SearchIndex.cs

using System;
using System.Collections.Generic;
using Statiq.Common;
using Statiq.Core;
using Statiq.Lunr;

namespace Statiq.Web.Pipelines
{
    public class SearchIndex : Pipeline
    {
        public SearchIndex()
        {
            Dependencies.AddRange(nameof(Content));

            PostProcessModules = new ModuleList
            {
                new ExecuteIf(Config.FromSetting("GenerateCustomSearchIndex", false))
                {
                    new ReplaceDocuments(nameof(Content)),
                    new FilterDocuments(Config.FromDocument(WebKeys.ShouldOutput, true)),
                    new FilterDocuments("Excerpt"),
                    new ExecuteConfig(Config.FromContext(ctx =>
                    {
                        // Figure out additional search and result fields
                        Dictionary<string, FieldType> additionalFields = new Dictionary<string, FieldType>(GenerateLunrIndex.DefaultFields, StringComparer.OrdinalIgnoreCase);
                        additionalFields["tags"] = FieldType.Searchable;
                        IReadOnlyList<string> additionalSearchableFields = ctx.GetList<string>(WebKeys.AdditionalSearchableFields);
                        if (additionalSearchableFields is object)
                        {
                            foreach (string additionalSearchableField in additionalSearchableFields)
                            {
                                additionalFields[additionalSearchableField] = additionalFields.ContainsKey(additionalSearchableField)
                                    ? additionalFields[additionalSearchableField] | FieldType.Searchable
                                    : FieldType.Searchable;
                            }
                        }
                        IReadOnlyList<string> additionalSearchResultFields = ctx.GetList<string>(WebKeys.AdditionalSearchResultFields);
                        if (additionalSearchResultFields is object)
                        {
                            foreach (string additionalSearchResultField in additionalSearchResultFields)
                            {
                                additionalFields[additionalSearchResultField] = additionalFields.ContainsKey(additionalSearchResultField)
                                    ? additionalFields[additionalSearchResultField] | FieldType.Result
                                    : FieldType.Result;
                            }
                        }

                        // Create the module
                        GenerateLunrIndex generateLunrIndex = new GenerateLunrIndex()
                            .WithScriptPath(ctx.GetPath(WebKeys.SearchScriptPath))
                            .ZipIndexFile(ctx.GetBool(WebKeys.ZipSearchIndexFile, true))
                            .ZipResultsFile(ctx.GetBool(WebKeys.ZipSearchResultsFile, true))
                            .IncludeHostInLinks(ctx.GetBool(WebKeys.SearchIncludeHost))
                            .AllowPositionMetadata(ctx.GetBool(WebKeys.SearchAllowPositionMetadata))
                            .WithoutAnyFields()
                            .WithFields(additionalFields)
                            .WithStemming(ctx.GetBool(WebKeys.SearchStemming));

                        // Set manual stop words
                        IReadOnlyList<string> stopWords = ctx.GetList<string>(WebKeys.SearchStopWords);
                        NormalizedPath stopWordsFilePath = ctx.GetPath(WebKeys.SearchStopWordsFilePath);
                        if (stopWords is object)
                        {
                            generateLunrIndex.WithStopWords(Config.FromValue((IEnumerable<string>)stopWords));
                        }
                        else if (!stopWordsFilePath.IsNullOrEmpty)
                        {
                            generateLunrIndex.WithStopWordsFromFile(stopWordsFilePath);
                        }

                        return generateLunrIndex;
                    }))
                }
            };

            OutputModules = new ModuleList
            {
                new WriteFiles()
            };
        }
    }
}