/// <summary>
/// Initiates a Search object to Scan a DynamoDB table, with the
/// specified filter.
///
/// No calls are made until the Search object is used.
/// </summary>
/// <param name="filter">Filter to apply to the scan.</param>
/// <returns>Resultant Search container.</returns>
public Search Scan(ScanFilter filter)
{
return(Scan(new ScanOperationConfig {
Filter = filter
}));
}
/// <summary>
/// Initiates a Search object to Scan a DynamoDB table, with the
/// specified filter.
///
/// No calls are made until the Search object is used.
/// </summary>
/// <param name="filter">Filter to apply to the scan.</param>
/// <returns>Resultant Search container.</returns>
public Search Scan(ScanFilter filter)
{
return Scan(new ScanOperationConfig { Filter = filter });
}
/// <summary>
/// Initializes a default Table.Scan config object
/// Filter is empty, Limit is Int32.MaxValue
/// </summary>
public ScanOperationConfig()
{
Filter = new ScanFilter();
Limit = Int32.MaxValue;
Select = SelectValues.AllAttributes;
ConditionalOperator = ConditionalOperatorValues.And;
}
/// <summary>
/// Prepares parameters for a scan operation from the list of conditions
/// </summary>
internal static ScanFilter GetScanFilterForTable(this TranslationResult translationResult, Table tableDefinition)
{
// the last thing to do is to make a full scan
var scanFilter = new ScanFilter();
//TODO: check for BETWEEN operator
foreach (var condition in translationResult.Conditions.Flatten())
{
if
(
(condition.Item2.Values.Length == 1)
&&
(condition.Item2.Values[0] == null)
)
{
switch (condition.Item2.Operator)
{
case ScanOperator.Equal:
scanFilter.AddCondition(condition.Item1, ScanOperator.IsNull );
break;
case ScanOperator.NotEqual:
scanFilter.AddCondition(condition.Item1, ScanOperator.IsNotNull);
break;
default:
throw new InvalidOperationException(string.Format("You cannot use {0} operator with null value", condition.Item2.Operator));
}
}
else
{
scanFilter.AddCondition(condition.Item1, condition.Item2.Operator, condition.Item2.Values);
}
}
return scanFilter;
}
public void CommandSubscribe() {
Table replyTable = Table.LoadTable(client, tableName);
Console.WriteLine("Listening to the events continuously.");
Int64 last_key = 0;
while (true) {
var scan_filter = new ScanFilter();
if (last_key > 0) {
scan_filter.AddCondition("K", ScanOperator.GreaterThan, last_key);
}
Search search = replyTable.Scan(scan_filter);
List<Document> documentList = new List<Document>();
do {
documentList = search.GetNextSet();
foreach (var document in documentList) {
Console.WriteLine("{0} : {1}", document["K"], document["V"]);
Int64 current_key = Int64.Parse(document["K"].AsString());
if (!(current_key > last_key)) {
Console.WriteLine("ERROR: {0} should be > {1}.", current_key, last_key);
}
else {
last_key = current_key;
}
}
} while (!search.IsDone);
// TODO(dkorolev): Do something smarter here, and wrap the whole thing into an IObservable<>.
