C# Indexing.FieldsToFetch类代码示例

			public IndexQueryOperation(Index parent, IndexQuery indexQuery, Func<IndexQueryResult, bool> shouldIncludeInResults,
										FieldsToFetch fieldsToFetch, OrderedPartCollection<AbstractIndexQueryTrigger> indexQueryTriggers)
			{
				this.parent = parent;
				this.indexQuery = indexQuery;
				this.shouldIncludeInResults = shouldIncludeInResults;
				this.fieldsToFetch = fieldsToFetch;
				this.indexQueryTriggers = indexQueryTriggers;

				if (fieldsToFetch.IsDistinctQuery)
					alreadyReturned = new HashSet<RavenJObject>(new RavenJTokenEqualityComparer());
			}

		protected virtual IndexQueryResult RetrieveDocument(Document document, FieldsToFetch fieldsToFetch, ScoreDoc score)
		{
			return new IndexQueryResult
			{
				Score = score.Score,
				Key = document.Get(Constants.DocumentIdFieldName),
				Projection = (fieldsToFetch.IsProjection || fieldsToFetch.FetchAllStoredFields) ? CreateDocumentFromFields(document, fieldsToFetch) : null
			};
		}

		public static RavenJObject CreateDocumentFromFields(Document document, FieldsToFetch fieldsToFetch)
		{
			var documentFromFields = new RavenJObject();
			var fields = fieldsToFetch.Fields;
			if (fieldsToFetch.FetchAllStoredFields)
				fields = fields.Concat(document.GetFields().Select(x => x.Name));


			var q = fields
				.Distinct()
				.SelectMany(name => document.GetFields(name) ?? new Field[0])
				.Where(x => x != null)
				.Where(
					x =>
					x.Name.EndsWith("_IsArray") == false &&
					x.Name.EndsWith("_Range") == false &&
					x.Name.EndsWith("_ConvertToJson") == false)
				.Select(fld => CreateProperty(fld, document))
				.GroupBy(x => x.Key)
				.Select(g =>
				{
					if (g.Count() == 1 && document.GetField(g.Key + "_IsArray") == null)
					{
						return g.First();
					}
					var ravenJTokens = g.Select(x => x.Value).ToArray();
					return new KeyValuePair<string, RavenJToken>(g.Key, new RavenJArray((IEnumerable)ravenJTokens));
				});
			foreach (var keyValuePair in q)
			{
				documentFromFields.Add(keyValuePair.Key, keyValuePair.Value);
			}
			return documentFromFields;
		}

		protected override IndexQueryResult RetrieveDocument(Document document, FieldsToFetch fieldsToFetch, ScoreDoc score)
		{
			fieldsToFetch.EnsureHasField(Constants.ReduceKeyFieldName);
			if (fieldsToFetch.HasExplicitFieldsToFetch)
			{
				return base.RetrieveDocument(document, fieldsToFetch, score);
			}
			var field = document.GetField(Constants.ReduceValueFieldName);
			if (field == null)
			{
				fieldsToFetch = fieldsToFetch.CloneWith(document.GetFields().Select(x => x.Name).ToArray());
				return base.RetrieveDocument(document, fieldsToFetch, score);
			}
			return new IndexQueryResult
			{
				Projection = RavenJObject.Parse(field.StringValue),
				Score = score.Score
			};
		}

			public DuplicateDocumentRecorder(Searchable indexSearcher,
				Index parent,
				HashSet<string> documentsAlreadySeenInPreviousPage,
				HashSet<RavenJObject> alreadyReturned,
				FieldsToFetch fieldsToFetch,
				bool isProjectionOrMapReduce)
			{
				this.indexSearcher = indexSearcher;
				this.parent = parent;
				this.isProjectionOrMapReduce = isProjectionOrMapReduce;
				this.alreadyReturned = alreadyReturned;
				this.fieldsToFetch = fieldsToFetch;
				this.documentsAlreadySeenInPreviousPage = documentsAlreadySeenInPreviousPage;
			}

		protected virtual IndexQueryResult RetrieveDocument(Document document, FieldsToFetch fieldsToFetch)
		{
			return new IndexQueryResult
			{
				Key = document.Get(Constants.DocumentIdFieldName),
				Projection = fieldsToFetch.IsProjection ? CreateDocumentFromFields(document, fieldsToFetch) : null
			};
		}

