Sitecore 9 Solr Highlight Search Results

Highlight Search Results

“Solr has a highlighting feature. This means that Solr returns fragment of the documents that match a query in the query response. Solr includes these fragments in a special section of the response that is called the highlighting section. Solr also includes formatting clues that you use to determine how you present these fragments (or snippets)” from documentation.

Environment: Sitecore 9 update 1, and Solr 6.6.2.
References: As this is Solr specific feature, we need to refer following assemblies from our project.
- SolrNet.dll
- Sitecore.ContentSearch.dll
- Sitecore.ContentSearch.SolrProvider.dll
- Sitecore.ContentSearch.SolrNetExtension.dll
Solr Configuration: No configuration is required to enable this feature.

For demo purpose, i have created a book template, and added couple of book items. I have a description field on book template, which is used for highlighting search results.

Highlighter:

To show Highlight search result, created Highlighter content item, and added Highlighter component (Controller Rendering) from the presentation details. (to main placeholder)

Following points, you can observe in the below code,

Passing search text through query string.
Using HighlightingParameters to pass field name, on which highlighting should run.
Passing query and queryoptions to IProviderSearchContext.Query() method.

Basic Layout code: (Basic.cshtml)

	@using Sitecore.Mvc

	<!doctype html>
	<html>
	<head>
	<title>Sitecore Demo</title>
	<meta name="viewport" content="width=device-width, initial-scale=1">
	</head>
	<body>
	<div>
	<div>
	@Html.Sitecore().Placeholder("top")
	</div>
	<div>
	@Html.Sitecore().Placeholder("main")
	</div>
	<div>
	@Html.Sitecore().Placeholder("bottom")
	</div>
	</div>
	</body>
	</html>

view raw basic.cshtml hosted with ❤ by GitHub

Highlighter component – Controller Rendering: (HighlighterController.cs)

	using SC9SolrDemo.Models;
	using Sitecore.ContentSearch;
	using Sitecore.ContentSearch.SearchTypes;
	using Sitecore.ContentSearch.SolrProvider.SolrNetIntegration;
	using SolrNet;
	using SolrNet.Commands.Parameters;
	using System.Collections.Generic;
	using System.Linq;
	using System.Web.Mvc;

	namespace SC9SolrDemo.Controllers
	{
	public class HighlighterController: Controller
	{
	public ActionResult Index()
	{
	string searchField = "description_t";

	string searchValue = Request.QueryString["text"] ?? string.Empty;

	if (string.IsNullOrEmpty(searchValue))
	return View();


	var queryOptions = new QueryOptions
	{
	Highlight = new HighlightingParameters
	{
	Fields = new[] { searchField },
	BeforeTerm = "<em style='color:red'>",
	AfterTerm = "</em>",
	Fragsize =10000
	}
	};

	var indexName = string.Format("sitecore_{0}_index", Sitecore.Context.Database.Name);
	var index = ContentSearchManager.GetIndex(indexName);

	List<HighlightResult> highlightResults = new List<HighlightResult>();

	using (var context = index.CreateSearchContext())
	{
	var results = context.Query<SearchResultItem>(
	new SolrQueryByField(searchField, searchValue), queryOptions);

	foreach (var result in results)
	{
	var highlights = results.Highlights[result.Fields["_uniqueid"].ToString()];

	if (highlights.Any())
	{
	foreach(var highlightResult in highlights)
	{
	highlightResults.Add(
	new HighlightResult
	{
	Name = result.Name,
	Value = string.Join(",", highlightResult.Value)
	});
	}
	}
	}
	}

	return View(highlightResults);
	}
	}
	}

view raw HighlighterController.cs hosted with ❤ by GitHub

View Model (HighlightResult.cs)

	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Web;

	namespace SC9SolrDemo.Models
	{
	public class HighlightResult
	{
	public string Name { get; set; }
	public string Value { get; set; }
	}
	}

view raw HighlightResult.cs hosted with ❤ by GitHub

View (Index.cshtml)

	@model IEnumerable<SC9SolrDemo.Models.HighlightResult>

	@if (Model != null)
	{
	<ul>
	@foreach (var highlight in Model)
	{
	<li>
	<h1>
	@highlight.Name
	</h1>
	</li>
	<li>
	<h3>
	@Html.Raw(highlight.Value)
	</h3>
	</li>
	}
	</ul>
	}