AWS 开发工具包 .NET DynamoDB 异步
AWS SDK .NET DynamoDB ASYNC
我正在尝试使用适用于 .NET Core 的 AWS SDK。
- 创建一个 table 来计算视频观看次数。
- 添加一天的观看次数。
- 增加一天的现有计数。
- 查询视频的两个日期之间的视频计数。
.NET Core AWS SDK 使用 AWS 中未记录的异步方法。在他们的 github 页面上有一个功能请求可以实现这一点……但它是去年的日期。 (https://github.com/aws/aws-sdk-net/issues/787)
创建 TABLE
这有效并在 AWS 控制台上创建了一个 table。
var ctRequest = new CreateTableRequest
{
AttributeDefinitions = new List<AttributeDefinition>()
{
new AttributeDefinition
{
AttributeName = "ViewUid",
AttributeType = ScalarAttributeType.S
},
new AttributeDefinition
{
AttributeName = "ViewDate",
AttributeType = ScalarAttributeType.S
}
},
KeySchema = new List<KeySchemaElement>
{
new KeySchemaElement
{
AttributeName = "ViewUid",
KeyType = KeyType.HASH //Partition key
},
new KeySchemaElement
{
AttributeName = "ViewDate",
KeyType = KeyType.RANGE
}
},
ProvisionedThroughput = new ProvisionedThroughput
{
ReadCapacityUnits = 5,
WriteCapacityUnits = 6
},
TableName = _settings.AWSDynamoDBViewCountTable
};
var response = _client.CreateTableAsync(ctRequest).Result;
具有自动递增字段的更新和项目
不幸的是,这是我遇到问题的地方。旧文档可在此处的原子计数器部分下找到。 (https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LowLevelDotNetItemCRUD.html)
Invalid ConditionExpression: Syntax error; token: \"SET\", near: \"SET
VC\"
var viewData = new Document();
viewData["ViewUid"] = videoUid; //Table entry UID
viewData["VideoId"] = videoId; // Video ID
viewData["ViewDate"] = date;
viewData["ViewCount"] = 0;
//Document result = await _viewCountTable.PutItemAsync(viewData);
Expression expr = new Expression();
expr.ExpressionStatement = "SET #VC = #VC + :val";
expr.ExpressionAttributeValues[":val"] = 1;
expr.ExpressionAttributeNames["#VC"] = "ViewCount";
var updateConfig = new UpdateItemOperationConfig() {
ConditionalExpression = expr,
ReturnValues = ReturnValues.UpdatedNewAttributes
};
var result = await _viewCountTable.UpdateItemAsync(viewData, updateConfig);
return result;
查询日期范围
获取一个视频在某个日期范围内的观看次数。
string queryTimeSpanStartString = dateFrom.ToString(AWSSDKUtils.ISO8601DateFormat);
string queryTimeSpanEndString = dateTo.ToString(AWSSDKUtils.ISO8601DateFormat);
var request = new QueryRequest
{
TableName = _settings.AWSDynamoDBViewCountTable,
KeyConditions = new Dictionary<string, Condition>()
{
{
"VideoId", new Condition()
{
ComparisonOperator = "EQ",
AttributeValueList = new List<AttributeValue>()
{
new AttributeValue { S = videoId }
}
}
},
{
"ViewDate",
new Condition
{
ComparisonOperator = "BETWEEN",
AttributeValueList = new List<AttributeValue>()
{
new AttributeValue { S = queryTimeSpanStartString },
new AttributeValue { S = queryTimeSpanEndString }
}
}
}
}
};
var response = await _client.QueryAsync(request);
如有任何帮助,我们将不胜感激。
我能够使用以下代码更新 ViewCount:
字符串table名称="videos";
var request = new UpdateItemRequest
{
Key = new Dictionary<string, AttributeValue>() { { "ViewUid", new AttributeValue { S = "replaceVideoIdhere" } } },
ExpressionAttributeNames = new Dictionary<string, string>()
{
{"#Q", "ViewCount"}
},
ExpressionAttributeValues = new Dictionary<string, AttributeValue>()
{
{":incr", new AttributeValue {N = "1"}}
},
UpdateExpression = "SET #Q = #Q + :incr",
TableName = tableName
};
var response = await _dynamoDbClient.UpdateItemAsync(request);
我创建了一个名为 "videos" 的 table,分区键名为 "ViewUid" 作为字符串。让我知道这是否适合你。