		protected override IndexQueryResult RetrieveDocument(Document document, FieldsToFetch fieldsToFetch, ScoreDoc score)
		{
			fieldsToFetch.EnsureHasField(Constants.ReduceKeyFieldName);
			if (fieldsToFetch.HasExplicitFieldsToFetch)
			{
				return base.RetrieveDocument(document, fieldsToFetch, score);
			}
			var field = document.GetField(Constants.ReduceValueFieldName);
			if (field == null)
			{
				fieldsToFetch = fieldsToFetch.CloneWith(document.GetFields().Select(x => x.Name).ToArray());
				return base.RetrieveDocument(document, fieldsToFetch, score);
			}
			var projection = RavenJObject.Parse(field.StringValue);
			if (fieldsToFetch.FetchAllStoredFields)
			{
				var fields = new HashSet<string>(document.GetFields().Select(x => x.Name));
				fields.Remove(Constants.ReduceKeyFieldName);
				var documentFromFields = new RavenJObject();
				AddFieldsToDocument(document, fields, documentFromFields);
				foreach (var kvp in projection)
				{
					documentFromFields[kvp.Key] = kvp.Value;
				}
				projection = documentFromFields;
			}
			return new IndexQueryResult
			{
				Projection = projection,
				Score = score.Score,
				ReduceVal = field.StringValue
			};
		}

		public IEnumerable<IndexQueryResult> Query(
			string index,
			IndexQuery query,
			Func<IndexQueryResult, bool> shouldIncludeInResults,
			FieldsToFetch fieldsToFetch,
			OrderedPartCollection<AbstractIndexQueryTrigger> indexQueryTriggers)
		{
			Index value;
			if (indexes.TryGetValue(index, out value) == false)
			{
				log.Debug("Query on non existing index '{0}'", index);
				throw new InvalidOperationException("Index '" + index + "' does not exists");
			}

			var indexQueryOperation = new Index.IndexQueryOperation(value, query, shouldIncludeInResults, fieldsToFetch, indexQueryTriggers);
			if (query.Query != null && query.Query.Contains(Constants.IntersectSeperator))
				return indexQueryOperation.IntersectionQuery();
			return indexQueryOperation.Query();
		}

	    public IEnumerable<IndexQueryResult> Query(
            string index, 
            IndexQuery query, 
            Func<IndexQueryResult, bool> shouldIncludeInResults,
			FieldsToFetch fieldsToFetch)
		{
			Index value;
			if (indexes.TryGetValue(index, out value) == false)
			{
				log.DebugFormat("Query on non existing index {0}", index);
				throw new InvalidOperationException("Index " + index + " does not exists");
			}
	    	return new Index.IndexQueryOperation(value, query, shouldIncludeInResults, fieldsToFetch).Query();
		}

		public QueryResultWithIncludes Query(string index, IndexQuery query, Action<QueryHeaderInformation> headerInfo, Action<RavenJObject> onResult)
		{
			index = IndexDefinitionStorage.FixupIndexName(index);
			var highlightings = new Dictionary<string, Dictionary<string, string[]>>();
			Func<IndexQueryResult, object> tryRecordHighlighting = queryResult =>
			{
				if (queryResult.Highligtings != null && queryResult.Key != null)
					highlightings.Add(queryResult.Key, queryResult.Highligtings);
				return null;
			};
			var stale = false;
			Tuple<DateTime, Etag> indexTimestamp = Tuple.Create(DateTime.MinValue, Etag.Empty);
			Etag resultEtag = Etag.Empty;
			var nonAuthoritativeInformation = false;

			if (string.IsNullOrEmpty(query.ResultsTransformer) == false)
			{
				query.FieldsToFetch = new[] { Constants.AllFields };
			}

			var idsToLoad = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
			TransactionalStorage.Batch(
				actions =>
				{
					var viewGenerator = IndexDefinitionStorage.GetViewGenerator(index);
					if (viewGenerator == null)
						throw new IndexDoesNotExistsException("Could not find index named: " + index);

