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EPiServer Full Text Search Client

Product version:

EPiServer Framework 6.1 / 6.2

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Overview

The EPiServer Full Text Search Client (FTS Client) is a new Framework component offering an API for adding, updating and removing searchable items in a full text search index. The component itself acts as a REST client, communicating over HTTP using Atom Syndication Format with extensions described inthis document. The EPiServer FTS Client API is shipped together with the EPiServer FTS Service which is a WCF REST service on top of an unmodified version of the open source search engine Lucene .Net (http://incubator.apache.org/projects/lucene.net.html). EPiServer FTS is an attempt to index any kind of data including CMS page data, Community entity data and files. Content in files will be indexed, the installed Ifilters will decide which files will be included.

Architecture overview

 

Assemblies and Namespaces

The EPiServer.Search assembly contains the following namespaces

  • EPiServer.Search
    Contains core classes for the EPiServer FTS Client API, most notably are the IndexRequestItem, IndexResponseItem and SearchHandler classes.
  • EPiServer.Search.Configuration
    Contains configuration classes for the EPiServer FTS Client API.
  • EPiServer.Search.Filter
    Contains classes to support providers for filtering search results.
  • EPiServer.Search.Queries
    Contains classes for querying the index service. Built in queries is found in the EPiServer.Search.Queries.Lucene namespace
     
  • EPiServer.Search.Data
    Contains classes for integration with the Dynamic Data Store which is used for the index request queue.

Updating the index

Any modifications to the index are done by:

  • Creating an IndexRequestItem specifying the unique (within the index) item Id and IndexAction  (add, update, remove).
  • Populating it with searchable data by assigning properties.
  • Calling the SearchHandler.Instance.UpdateIndex method, passing the IndexRequestItem.

The EPiServer FTS Client requests are asynchronous, meaning that the request will immediately be enqueued, and later dequeued in a separate thread in a configurable time interval or when a queue  flush is explicitly  requested. The queue items are added to an Atom feed which is sent to the FTS service. If the request fails, the batch will be kept and resent the next time interval until it succeeds. Since the items needs to be indexed in the same order they are added, updated or removed, any failing batch will block all subsequent batches. The feed itself also contains a feed attribute extension “Version” that contains the name and current version of the EPiServer FTS Client so that the current indexing service can handle different versions of the client.

The SearchHandler.Instance.UpdateIndex has two overloads:

  • void UpdateIndex(IndexRequestItem item)
    Updates the default configured indexing servicehttp://world.episerver.com/Util/Editor/tinymce/plugins/table/cell.htm
  • void UpdateIndex(IndexRequestItem item, string namedIndexingService)
    Updates the configured namedIndexingService. The EPiServer FTS Client can thus be configured to use multiple services.

IndexItemBase

The IndexItemBase is an abstract class inherited by IndexRequestItem and IndexResponseItem with the following public members:

Property

Type

Comment

AccessControlList

Collection<string>

A list of groups and users that have access to this item. See AccessControlList.

Authors

Collection<string>

A list of authors to associate with this item.

BoostFactor

float

The boost factor is used to explicitly set a higher rank of this item when searching.

Categories

Collection<string>

A list of categories to associate with this item. See Categories.

Created

DateTime

The date when this item was created.

Culture

string

The culture for this item.

DataUri

Uri

A Uri to where the indexing service should fetch external data that is not part of the feed, e.g. files.

DisplayText

string

The part of the searchable text that is supposed to be returned by the indexing service when getting search results.

Id

string

The unique identified for this item within this named index.

ItemStatus

ItemStatus

The status (Approved, Pending, Removed) for this item.

Metadata

string

Additional searchable data of “unlimited” size that is not supposed to be returned or displayed together with the search results.

ItemType

string

The type of this item. E.g. “EPiServer.Community.Blog”, “EPiServer.Core.PageData”.

Modified

DateTime

The date when this item was last modified.

NamedIndex

string

Specifies the named index to update when multiple indexes are configured in the indexing service. See Named indexes and Multi search in the FTS Service technote.

PublicationEnd

DateTime?

The expiration date for this item, after this date the item will not be returned in searches.

