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Searching for Content in Liferay

To stay organized, I (RS) used to use a paper-based planner. It had different sections for various areas of my life. Its initial incarnation came from a commercial company, but over the years I tweaked it into something that worked for me. This final version (before I went digital) had different tabs for different areas of my life that I wanted to keep track of: daily items like tasks, notes, a spiritual section, and agenda pages that kept track of things I needed to go over with specific people. A planning section had tabs for projects, family, future items, and reference.

Of course, since this was paper-based, it had its limitations. It was kind of hard to find stuff. Did I put the note I’d written about that new toy my daughter wanted in the notes section or in the family section? Or maybe it was on my While Out list, so I would remember to buy it before her birthday?

Liferay content can be like this. That important information you remember seeing–was it in a wiki article, a message boards post, or web content? Did you remember to tag it? If you don’t have this kind of information, browsing to the content you’re looking for could be difficult. Thankfully, Liferay includes a powerful, faceted search function. You can access this function through the Search portlet, which lets you drill down through the different types of content, tags, and categories to refine your search. Let’s look at the search features Liferay provides for specific kinds of content and then examine how to use Liferay’s faceted search.

Searching for Specific Types of Content

Liferay provides several applications that allow users and administrators to search for content. First, there’s the Search portlet. The Search portlet can be placed on a page to allow users to search for assets of any type. We’ll learn how to use the Search portlet when we discuss Liferay’s faceted search feature in the next section. There’s also a Web Content Search portlet. This portlet can be placed on a page to allow users to search for web content instances. Users can’t use the Web Content Search portlet to search for other kinds of content. However, the Blogs, Wiki, Message Boards, Documents and Media, and Web Content portlets all provide search bars that allow users to search among the specific types of assets with which these portlets allow users to interact. Note that all of these portlets are accessible from the Control Panel. They can also, except for the Web Content portlet, be placed on portal pages for end-users to use. The Web Content portlet is not designed for end users; it’s intended for administrative use only.

In order for content to be searchable, it must first be indexed. Liferay uses Lucene for indexing and searching for content. Please refer to the Lucene section of the portal properties file if you’d like to customize Liferay’s indexing and search behavior. By default, Liferay indexes blog posts, wiki articles, and message board posts, Documents and Media files’ descriptions, and web content instances. If a Documents and Media file is a text file, the file’s content is indexed as well. Comments on blog posts, wiki articles, and Documents and Media files and text file attachments to wiki articles and message board posts are also indexed. Liferay automatically indexes content as it’s added to the portal.

If you’d like to search among assets of a specific type and you’d like to include comments and attachments in your search, use the search bar of the appropriate portlet. For example, if you’d like to search for the term Liferay among wiki articles, enter the term Liferay into the Wiki portlet’s search bar.

wiki-search.png

Figure 6.7: When using the Wiki portlet’s search bar to search for Liferay, wiki articles, comments, and attachments containing the word Liferay are returned.

Wiki articles, comments, and text file attachments containing the word Liferay are returned as search results. The search results clearly show whether an individual search result is a wiki article, a comment, or an attachment. In the next section, we’ll see how the Search portlet can be used to search through multiple types of content on Liferay. Its faceted search feature is a powerful tool that allows users to include or not include specific types of assets in a search. However, the Search portlet does not return comments or attachments as search results.

Searching for Localized Web Content

Liferay Portal supports localizing web content as well as searching for localized web content. Recall that to add a translation of a web content article, you need to edit the article, choose a language, and then add the translation and click Save. Here’s how searching for localized content works in Liferay:

  • Web content articles whose default language matches the portal’s default language are searched.
  • Web content articles whose default language is en_US (American English) are searched, regardless of the portal’s default language.
  • If the language of a translation of an article matches the portal’s default language, the article is searched.
  • Any article with an en_US translation can be searched regardless of the portal’s default language.
  • A user’s default language does not affect search results.

Note: The latest approved version of a web content article is always the version that is searched. To change the current approved version of a web content article, edit the article, click on the View History button, click on the Actions button next to a version of the article, then click on Expire.

