fix(rust-server): Handle multiple content-types in responses (#24179)

* fix(rust-server): dispatch response bodies on Content-Type for multi-content-type responses (#24097)

* Review markups

* Regenerate rust-server sample after merging master

Merging upstream master (which includes PR #24192, a fix to
InlineModelResolver's inline-schema merging) surfaces a previously
orphaned model for the testEnumParameters enum_header_string
parameter's inline enum. Regenerating picks up the new model_doc.mustache
formatting for it.

Author: dsteeley

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java

@@ -29,7 +29,8 @@ use multipart::client::lazy::Multipart;
 {{/apiUsesMultipartFormData}}
 {{#apiUsesMultipartRelated}}
 use hyper::header::HeaderMap;
-use mime_multipart::{Node, Part, write_multipart};
+use log::warn;
+use mime_multipart::{read_multipart_body, Node, Part, write_multipart};
 {{/apiUsesMultipartRelated}}
 
 use crate::models;

modules/openapi-generator/src/main/resources/rust-server/client-imports.mustache

@@ -191,7 +191,10 @@
 {{#responses}}
             {{{code}}} => {
 {{#headers}}
-                let response_{{{name}}} = match response.headers().get(HeaderName::from_static("{{{nameInLowerCase}}}")) {
+{{#-first}}
+                let (header, body) = response.into_parts();
+{{/-first}}
+                let response_{{{name}}} = match header.headers.get(HeaderName::from_static("{{{nameInLowerCase}}}")) {
                     Some(response_{{{name}}}) => {
                         let response_{{{name}}} = response_{{{name}}}.clone();
                         let response_{{{name}}} = match TryInto::<header::IntoHeaderValue<{{{dataType}}}>>::try_into(response_{{{name}}}) {
@@ -217,14 +220,25 @@
 
 {{/headers}}
 {{#dataType}}
-                let body = response.into_body();
+{{#headers}}{{#-first}}
+                let body = http_body_util::BodyExt::collect(body)
+{{/-first}}{{/headers}}
+{{^headers}}
+{{#vendorExtensions.x-response-content-types}}
+{{#-first}}
+                let (header, body) = response.into_parts();
                 let body = http_body_util::BodyExt::collect(body)
+{{/-first}}
+{{/vendorExtensions.x-response-content-types}}
+{{^vendorExtensions.x-response-content-types}}
+                let body = http_body_util::BodyExt::collect(response.into_body())
+{{/vendorExtensions.x-response-content-types}}
+{{/headers}}
                         .await
                         .map(|f| f.to_bytes().to_vec())
                         .map_err(|e| ApiError(format!("Failed to read response: {}", e.into())))?;
 
-{{>client-response-body-instance}}
-
+{{>client-response-body}}
 
                 Ok({{{operationId}}}Response::{{#exts}}{{x-response-id}}{{/exts}}
 {{^headers}}

modules/openapi-generator/src/main/resources/rust-server/client-operation.mustache

@@ -3,7 +3,6 @@
 
         // Consumes multipart/form body
 {{>client-request-body-multipart-form}}
-
   {{/x-consumes-multipart-form}}
   {{#x-consumes-multipart-related}}
 

modules/openapi-generator/src/main/resources/rust-server/client-request-body-instance.mustache

@@ -21,7 +21,6 @@
             multipart.add_stream("{{{paramName}}}",  {{{paramName}}}_cursor,  None as Option<&str>, Some({{{paramName}}}_mime));
           {{/jsonSchema}}
         {{/isByteArray}}
-
         {{#isByteArray}}
             let {{{paramName}}}_vec = param_{{{paramName}}}.to_vec();
 

modules/openapi-generator/src/main/resources/rust-server/client-request-body-multipart-form.mustache

@@ -0,0 +1,22 @@
+{{#exts}}
+  {{#x-produces-bytes}}
+                        let body = swagger::ByteArray(body.to_vec());
+  {{/x-produces-bytes}}
+  {{^x-produces-bytes}}
+                        let body = str::from_utf8(&body)
+                            .map_err(|e| ApiError(format!("Response was not valid UTF8: {e}")))?;
+    {{#x-produces-xml}}
+                        // ToDo: this will move to swagger-rs and become a standard From conversion trait
+                        // once https://github.com/RReverser/serde-xml-rs/pull/45 is accepted upstream
+                        let body = serde_xml_rs::from_str::<{{{dataType}}}>(body)
+                            .map_err(|e| ApiError(format!("Response body did not match the schema: {e}")))?;
+    {{/x-produces-xml}}
+    {{#x-produces-json}}
+                        let body = serde_json::from_str::<{{{dataType}}}>(body)
+                            .map_err(|e| ApiError(format!("Response body did not match the schema: {e}")))?;
+    {{/x-produces-json}}
+    {{#x-produces-plain-text}}
+                        let body = body.to_string();
+    {{/x-produces-plain-text}}
+  {{/x-produces-bytes}}
+{{/exts}}

modules/openapi-generator/src/main/resources/rust-server/client-response-body-variant-instance.mustache