PublicationStart

DateTime?

The start date for when this item should be included in searches.

ReferenceId

string

A reference to a “parent” item in the index and is used when having searchable content in sub items (e.g. Comments) where matches in the sub item should result in search hit for the parent item. See the ReferenceId section in the FTS Service technote.

Title

string

The title of the item.

Uri

Uri

The Uri to use when linking the search result item to the content source.

VirtualPathNodes

Collection<string>

A list of nodes that will build a path under which the item can be found. Used together with trailing wildcard queries. E.g. if “item1” has a path of “A/B” and “item2” has a path of “A”, a query like “A*” would result in 2 hits (“item1” and “item2”) while a query like “A/B*” would result in 1 hit (“item1”). Note that any white spaces within a node will automatically be removed. See VirtualPath in the FTS Service technote.

 

IndexRequestItem

The IndexRequestItem class inherits the IndexItemBase and holds the searchable content to be indexed.

Property

Type

Comment

IndexAction

 IndexAction

Enum for Add, Update, Remove.

 

IndexResponseItem

The IndexResponseItem class inherits the IndexItemBase and holds the content returned by the indexing service.

Property

Type

Comment

Score

float

The score set by the indexing service for this IndexResponseItem.

Querying the index

Querying the index is done by passing an object of type IQueryExpression to SearchHandler.Instance.GetSearchResults. The IQueryExpression interface defines the property string QueryExpression which returns the textual representation of the expression to be parsed by the indexing service.

The SearchHandler.Instance.GetSearchResults has two overloads:

  • SearchResults GetSearchResults(IQueryExpression queryExpression,  int page, int pageSize)
    Searches the default configured namedIndexingService and the default namedIndex in the service for matches for the passed queryExpression.
  • SearchResults GetSearchResults(IQueryExpression queryExpression,  string namedIndexingService, List<string> namedIndexes, int page, int pageSize)
    Connects to the passed namedIndexingService and searches the list of passed namedIndexes by performing a multi search. See Named indexes and Multi search in the FTS Service technote.

The page and pageSize parameter together with the SearchResults.TotalHits enables paging of search results. See Paging in the FTS Service technote..

Query enums

The EPiServer.Search.Queries.Lucene namespace contains two enums that are used by many of the query expressions:

Enum

Comment
Field

The Field enum hold values for fields that are separately searchable in the indexing service by queries taking a Field in the constructor. E.g. finding occurrences for “hello world” in the Field.Title and/or “sv” in the Field.Culture.

LuceneOperator

The Operator enum hold values for AND, OR and NOT

 

Implemented queries

The EPiServer.Search.Queries.Lucene namespace contains a number of query expression implementations compatible with the EPiServer FTS Service:

Class

Constructor

Comment

AccessControlQuery

LuceneOperator innerOperator

Empty constructor. The property “AccessControlList” returns a List<string> where users and groups can be added that should have read access to the index document. Any group or user added to the query must match at least one group or user in the IndexItemBase.AccessControlList. The default innerOperator is “OR”.

CategoryQuery

LuceneOperator innerOperator

Queries the index for occurrences where there is an exact match for the category literal in the query.

CreatedDateRangeQuery

DateTime start,
DateTime end,
bool inclusive

Inherits RangeQuery. Match occurrences where the Created field lies within the start and end parameters.

FieldQuery

string queryExpression,
Field field

Queries the index with the passed queryExpression (typically a word or a phrase) for the passed Field. If no Field is passed the Field.Default is used. Example:

FieldQuery q = new FieldQuery(“\” looking for something\””);

would return occurrences where any searchable field contains the phrase “looking for something”.

FuzzyQuery

string word,
Field field,
float similarityFactor

Queries the index for occurrences of similar words for the passed word. The higher similarityFactor the more similar the word needs to be to create an index hit. E.g. a field containing “you may  reconsider” and “this is a reconsideration” would match for a certain similarityFactor.

