private DataPage <TResource> ExecuteAdjustedQuery <TResource>(string query, Pagination pagination, SortingInstructions sorting, AttributesToFetch attributes = null) where TResource : RmResource { attributes = attributes ?? AttributesToFetch.All; Initialize(); var ctx = LogContext.WithConfigFormat(); _log.Debug(ctx.Format("Executing query {0} with paging: {1}, sorting {2} and attributes {3}"), query, pagination.ToJSON(), sorting.ToJSON(), attributes.GetNames().ToJSON()); // first request - only to get enumeration context and total rows count var enumerationRequest = new EnumerationRequest(query); // do not fetch any items - total count only; however this cannot be set to 0 because then total count is not returned (is always set to 0) enumerationRequest.MaxElements = 1; // get only ObjectID attribute to minimize overhead caused by this operation which returns elements not used for further processing enumerationRequest.Selection = new List <string> { RmResource.AttributeNames.ObjectID.Name }; var enumerateResponse = _pagedQueriesClient.Enumerate(enumerationRequest); long totalCount = enumerateResponse.Count ?? 0; // second request - to actually get desired data var pullRequest = new PullRequest(); // set enumeration context from previous query pullRequest.EnumerationContext = enumerateResponse.EnumerationContext; // if attributes names to fetch defined... var attributeNames = attributes.GetNames(); if (attributeNames != null) { // ... set them to context pullRequest.EnumerationContext.Selection = new Selection(); pullRequest.EnumerationContext.Selection.@string = attributeNames.ToList(); } else { pullRequest.EnumerationContext.Selection = null; } // if paging defined... if (pagination.PageSize != Pagination.AllPagesSize) { // set current page's first row index... pullRequest.EnumerationContext.CurrentIndex = pagination.GetFirstRowIndex(); // ...and page size pullRequest.MaxElements = pagination.PageSize; } // ... if not - get all elements else { // reset current row index... pullRequest.EnumerationContext.CurrentIndex = 0; // ... page size to max (this may throw if message size exceeds configured maximum, but this situation - getting all items using this method - is not likely to happen) pullRequest.MaxElements = int.MaxValue; } // if sorting defined... if (sorting != SortingInstructions.None) { var sortingAttribute = new SortingAttribute() { Ascending = sorting.Order == SortOrder.Ascending, Value = sorting.AttributeName }; // due to implementation details of these classes, new instances of each of them needs to be created pullRequest.EnumerationContext.Sorting = new Sorting { SortingAttribute = new List <SortingAttribute> { sortingAttribute } }; } var pullResponse = _pagedQueriesClient.Pull(pullRequest); var results = _defaultClient.ResourceFactory.CreateResource(pullResponse) .Cast <TResource>() .ToList(); log_query_executed(ctx, "Paged query {0} returned {1} results and {2} total count", query, results.Count, totalCount); return(new DataPage <TResource>(results, totalCount)); }
public bool MoveNext() { lock (this.client) { if (resultIndex < results.Count) { this.current = results[resultIndex++]; return(true); } else { PullResponse response; if (this.context == null) { if (resultIndex > 0) { // case: previous pull returned an invalid context return(false); } EnumerationRequest request = new EnumerationRequest(filter); if (attributes != null) { request.Selection = new List <string>(); request.Selection.AddRange(this.attributes); } response = client.Enumerate(request); this.endOfSequence = response.EndOfSequence != null; } else { if (this.endOfSequence == true) { // case: previous pull returned an end of sequence flag this.current = null; return(false); } PullRequest request = new PullRequest(); request.EnumerationContext = this.context; response = client.Pull(request); } if (response == null) { return(false); } resultIndex = 0; this.results = resourceFactory.CreateResource(response); this.context = response.EnumerationContext; this.endOfSequence = response.IsEndOfSequence; if (this.results.Count > 0) { this.current = results[resultIndex++]; return(true); } else { this.current = null; return(false); } } } }