Searching for Portal Content Using Facets

To get started using faceted search, drop the Search portlet on a page and search for something. You’ll see a page with results on the right and a collection of facets on the left.

faceted-search-1.png

Figure 6.8: The first set of facets is content types. You can drill down to specific types of content that contain the search terms you entered.

Facets allow users of the Search portlet to select criteria with which to filter search results. A facet is a combination of the information about a specific indexed field, its terms, and their frequency. Facets are typically named by the field in question. From the Search portlet’s Configuration window, administrators can configure the facets available to users for filtering search results. The default facets include the following:

  • Site
  • Asset type
  • Asset tag
  • Asset category
  • Folder
  • User
  • Modified time range

For example, after searching for a certain term in the Search portlet, clicking on a specific site filters the search results to only display assets within the specified site. Clicking on a specific user filters the search results to only display assets added by the specified user. The frequency with which the term was found for each facet is listed in parentheses after the facet. It may jog your memory to see that the term you searched for appears in a blog entry, and that may be all you need to find what you were looking for. If, however, your memory is more foggy than that, or you’re searching for something you’re not sure is actually there, then the asset tags or asset categories facets may be more helpful to you.

faceted-search-2.png

Figure 6.9: Asset tag facets let you see how many assets contain the terms for which you searched and contain certain tags. Click on a specific tag to narrow down the list of search results to those to which the tag has been applied.

For example, if you searched for a wireless phone, you might be more interested in content that has your search terms in it and has also been tagged by users. One or more tags might help you to find what you’re looking for. Note that the number of tags that appear is configurable: by default it’s 10, but there could be many more as a result of a particular search. We’ll look at the configuration options later in the chapter. For now, let’s learn how to drill down to narrow search results.

To drill down into the search, click on a facet to add it to the filter list. The results to the right are refined by the selected facets.

05-faceted-search-drill-down-1.png

Figure 6.10: Drilling down creates a list of what you selected at the top of the screen.

Here, we’ve refined the search to only show documents. We’ve also selected one of the tags, cool, to refine the search. The facets we’ve selected, Document and cool, appear in a list at the top, and there’s a red “X” next to it that lets us remove it from our filter as we work to refile our search. Suppose that the two facets we selected weren’t enough to filter our search into a small enough list to sort through. In this case, we could further refine the search by selecting another facet, as below.

05-faceted-search-drill-down-2.png

Figure 6.11: Selecting another facet further refines the search.

Now we’ve also selected the Music category, which reduces the list of search hits on the right. In this way, you can interactively tweak the search results to narrow them down, making it easier to find that proverbial needle within the haystack.

Asset Types

Searching can only be done on assets. As has already been described in this chapter, just about any entity in the portal is an asset and can be indexed and searched. Under the hood, this means that these entities use Liferay’s Asset API and have an Indexer class defined.

Developers can create custom searchable assets within the portal. This is described in the Asset Framework. section of the Developer’s Guide. For this reason, you can have additional asset types defined in your portal beyond the ones that Liferay ships with by default. If this is the case, you might want to tweak the frequencyThreshold and the maxTerms settings to increase the number of asset types displayed past the default of 10. This is covered in the section below on search options.

Note that although users can be appear as search results in the Search portlet, they behave differently than other assets. For example, you cannot select a user as a related asset. Also, users cannot be displayed by the Asset Publisher portlet. Usually, when you click on an asset from a list of results in the Search portlet, the selected asset is displayed in an Asset Publisher portlet. If you click on a user, however, you’re taken to the user’s profile page. If public personal pages have been disabled, clicking on a user from list of search results does nothing. To disable public personal pages, you can set the following portal properties:

layout.user.public.layouts.enabled=false
layout.user.public.layouts.auto.create=false
layout.user.public.layouts.power.user.required=true

The technical reason for this behavior is that although an AssetEntry object is created for each User object, the AssetEntries objects of users are created as non-visible assets. Instead of displaying users in the Asset Publisher, Liferay uses the displayURL of each user as the link from a list of search results.