System.Threading.Thread.Sleep(50);
}
}
public static void RunDocumentModelSample()
{
Console.WriteLine("Loading Businesses table");
Table table = Table.LoadTable(client, "Businesses");
Console.WriteLine("Creating and saving first item");
Document chainStore2 = new Document();
chainStore2["Name"] = "Big Sales Inc";
chainStore2["Id"] = 2;
chainStore2["Owner"] = "Big Sales Corp";
chainStore2["Managers"] = new List<string> { "Samantha Jones", "Richard Frost" };
chainStore2["FoundedDate"] = new DateTime(1980, 7, 4);
chainStore2["Address"] = "123 Main Street, New York, New York";
chainStore2["Employees"] = 46;
chainStore2["State"] = "NY";
table.PutItem(chainStore2);
Console.WriteLine("Creating and saving first item");
Document chainStore13 = new Document();
chainStore13["Name"] = "Big Sales Inc";
chainStore13["Id"] = 13;
chainStore13["Owner"] = "Big Sales Corp";
chainStore13["Managers"] = new List<string> { "Anil Garg", "Alex Short" };
chainStore13["FoundedDate"] = new DateTime(1999, 3, 15);
chainStore13["Address"] = "1999 West Ave, Chicago, Illinois";
chainStore13["Employees"] = 54;
chainStore13["State"] = "IL";
table.PutItem(chainStore13);
Console.WriteLine("Creating and saving second item");
Document tinyDiner = new Document();
tinyDiner["Name"] = "Tiny Map-themed Diner";
tinyDiner["Id"] = 0;
tinyDiner["Owner"] = "John Doe";
tinyDiner["FoundedDate"] = new DateTime(1974, 12, 10);
tinyDiner["Address"] = "800 Lincoln Ave, Seattle, Washington";
tinyDiner["State"] = "WA";
table.PutItem(tinyDiner);
Console.WriteLine("Creating and saving third item");
Document internetStore = new Document();
internetStore["Name"] = "Best Online Store Ever";
internetStore["Id"] = 0;
internetStore["Owner"] = "Jane Doe";
internetStore["FoundedDate"] = new DateTime(1994, 2, 19);
internetStore["Employees"] = 5;
internetStore["Url"] = "http://www.best-online-store-ever.fake";
internetStore["Phone"] = "425-555-1234";
table.PutItem(internetStore);
Console.WriteLine("Loading item");
Document doc1 = table.GetItem("Big Sales Inc", 2);
Console.WriteLine("Attribute counts match (should be true): " +
(chainStore2.GetAttributeNames().Count == doc1.GetAttributeNames().Count));
Console.WriteLine("Loading item...");
Document doc2 = table.GetItem("Best Online Store Ever", 0);
Console.WriteLine("Attribute counts match (should be true): " +
(chainStore2.GetAttributeNames().Count == doc1.GetAttributeNames().Count));
Console.WriteLine("Change item: remove one attribute, add one, modify one attribute");
doc2["Phone"] = null;
doc2["Twitter"] = "best-online-store-ever";
doc2["Employees"] = 4;
Console.WriteLine("Updating item");
table.UpdateItem(doc2);
Console.WriteLine("Reloading item");
doc2 = table.GetItem("Best Online Store Ever", 0);
Console.WriteLine("Phone attribute present (should be false): " + doc2.Contains("Phone"));
Console.WriteLine("Twitter attribute present (should be true): " + doc2.Contains("Twitter"));
Console.WriteLine("Employees attribute equals 4: " + (object.Equals(doc2["Employees"].AsPrimitive().Value, "4")));
Console.WriteLine("Loading nonexistent item");
Document doc3 = table.GetItem("Big Sales Inc", 3);
Console.WriteLine("Returned document == null (should be true): " + (doc3 == null));
Search query;
Console.WriteLine();
Console.WriteLine("Querying for items (Equals)");
query = table.Query("Big Sales Inc", new QueryFilter("Id", QueryOperator.Equal, 2));
List<Document> queryItems1 = query.GetRemaining();
Console.WriteLine("Number of items returned (should be 1): " + queryItems1.Count);
Console.WriteLine();
Console.WriteLine("Querying for items (Between)");
QueryFilter filter = new QueryFilter();
filter.AddCondition("Name", QueryOperator.Equal, "Big Sales Inc");
filter.AddCondition("Id", QueryOperator.Between, 0, 15);
QueryOperationConfig queryConfig = new QueryOperationConfig
{
Filter = filter,
Limit = 1
};
query = table.Query(queryConfig);
int totalItems = 0;
while (!query.IsDone)
{
Console.WriteLine("Retrieving next set (page) of items");
List<Document> querySet = query.GetNextSet();
