Lucene (OrchardCore.Search.Lucene)

The Lucene module allows you to manage Lucene indices.

Recipe step

Lucene indices can be created during recipe execution using the lucene-index step.
Here is a sample step:

{
  "steps":[
    {
      "name":"lucene-index",
      "Indices":[
        {
          "Search":{
            "AnalyzerName":"standardanalyzer",
            "IndexLatest":false,
            "IndexedContentTypes":[
              "Article",
              "BlogPost"
            ]
          }
        }
      ]
    }
  ]
}

Queries recipe step

Here is an example for creating a Lucene query from a Queries recipe step:

{
  "steps": [
    {
      "Source": "Lucene",
      "Name": "RecentBlogPosts",
      "Index": "Search",
      "Template":"...", // JSON encoded query template.
      "ReturnContentItems": true
    }
  ]
}

Web APIs

api/lucene/content

Executes a query with the specified name and returns the corresponding content items.

Verbs: POST and GET

Parameter	Example	Description
indexName	search	The name of the index to query.
query	{ "query": { "match_all": {} } }	A JSON object representing the query.
parameters	{ size: 3}	A JSON object representing the parameters of the query.

api/lucene/documents

Executes a query with the specified name and returns the corresponding Lucene documents. Only the stored fields are returned.

Verbs: POST and GET

Parameter	Example	Description
indexName	search	The name of the index to query.
query	{ "query": { "match_all": {} } }	A JSON object representing the query.
parameters	{ size: 3}	A JSON object representing the parameters of the query.

Lucene Worker (OrchardCore.Search.Lucene.Worker)

This feature creates a background task that will keep the local file system index synchronized with other instances that could have their own local index.
It is recommended to use it only if you are running the same tenant on multiple instances (farm) and are using a Lucene file system index.

If you are running on Azure App Services or if you are using Elasticsearch, then you don't need this feature.

Lucene Queries

The Lucene module provides a management UI and APIs for querying Lucene data using ElasticSearch Queries. See: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl.html

Recipe step

Lucene indices can be created during recipe execution using the ElasticIndexSettings step.
Here is a sample step:

{
  "steps":[
    {
      "name":"LuceneIndexSettings",
      "Indices":[
        {
          "Search":{
            "AnalyzerName":"standardanalyzer",
            "IndexLatest":false,
            "Culture":"",
            "StoreSourceData":false,
            "IndexedContentTypes":[
              "Article",
              "BlogPost"
            ]
          }
        }
      ]
    }
  ]
}

Lucene settings recipe step

Here is an example for setting default search settings:

{
  "steps":[
    {
      // Create the search settings.
      "name":"Settings",
      "LuceneSettings":{
        "SearchIndex":"search",
        "DefaultSearchFields":[
          "Content.ContentItem.FullText"
        ],
        "AllowLuceneQueriesInSearch":false
      }
    }
  ]
}

Reset Lucene Index Step

This Reset Index Step resets an Lucene index. Restarts the indexing process from the beginning in order to update current content items. It doesn't delete existing entries from the index.

{
  "steps":[
    {
      "name":"lucene-index-reset",
      "Indices":[
        "IndexName1",
        "IndexName2"
      ]
    }
  ]
}

To reset all indices:

{
  "steps":[
    {
      "name":"lucene-index-reset",
      "IncludeAll":true
    }
  ]
}

Rebuild Lucene Index Step

This Rebuild Index Step rebuilds an Lucene index. Deletes and recreates the full index content.

{
  "steps":[
    {
      "name":"lucene-index-rebuild",
      "Indices":[
        "IndexName1",
        "IndexName2"
      ]
    }
  ]
}

To rebuild all indices:

{
  "steps":[
    {
      "name":"lucene-index-rebuild",
      "IncludeAll":true
    }
  ]
}

Query Filters

Query filters are used to retrieve records from Lucene without taking care of the boost values on them. So, it is retrieving records just like a SQL database would do.

Here is an example of a filtered query:

{
  "query":{
    "bool":{
      "filter":[
        {
          "term":{
            "Content.ContentItem.Published":"true"
          }
        },
        {
          "wildcard":{
            "Content.ContentItem.DisplayText":"Main*"
          }
        }
      ]
    }
  }
}

With a must query in the bool Query. "finding specific content type(s)"

{
  "query":{
    "bool":{
      "must":{
        "term":{
          "Content.ContentItem.ContentType.keyword":"Menu"
        }
      },
      "filter":[
        {
          "term":{
            "Content.ContentItem.Published":"true"
          }
        },
        {
          "wildcard":{
            "Content.ContentItem.DisplayText":"Main*"
          }
        }
      ]
    }
  }
}

Using the query_string Lucene query with the Query Parser Syntax (with syntax like "exact match" and should AND contain):

{
    "query": {
        "query_string": {
            "query": "Content.ContentItem.FullText:\"exploration\""
        }
    }
}

Or in a way that you don't have to select the fields in the query (to allow users to do simpler search):

{
  "query":{
    "query_string":{
      "query":"\"exploration\"",
      "default_field":"Content.ContentItem.FullText"
    }
  }
}

An alternative to the previous one with simple_query_string:

{
  "query":{
    "simple_query_string":{
      "query":"\"exploration\"",
      "fields":[
        "Content.ContentItem.FullText"
      ]
    }
  }
}

As you can see it allows to filter on multiple query types. All of the Query types that are available in Lucene are also filters.

So you can use:

• bool
• geo_distance
• geo_bounding_box
• fuzzy
• match
• match_all
• match_phrase
• prefix
• query_string
• range
• regexp
• simple_query_string
• term
• terms
• wildcard

See ElasticSearch documentation for more details: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-filter-context.html

Automatic mapping

Starting from OC version 1.5 the Lucene module will automatically map text fields with a .keyword suffix as a stored value in the index unless the document is already set to be stored explicitly. It will ignore any value that has a length higher than 256 chars. This way, any TextField can be used as a technical value and searched by using a term query.

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