Asset Tags

If tags have been applied to any asset that appears in the result set, it may be displayed in the Asset Tag facet. Tags are handled in a similar way to how asset types are handled: not all tags may appear. There may be many more than the 10 tags listed, but the default configuration for this facet is to show the top 10 most frequent terms. As with asset types, this can be modified by setting the max terms property.

Asset Categories

If categories have been applied to any asset that appears in the result set, they may be displayed in the Asset Categories facet. Asset categories work just like asset tags. As with asset tags, you can modify the number of categories listed in the search by setting the max terms property.

Let’s move on to advanced searching.

Advanced Searching

The Search portlet’s search box is deceptively simple. Though you have only a single field for search, there’s a search syntax inherited from Lucene that lets you create very powerful search queries. Let’s look at some ways you can use search queries.

Searching for specific fields: By default, searches are performed against a long list of fields. Sometimes you want results for a term within a particular field. This can be achieved using the field search syntax [field]:[term]. For example, to search in the Title field for Liferay, use the following syntax:

title:liferay

If you search for a phrase within a field, surround the term with double quotation marks:

title:"Liferay Portal"

Wildcards: You can use wildcards in exactly the way you use them with your operating system: for a single character wildcard, use ?; for the multiple character wildcard, use *.

Boolean operators: You can use logic operators, such as AND, OR, NOT, +, and - in your searches. The AND operator matches assets in which the terms between the AND operator exist. For example, to search for both Liferay and Kaleo Workflow, use this query:

"liferay" AND "kaleo workflow"

The OR operator is the default; if there’s no operator between two terms, the OR operator takes effect. OR finds matches if any term exists in an asset.

The + operator requires that the term exists somewhere in some field in the asset. If you wanted to search for something that must contain liferay and may contain portal, use this query:

+liferay portal

The NOT operator excludes assets that contain the term after the NOT operator. It requires that at least two terms be present:

"Liferay Portal" NOT "Liferay Social Office" 

The - operator is similar: it excludes assets that contain the term after the - symbol:

"Liferay Portal" - "Liferay Social Office" 

Grouping: You can use parentheses within your queries to form sub-queries, in a similar fashion to an SQL statement. For example, to search for liferay or social office and website, use this query:

(liferay OR "social office") AND website

As you can see, the search syntax is very powerful. There’s more you can do with it than what is listed here; to view the full syntax, visit the Lucene URL above.

Next, we’ll look at how the Search portlet can be configured.

Setting Search Options

As with Liferay’s other portlets, you can configure the Search portlet via the configuration screen, which looks like the below illustration.

05-faceted-search-configuration.png

Figure 6.12: Basic search configuration is pretty straightforward.

Display Asset Type Facet: Toggles whether the Asset Type facet appears.

Display Asset Tags Facet: Toggles whether the Asset Tags facet appears.

Display Asset Categories Facet: Toggles whether the Asset Categories facet appears.

Display Modified Range Facet: Toggles whether the date modified range facet appears.

Display Results in Document Form: Never use this in production. Developers use this feature to view search responses in their generic, Document-based format. Part of a developer’s job when writing search indexers is to convert Documents (the objects that get indexed) to the actual object and back again. This option allows developers to see how their objects are being indexed.

View in Context: When an asset is clicked, show it in the portlet to which it belongs.

Display Main Query: Show the exact search query that the portlet generated to the search engine. Again, never use this in production; this is for development purposes only.

Display Open Search Results: Shows results from third party Open Search plugins, if they are installed. This is for backward compatibility only: developers are encouraged to re-design their search code as described in Liferay in Action, and then custom assets are aggregated with native portal assets seamlessly.

These are the basic options. But you didn’t miss the fact that there are also advanced options, did you?

Configuring advanced search requires a bit more technical acumen than you might expect, because there are so many properties to tweak. Thankfully, in most instances, you shouldn’t need to change a thing. If you do, however, the configuration is done through a JSON object.