Console.WriteLine("Number of items returned in set (should be 1, unless last set, which will be 0): " + querySet.Count);
foreach (Document doc in querySet)
{
Console.WriteLine("Retrieving individual properties");
Primitive name = doc["Name"].AsPrimitive();
Primitive id = doc["Id"].AsPrimitive();
PrimitiveList managers = doc["Managers"].AsPrimitiveList();
Console.WriteLine("Name = {0}, Id = {1}, # of managers = {2}", name.Value, id.Value, managers.Entries.Count);
totalItems++;
}
}
Console.WriteLine("Total items found (should be 2): " + totalItems);
Search scan;
ScanFilter scanFilter;
Console.WriteLine();
Console.WriteLine("Scanning for items (GreaterThan)");
scanFilter = new ScanFilter();
scanFilter.AddCondition("Employees", ScanOperator.GreaterThan, 50);
scan = table.Scan(scanFilter);
List<Document> scanItems1 = scan.GetRemaining();
Console.WriteLine("Number of items returned (should be 1): " + scanItems1.Count);
Console.WriteLine();
Console.WriteLine("Scanning for items (GreaterThan and LessThan)");
scanFilter = new ScanFilter();
scanFilter.AddCondition("Employees", ScanOperator.GreaterThan, 2);
scanFilter.AddCondition("FoundedDate", ScanOperator.LessThan, new DateTime(1993, 1, 1));
scan = table.Scan(scanFilter);
List<Document> scanItems2 = scan.GetRemaining();
Console.WriteLine("Number of items returned (should be 1): " + scanItems2.Count);
Console.WriteLine();
Console.WriteLine("Retrieving an item");
Document existingDoc = table.GetItem("Big Sales Inc", 13);
Console.WriteLine("Returned document == null (should be false): " + (existingDoc == null));
Console.WriteLine("Deleting item");
table.DeleteItem("Big Sales Inc", 13);
Console.WriteLine("Retrieving same item");
existingDoc = table.GetItem("Big Sales Inc", 13);
Console.WriteLine("Returned document == null (should be true): " + (existingDoc == null));
Console.WriteLine();
Console.WriteLine("Scanning for items (no filter) and deleting all");
scanFilter = new ScanFilter();
scan = table.Scan(scanFilter);
List<Document> scanItems3 = scan.GetRemaining();
Console.WriteLine("Number of items returned (should be 3): " + scanItems3.Count);
for (int i = 0; i < scanItems3.Count; i++)
{
Document item = scanItems3[i];
Console.WriteLine("Deleting item {0} of {1}", i + 1, scanItems3.Count);
table.DeleteItem(item);
}
Console.WriteLine("Scanning table again");
scan = table.Scan(scanFilter);
scanItems3 = scan.GetRemaining();
Console.WriteLine("Number of items returned (should be 0): " + scanItems3.Count);
}
/// <summary>
/// Initializes a default Table.Scan config object
/// Filter is empty, Limit is Int32.MaxValue
/// </summary>
public ScanOperationConfig()
{
Filter = new ScanFilter();
Limit = Int32.MaxValue;
Select = SelectValues.AllAttributes;
}
/// <summary>
/// A utility method for cleaning up expired sessions that IIS failed to delete. The method performs a scan on the table
/// with a condition that the expiration date is in the past and calls delete on all the keys returned. Scans can be costly on performance
/// so use this method sparingly like a nightly or weekly clean job.
/// </summary>
/// <param name="dbClient">The AmazonDynamoDB client used to find a delete expired sessions.</param>
/// <param name="tableName">The table to search.</param>
public static void DeleteExpiredSessions(IAmazonDynamoDB dbClient, string tableName)
{
LogInfo("DeleteExpiredSessions");
Table table = Table.LoadTable(dbClient, tableName, DynamoDBEntryConversion.V1);
ScanFilter filter = new ScanFilter();
filter.AddCondition(ATTRIBUTE_EXPIRES, ScanOperator.LessThan, DateTime.Now);
ScanOperationConfig config = new ScanOperationConfig();
config.AttributesToGet = new List<string> { ATTRIBUTE_SESSION_ID };
config.Select = SelectValues.SpecificAttributes;
config.Filter = filter;
DocumentBatchWrite batchWrite = table.CreateBatchWrite();
Search search = table.Scan(config);
do
{
List<Document> page = search.GetNextSet();
foreach (var document in page)
{
batchWrite.AddItemToDelete(document);
}
} while (!search.IsDone);
batchWrite.Execute();
}