Michael Peters

NAME

CGI::Application::Search - Base class for CGI::App Swish-e site engines

SYNOPSIS

    package My::Search;
    use base 'CGI::Application::Search';

    sub cgiapp_init {
        my $self = shift;
        $self->param(
            'SWISHE_INDEX' => 'my-swishe.index',
            'TEMPLATE'     => 'search_results.tmpl',
        );
    }

    sub cgiapp_prerun {
        my $self  = shift;
        my $query = $self->query;

        # let the user turn context highlighting off
        $self->param('HIGHLIGHT' => 0) if $query->param('highlight_off');

        # let the user change which property is used in the sort
        my $sort_by = $query->param('sort_by');
        $self->param('SORT_BY' => $sort_by) if $sort_by;
    }

    1;

DESCRIPTION

A CGI::Application based control module that uses Swish-e API in perl (http://swish-e.org) to to perform searches on a swish-e index of documents.

Features

  • Sub-Classable. Unlike the Perl examples that come with swish-e, this is not a script, and can be customized without modifiying the original so that several sites may share the same underlying code.

  • Uses CGI::Application::Plugin::AnyTemplate to allow flexibility in template engine choice (HTML::Template, Template-Toolkit or Petal).

  • Built-in templates to use out of box or as examples for your own templates

  • HiLighted search results

  • HiLighted pages linked from search results

  • AJAX results sent to page without need of a page reload

  • AJAX powered 'auto-suggest' to give the user list of choices available for search

TUTORIAL

If this is your first time using Swish-e (or you think you need a refresher) or if you want step-by-step instructions on how to use the AJAX capabilities of this module, then please see the "Tutorial".

RUN_MODES

The start_mode is show_search.

This method will load the template pointed to by the TEMPLATE param (falling back to a default internal template if none is specified) and display it to the user. It will 'associate' this template with $self so that any parameters in $self->param() are also accessible to the template. It will also use HTML::FillInForm to fill in the search form with the previously selected parameters (unless it's a 'non-page-refresh' AJAX search).

This is where the meat of the searching is performed. We create a SWISH::API object on the SWISHE_INDEX and create the query for the search based on the value of the keywords parameter in CGI and any other EXTRA_PROPERTIES. The search is executed and if HIGHLIGHT is true we will use Search::Tools::HiLiter to highlight it and then format the results, only showing PER_PAGE number of elements A paging list is also shown for navigating through the results. Then we will return to the show_search() method for displaying everything.

highlight_remote_page

This run mode will fetch a remote page (with either a relative, or absolute URL using the url Query param) and highlight the keywords used in the search on that page (the keywords Query param) using the HIGHLIGHT_TAG, HIGHLIGHT_CLASS or HIGHLIGHT_COLORS options. This run mode is best used in the links of the search results listing.

    <a href="?rm=highlight_remote_page;url=http%3A%2F%2Fexample.com%2Fabout_us%2Findex.html;keywords=Us">about us</a>

highlight_local_page

This run mode will fetch a local page (only allowing relative files based in the DOCUMENT_ROOT config var and the path using the path Query param) and highlight the keywords used in the search on that page (the keywords Query param) using the HIGHLIGHT_TAG, HIGHLIGHT_CLASS or HIGHLIGHT_COLORS options. This run mode is best used in the links of the search results listing.

    <a href="?rm=highlight_local_page;path=%2Fabout_us%2Findex.html;keywords=Us">about us</a>

suggestions

This run mode will return an AJAX listing of words that should be suggested to the user for the words that they have typed so far. It uses the suggested_words() method to actually choose which words to send back.

OTHER METHODS

Most of the time you will not need to call the methods that are implemented in this module. But in some cases customizing the templates is not enought. If so, it might be prudent to override or extend these methods in your derived class.

new()

We simply override and extend the CGI::Application new() to setup our defaults.

setup()

Here's were we setup our run modes. If you override this method, make sure you also call it in your base class

    sub setup {
        my $self = shift;
        # do your thing
        ...
        $self->SUPER::setup();
    }

generate_search_query($keywords)

This method is used to generate the query for swish-e from the $keywords (by default the 'keywords' CGI parameter), as well as any EXTRA_PROPERTIES that are present.

If you wish to generate your own search query then you should override this method. This is common if you need to have access/authorization control that will need to be taken into account for your search. (eg, anything under /protected can't be seen by someone not logged in).