我正在尝试使用适用于 .NET Core 的 AWS SDK。
- 创建一个 table 来计算视频观看次数。
- 添加一天的观看次数。
- 增加一天的现有计数。
- 查询视频的两个日期之间的视频计数。
.NET Core AWS SDK 使用 AWS 中未记录的异步方法。在他们的 github 页面上有一个功能请求可以实现这一点……但它是去年的日期。 (https://github.com/aws/aws-sdk-net/issues/787)
创建 TABLE
这有效并在 AWS 控制台上创建了一个 table。
var ctRequest = new CreateTableRequest
{
AttributeDefinitions = new List<AttributeDefinition>()
{
new AttributeDefinition
{
AttributeName = "ViewUid",
AttributeType = ScalarAttributeType.S
},
new AttributeDefinition
{
AttributeName = "ViewDate",
AttributeType = ScalarAttributeType.S
}
},
KeySchema = new List<KeySchemaElement>
{
new KeySchemaElement
{
AttributeName = "ViewUid",
KeyType = KeyType.HASH //Partition key
},
new KeySchemaElement
{
AttributeName = "ViewDate",
KeyType = KeyType.RANGE
}
},
ProvisionedThroughput = new ProvisionedThroughput
{
ReadCapacityUnits = 5,
WriteCapacityUnits = 6
},
TableName = _settings.AWSDynamoDBViewCountTable
};
var response = _client.CreateTableAsync(ctRequest).Result;
具有自动递增字段的更新和项目
不幸的是,这是我遇到问题的地方。旧文档可在此处的原子计数器部分下找到。 (https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LowLevelDotNetItemCRUD.html)
Invalid ConditionExpression: Syntax error; token: \"SET\", near: \"SET VC\"
var viewData = new Document();
viewData["ViewUid"] = videoUid; //Table entry UID
viewData["VideoId"] = videoId; // Video ID
viewData["ViewDate"] = date;
viewData["ViewCount"] = 0;
//Document result = await _viewCountTable.PutItemAsync(viewData);
Expression expr = new Expression();
expr.ExpressionStatement = "SET #VC = #VC + :val";
expr.ExpressionAttributeValues[":val"] = 1;
expr.ExpressionAttributeNames["#VC"] = "ViewCount";
var updateConfig = new UpdateItemOperationConfig() {
ConditionalExpression = expr,
ReturnValues = ReturnValues.UpdatedNewAttributes
};
var result = await _viewCountTable.UpdateItemAsync(viewData, updateConfig);
return result;
查询日期范围
获取一个视频在某个日期范围内的观看次数。
string queryTimeSpanStartString = dateFrom.ToString(AWSSDKUtils.ISO8601DateFormat);
string queryTimeSpanEndString = dateTo.ToString(AWSSDKUtils.ISO8601DateFormat);
var request = new QueryRequest
{
TableName = _settings.AWSDynamoDBViewCountTable,
KeyConditions = new Dictionary<string, Condition>()
{
{
"VideoId", new Condition()
{
ComparisonOperator = "EQ",
AttributeValueList = new List<AttributeValue>()
{
new AttributeValue { S = videoId }
}
}
},
{
"ViewDate",
new Condition
{
ComparisonOperator = "BETWEEN",
AttributeValueList = new List<AttributeValue>()
{
new AttributeValue { S = queryTimeSpanStartString },
new AttributeValue { S = queryTimeSpanEndString }
}
}
}
}
};
var response = await _client.QueryAsync(request);
如有任何帮助,我们将不胜感激。
我能够使用以下代码更新 ViewCount:
字符串table名称="videos";
var request = new UpdateItemRequest
{
Key = new Dictionary<string, AttributeValue>() { { "ViewUid", new AttributeValue { S = "replaceVideoIdhere" } } },
ExpressionAttributeNames = new Dictionary<string, string>()
{
{"#Q", "ViewCount"}
},
ExpressionAttributeValues = new Dictionary<string, AttributeValue>()
{
{":incr", new AttributeValue {N = "1"}}
},
UpdateExpression = "SET #Q = #Q + :incr",
TableName = tableName
};
var response = await _dynamoDbClient.UpdateItemAsync(request);
我创建了一个名为 "videos" 的 table,分区键名为 "ViewUid" 作为字符串。让我知道这是否适合你。