[Multipart] Support model format for @multipartBody

.chronus/changes/multipart-implementation-2024-5-28-10-50-5.md

@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+Support model format of `@multipartBody`

packages/typespec-client-generator-core/src/interfaces.ts

@@ -391,11 +391,28 @@ export type SdkModelPropertyType =
   | SdkBodyParameter
   | SdkHeaderParameter;
 
+export interface MultipartOptionsType {
+  // whether this part is for file
+  isFilePart: boolean;
+  // whether this part is multi in request payload
+  multi: boolean;
+  // undefined if filename is not set explicitly in Typespec
+  filename?: SdkModelPropertyType;
+  // undefined if contentType is not set explicitly in Typespec
+  contentType?: SdkModelPropertyType;
+  // defined in Typespec or calculated by Typespec complier
+  defaultContentTypes: string[];
+}
+
 export interface SdkBodyModelPropertyType extends SdkModelPropertyTypeBase {
   kind: "property";
   discriminator: boolean;
   serializedName: string;
+  /*
+    @deprecated This property is deprecated. Use `.multipartOptions?.isFilePart` instead.
+  */
   isMultipartFileInput: boolean;
+  multipartOptions?: MultipartOptionsType;
   visibility?: Visibility[];
   flatten: boolean;
 }

packages/typespec-client-generator-core/src/types.ts

@@ -31,10 +31,13 @@ import {
 } from "@typespec/compiler";
 import {
   Authentication,
+  HttpOperationPart,
   Visibility,
   getAuthentication,
+  getHttpPart,
   getServers,
   isHeader,
+  isOrExtendsHttpFile,
   isStatusCode,
 } from "@typespec/http";
 import {
@@ -855,7 +858,14 @@ export function getClientTypeWithDiagnostics(
     case "Model":
       retval = diagnostics.pipe(getSdkArrayOrDictWithDiagnostics(context, type, operation));
       if (retval === undefined) {
-        retval = diagnostics.pipe(getSdkModelWithDiagnostics(context, type, operation));
+        const httpPart = getHttpPart(context.program, type);
+        if (httpPart === undefined) {
+          retval = diagnostics.pipe(getSdkModelWithDiagnostics(context, type, operation));
+        } else {
+          retval = diagnostics.pipe(
+            getClientTypeWithDiagnostics(context, httpPart.type, operation)
+          );
+        }
       }
       break;
     case "Intrinsic":
@@ -1060,45 +1070,102 @@ export function getSdkModelPropertyTypeBase(
   });
 }
 
-export function getSdkModelPropertyType(
+function updateMultiPartInfo(
   context: TCGCContext,
   type: ModelProperty,
-  operation?: Operation
-): [SdkModelPropertyType, readonly Diagnostic[]] {
+  base: SdkBodyModelPropertyType,
+  operation?: Operation,
+  httpOperationPart?: HttpOperationPart
+): [void, readonly Diagnostic[]] {
   const diagnostics = createDiagnosticCollector();
-  const base = diagnostics.pipe(getSdkModelPropertyTypeBase(context, type, operation));
+  const isBytesInput =
+    base.type.kind === "bytes" ||
+    (base.type.kind === "array" && base.type.valueType.kind === "bytes");
 