If you don’t know what a JSON object is, don’t worry: it’s not a difficult concept. JSON stands for *JavaScript Object N*otation. An Object is a software development term for anything that can be represented in code. Objects have attributes, or sometimes these are called fields, and they are very similar to fields you’d find on a form that you’re filling out. Software developers use the word object to refer generically to anything like this that they can describe in the software; for all intents and purposes, objects could just as easily have been called Things. For example, one type of object used in Liferay is a User. A User can be represented in code, and it has many fields, such as a name, an email address, and more. JSON is one way of describing objects like this.

The object we’re concerned with is called facets. Here’s what it looks like, in all its glory, in JSON. Explanation of the settings follows the object below.

{"facets": [
    {
    "displayStyle": "asset_entries",
    "weight": 1.5,
    "static": false,
    "order": "OrderHitsDesc",
    "data": {
        "values": [
       "com.liferay.portlet.bookmarks.model.BookmarksEntry",
       "com.liferay.portlet.blogs.model.BlogsEntry",
       "com.liferay.portlet.calendar.model.CalEvent",
       "com.liferay.portlet.documentlibrary.model.DLFileEntry",
       "com.liferay.portlet.journal.model.JournalArticle",
       "com.liferay.portlet.messageboards.model.MBMessage",
       "com.liferay.portlet.wiki.model.WikiPage",
       "com.liferay.portal.model.User"
        ],
        "frequencyThreshold": 1
    },
    "label": "asset-type",
    "className": "com.liferay.portal.kernel.search.facet.AssetEntriesFacet",
    "fieldName": "entryClassName"
    },
    {
    "displayStyle": "asset_tags",
    "weight": 1.4,
    "static": false,
    "order": "OrderHitsDesc",
    "data": {
        "maxTerms": 10,
        "displayStyle": "list",
        "frequencyThreshold": 1,
        "showAssetCount": true
    },
    "label": "tag",
    "className": "com.liferay.portal.kernel.search.facet.MultiValueFacet",
    "fieldName": "assetTagNames"
    },
    {
    "displayStyle": "asset_tags",
    "weight": 1.3,
    "static": false,
    "order": "OrderHitsDesc",
    "data": {
        "maxTerms": 10,
        "displayStyle": "list",
        "frequencyThreshold": 1,
        "showAssetCount": true
    },
    "label": "category",
    "className": "com.liferay.portal.kernel.search.facet.MultiValueFacet",
    "fieldName": "assetCategoryTitles"
    },
    {
    "displayStyle": "modified",
    "weight": 1.1,
    "static": false,
    "order": "OrderHitsDesc",
    "data": {
        "ranges": [
       {
           "range": "[past-hour TO *]",
           "label": "past-hour"
       },
       {
           "range": "[past-24-hours TO *]",
           "label": "past-24-hours"
       },
       {
           "range": "[past-week TO *]",
           "label": "past-week"
       },
       {
           "range": "[past-month TO *]",
           "label": "past-month"
       },
       {
           "range": "[past-year TO *]",
           "label": "past-year"
       }
        ],
        "frequencyThreshold": 0
    },
    "label": "modified",
    "className": "com.liferay.portal.kernel.search.facet.ModifiedFacet",
    "fieldName": "modified"
    }
]}

Now that you’ve seen the object, don’t be daunted by it. Here are all the settings within the object that you can tweak.

“className”: This field must contain a string value which is the FQCN (fully qualified class name) of a java implementation class implementing the Facet interface. Liferay provides the following implementations by default:

com.liferay.portal.kernel.search.facet.AssetEntriesFacet
com.liferay.portal.kernel.search.facet.ModifiedFacet
com.liferay.portal.kernel.search.facet.MultiValueFacet
com.liferay.portal.kernel.search.facet.RangeFacet
com.liferay.portal.kernel.search.facet.ScopeFacet
com.liferay.portal.kernel.search.facet.SimpleFacet

“data”: This field takes an arbitrary JSON object (a.k.a. {}) for use by a specific facet implementation. As such, there is no fixed definition of the data field. Each implementation is free to structure it as needed. The value defined here matches the implementation that’s selected in the className attribute above.