					resultEtag = GetIndexEtag(index, null);

					stale = actions.Staleness.IsIndexStale(index, query.Cutoff, query.CutoffEtag);

					indexTimestamp = actions.Staleness.IndexLastUpdatedAt(index);
					var indexFailureInformation = actions.Indexing.GetFailureRate(index);
					if (indexFailureInformation.IsInvalidIndex)
					{
						throw new IndexDisabledException(indexFailureInformation);
					}
					var docRetriever = new DocumentRetriever(actions, ReadTriggers, query.QueryInputs, idsToLoad);
					var indexDefinition = GetIndexDefinition(index);
					var fieldsToFetch = new FieldsToFetch(query.FieldsToFetch, query.AggregationOperation,
														  viewGenerator.ReduceDefinition == null
															? Constants.DocumentIdFieldName
															: Constants.ReduceKeyFieldName);
					Func<IndexQueryResult, bool> shouldIncludeInResults =
						result => docRetriever.ShouldIncludeResultInQuery(result, indexDefinition, fieldsToFetch);
					var indexQueryResults = IndexStorage.Query(index, query, shouldIncludeInResults, fieldsToFetch, IndexQueryTriggers);
					indexQueryResults = new ActiveEnumerable<IndexQueryResult>(indexQueryResults);

					var transformerErrors = new List<string>();
					var results = GetQueryResults(query, viewGenerator, docRetriever,
					                              from queryResult in indexQueryResults
					                              let doc = docRetriever.RetrieveDocumentForQuery(queryResult, indexDefinition, fieldsToFetch)
					                              where doc != null
					                              let _ = nonAuthoritativeInformation |= (doc.NonAuthoritativeInformation ?? false)
					                              let __ = tryRecordHighlighting(queryResult)
					                              select doc, transformerErrors);

					if (headerInfo != null)
					{
						headerInfo(new QueryHeaderInformation
						{
							Index = index,
							IsStable = stale,
							ResultEtag = resultEtag,
							IndexTimestamp = indexTimestamp.Item1,
							IndexEtag = indexTimestamp.Item2,
							TotalResults = query.TotalSize.Value
						});
					}
					using (new CurrentTransformationScope(docRetriever))
					{
						foreach (var result in results)
						{
							onResult(result);
						}

						if (transformerErrors.Count > 0)
						{
							throw new InvalidOperationException("The transform results function failed.\r\n" + string.Join("\r\n", transformerErrors));
						}

					}


				});
			return new QueryResultWithIncludes
			{
				IndexName = index,
				IsStale = stale,
				NonAuthoritativeInformation = nonAuthoritativeInformation,
				SkippedResults = query.SkippedResults.Value,
				TotalResults = query.TotalSize.Value,
				IndexTimestamp = indexTimestamp.Item1,
				IndexEtag = indexTimestamp.Item2,
				ResultEtag = resultEtag,
				IdsToInclude = idsToLoad,
				LastQueryTime = SystemTime.UtcNow,
				Highlightings = highlightings
			};
//.........这里部分代码省略.........

		public Query GetLuceneQuery(string index, IndexQuery query, OrderedPartCollection<AbstractIndexQueryTrigger> indexQueryTriggers)
		{
			Index value;
			if (indexes.TryGetValue(index, out value) == false)
			{
				log.Debug("Query on non existing index {0}", index);
				throw new InvalidOperationException("Index '" + index + "' does not exists");
			}
			var fieldsToFetch = new FieldsToFetch(new string[0], AggregationOperation.None, null);
			return new Index.IndexQueryOperation(value, query, _ => false, fieldsToFetch, indexQueryTriggers).GetLuceneQuery();
		}

	    public QueryResult Query(string index, IndexQuery query)
		{
			index = IndexDefinitionStorage.FixupIndexName(index);
			var list = new List<RavenJObject>();
			var stale = false;
	    	Tuple<DateTime, Guid> indexTimestamp = Tuple.Create(DateTime.MinValue, Guid.Empty);
			TransactionalStorage.Batch(
				actions =>
				{

					var viewGenerator = IndexDefinitionStorage.GetViewGenerator(index);
					if (viewGenerator == null)
						throw new InvalidOperationException("Could not find index named: " + index);

