public static Set generateErrorDispatcher()

in codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/HttpProtocolGeneratorUtils.java [94:152]
47 lines of code
1 McCabe index (conditional complexity)

    public static Set<StructureShape> generateErrorDispatcher(
            GenerationContext context,
            OperationShape operation,
            Symbol responseType,
            Consumer<GenerationContext> errorMessageCodeGenerator,
            BiFunction<GenerationContext, OperationShape, Map<String, ShapeId>> operationErrorsToShapes,
            DefaultBlockWriter defaultBlockWriter
    ) {
        GoWriter writer = context.getWriter().get();
        ServiceShape service = context.getService();
        String protocolName = context.getProtocolName();
        Set<StructureShape> errorShapes = new TreeSet<>();

        String errorFunctionName = ProtocolGenerator.getOperationErrorDeserFunctionName(
                operation, service, protocolName);

        writer.addUseImports(SmithyGoDependency.SMITHY_MIDDLEWARE);
        writer.openBlock("func $L(response $P, metadata *middleware.Metadata) error {", "}",
                errorFunctionName, responseType, () -> {
                    writer.addUseImports(SmithyGoDependency.BYTES);
                    writer.addUseImports(SmithyGoDependency.IO);

                    // Copy the response body into a seekable type
                    writer.write("var errorBuffer bytes.Buffer");
                    writer.openBlock("if _, err := io.Copy(&errorBuffer, response.Body); err != nil {", "}", () -> {
                        writer.write("return &smithy.DeserializationError{Err: fmt.Errorf("
                                + "\"failed to copy error response body, %w\", err)}");
                    });
                    writer.write("errorBody := bytes.NewReader(errorBuffer.Bytes())");
                    writer.write("");

                    // Set the default values for code and message.
                    writer.write("errorCode := \"UnknownError\"");
                    writer.write("errorMessage := errorCode");
                    writer.write("");

                    // Dispatch to the message/code generator to try to get the specific code and message.
                    errorMessageCodeGenerator.accept(context);

                    writer.openBlock("switch {", "}", () -> {
                        operationErrorsToShapes.apply(context, operation).forEach((name, errorId) -> {
                            StructureShape error = context.getModel().expectShape(errorId).asStructureShape().get();
                            errorShapes.add(error);
                            String errorDeserFunctionName = ProtocolGenerator.getErrorDeserFunctionName(
                                    error, service, protocolName);
                            writer.addUseImports(SmithyGoDependency.STRINGS);
                            writer.openBlock("case strings.EqualFold($S, errorCode):", "", name, () -> {
                                writer.write("return $L(response, errorBody)", errorDeserFunctionName);
                            });
                        });

                        // Create a generic error
                        writer.addUseImports(SmithyGoDependency.SMITHY);
                        defaultBlockWriter.write(writer);
                    });
                }).write("");

        return errorShapes;
    }