/// <summary>
/// retrieves list of resources according to query parameters
/// </summary>
/// <param name="queryParams"> hashtable containing query parameters </param>
/// <param name="token"> resumption token details </param>
/// <param name="isListRecords"> if isListRecords then load resources with authors and tags</param>
/// <returns> list of resources </returns>
internal List <Core.Resource> GetResources(Hashtable queryParams, MetadataProviderHelper.TokenDetails token, bool isListRecords)
{
// Algorithm:
List <Core.Resource> listOfResources = new List <Core.Resource>();
try
{
Type set = null;
if (queryParams.ContainsKey("set"))
{
set = CoreHelper.GetSystemResourceType(queryParams["set"] as string);
if (null == set)
{
throw new ArgumentException(MetadataProviderHelper.Error_Message_Invalid_QueryParams, "queryParams");
}
}
if (null == set)
{
set = typeof(Core.Resource);
}
//make generic call
MethodInfo getResourceListMethod = getResourceListMethod = this.GetType().GetMethod("GetResourceList",
BindingFlags.NonPublic | BindingFlags.Instance);
if (null != getResourceListMethod)
{
listOfResources = (List <Core.Resource>)getResourceListMethod.MakeGenericMethod(set).Invoke(this, new object[] { queryParams, token.QueryExecutionDateTime, isListRecords, true, token });
}
}
catch (TargetInvocationException ex)
{
if (null != ex.InnerException)
{
throw ex.InnerException;
}
throw;
}
catch (Exception)
{
throw;
}
return(listOfResources);
}
private List <Core.Resource> GetResourceList <T>(
Hashtable queryParams,
DateTime initialQueryExecutionTime,
bool isListRecords,
bool isResumptionTokenSpecified,
MetadataProviderHelper.TokenDetails token) where T : Core.Resource
{
List <Core.Resource> listOfResources = new List <Core.Resource>();
IQueryable <T> resourceQuery = null;
// 1) Build the query
DateTime from = DateTime.MinValue;
DateTime until = DateTime.MinValue;
if (queryParams.ContainsKey("from"))
{
from = ValidateDate(queryParams["from"], false);
}
if (queryParams.ContainsKey("until"))
{
until = ValidateDate(queryParams["until"], true);
}
using (Core.ZentityContext context = CoreHelper.CreateZentityContext())
{
AuthenticatedToken authenticatedToken = GetAuthenticationToken();
if (from != DateTime.MinValue)
{
if ((until != DateTime.MinValue))
{
if (from > until)
{
throw new ArgumentException(MetadataProviderHelper.Error_Message_Invalid_QueryParams, "queryParams");
}
resourceQuery = FilterQuery(context).OfType <T>().
Where(resource =>
resource.DateModified >= from &&
resource.DateModified <= until &&
resource.DateModified < initialQueryExecutionTime)
.Authorize("Read", context, authenticatedToken)
.OrderByDescending(resource => resource.DateModified);
}
else
{
resourceQuery = FilterQuery(context).OfType <T>().
Where(resource =>
resource.DateModified >= from &&
resource.DateModified < initialQueryExecutionTime)
.Authorize("Read", context, authenticatedToken)
.OrderByDescending(resource => resource.DateModified);
}
}
else
{
resourceQuery = FilterQuery(context).OfType <T>().
Where(resource =>
resource.DateModified < initialQueryExecutionTime)
.Authorize("Read", context, authenticatedToken)
.OrderByDescending(resource => resource.DateModified);
}
// 2) Retrieve resources count
this.totalResourceCount = this.actualRecordCount = resourceQuery.Count();
if (this.totalResourceCount <= 0)
{
throw new ArgumentException(MetadataProviderHelper.Error_Message_NoRecords,
"queryParams");
}
if (!isResumptionTokenSpecified)
{
// 3) If count greater than maxharvestcount then
// retrieve resources according to harvest count
// else
// retrieve resources according to original count
if (MetadataProviderHelper.IsResumptionRequired(this.totalResourceCount))
{
listOfResources = CoreHelper.FilterResources <T>(
resourceQuery.Take(PlatformSettings.MaximumHarvestCount),
isListRecords);
this.actualHarvestedCount = listOfResources.Count;
}
else
{
listOfResources = CoreHelper.FilterResources <T>(resourceQuery, isListRecords);
}
}
else
{
// 4) retrieve pending resources i.e : according to maximum harvest count
int noOfRecordsToSkip = token.ActualHarvestedRecords;
listOfResources = CoreHelper.FilterResources <T>(resourceQuery.
Skip(noOfRecordsToSkip).
Take(PlatformSettings.MaximumHarvestCount), isListRecords);
this.actualHarvestedCount = noOfRecordsToSkip + listOfResources.Count;
}
}
return(listOfResources);
}