					stale = actions.Staleness.IsIndexStale(index, query.Cutoff, query.CutoffEtag);
					indexTimestamp = actions.Staleness.IndexLastUpdatedAt(index);
					var indexFailureInformation = actions.Indexing.GetFailureRate(index);
					if (indexFailureInformation.IsInvalidIndex)
					{
						throw new IndexDisabledException(indexFailureInformation);
					}
					var docRetriever = new DocumentRetriever(actions, ReadTriggers);
					var indexDefinition = GetIndexDefinition(index);
					var fieldsToFetch = new FieldsToFetch(query.FieldsToFetch, query.AggregationOperation,
					                                      viewGenerator.ReduceDefinition == null
					                                      	? Constants.DocumentIdFieldName
					                                      	: Constants.ReduceKeyFieldName);
					var collection = from queryResult in IndexStorage.Query(index, query, result => docRetriever.ShouldIncludeResultInQuery(result, indexDefinition, fieldsToFetch), fieldsToFetch, IndexQueryTriggers)
									 select docRetriever.RetrieveDocumentForQuery(queryResult, indexDefinition, fieldsToFetch)
										 into doc
										 where doc != null
										 select doc;

					var transformerErrors = new List<string>();
					IEnumerable<RavenJObject> results;
					if (query.SkipTransformResults == false && 
						query.PageSize > 0 && // maybe they just want the stats?
						viewGenerator.TransformResultsDefinition != null)
					{
						var dynamicJsonObjects = collection.Select(x => new DynamicJsonObject(x.ToJson())).ToArray();
						var robustEnumerator = new RobustEnumerator(dynamicJsonObjects.Length)
						{
							OnError =
								(exception, o) =>
								transformerErrors.Add(string.Format("Doc '{0}', Error: {1}", Index.TryGetDocKey(o),
														 exception.Message))
						};
						results =
							robustEnumerator.RobustEnumeration(
								dynamicJsonObjects,
								source => viewGenerator.TransformResultsDefinition(docRetriever, source))
								.Select(JsonExtensions.ToJObject);
					}
					else
					{
						results = collection.Select(x => x.ToJson());
					}

					if (query.PageSize > 0) // maybe they just want the query stats?
						list.AddRange(results);

					if (transformerErrors.Count > 0)
					{
						throw new InvalidOperationException("The transform results function failed.\r\n" + string.Join("\r\n", transformerErrors));
					}

				});
			return new QueryResult
			{
				IndexName = index,
				Results = list,
				IsStale = stale,
				SkippedResults = query.SkippedResults.Value,
				TotalResults = query.TotalSize.Value,
				IndexTimestamp = indexTimestamp.Item1,
				IndexEtag = indexTimestamp.Item2
			};
		}

		public QueryResultWithIncludes Query(string index, IndexQuery query)
		{
			index = IndexDefinitionStorage.FixupIndexName(index);
			var list = new List<RavenJObject>();
			var highlightings = new Dictionary<string, Dictionary<string, string[]>>();
			var stale = false;
			Tuple<DateTime, Guid> indexTimestamp = Tuple.Create(DateTime.MinValue, Guid.Empty);
			Guid resultEtag = Guid.Empty;
			var nonAuthoritativeInformation = false;
			var idsToLoad = new HashSet<string>(StringComparer.InvariantCultureIgnoreCase);
			TransactionalStorage.Batch(
				actions =>
				{
					var viewGenerator = IndexDefinitionStorage.GetViewGenerator(index);
					if (viewGenerator == null)
						throw new IndexDoesNotExistsException("Could not find index named: " + index);

					resultEtag = GetIndexEtag(index, null);

					stale = actions.Staleness.IsIndexStale(index, query.Cutoff, query.CutoffEtag);