GroupQuery

LuceneOperator innerOperator

Group queries do not query result in any query expression in itself but is used to group queries with an operator between then. The property QueryExpressions returns a List<IQueryExpression> where query expressions can be added with the innerOperator between them. GroupQuery is an IQueryExpression which makes it possible to combine groups and expressions with their respective inner operators recursively.
ItemStatusQuery ItemStatus status

Inherits GroupQuery. Match occurances where the ItemStatus value matches any of passed ItemStatus flags.

You can pass several ItemStatus values to the constructor by using bit operands, e.g. new ItemStatusQuery(ItemStatus.Approved | ItemStatus.Pending). Occurances that match ANY of the passed ItemStatus values will be accepted as matches.

You should not add additional queries to the ItemStatusQuery's QueryExpressions list. If you want to combine an ItemStatusQuery with another query you should combine them using a GroupQuery.

ModifiedDateRangeQuery

DateTime start,
DateTime end,
bool inclusive

Inherits RangeQuery. Match occurrences where the Modified field lies within the start and end parameters.

ProximityQuery

String phrase,
Field field,
int distance

Queries the index for occurrences where the words in the passed phrase exist with the passed distance from each other. E.g. A document with the phrase “EPiServer for the win” would match the ProximityQuery phrase “EPiServer win” with the passed distance of 2.

RangeQuery

String start,
string end,
Field field,
bool inclusive

Queries the index for occurrences within the passed literal start and end. E.g. "20010202", "20030303", Field.Modified, true match index documents with the Field.Modified set between (and included) the start and end.

TermBoostQuery

String phrase,
Field field,
float boostFactor

Queries the index with a boost factor for the field, giving occurrences for the phrase in the field higher scores/relevance.

VirtualPathQuery

()

Empty constructor. The property VirtualPathNodes returns a List<string> where path nodes can be added in the order they appear from the root. The resulting path will match any index items with a path that starts with the query path.

 

SearchResults

The SearchResults class holds data from an indexing service response and is assigned internally when getting IndexResponseItems back from the service:

Property

Type

Comment

IndexResponseItems

 List<IndexResponseItem>

Gets a list of IndexResponseItems returned by the indexing service

TotalHits

 int

Gets the number of the total matching items in the indexing service

Version

 string

Gets the current indexing service name and version.

Filtering search results

The EPiServer FTS Client enables the possibility to plug in one or many filter providers to explicitly include or exclude specific items from the results. This is done by overriding the SearchResultFilter SearchResultFilterProvider.Filter(IndexResponseItem item) method and adding a provider to the configuration. The return type SearchResultFilter is an Enum with values for Include, Exclude and NotHandled where NotHandled that the IndexResponseItem was not handled by this provider and the system should forward it to the next configured provider. If the IndexResponseItem is not handled by any configured provider, the configured defaultInclude behaviour will be used.

Atom and Extensions

The standard Atom format is extended with both attributes and elements with the default namespace “EPiServer.Search.IndexingService” to map the data in the IndexRequestItem and IndexResponseItem as shown in the table below:

Property

Name

Extension

IndexItemBase.AccessControlList

 ACL

Element Extension

IndexItemBase.Authors

Authors

No

IndexItemBase.BoostFactor

BoostFactor

Attribute extension

IndexItemBase.Categories

Categories

 No

IndexItemBase.Created

PublishDate

No

IndexItemBase.Culture

Culture

Attribute extension

IndexItemBase.DataUri

DataUri

Attribute extension

IndexItemBase.DisplayText

Content

No

IndexItemBase.Id

Id

No

IndexItemBase.ItemType

Type

Attribute extension

IndexItemBase.Metadata

Metadata

Element extension

IndexItemBase.Modified

LastUpdatedTime

No

IndexItemBase.NamedIndex

NamedIndex

Attribute extension

IndexItemBase.ReferenceId

ReferenceId

Attribute extension

IndexItemBase.Title

Title

No

IndexItemBase.Uri

BaseUri

No

IndexItemBase.Version

Version

Attribute extension

IndexItemBase.VirtualPath

VirtualPath

Element extension

IndexRequestItem.IndexAction

IndexAction

Attribute extension

IndexResponseItem.Score

Score

Attribute extension

 

