/// <summary>
/// Gets message metadata.
/// </summary>
/// <param name="query">Query.</param>
/// <param name="maxItems">The maximum number of items to return.</param>
/// <returns>Metadata.</returns>
/// <exception cref="ArgumentException">Thrown if DateTime kind is not UTC.</exception>
/// <exception cref="ObjectDisposedException">Thrown if disposed.</exception>
public SysColl.List <Metadata> Get(MetadataQuery query, int maxItems)
{
ExpectNotDisposed(); // throws ObjectDisposedException
var retval = new SysColl.List <Metadata>();
// Setting query defaults for the timestamps
var startForQuery = DateTime.SpecifyKind(DateTime.MinValue, DateTimeKind.Utc);
var endForQuery = DateTime.SpecifyKind(DateTime.MaxValue, DateTimeKind.Utc);
// Getting the actual datetime values in the query
if (query.TimeWindowStart.HasValue)
{
startForQuery = query.TimeWindowStart.Value;
}
if (query.TimeWindowEnd.HasValue)
{
endForQuery = query.TimeWindowEnd.Value;
}
// Requiring UTC as the DateTime kind
ExpectUtc(startForQuery);
ExpectUtc(endForQuery);
var discoveredItems = from md in m_messageContext.DbMetadataItem
select md;
// Filtering by host and exchange;
// filtering by start and end time
discoveredItems = discoveredItems.Where(md =>
md.Host == query.Host &&
md.Exchange == query.Exchange &&
md.ReceivedAt >= startForQuery.Ticks &&
md.ReceivedAt <= endForQuery.Ticks
);
// Filtering by topic if specified
if (!string.IsNullOrEmpty(query.Topic))
{
discoveredItems = discoveredItems.Where(md => md.Topic == query.Topic);
}
// Limiting the number of items
discoveredItems = discoveredItems.Take(maxItems);
// Converting to the Entify-Framework-independent format
foreach (var efMeta in discoveredItems.ToList()) // ToList() requires System.Linq
{
var metadata = ConvertForOutput(efMeta);
retval.Add(metadata);
}
return(retval);
}
/// <summary>
/// Returns all topics in given host and exchange.
/// </summary>
/// <param name="host">Host.</param>
/// <param name="exc">Exchange.</param>
/// <returns>Topics.</returns>
public SysColl.List <string> GetTopics(string host, string exc)
{
ExpectNotDisposed(); // throws ObjectDisposedException
var items = m_messageContext.DbMetadataItem
.Where(m => m.Host == host && m.Exchange == exc)
.Select(m => new { m.Topic })
.Distinct()
.OrderBy(m1 => m1.Topic);
// Convert to strings
var retval = new SysColl.List <string>();
foreach (var i in items)
{
retval.Add(i.Topic);
}
return(retval);
}