-  if (isSdkHttpParameter(context, type)) return getSdkHttpParameter(context, type, operation!);
-  // I'm a body model property
-  let operationIsMultipart = false;
-  if (operation) {
+  if (httpOperationPart) {
+    // body decorated with @multipartBody
+    const httpPart = getHttpPart(context.program, type.type);
+    base.multipartOptions = {
+      isFilePart:
+        isBytesInput ||
+        (httpPart !== undefined && isOrExtendsHttpFile(context.program, httpPart.type)),
+      multi: httpOperationPart.multi,
+      filename: httpOperationPart.filename
+        ? diagnostics.pipe(getSdkModelPropertyType(context, httpOperationPart.filename, operation))
+        : undefined,
+      contentType: httpOperationPart.body.contentTypeProperty
+        ? diagnostics.pipe(
+            getSdkModelPropertyType(context, httpOperationPart.body.contentTypeProperty, operation)
+          )
+        : undefined,
+      defaultContentTypes: httpOperationPart.body.contentTypes,
+    };
+  } else if (operation) {
+    // common body
     const httpOperation = getHttpOperationWithCache(context, operation);
-    operationIsMultipart = Boolean(
+    const operationIsMultipart = Boolean(
       httpOperation && httpOperation.parameters.body?.contentTypes.includes("multipart/form-data")
     );
+    if (operationIsMultipart) {
+      // Currently we only recognize bytes and list of bytes as potential file inputs
+      if (isBytesInput && getEncode(context.program, type)) {
+        diagnostics.add(
+          createDiagnostic({
+            code: "encoding-multipart-bytes",
+            target: type,
+          })
+        );
+      }
+      base.multipartOptions = {
+        isFilePart: isBytesInput,
+        multi: base.type.kind === "array",
+        defaultContentTypes: [],
+      };
+    }
   }
-  // Currently we only recognize bytes and list of bytes as potential file inputs
-  const isBytesInput =
-    base.type.kind === "bytes" ||
-    (base.type.kind === "array" && base.type.valueType.kind === "bytes");
-  if (isBytesInput && operationIsMultipart && getEncode(context.program, type)) {
-    diagnostics.add(
-      createDiagnostic({
-        code: "encoding-multipart-bytes",
-        target: type,
-      })
-    );
+  if (base.multipartOptions !== undefined) {
+    base.isMultipartFileInput = base.multipartOptions.isFilePart;
   }
-  return diagnostics.wrap({
+  if (base.multipartOptions?.multi && base.type.kind === "array") {
+    // for "images: T[]" or "images: HttpPart<T>[]", return type shall be "T" instead of "T[]"
+    base.type = base.type.valueType;
+  }
+
+  return diagnostics.wrap(undefined);
+}
+
+export function getSdkModelPropertyType(
+  context: TCGCContext,
+  type: ModelProperty,
+  operation?: Operation,
+  httpOperationPart?: HttpOperationPart
+): [SdkModelPropertyType, readonly Diagnostic[]] {
+  const diagnostics = createDiagnosticCollector();
+  const base = diagnostics.pipe(getSdkModelPropertyTypeBase(context, type, operation));
+
+  if (isSdkHttpParameter(context, type)) return getSdkHttpParameter(context, type, operation!);
+  const result: SdkBodyModelPropertyType = {
     ...base,
     kind: "property",
     optional: type.optional,
     visibility: getSdkVisibility(context, type),
     discriminator: false,
     serializedName: getPropertyNames(context, type)[1],
-    isMultipartFileInput: isBytesInput && operationIsMultipart,
+    isMultipartFileInput: false,
     flatten: shouldFlattenProperty(context, type),
-  });
+  };
+  diagnostics.pipe(updateMultiPartInfo(context, type, result, operation, httpOperationPart));
+  return diagnostics.wrap(result);
+}
+
+function getHttpOperationParts(context: TCGCContext, operation?: Operation): HttpOperationPart[] {
+  if (operation) {
+    const body = getHttpOperationWithCache(context, operation).parameters.body;
+    if (body?.bodyKind === "multipart") {
+      return body.parts;
+    }
+  }
+  return [];
 }
 
 function addPropertiesToModelType(
@@ -1108,15 +1175,19 @@ function addPropertiesToModelType(
   operation?: Operation
 ): [void, readonly Diagnostic[]] {
   const diagnostics = createDiagnosticCollector();
-  for (const property of type.properties.values()) {
+  const httpOpParts = getHttpOperationParts(context, operation);
+  for (const [index, property] of Array.from(type.properties.values()).entries()) {
     if (
       isStatusCode(context.program, property) ||
       isNeverOrVoidType(property.type) ||
       sdkType.kind !== "model"
     ) {
       continue;
     }
-    const clientProperty = diagnostics.pipe(getSdkModelPropertyType(context, property, operation));
+    const httpOpPart = httpOpParts.length > index ? httpOpParts[index] : undefined;
+    const clientProperty = diagnostics.pipe(
+      getSdkModelPropertyType(context, property, operation, httpOpPart)
+    );
     if (sdkType.properties) {
       sdkType.properties.push(clientProperty);
     } else {