					indexTimestamp = actions.Staleness.IndexLastUpdatedAt(index);
					var indexFailureInformation = actions.Indexing.GetFailureRate(index);
					if (indexFailureInformation.IsInvalidIndex)
					{
						throw new IndexDisabledException(indexFailureInformation);
					}
					var docRetriever = new DocumentRetriever(actions, ReadTriggers, idsToLoad);
					var indexDefinition = GetIndexDefinition(index);
					var fieldsToFetch = new FieldsToFetch(query.FieldsToFetch, query.AggregationOperation,
														  viewGenerator.ReduceDefinition == null
															? Constants.DocumentIdFieldName
															: Constants.ReduceKeyFieldName);
					Func<IndexQueryResult, bool> shouldIncludeInResults =
						result => docRetriever.ShouldIncludeResultInQuery(result, indexDefinition, fieldsToFetch);
					var collection =
						from queryResult in
							IndexStorage.Query(index, query, shouldIncludeInResults, fieldsToFetch, IndexQueryTriggers)
						select new
						{
							Document = docRetriever.RetrieveDocumentForQuery(queryResult, indexDefinition, fieldsToFetch),
							Fragments = queryResult.Highligtings
						}
						into docWithFragments
						where docWithFragments.Document != null
						let _ = nonAuthoritativeInformation |= (docWithFragments.Document.NonAuthoritativeInformation ?? false)
						select docWithFragments;

					var transformerErrors = new List<string>();
					IEnumerable<RavenJObject> results;
					if (query.SkipTransformResults == false &&
						query.PageSize > 0 && // maybe they just want the stats?
						viewGenerator.TransformResultsDefinition != null)
					{
						var dynamicJsonObjects = collection.Select(x => new DynamicJsonObject(x.Document.ToJson())).ToArray();
						var robustEnumerator = new RobustEnumerator(workContext, dynamicJsonObjects.Length)
						{
							OnError =
								(exception, o) =>
								transformerErrors.Add(string.Format("Doc '{0}', Error: {1}", Index.TryGetDocKey(o),
														 exception.Message))
						};
						results =
							robustEnumerator.RobustEnumeration(
								dynamicJsonObjects.Cast<object>().GetEnumerator(),
								source => viewGenerator.TransformResultsDefinition(docRetriever, source))
								.Select(JsonExtensions.ToJObject);
					}
					else
					{
						var resultList = new List<RavenJObject>();
						foreach (var docWithFragments in collection)
						{
							resultList.Add(docWithFragments.Document.ToJson());

							if (docWithFragments.Fragments != null && docWithFragments.Document.Key != null)
								highlightings.Add(docWithFragments.Document.Key, docWithFragments.Fragments);
						}
						results = resultList;
					}

					list.AddRange(results);

					if (transformerErrors.Count > 0)
					{
						throw new InvalidOperationException("The transform results function failed.\r\n" + string.Join("\r\n", transformerErrors));
					}
				});
			return new QueryResultWithIncludes
			{
				IndexName = index,
				Results = list,
				IsStale = stale,
				NonAuthoritativeInformation = nonAuthoritativeInformation,
				SkippedResults = query.SkippedResults.Value,
				TotalResults = query.TotalSize.Value,
				IndexTimestamp = indexTimestamp.Item1,
				IndexEtag = indexTimestamp.Item2,
				ResultEtag = resultEtag,
				IdsToInclude = idsToLoad,
//.........这里部分代码省略.........

			public IndexQueryOperation(
				Index parent,
				IndexQuery indexQuery,
				Func<IndexQueryResult, bool> shouldIncludeInResults,
				FieldsToFetch fieldsToFetch)
			{
				this.parent = parent;
				this.indexQuery = indexQuery;
				this.shouldIncludeInResults = shouldIncludeInResults;
				this.fieldsToFetch = fieldsToFetch;

				if (fieldsToFetch.IsDistinctQuery)
					alreadyReturned = new HashSet<JObject>(new JTokenEqualityComparer());
				
			}

		public Query GetDocumentQuery(string index, IndexQuery query, OrderedPartCollection<AbstractIndexQueryTrigger> indexQueryTriggers)
		{
			var value = TryIndexByName(index);
			if (value == null)
			{
				log.Debug("Query on non existing index {0}", index);
				throw new InvalidOperationException("Index '" + index + "' does not exists");
			}
			var fieldsToFetch = new FieldsToFetch(new string[0], false, null);
			return new Index.IndexQueryOperation(value, query, _ => false, fieldsToFetch, indexQueryTriggers).GetDocumentQuery();
		}