feat: add async file stream support for reqwest client (#21771)

Author: andershausding

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

@@ -672,6 +672,7 @@ public void postProcessParameter(CodegenParameter parameter) {
     @Override
     public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<ModelMap> allModels) {
         OperationMap objectMap = objs.getOperations();
+        boolean useAsyncFileStream = false;
         List<CodegenOperation> operations = objectMap.getOperation();
         for (CodegenOperation operation : operations) {
             if (operation.pathParams != null && operation.pathParams.size() > 0) {
@@ -707,6 +708,17 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
                 }
             }
 
+            // If we use a file parameter, we need to include the imports and crates for it
+            // But they should be added only once per file 
+            for (var param: operation.allParams) {
+                if (param.isFile && supportAsync && !useAsyncFileStream) {
+                    useAsyncFileStream = true;
+                    additionalProperties.put("useAsyncFileStream", Boolean.TRUE);
+                    operation.vendorExtensions.put("useAsyncFileStream", Boolean.TRUE);
+                    break;
+                }
+            }
+
             // http method verb conversion, depending on client library (e.g. Hyper: PUT => Put, Reqwest: PUT => put)
             if (HYPER_LIBRARY.equals(getLibrary())) {
                 operation.httpMethod = StringUtils.camelize(operation.httpMethod.toLowerCase(Locale.ROOT));

modules/openapi-generator/src/main/resources/rust/Cargo.mustache

@@ -69,7 +69,14 @@ reqwest-middleware = { version = "^0.4", features = ["json", "blocking", "multip
 {{/supportMiddleware}}
 {{/supportAsync}}
 {{#supportAsync}}
+{{#useAsyncFileStream}}
+tokio = { version = "^1.46.0", features = ["fs"] }
+tokio-util = { version = "^0.7", features = ["codec"] }
+reqwest = { version = "^0.12", default-features = false, features = ["json", "multipart", "stream"] }
+{{/useAsyncFileStream}}
+{{^useAsyncFileStream}}
 reqwest = { version = "^0.12", default-features = false, features = ["json", "multipart"] }
+{{/useAsyncFileStream}}
 {{#supportMiddleware}}
 reqwest-middleware = { version = "^0.4", features = ["json", "multipart"] }
 {{/supportMiddleware}}

modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache

@@ -4,6 +4,14 @@ use reqwest;
 use serde::{Deserialize, Serialize, de::Error as _};
 use crate::{apis::ResponseContent, models};
 use super::{Error, configuration, ContentType};
+{{#operations}}
+{{#operation}}
+{{#vendorExtensions.useAsyncFileStream}}
+use tokio::fs::File as TokioFile;
+use tokio_util::codec::{BytesCodec, FramedRead};
+{{/vendorExtensions.useAsyncFileStream}}
+{{/operation}}
+{{/operations}}
 
 {{#operations}}
 {{#operation}}
@@ -445,7 +453,23 @@ pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration:
     {{#hasBodyParam}}
     {{#bodyParams}}
     {{#isFile}}
+    {{#supportAsync}}
+    {{#required}}
+    let file = TokioFile::open({{{vendorExtensions.x-rust-param-identifier}}}).await?;
+    let stream = FramedRead::new(file, BytesCodec::new());
+    req_builder = req_builder.body(reqwest::Body::wrap_stream(stream));
+    {{/required}}
+    {{^required}}
+    if let Some(param_value) = {{{vendorExtensions.x-rust-param-identifier}}} {
+        let file = TokioFile::open(param_value).await?;
+        let stream = FramedRead::new(file, BytesCodec::new());
+        req_builder = req_builder.body(reqwest::Body::wrap_stream(stream));
+    }
+    {{/required}}
+    {{/supportAsync}}
+    {{^supportAsync}}
     req_builder = req_builder.body({{{vendorExtensions.x-rust-param-identifier}}});
+    {{/supportAsync}}
     {{/isFile}}
     {{^isFile}}
     req_builder = req_builder.json(&{{{vendorExtensions.x-rust-param-identifier}}});

modules/openapi-generator/src/test/resources/file_stream_test.yaml

@@ -0,0 +1,23 @@
+# file_streaming_test.yaml
+swagger: "2.0"
+info:
+  title: File Streaming Test API
+  version: 1.0.0
+
+paths:
+    /upload:
+      post:
+        consumes:
+            - application/octet-stream
+        description: Upload a file from the local filesystem
+        operationId: uploadFile
+        parameters:
+          - description: A test file
+            in: body
+            name: inputStream
+            schema:
+              format: binary
+              type: string
+        responses:
+          '200':
+            description: Success