Example of a typical update index request

Request

POST http://localhost.:8072/IndexingService/update/?accesskey=accesskey1 HTTP/1.1
Content-Type: f
Host: localhost.:8072
Content-Length: 773
Expect: 100-continue
<?xml version="1.0" encoding="utf-8"?>
<feed p1:Version="EPiServer.Search v.6.1.28.0" xmlns:p1="EPiServer.Search.IndexingService" xmlns="http://www.w3.org/2005/Atom">
<title></title>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=12</id>
<updated>2010-04-26T20:02:02Z</updated>
<entry p1:IndexAction="add" p1:BoostFactor="1" p1:Type="" p1:Culture="" p1:NamedIndex="testindex2" p1:ReferenceId="">
<id>1</id>
<title></title>
<published>2010-04-26T22:02:02+02:00</published>
<updated>2010-04-26T22:02:02+02:00</updated>
<content></content>
<p1:Metadata xmlns:p1="EPiServer.Search.IndexingService"></p1:Metadata>
<ACL xmlns="EPiServer.Search.IndexingService"></ACL>
<VirtualPath xmlns="EPiServer.Search.IndexingService"></VirtualPath>
</entry>
</feed>

Response

HTTP/1.1 200 OK
Content-Length: 0
Server: Microsoft-HTTPAPI/1.0
Date: Mon, 26 Apr 2010 20:02:02 GMT

Example of a typical get search results response

Request

GET http://localhost.:8072/IndexingService/search/?q=EPISERVER_SEARCH_ID%3a(1)&namedindexes=&offset=0&limit=20&format=xml&accesskey=accesskey1 HTTP/1.1
Content-Type: application/xml
Host: localhost.:8072

Response

HTTP/1.1 200 OK
Content-Length: 638
Content-Type: application/xml; charset=utf-8
Server: Microsoft-HTTPAPI/1.0
Date: Mon, 26 Apr 2010 20:02:02 GMT
<feed a:TotalHits="1" a:Version="EPiServer.Search v.1.0.517.236" xmlns="http://www.w3.org/2005/Atom" xmlns:a="EPiServer.Search.IndexingService">
<title/>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=11</id>
<updated>2010-04-26T20:02:02Z</updated>
<entry xml:base="http://www.google.com/" a:Culture="sv" a:Type="EPiServer.Search.IndexItem, EPiServer.Search" a:Score="0.3068528" a:DataUri="" a:BoostFactor="1" a:NamedIndex="default">
<id>1</id>
<title>Header test</title>
<published>2010-04-26T22:02:00+02:00</published>
<updated>2010-04-26T22:02:00+02:00</updated>
<content>Body test</content>
</entry>
</feed>

Example of a typical reset index request

Request

POST http://localhost.:8072/IndexingService/reset/?namedindex=default&accesskey=accesskey1 HTTP/1.1
Content-Type: application/xml
Host: localhost.:8072
Content-Length: 0

Response

HTTP/1.1 200 OK
Content-Length: 0
Server: Microsoft-HTTPAPI/1.0
Date: Mon, 26 Apr 2010 20:02:00 GMT

Example of a typical get named indexes request

Request

GET http://localhost.:8072/IndexingService/namedindexes/?accesskey=accesskey1 HTTP/1.1
Content-Type: application/xml
Host: localhost.:8072
Connection: Keep-Alive

Response

HTTP/1.1 200 OK
Content-Length: 1048
Content-Type: application/xml; charset=utf-8
Server: Microsoft-HTTPAPI/1.0
Date: Mon, 26 Apr 2010 20:02:00 GMT
<feed xmlns="http://www.w3.org/2005/Atom">
<title/>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=1</id>
<updated>2010-04-26T20:02:00Z</updated>
<entry>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=2</id>
<title>default</title>
<updated>2010-04-26T20:02:00Z</updated>
</entry>
<entry>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=3</id>
<title>testindex2</title>
<updated>2010-04-26T20:02:00Z</updated>
</entry>
<entry>
<id>uuid:6d85bc21-020e-4058-994c-090061f9d89c;id=4</id>
<title>testindex3</title>
<updated>2010-04-26T20:02:00Z</updated>
</entry>
</feed>

Related Information

See also the following: