Solr

Table of Contents

Setup
Usage
Hit highlighting

The Solr search adapter brokers all communication with the Solr search engine. To work with SolrCloud deployments, read about our SolrCloud search adapter.

Setup

To add Solr search connectors to a Maven project, you must add this dependency to your project’s pom.xml file:

<dependency>
    <groupId>twigkit</groupId>
    <artifactId>twigkit.solr.runtime</artifactId>
    <version>${project.parent.version}</version>
</dependency>

Assuming you have added the correct dependencies to your project (see above), the Solr platform configuration can be accessed by pointing to it in the search:platform tag. In this case the platform is placed in a variable named platform using the var attribute, and points to a platform configuration in ../conf/platforms/solr/solr.conf:

<search:platform var="platform" conf="platforms.solr"></search:platform>

platforms/solr/solr.conf

In this example platform configuration, we set some general settings for the platform:

name: twigkit.search.solr.Solr
resultIDField: id
defaultQuery: *:*
url: http://100.200.300.400:8983/solr/myCollection
defaultFacets: age,weight

Required attributes

url (java.lang.String)
The URL of the Solr Server. Must be specified using the full URL (for example, http://localhost:8983/solr/collection - localhost:8983 will not work). If a value for url is found in the configuration, this will take precedence over other parameters found for protocol, host, port, and collection.

protocol (java.lang.String) The protocol used to send requests to the Solr Server, for example, https in https://localhost:8983/solr/collection.
Default: http

host (java.lang.String)
The domain name of the Solr server, for example, localhost in http://localhost:8983/solr/collection.

Use of host as the URI of the Solr Server is deprecated.

port (java.lang.String)
The port used to access the Solr Server, for example, 8983 in https://localhost:8983/solr/collection.
Default: 8983

collection (java.lang.String)
The Solr collection being accessed, for example, collection in https://localhost:8983/solr/collection.

As mentioned above for the host attribute, if a non-empty value for url is found in the configuration, this will take precedence over other attributes found for protocol, host, port, and collection. If no url attribute is found, and a value for host is found that begins with http, https, file or / then this will be taken as the full URL. Finally, if the latter condition is also not met, the URL will be built from attributes protocol, host, port, and collection if present.

Optional attributes

requestHandler (java.lang.String)
Name of the Request Handler to use. Use this to specify an alternate Request Handler to use for example, the '/dismax' request handler. Note you can override this by specifying a 'custom' attribute on the query.

requestMethod (java.lang.String)
Which HTTP request method to use (GET or POST).

strategy (java.lang.String)
Whether to cluster multiple hosts (value should be either combine, or round-robin). To enable sharding, set strategy to combine.

groupField (java.lang.String)
Setting this enables Solr Result Grouping or Field Collapsing on the given field. This will create a Result for each Group returned. Matching documents for the group will be available as related results.

timeOut (java.lang.Integer)
Time out for platform query requests (in milliseconds).
Default: 5000

ignoreAppliedFilters (java.lang.Boolean)
If this is set to false, facet filters that have already been applied to the Query are added to the list of filters for the facet.
Default: true

backwardsCompatible (java.lang.Boolean)
For Solr 1.x (for example, 1.4) set backwardsCompatible to true.
Default: false

highlight (java.lang.Boolean)
Whether to enable hit highlighting (hl parameter) in Solr.
Default: true

Attributes shared across platforms

name (java.lang.String) The display name of this Platform instance. Used for identifying different platforms in the user interface.

aliases (java.lang.String)
Manage mappings from field names to aliases (use a comma-separated list). All references to the field (via this platform) in results, facets, filters, and query strings are mapped. For example, to refer to a field in the index named firstnamelastname as name and countryofresidence as country, use these mappings: aliases="firstnamelastname=name,countryofresidence=country"

defaultQuery (java.lang.String)
Default query to use when none is specified. For Solr use : to bring back all items (for example, for 'zero term search').

defaultFacets (java.lang.String)
Default facets to request when none are specified. This is a comma separated list.

spellCheck (java.lang.Boolean)
Spellcheck the Query term if supported by the Platform.
Default: true

expandQuery (java.lang.Boolean)
Apply advanced linguistics such as stemming or lemmatization if supported by the Platform.
Default: true

autoCorrect (java.lang.Boolean)
Whether to auto-correct and resubmit futile queries (queries with zero results).
Default: true

fileTypeField (java.lang.String)
Set which field contains information about file type (mime type).

resultIDField (java.lang.String)
Set which field represents the unique identifier for a given result. Should correspond to the <uniqueKey> element in the Solr schema.xml.

pageLimit (java.lang.Long)
A limitation to which page the platform will offset.

Hit highlighting

Hit highlighting is enabled by default, and assumes that the uniques uniqueKey field in the Solr schema.xml file is named id. If your uniqueKey is set to a different field highlighting will not work unless you set the resultIDfield key in the Appkit configuration to the right field.

resultIDField = yourUniqueKey

Appkit expects that Solr’s default highlighting tags of <em></em> are used. Ensure that this has not been set to something different using hl.simple.pre and hl.simple.post settings in the Solr or request handler configurations.