public DynamoDbCityService(string environment)
{
this.environment = environment;
DynamoDBContextConfig config = new DynamoDBContextConfig()
{
TableNamePrefix = environment + "-"
};
dynamoDbContext = new DynamoDBContext(DynamoDbClientService.getDynamoDBClient(environment), config);
tableName = environment + "-City";
}
public async Task DeleteUserByUserName(string username)
{
var Req = new Amazon.DynamoDBv2.Model.DeleteItemRequest
{
TableName = this.tableName,
Key = new Dictionary <string, Amazon.DynamoDBv2.Model.AttributeValue>()
{
{ "username", new Amazon.DynamoDBv2.Model.AttributeValue {
S = username.ToString()
} }
}
};
var response = await DynamoDbClientService.getDynamoDBClient(environment).DeleteItemAsync(Req);
var attributeList = response.Attributes;
}
public async Task DeleteCitybyCompositeKey(string state, string city)
{
var deleteItemRequest = new Amazon.DynamoDBv2.Model.DeleteItemRequest
{
TableName = this.tableName,
Key = new Dictionary <string, Amazon.DynamoDBv2.Model.AttributeValue>()
{
{ "state", new Amazon.DynamoDBv2.Model.AttributeValue {
S = state.ToString()
} },
{ "city", new Amazon.DynamoDBv2.Model.AttributeValue {
S = city.ToString()
} }
}
};
var response = await DynamoDbClientService.getDynamoDBClient(environment).DeleteItemAsync(deleteItemRequest);
var attributeList = response.Attributes;
}
public async Task GetCitiesByStateUsingPopulationLSI(string state, bool ascendingOrder)
{
try
{
//Note: For this Query Request
//Sometimes you might encounter an exception such as:
//Invalid KeyConditionExpression: Attribute name is a reserved keyword; reserved keyword: state:
//It is for this reason that you will need to include the ExpressionAttributeNames below
//(for the KeyConditionExpression and the ProjectionExpression
//You can note that the records that are pulled for each state will be sorted by the default sort key(city)
//ProjectExpression identifies the attributes that you want
//ScanIndexForward will determine if you will use Ascending or descending order on the Sort Key(the LSI in this case)
var request = new QueryRequest
{
TableName = this.tableName,
IndexName = this.LSIPopulationIndex,
KeyConditionExpression = "#state = :state",
ExpressionAttributeNames = new Dictionary <string, string>
{
{ "#state", "state" },
},
ExpressionAttributeValues = new Dictionary <string, AttributeValue> {
{ ":state", new AttributeValue {
S = state
} }
},
ProjectionExpression = "#state, city, iscapital, population",
ScanIndexForward = ascendingOrder,
ConsistentRead = true
};
var response = await DynamoDbClientService.getDynamoDBClient(environment).QueryAsync(request);
this.cities = new ArrayList();
var items = response.Items;
City currentCity = null;
foreach (var currentItem in items)
{
currentCity = new City();
foreach (string attr in currentItem.Keys)
{
if (attr == "state")
{
currentCity.state = currentItem[attr].S;
}
if (attr == "city")
{
currentCity.city = currentItem[attr].S;
}
;
if (attr == "iscapital")
{
currentCity.iscapital = currentItem[attr].BOOL;
}
;
if (attr == "population")
{
currentCity.population = int.Parse(currentItem[attr].N);
}
;
}
this.cities.Add(currentCity);
}
}
catch (Exception exc)
{
this.log += "Exception: " + exc.Message + ":" + exc.StackTrace;
}
}
public async Task GetUserByEmailGSI(string email)
{
try
{
QueryRequest queryRequest = new QueryRequest
{
TableName = this.tableName,
IndexName = this.GSIEmailIndex,
KeyConditionExpression = "#email = :email",
//placeholder that you use in an Amazon DynamoDB expression as an alternative to an actual attribute name
ExpressionAttributeNames = new Dictionary <String, String> {
{ "#email", "email" }
},
//substitutes for the actual values that you want to compare
ExpressionAttributeValues = new Dictionary <string, AttributeValue> {
{ ":email", new AttributeValue {
S = email
} }
},
ScanIndexForward = true
};
var response = await DynamoDbClientService.getDynamoDBClient(environment).QueryAsync(queryRequest);
var items = response.Items;
this.users = new ArrayList();
User currentUser = null;
foreach (var currentItem in items)
{
currentUser = new User();
foreach (string attr in currentItem.Keys)
{
if (attr == "username")
{
currentUser.username = currentItem[attr].S;
}
if (attr == "firstname")
{
currentUser.firstname = currentItem[attr].S;
}
;
if (attr == "lastname")
{
currentUser.lastname = currentItem[attr].S;
}
;
if (attr == "email")
{
currentUser.email = currentItem[attr].S;
}
;
}
this.users.Add(currentUser);
}
//this.log += "F";
}
catch (Exception exc)
{
this.log += "EXC: " + exc.Message + ":" + exc.StackTrace;
}
}