Please see the swish-e documentation on the exact syntax for the query.

suggested_words($word)

This object method is used by the AUTO_SUGGEST flag to return the words that should be suggested to the user after they have typed a $word. It returns an array reference of those words.

By default it will just look for words in the AUTO_SUGGEST_FILE that begin with $word. If you need more performance or flexibility (eg, storing your words in a database and querying for them) you are encouraged to override this method.

CONFIGURATION

There are several configuration parameters that you can set at any time (using param() in your cgiapp_init, or PARAMS hash in new()) before the run mode is called that will affect the search and display of the results. They are:

SWISHE_INDEX

This is the swishe index used for the searches. The default is 'data/swish-e.index'. You will probably set this every time.

AJAX

This is a boolean indicating whether or not a non-page-refresh AJAX search will be permitted.

Please see the "Tutorial" for more information on how to use the AJAX capabilities of this module.

TEMPLATE

The name of the search interface template. Default templates are included with this distribution and will be used if you don't specify one. Which default template is used depends on which TEMPLATE_TYPE you are using (HTMLTemplate or TemplateToolkit) and whether or not the AJAX flag is true.

These sample templates are installed with the module, or you can view them by looking under the templates/ directory of the source distribution (.tar.gz).

Please see "TEMPLATE USAGE" for more information on which variables are passed into your template.

TEMPLATE_TYPE

This module uses CGI::Application::Plugin::AnyTemplate to allow flexibility in choosing which templating system to use for your search. This works especially well when you are trying to integrate the Search into an existing app with an existing templating structure.

This value is passed to the $self->template->config() method as the default_type. By default it is 'HTMLTemplate'. Please see CGI::Application::Plugin::AnyTemplate for more options.

If you want more control of configuration for the template the it would probably best be done by subclassing CGI::Application::Search and passing your desired params to $self->template->config.

PER_PAGE

How many search result items to display per page. The default is 10.

HIGHLIGHT

Boolean indicating whether or not we should highlight the description given to the templates. The default is true.

HIGHLIGHT_TAG

The HTML tag used to surround the highlighted context. The default is strong.

HIGHLIGHT_CLASS

The class attribute of the HIGHLIGHT_TAG HTML tag. This is useful when you want to dictacte the style through a CSS style sheet. If given, this value will override that of HIGHLIGHT_COLORS. It has no value by default.

HIGHLIGHT_COLORS

This is an array ref of acceptable HTML colors. If provided, it will highlight each matching word/phrase in an alternating style. For instance, if given 2 colors, every other highlighted phrase would be a different color. By default it is an empty array.

EXTRA_PROPERTIES

This is an array ref of extra properties used in the search. By default, the module will only use the value of the 'keywords' parameter coming in the CGI query. If anything is provided as an extra property then it will be added to the query used in the search.

An example: You have some of you pages designated into categories. You want the user to have the option of narrowing his results by category. You add the word 'category' to the 'EXTRA_PROPERTIES' list and then you add a 'category' form element that the user has the option of giving a value to your search form. If the user gives that element a value, then it will be seen and applied to the search. This will also only work if you have the 'category' element defined for your documents (see SWISH-E Configuration and 'MetaNames' in the swish-e.org SWISH-CONF documentation).

By default, this list is empty.

EXTRA_RANGE_PROPERTIES

This is almost exactly like the EXTRA_PROPERTIES above except that instead of searching for the given properties as simple strings, we will use a range. Since ranges need to values, if you're searching for the foo property, then you need to have a foo_start and a foo_end value coming from the query. So if foo is in your EXTRA_RANGE_PROPERTIES and you have a CGI query string like this:

    ?foo_start=123&foo_end=234

Then we will a generate a Swish-E query that looks something like this:

  -L foo 123 234

DESCRIPTION_LENGTH

This is the maximum length for the context (in chars) that is displayed for each search result. The default is 250 characters.

DESCRIPTION_CONTEXT

This is the number of words on either side of the searched for words and phrases (keywords) that will be displayed as part of the description. If this is 0, then the entire description will be displayed. The default is 0.

NOTE: This directive will cause Search to use Text::Context, which can be slow and CPU intensive at times. These computations may prove to be too much for some servers (eg, a shared hosting environment).

AUTO_SUGGEST

If true, then this will allow the broswer to give suggestions to the user as they type. To use this, you must either use the AUTO_SUGGEST_FILE configuration option, or override the suggested_words() method.

You template must also have the appropriate JavaScript code. Please see the "Tutorial" for more details.

