feat: Add eventstream input support for protocols that use XML for requests #680
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…to handle empty structs with zero properties.
…and returns the marshalled EventStream.Message. Also add jsonMarshalClosure utility method that wraps the old marshall() methods code-generated for each streaming union shape in JSON protocols within the returned MarshalClosure.
…odyMiddleware with marshalClosure. Add marshalClosure to constructor of the middleware, and pass it along to DefaultMessageEncoderStream instead of requestEncoder.
…uctor call-site codegen. If request wire protocol is XML, uses static marshal closure (codegen for this is upcoming). If request wire protocol is JSON, calls the runtime utility function jsonMarshalClosure to get MarshalClosure.
| @@ -13,42 +13,42 @@ extension EventStream { | |||
| let stream: AsyncThrowingStream<Event, Error> | |||
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Here, the usage of requestEncoder is completely replaced by marshalClosure. This has to be done because XML serialization does not rely on Swift's Codable interface. For JSON serialization, the closure passed here will use JSONEncoder behind the scenes. For XML serialization, the closure passed here will use XMLWriter behind the scenes.
| @@ -16,3 +16,16 @@ public protocol MessageMarshallable { | |||
| /// - Returns: The marshalled `Message`. | |||
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Defines a new typealias for closure that takes a stream struct, determines the specific instance of Event, and returns an EventStream.Message that has values "serialized" into it from the original Event for generic handling and encoding into Data.
A utility method jsonMarshalClosure is defined here that returns a closure which simply uses the old marshall method - that gets code-generated for each streaming union shape within the MessageMarshallable protocol conformance - to return an instance of EventStream.Message.
| @@ -17,13 +17,16 @@ public struct EventStreamBodyMiddleware<OperationStackInput, | |||
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Instead of getting the requestEncoder from middleware context and passing it along to DefaultMessageEncoderStream, the middleware now takes in a marshalClosure at initialization and passes it along to DefaultMessageEncoderStream.
| @@ -21,7 +21,9 @@ import software.amazon.smithy.swift.codegen.SwiftWriter | |||
| import software.amazon.smithy.swift.codegen.integration.ProtocolGenerator | |||
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Depending on the request wire protocol, either pass in the utility method defined for JSON, or pass in the newly-added code-generated marshal static function variable of the streaming shape.
| @@ -38,7 +38,7 @@ open class StructDecodeXMLGenerator( | |||
| SmithyXMLTypes.Reader | |||
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This additional condition fixes the error thrown when handling EndEvent that's returned as part of the event stream output of the call to S3:SelectObjectContent. The S3 docs say the payload of this event is empty (not an empty XML object like <EndEvent></EndEvent>, just literally empty), which causes an issue with deserializing in SDK side. The additional condition checks if the S3 struct being deserialized has any properties, and if it doesn't, returns a new instance rather than returning nil.
…y for S3 shapes that have no members.
…ork for RPC protocols.
Issue #
awslabs/aws-sdk-swift#1379
Companion PR: awslabs/aws-sdk-swift#1404
Description of changes
Currently the Swift SDK does not support event stream input for protocols that use XML as request wire protocol (e.g., restXml).
Fortunately, currently there is no AWS service that uses restXml AND uses event stream input for an operation in their API either.
However, if any service that uses restXml adds an operation that takes in an event stream input in the future, our SDK would break the customers.
This PR and the companion PR in
aws-sdk-swiftlinked above do the groundwork for supporting event stream input for protocols that use XML as request wire protocol (e.g., restXml).Detailed descriptions of each change will be put as comments on the Github diff.
Scope
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.