Unverified Commit e74ecf34 authored by david-perez's avatar david-perez Committed by GitHub
Browse files

Simplify implementation of rendering prefix headers (#1841) 

The implementation that binds the target of
`@httpPrefixHeaders`-annotated member shapes is overly complex in that
it accounts for the possibility of it targeting a list shape. However,
`@httpPrefixHeaders` can only be applied to structure members targeting
map shapes:

* https://awslabs.github.io/smithy/1.0/spec/core/http-traits.html#httpprefixheaders-trait
* https://awslabs.github.io/smithy/2.0/spec/http-bindings.html#httpprefixheaders-trait

The existing implementation likely came to be by copy-pasting the
`RustWriter.renderHeaders` extension function.

I've also taken the liberty of reformatting and renaming variables for
clarity and consistency.
parent b4f0b28b

codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/http/HttpBindingGenerator.kt

+26 −20
Original line number Diff line number Diff line
@@ -471,13 +471,15 @@ class HttpBindingGenerator( 
    }



    private fun RustWriter.renderHeaders(httpBinding: HttpBinding) {

        check(httpBinding.location == HttpLocation.HEADER)

        val memberShape = httpBinding.member

        val memberType = model.expectShape(memberShape.target)

        val targetShape = model.expectShape(memberShape.target)

        val memberSymbol = symbolProvider.toSymbol(memberShape)

        val memberName = symbolProvider.toMemberName(memberShape)

        ifSet(memberType, memberSymbol, "&input.$memberName") { field ->

            val isListHeader = memberType is CollectionShape

            listForEach(memberType, field) { innerField, targetId ->



        ifSet(targetShape, memberSymbol, "&input.$memberName") { field ->

            val isListHeader = targetShape is CollectionShape

            listForEach(targetShape, field) { innerField, targetId ->

                val innerMemberType = model.expectShape(targetId)

                if (innerMemberType.isPrimitive()) {

                    val encoder = CargoDependency.SmithyTypes(runtimeConfig).asType().member("primitive::Encoder")
@@ -491,9 +493,14 @@ class HttpBindingGenerator( 
                        """

                        let header_value = $safeName;

                        let header_value = http::header::HeaderValue::try_from(&*header_value).map_err(|err| {

                            #{build_error}::InvalidField { field: "$memberName", details: format!("`{}` cannot be used as a header value: {}", &${

                        memberShape.redactIfNecessary(model, "header_value")

                        }, err)}

                            #{build_error}::InvalidField { 

                                field: "$memberName", 

                                details: format!(

                                    "`{}` cannot be used as a header value: {}", 

                                    &${memberShape.redactIfNecessary(model, "header_value")},

                                    err,

                                )

                            }

                        })?;

                        builder = builder.header("${httpBinding.locationName}", header_value);

                        """,
@@ -505,17 +512,14 @@ class HttpBindingGenerator( 
    }



    private fun RustWriter.renderPrefixHeader(httpBinding: HttpBinding) {

        check(httpBinding.location == HttpLocation.PREFIX_HEADERS)

        val memberShape = httpBinding.member

        val memberType = model.expectShape(memberShape.target)

        val targetShape = model.expectShape(memberShape.target, MapShape::class.java)

        val memberSymbol = symbolProvider.toSymbol(memberShape)

        val memberName = symbolProvider.toMemberName(memberShape)

        val target = when (memberType) {

            is CollectionShape -> model.expectShape(memberType.member.target)

            is MapShape -> model.expectShape(memberType.value.target)

            else -> UNREACHABLE("unexpected member for prefix headers: $memberType")

        }

        ifSet(memberType, memberSymbol, "&input.$memberName") { field ->

            val listHeader = memberType is CollectionShape

        val valueTargetShape = model.expectShape(targetShape.value.target)



        ifSet(targetShape, memberSymbol, "&input.$memberName") { field ->

            rustTemplate(

                """

                for (k, v) in $field {
@@ -523,17 +527,19 @@ class HttpBindingGenerator( 
                    let header_name = http::header::HeaderName::from_str(&format!("{}{}", "${httpBinding.locationName}", &k)).map_err(|err| {

                        #{build_error}::InvalidField { field: "$memberName", details: format!("`{}` cannot be used as a header name: {}", k, err)}

                    })?;

                    let header_value = ${headerFmtFun(this, target, memberShape, "v", listHeader)};

                    let header_value = ${headerFmtFun(this, valueTargetShape, memberShape, "v", isListHeader = false)};

                    let header_value = http::header::HeaderValue::try_from(&*header_value).map_err(|err| {

                        #{build_error}::InvalidField {

                            field: "$memberName",

                            details: format!("`{}` cannot be used as a header value: {}", ${

                memberShape.redactIfNecessary(model, "v")

                }, err)}

                            details: format!(

                                "`{}` cannot be used as a header value: {}", 

                                ${memberShape.redactIfNecessary(model, "v")},

                                err,

                            )

                        }

                    })?;

                    builder = builder.header(header_name, header_value);

                }



                """,

                "build_error" to runtimeConfig.operationBuildError(),

            )