use empty {} in place of empty body when parsing json (#551) (f9311e9b) · Commits · Public Repositories / Smithy Rust

codegen/src/main/kotlin/software/amazon/smithy/rust/codegen/smithy/protocols/parse/JsonParserGenerator.kt

+27 −14

Original line number	Diff line number	Diff line
		@@ -73,6 +73,7 @@ class JsonParserGenerator(
		"Peekable" to RuntimeType.std.member("iter::Peekable"),
		"skip_value" to smithyJson.member("deserialize::token::skip_value"),
		"Token" to smithyJson.member("deserialize::Token"),
		"or_empty" to orEmptyJson()
		)

		override fun payloadParser(member: MemberShape): RuntimeType {
		@@ -87,7 +88,7 @@ class JsonParserGenerator(
		) {
		rustTemplate(
		"""
		let mut tokens_owned = #{json_token_iter}(input).peekable();
		let mut tokens_owned = #{json_token_iter}(#{or_empty}(input)).peekable();
		let tokens = &mut tokens_owned;
		""",
		*codegenScope
		@@ -116,10 +117,9 @@ class JsonParserGenerator(
		"Builder" to outputShape.builderSymbol(symbolProvider),
		*codegenScope
		) {
		rustBlock("if !input.is_empty()") {
		rustTemplate(
		"""
		let mut tokens_owned = #{json_token_iter}(input).peekable();
		let mut tokens_owned = #{json_token_iter}(#{or_empty}(input)).peekable();
		let tokens = &mut tokens_owned;
		#{expect_start_object}(tokens.next())?;
		""",
		@@ -127,7 +127,6 @@ class JsonParserGenerator(
		)
		deserializeStructInner(httpDocumentMembers)
		expectEndOfTokenStream()
		}
		rust("Ok(builder)")
		}
		}
		@@ -146,7 +145,7 @@ class JsonParserGenerator(
		) {
		rustTemplate(
		"""
		let mut tokens_owned = #{json_token_iter}(input).peekable();
		let mut tokens_owned = #{json_token_iter}(#{or_empty}(input)).peekable();
		let tokens = &mut tokens_owned;
		#{expect_start_object}(tokens.next())?;
		""",
		@@ -181,6 +180,20 @@ class JsonParserGenerator(
		}
		}

		private fun orEmptyJson(): RuntimeType = RuntimeType.forInlineFun("or_empty_doc", "json_deser") {
		it.rust(
		"""
		pub fn or_empty_doc(data: &[u8]) -> &[u8] {
		if data.is_empty() {
		b"{}"
		} else {
		data
		}
		}
		"""
		)
		}

		private fun RustWriter.expectEndOfTokenStream() {
		rustBlock("if tokens.next().is_some()") {
		rustTemplate(

codegen/src/test/kotlin/software/amazon/smithy/rust/codegen/smithy/protocols/parse/JsonParserGeneratorTest.kt

+22 −0

Original line number	Diff line number	Diff line
		@@ -91,9 +91,16 @@ class JsonParserGeneratorTest {
		top: Top
		}

		@error("client")
		structure Error {
		message: String,
		reason: String
		}

		@http(uri: "/top", method: "POST")
		operation Op {
		output: OpOutput,
		errors: [Error]
		}
		""".asSmithyModel()

		@@ -108,6 +115,7 @@ class JsonParserGeneratorTest {
		val operationGenerator = parserGenerator.operationParser(model.lookup("test#Op"))
		val documentGenerator = parserGenerator.documentParser(model.lookup("test#Op"))
		val payloadGenerator = parserGenerator.payloadParser(model.lookup("test#OpOutput\$top"))
		val errorParser = parserGenerator.errorParser(model.lookup("test#Error"))

		val project = TestWorkspace.testProject(testSymbolProvider(model))
		project.lib { writer ->
		@@ -132,6 +140,17 @@ class JsonParserGeneratorTest {
		assert_eq!(Some(45), top.extra);
		assert_eq!(Some("something".to_string()), top.field);
		assert_eq!(Some(Choice::Int(5)), top.choice);
		let output = ${writer.format(operationGenerator!!)}(b"", output::op_output::Builder::default()).unwrap().build();
		assert_eq!(output.top, None);


		// empty error
		let error_output = ${writer.format(errorParser!!)}(b"", error::error::Builder::default()).unwrap().build();
		assert_eq!(error_output.message, None);

		// error with message
		let error_output = ${writer.format(errorParser!!)}(br#"{"message": "hello"}"#, error::error::Builder::default()).unwrap().build();
		assert_eq!(error_output.message.expect("message should be set"), "hello");
		"""
		)
		}
		@@ -145,6 +164,9 @@ class JsonParserGeneratorTest {
		project.withModule(RustModule.default("output", public = true)) {
		model.lookup<OperationShape>("test#Op").outputShape(model).renderWithModelBuilder(model, symbolProvider, it)
		}
		project.withModule(RustModule.default("error", public = true)) {
		model.lookup<StructureShape>("test#Error").renderWithModelBuilder(model, symbolProvider, it)
		}
		println("file:///${project.baseDir}/src/json_deser.rs")
		println("file:///${project.baseDir}/src/lib.rs")
		println("file:///${project.baseDir}/src/model.rs")