fix malformed body and include additional optional data

Author: p30arena

packages/abstractions/src/multipartBody.ts

@@ -31,6 +31,7 @@ export class MultipartBody implements Parsable {
     partName: string,
     partContentType: string,
     content: T,
+    additionalKV: {[key: string]: string} | undefined,
     serializationCallback?: ModelSerializerFunction<Parsable>,
   ): void {
     if (!partName) throw new Error("partName cannot be undefined");
@@ -43,6 +44,7 @@ export class MultipartBody implements Parsable {
       contentType: partContentType,
       content,
       originalName: partName,
+      additionalKV: additionalKV,
       serializationCallback,
     };
   }
@@ -94,6 +96,7 @@ interface MultipartEntry {
   contentType: string;
   content: any;
   originalName: string;
+  additionalKV: {[key: string]: string} | undefined;
   serializationCallback?: ModelSerializerFunction<Parsable>;
 }
 
@@ -128,13 +131,18 @@ export function serializeMultipartBody(
     writer.writeStringValue(undefined, "--" + boundary);
     const part = parts[partName];
     writer.writeStringValue("Content-Type", part.contentType);
+    let dispositionValue = 'form-data; name="' + part.originalName + '"';
+    if(part.additionalKV && Object.keys(part.additionalKV).length) {
+      const additionalString = Object.entries(part.additionalKV).map(([k, v]) => `${k}="${v}"`).join("; ");
+      dispositionValue += "; " + additionalString;
+    }
     writer.writeStringValue(
       "Content-Disposition",
-      'form-data; name="' + part.originalName + '"',
+      dispositionValue,
     );
     writer.writeStringValue(undefined, "");
     if (typeof part.content === "string") {
-      writer.writeStringValue(undefined, part.content);
+      writer.writeStringValue(undefined, part.content, false);
     } else if (part.content instanceof ArrayBuffer) {
       writer.writeByteArrayValue(undefined, new Uint8Array(part.content));
     } else if (part.content instanceof Uint8Array) {

packages/abstractions/src/serialization/serializationWriter.ts

@@ -19,7 +19,7 @@ export interface SerializationWriter {
    * @param key the key to write the value with.
    * @param value the value to write to the stream.
    */
-  writeStringValue(key?: string | undefined, value?: string | undefined): void;
+  writeStringValue(key?: string | undefined, value?: string | undefined, newline?: boolean): void;
   /**
    * Writes the specified boolean value to the stream with an optional given key.
    * @param key the key to write the value with.

packages/serialization/multipart/src/multipartSerializationWriter.ts

@@ -32,7 +32,7 @@ export class MultipartSerializationWriter implements SerializationWriter {
   public onStartObjectSerialization:
     | ((value: Parsable, writer: SerializationWriter) => void)
     | undefined;
-  public writeStringValue = (key?: string, value?: string): void => {
+  public writeStringValue = (key?: string, value?: string, newline: boolean = true): void => {
     if (key) {
       this.writeRawStringValue(key);
     }
@@ -42,7 +42,9 @@ export class MultipartSerializationWriter implements SerializationWriter {
       }
       this.writeRawStringValue(value);
     }
-    this.writeRawStringValue("\r\n");
+    if(newline) {
+      this.writeRawStringValue("\r\n");
+    }
   };
   private writeRawStringValue = (value?: string): void => {
     if (value) {