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https://issues.apache.org/jira/browse/CAMEL-22029?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17947886#comment-17947886
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Kumar Gaurav commented on CAMEL-22029:
--------------------------------------
WE are using the camel-aws-ddb component with routeTemplates – > kamelets
within springboot app. We are writing routes using route yaml dsl and invoking
those kamelets from those actual routes.
> aws dynamodb scan and query not implemented with attributes-to-get and
> projection and filter expressions
> --------------------------------------------------------------------------------------------------------
>
> Key: CAMEL-22029
> URL: https://issues.apache.org/jira/browse/CAMEL-22029
> Project: Camel
> Issue Type: Improvement
> Components: camel-aws
> Affects Versions: 4.4.5
> Reporter: Kumar Gaurav
> Assignee: Andrea Cosentino
> Priority: Major
>
> {*}Context{*}:
> 1- QUERY operation:
>
> Users want to query the data using key column only to bring all the
> attributes related to items with that key.
> However, Camel DynamoDB component makes it mandatory to send
> attributes-to-get. Please note - It has also not been upgraded to use
> projection and filter expressions.
>
> 2- Scan operation:
> Users want to scan a DynamoDB table and return only a *subset of attributes.*
> However, aws-camel-sdk for DynamoDB does not support attributes-to-get
> parameter. Moreover, It has also not been upgraded to use projection and
> filter expressions.
>
>
> {*}Problem{*}:
> QUERY -
> aws-sdk has a validation that if attribute-to-get is being passed it cannot
> have 0 items. therefore, we are getting an exception as ddb component which
> always adds this attributes with zero items if it is not supplied from
> kamelet.
> SCAN -
> We need to fix _ScanCommand_ class of camel-aws-ddb lib to support his
> operation which is already supported by aws-sdk for dynamodab .
>
> {*}Solution{*}:
>
> Modify the class and refactor the below code to send attribute-to-get only if
> it is provided by customer. If it is not supplied (header '' is empty or
> null), this parameter shall not be sent as part of ddb query request object.
>
>
> *For reference:*
> [*AttributesToGet*|https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Query.html#API_Query_RequestSyntax]
> This is a legacy parameter. Use {{ProjectionExpression}} instead. For more
> information, see
> [AttributesToGet|https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html]
> in the {_}Amazon DynamoDB Developer Guide{_}.
> Type: Array of strings
> Array Members: Minimum number of 1 item.
> Length Constraints: Maximum length of 65535.
> Required: No
> The legacy conditional parameter {{AttributesToGet}} is an array of one or
> more attributes to retrieve from DynamoDB. If no attribute names are
> provided, then all attributes will be returned. If any of the requested
> attributes are not found, they will not appear in the result.
> [http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html]
>
> scan operation supports attributes-to-get -
> *[https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html]*
>
> *Proposed solution*
> *1.* Scan operation(ScanCommand class) need to be enhanced to support
> attributes-to-get and additionally projection and filter expression.
> Scan operation has been enhanced to use the latest projection expression and
> filter expresion supported by aws .
> The new inputs would follow the pattern given as:
> {
> "projection-expression": "#id, #fname",
> "filter-expression": "#fname = :val",
> "select": "SPECIFIC_ATTRIBUTES",
> "expression-attribute-names":
> { "#id": "Id", "#fname": "FirstName" }
> ,
> "expression-attribute-values": {
> ":val":
> { "S": "Kim" }
> }}
> 2. Enhance QueryComand class to accept global secondary indexes and
> attributes-to-get with empty values. When attributes-to-get is null or empty
> - it shall not throw a validation exception.
>
> {color:#007200}// Check if we have set an Index Name{color}
> {color:#000000} {color}{color:#0000ff}if{color}{color:#000000}
> (exchange.getIn().getHeader(Ddb2Constants.INDEX_NAME,
> String.{color}{color:#0000ff}class{color}{color:#000000}) != null) {{color}
> {color:#000000}
> query.indexName(exchange.getIn().getHeader(Ddb2Constants.INDEX_NAME,
> String.{color}{color:#0000ff}class{color}{color:#000000}));{color}
> {color:#000000} }{color}
> {color:#000000} {color}{color:#007200}//skip adding attribute-to-get
> from 'CamelAwsDdbAttributeNames' if the header is null or empty list.{color}
> {color:#000000}
> {color}{color:#0000ff}if{color}{color:#000000}(exchange.getIn().getHeader(Ddb2Constants.ATTRIBUTE_NAMES)
> != null &&{color}
> {color:#000000}
> !exchange.getIn().getHeader(Ddb2Constants.ATTRIBUTE_NAMES,
> Collection.{color}{color:#0000ff}class{color}{color:#000000}).isEmpty()){{color}
> {color:#000000}
> query.attributesToGet(determineAttributeNames());{color}
> {color:#000000} }{color}
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