AUTO_SUGGEST_FILE

The name of the file where the suggested words are stored. These words should be in alphabetical order with one word per line.

AUTO_SUGGEST_CACHE

A boolean indicating whether or not the results of the AUTO_SUGGEST_FILE should be cached in memory or not. This will save repeated file accesses when used in a persistant environment.

AUTO_SUGGEST_LIMIT

An integer count of the most suggestions to show the user at a time. This is useful when you don't want to overwhelm the end user and take over their screen with all of your helpful suggestions.

DOCUMENT_ROOT

This is the root directory to use when looking for files when using the highlight_local_page run mode.

SORT_BY

This is a string used by Swish-e to sort the results. The string is a space separated list of valid document properties. Each property may contain a qualifier (either asc or desc) that sets the direction of the sort. Leave it alone and Swish-e will sort by swishrank in descending order. But say you wanted to reverse that for some reason. You could specify a SORT_BY of

    swishrank asc

FIF_DEFAULTS

A hash reference of extra parameters that are passed to HTML::FillInForm when it does it's business with the forms. This is useful to telling HTML::FillInForm to skip certain forms or form elements.

TEMPLATE USAGE

Sample templates are included with this distribution. These sample templates are installed with the module, or you can view them by looking under the templates/ directory of the source distribution (.tar.gz).

Please feel free to copy and change them in what ever way you see fit. To help give you more information to display (or not display, depending on your preference) the following variables are available for your templates:

Global Tmpl Vars

These variables are available throughout the templates and contain information related to the search as a whole:

  • ajax

    A boolean indicating whether or not this search is an AJAX search or not. You can use this flag to exclude everything but your search results in your template.

  • url

    The URL of this application. This is useful if you want to use the same templates in multiple applications, especially if you are using the AJAX capabilities since they require the URL to submit to.

  • searched

    A boolean indicating whether or not a search was performed.

  • keywords

    The exact string that was recieved by the server from the input named 'keywords'

  • elapsed_time

    A string representing the number of seconds that the search took. This will be a floating point number with a precision of 3.

  • hits

    This is an array of hashs (TMPL_LOOP in H::T) that contains one entry for each result returned (for the current page). Each entry contains the following keys:

    reccount

    The swishreccount property of the results as indexed by SWISH-E

    rank

    The rank to the result as given by SWISH-E (the swishrank property)

    title

    The swishtitle property of the results as indexed by SWISH-E

    path

    The swishdocpath property of the results as indexed by SWISH-E

    last_modified

    The swishlastmodified property of the results as indexed by SWISH-E and then formatted using Time::Piece's strftime() method with a format string of %B %d, %Y.

    size

    The swishdocsize property of the results as indexed by SWISH-E and then formatted with Number::Format's format_bytes() method.

    description

    The swishdescription property of the results as indexed by SWISH-E. If HIGHLIGHT is true, then this description will also have search terms highlighted and will only be, at most, DESCRIPTION_LENGTH characters long.

  • pages

    This is an array of hashes (TMPL_LOOP in H::T) that contains paging information for the results. It contains the following keys:

    current

    A boolean indicating whether or not this iteration is the current page or not.

    page_num

    The integer number of the page.

  • first_page

    This is a boolean indicating whether or not this page of the results is the first or not.

  • last_page

    This is a boolean indicating whether or not this page of the results is the last or not.

  • prev_page

    The integer number of the previous page. Will be 0 if there is no previous page.

  • next_page

    The integer number of the next page. Will be 0 if there is no next page.

  • start_num

    This is the number of the first result on the current page

  • stop_num

    This is the number of the last result on the current page

  • total_entries

    The total number of results in their search, not the total number shown on the page.

OTHER NOTES

  • If at any time prior to the execution of the 'perform_search' run mode you set the $self->param('results') parameter, a search will not be performed. Instead those results are returned. This is helpful when you decide in the cgiapp_init stage that this user does not have permissions to perform the desired search.

  • You must use the StoreDescription setting in your Swish-e configuration file. If you don't you'll get an error when C::A::Search tries to retrieve a description for each hit.

AUTHOR

Michael Peters <mpeters@plusthree.com>

Thanks to Plus Three, LP (http://www.plusthree.com) for sponsoring my work on this module.

CONTRIBUTORS

Sam Tregar <sam@tregar.com>
Mark Stosberg <mark@summersault.com>
Eric Folley <efolley@plusthree.com>