes which avoids the startup time required by a Perl CGI script.
Install SpeedyCGI from http://daemoninc.com/ (your OS may provide a
packaged version of SpeedyCGI) and then change the first line of
swish.cgi. For example, if the speedy binary is installed in
/usr/bin/speedy, use the line:
#! /usr/bin/speedy -w -- -t60
The -w option is passed to Perl, and all options following the double-
dash are SpeedyCGI options.
Note that when using SpeedyCGI configuration data is cached in memory.
If you change the swish.cgi configuration file (.swishcgi.conf) then
touch the main swish.cgi script to force reloading of configuration
data.
Spidering
There are two ways to spider with swish-e. One uses the "http" input
method that uses code that’s part of swish. The other way is to use
the new "prog" method along with a perl helper program called
"spider.pl".
Here’s an example of a configuration file for spidering with the "http"
input method. You can see that the configuration is not much different
than the file system input method. (But, don’t use the http input
method -- use the -S prog method shown below.)
# Define what to index
IndexDir http://www.myserver.name/index.html
IndexOnly .html .htm
IndexContents HTML* .html .htm
DefaultContents HTML*
StoreDescription HTML* <body> 200000
MetaNames swishdocpath swishtitle
# Define http method specific settings -- see swish-e documentation
SpiderDirectory ../swish-e/src/
Delay 0
You index with the command:
swish-e -S http -c spider.conf
Note that this does take longer. For example, spidering the Apache
documentation on a local web server with this method took over a
minute, where indexing with the file system took less than two seconds.
Using the "prog" method can speed this up.
Here’s an example configuration file for using the "prog" input method:
# Define the location of the spider helper program
IndexDir ../swish-e/prog-bin/spider.pl
# Tell the spider what to index.
SwishProgParameters default http://www.myserver.name/index.html
IndexContents HTML* .html .htm
DefaultContents HTML*
StoreDescription HTML* <body> 200000
MetaNames swishdocpath swishtitle
Then to index you use the command:
swish-e -c prog.conf -S prog -v 0
Spidering with this method took nine seconds.
Stemmed Indexes
Many people enable a feature of swish called word stemming to provide
"fuzzy" search options to their users. The stemming code does not
actually find the "stem" of word, rather removes and/or replaces common
endings on words. Stemming is far from perfect, and many words do not
stem as you might expect. Plus, currently only English is supported.
But, it can be a helpful tool for searching your site. You may wish to
create both a stemmed and non-stemmed index, and provide a checkbox for
selecting the index file.
To enable a stemmed index you simply add to your configuration file:
UseStemming yes
If you want to use a stemmed index with this program and continue to
highlight search terms you will need to install a perl module that will
stem words. This section explains how to do this.
The perl module is included with the swish-e distribution. It can be
found in the examples directory (where you found this file) and called
something like:
SWISH-Stemmer-0.05.tar.gz
The module should also be available on CPAN (http://search.cpan.org/).
Here’s an example session for installing the module. (There will be
quite a bit of output when running make.)
% gzip -dc SWISH-Stemmer-0.05.tar.gz |tar xof -
% cd SWISH-Stemmer-0.05
% perl Makefile.PL
or
% perl Makefile.PL PREFIX=$HOME/perl_lib
% make
% make test
(perhaps su root at this point if you did not use a PREFIX)
% make install
% cd ..
Use the PREFIX if you do not have root access or you want to install
the modules in a local library. If you do use a PREFIX setting, add a
"use lib" statement to the top of this swish.cgi program.
For example:
use lib qw(
/home/bmoseley/perl_lib/lib/site_perl/5.6.0
/home/bmoseley/perl_lib/lib/site_perl/5.6.0/i386-linux/
);
Once the stemmer module is installed, and you are using a stemmed
index, the "swish.cgi" script will automatically detect this and use
the stemmer module.
DISCLAIMER
Please use this CGI script at your own risk.
This script has been tested and used without problem, but you should
still be aware that any code running on your server represents a risk.
If you have any concerns please carefully review the code.
See http://www.w3.org/Security/Faq/www-security-faq.html
Security on Windows questionable.
SUPPORT
The SWISH-E discussion list is the place to ask for any help regarding
SWISH-E or this example script. See http://swish-e.org.
Before posting please review:
http://swish-e.org/2.2/docs/INSTALL.html#When_posting_please_provide_the_
Please do not contact the author or any of the swish-e developers
directly.
LICENSE
swish.cgi $Revision: 1830 $ Copyright (C) 2001 Bill Moseley
search@hank.org Example CGI program for searching with SWISH-E
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
AUTHOR
Bill Moseley