“displayStyle”: This field takes a string value and represents a particular template implementation which is used to render the facet. These templates are normally JSP pages (but can also be implemented as Velocity or Freemarker templates provided by a theme if the portal property theme.jsp.override.enabled is set to true). The method of matching the string to a JSP is simply done by prefixing the string with /html/portlet/search/facets/ and appending the .jsp extension.

For example, "displayStyle": "asset_tags" maps to the JSP

/html/portlet/search/facets/asset_tags.jsp

Armed with this knowledge a crafty developer could create custom display styles by deploying custom (new or overriding) JSPs using a JSP hook. See the Developer’s Guide or Liferay in Action for more information on hook plugins.

“fieldName”: This field takes a string value and defines the indexed field on which the facet operates.

For example, "fieldName": "entryClassName" indicates that the specified facet implementation operates on the entryClassName indexed field.

“label”: This field takes a string value and represents the language key that is used for localizing the title of the facet when it’s rendered.

“order”: This field takes a string value. There are two possible values:

OrderValueAsc: This tells the facet to sort it’s results by the term values, in ascending order.

OrderHitsDesc: This tells the facet to sort it’s results by the term frequency, in descending order.

“static”: This field takes a boolean value (true or false). The default value is false. A value of true means that the facet should not actually be rendered in the UI. It also means that it should use pre-set values (stored in its data field) rather than inputs dynamically applied by the end user. This allows for the creation of pre-configured search results.

Imagine you would like to create a pre-configured search that returns only images (i.e. the asset type is com.liferay.portlet.documentlibrary.model.DLFileEntry and the indexed field extension should contain the values bmp, gif, jpeg, jpg, odg, png, or svg). We would need two static facets, one with “fieldName”: “entryClassName” and another with “fieldName”: “extension”. This could be represented using the following facet configuration:

{
    "displayStyle": "asset_entries",
    "static": true,
    "weight": 1.5,
    "order": "OrderHitsDesc",
    "data": {
    "values": [
        "com.liferay.portlet.documentlibrary.model.DLFileEntry"
    ],
    "frequencyThreshold": 0
    },
    "className": "com.liferay.portal.kernel.search.facet.AssetEntriesFacet",
    "label": "asset-type",
    "fieldName": "entryClassName"
},
{
    "displayStyle": "asset_entries",
    "static": true,
    "weight": 1.5,
    "order": "OrderHitsDesc",
    "data": {
    "values": ["bmp", "gif", "jpeg", "jpg", "odg", "png", "svg"],
    "frequencyThreshold": 0
    },
    "className": "com.liferay.portal.kernel.search.facet.MultiValueFacet",
    "label": "images",
    "fieldName": "extension"
}

“weight”: This field takes a floating point (or double) value and is used to determine the ordering of the facets in the facet column of the search portlet. Facets are positioned with the largest values at the top. (yes, the current implementation is counter-intuitive and perhaps could be reversed in future versions).

Configuring search using a JSON object is a bit unusual, but as you can see, it’s not as hard as it looks initially.

Summary

Search is a powerful component of Liferay Portal’s asset framework. The proclivity of assets means that there is an extensible, robust, and configurable search mechanism throughout the portal that allows administrators to optimize the search experience of their users. Users also get an easy to use search interface that makes use of the tags and categories that they themselves apply to various pieces of content, regardless of the type of content. This makes Liferay’s search truly “for the people.”

Power users can learn an extended search syntax that lets them craft very specific searches. These searches can be used on large installations with lots of data to find the proverbial needle in the proverbial haystack. Administrators can tune the configuration of search portlets so that they are optimized for the contents of their communities.

Next, we’ll look at how the Asset Publisher portlet makes even more extensive use of Liferay’s asset framework to bring relevant content to users.

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