@@ -0,0 +1,28 @@
+{{#vendorExtensions.x-response-content-types}}
+  {{#-first}}
+                // Body has multiple variant schemas
+                let content_type = if let Some(content_type) = header.headers.get(CONTENT_TYPE) {
+                    content_type.to_str()
+                } else {
+                    return Err(ApiError(String::from("Missing content type header")));
+                };
+
+                let content_type = content_type.map(|s|
+                    s.split(';').next().expect("Splitting content type header failed").trim());
+
+                let body = match content_type {
+  {{/-first}}
+                    Ok(ct) if ct.eq_ignore_ascii_case("{{{contentType}}}") => {
+{{>client-response-body-variant-instance}}
+                        {{{variantName}}}(body)
+                    },
+  {{#-last}}
+                    e => {
+                        return Err(ApiError(format!("Unexpected content type: {:?}", e)));
+                    }
+                };
+  {{/-last}}
+{{/vendorExtensions.x-response-content-types}}
+{{^vendorExtensions.x-response-content-types}}
+{{>client-response-body-instance}}
+{{/vendorExtensions.x-response-content-types}}

modules/openapi-generator/src/main/resources/rust-server/client-response-body.mustache

@@ -1,9 +1,16 @@
 {{#models}}{{#model}}# {{{classname}}}
 
+{{#vars}}
+{{#-first}}
 ## Properties
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-{{#vars}}**{{{name}}}** | {{#isPrimitiveType}}**{{{dataType}}}**{{/isPrimitiveType}}{{^isPrimitiveType}}[**{{^isContainer}}{{^isDateTime}}*{{/isDateTime}}{{/isContainer}}{{{dataType}}}**]({{{complexType}}}.md){{/isPrimitiveType}} | {{{description}}} | {{^required}}[optional] {{/required}}{{#isReadOnly}}[readonly] {{/isReadOnly}}{{#defaultValue}}[default to {{{.}}}]{{/defaultValue}}
+{{/-first}}
+**{{{name}}}** | {{#isPrimitiveType}}**{{{dataType}}}**{{/isPrimitiveType}}{{^isPrimitiveType}}[**{{^isContainer}}{{^isDateTime}}*{{/isDateTime}}{{/isContainer}}{{{dataType}}}**]({{{complexType}}}.md){{/isPrimitiveType}} | {{{description}}} | {{^required}}[optional] {{/required}}{{#isReadOnly}}[readonly] {{/isReadOnly}}{{#defaultValue}}[default to {{{.}}}]{{/defaultValue}}
+{{/vars}}
+{{^vars}}
+## Type
+{{#arrayModelType}}**Vec<{{{arrayModelType}}}>**{{/arrayModelType}}{{^arrayModelType}}**{{{dataType}}}**{{/arrayModelType}}
 {{/vars}}
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)

modules/openapi-generator/src/main/resources/rust-server/model_doc.mustache

@@ -242,7 +242,7 @@ where
       {{/bodyParam.exts.x-consumes-plain-text}}
     {{/exts.x-consumes-form}}
   {{/exts.x-consumes-multipart-form}}
-{{>server-request-body-instance}}
+{{>server-request-body}}
 
 {{/exts.x-has-request-body}}
                                 let result = api_impl.{{#exts}}{{{x-operation-id}}}{{/exts}}(
@@ -331,7 +331,7 @@ where
                                                     }
   {{/required}}
 {{/headers}}
-{{>server-response-body-instance}}
+{{>server-response-body}}
 
                                                 },
 {{/responses}}

modules/openapi-generator/src/main/resources/rust-server/server-operation-handler.mustache

@@ -0,0 +1,20 @@
+{{#exts}}
+  {{#x-consumes-multipart}}
+    {{#x-consumes-multipart-related}}
+{{>server-request-body-multipart-related}}
+    {{/x-consumes-multipart-related}}
+    {{^x-consumes-multipart-related}}
+      {{^bodyParams}}
+{{>server-request-body-multipart-form}}
+      {{/bodyParams}}
+    {{/x-consumes-multipart-related}}
+  {{/x-consumes-multipart}}
+  {{^x-consumes-multipart}}
+    {{#bodyParams}}
+{{>server-request-body-basic}}
+    {{/bodyParams}}
+    {{^bodyParams}}
+{{>server-request-body-form}}
+    {{/bodyParams}}
+  {{/x-consumes-multipart}}
+{{/exts}}