public void ConditionalUpdate <T>(T tObject, string condAttribute, object expectedValue)
{
var splittedAttributes = condAttribute.Split('.');
var specificAttributeToCheck = condAttribute;
string first = "";
string last = condAttribute;
if (splittedAttributes.Length > 1)
{
last = splittedAttributes.Last();
first = condAttribute.Remove(condAttribute.Length - last.Length);
}
Expression expr = new Expression();
expr.ExpressionStatement = first + "#Cond = :Cond";
expr.ExpressionAttributeNames["#Cond"] = last;
if (expectedValue.GetType() == typeof(int))
{
expr.ExpressionAttributeValues[":Cond"] = (int)expectedValue;
}
if (expectedValue.GetType() == typeof(string))
{
expr.ExpressionAttributeValues[":Cond"] = (string)expectedValue;
}
UpdateItemOperationConfig config = new UpdateItemOperationConfig()
{
ConditionalExpression = expr,
ReturnValues = ReturnValues.AllNewAttributes
};
dynamoDBTable.UpdateItem(AWSDocumentConverter.ToDocument(tObject), config);
}
private UpdateItemOperationConfig GetUpdateItemOperationConfigForConditionalUpdate(string condAttribute, object expectedValue)
{
var splittedAttributes = condAttribute.Split('.');
var specificAttributeToCheck = condAttribute;
string first = "";
string last = condAttribute;
if (splittedAttributes.Length > 1)
{
last = splittedAttributes.Last();
first = condAttribute.Remove(condAttribute.Length - last.Length);
}
Expression expr = new Expression();
expr.ExpressionStatement = first + "#Cond = :Cond";
expr.ExpressionAttributeNames["#Cond"] = last;
if (expectedValue.GetType() == typeof(int))
{
expr.ExpressionAttributeValues[":Cond"] = (int)expectedValue;
}
if (expectedValue.GetType() == typeof(string))
{
expr.ExpressionAttributeValues[":Cond"] = (string)expectedValue;
}
UpdateItemOperationConfig config = new UpdateItemOperationConfig()
{
ConditionalExpression = expr,
ReturnValues = ReturnValues.None
};
return(config);
}
/// <summary>
/// Initiates a Search object to Query a DynamoDB table, with the
/// specified hash primary key and expression.
///
/// No calls are made until the Search object is used.
/// </summary>
/// <param name="hashKey">Value of the hash key for the query operation.</param>
/// <param name="filterExpression">Expression to use.</param>
/// <returns>Resultant Search container.</returns>
public Search Query(Primitive hashKey, Expression filterExpression)
{
string hashKeyName = this.HashKeys[0];
QueryFilter hashKeyFilter = new QueryFilter();
hashKeyFilter.AddCondition(hashKeyName, QueryOperator.Equal, hashKey);
QueryOperationConfig config = new QueryOperationConfig
{
Filter = hashKeyFilter,
FilterExpression = filterExpression
};
return Query(config);
}
/// <summary>
/// Initiates a Search object to Scan a DynamoDB table, with the
/// specified expression.
///
/// No calls are made until the Search object is used.
/// </summary>
/// <param name="filterExpression">Expression to apply to the scan.</param>
/// <returns>Resultant Search container.</returns>
public Search Scan(Expression filterExpression)
{
ScanOperationConfig config = new ScanOperationConfig
{
FilterExpression = filterExpression
};
return Scan(config);
}
/// <summary>
/// Allows to specify custom FilterExpression for DynamoDb queries and scans
/// </summary>
public static IQueryable <T> WithFilterExpression <T>(this IQueryable <T> source, Amazon.DynamoDBv2.DocumentModel.Expression expression)
{
source.AsQuery().UpdateCustomizationHooks(hooks => hooks.CustomFilterExpression = expression);
return(source);
}
internal static void ApplyExpression(QueryRequest request, DynamoDBEntryConversion conversion,
Expression keyExpression, Expression filterExpression)
{
if (keyExpression == null)
keyExpression = new Expression();
if (filterExpression == null)
filterExpression = new Expression();
if (!keyExpression.IsSet && !filterExpression.IsSet)
return;
if (keyExpression.IsSet)
request.KeyConditionExpression = keyExpression.ExpressionStatement;
if (filterExpression.IsSet)
request.FilterExpression = filterExpression.ExpressionStatement;
var kean = keyExpression.ExpressionAttributeNames;
var fean = filterExpression.ExpressionAttributeNames;
var combinedEan = Common.Combine(kean, fean, StringComparer.Ordinal);
request.ExpressionAttributeNames = combinedEan;
var keav = new Document(keyExpression.ExpressionAttributeValues).ForceConversion(conversion);
var feav = new Document(filterExpression.ExpressionAttributeValues).ForceConversion(conversion);
var combinedEav = Common.Combine(keav, feav, null);
request.ExpressionAttributeValues = ConvertToAttributeValues(combinedEav, conversion);
}
