feat: support custom filename when file is Buffer or Readable (#508)

> Uploading files with Buffer defaults the filename to the key or path,
which can conflict with middleware checks.

* 🤖 files as an object defaults filename to the key.
~~* 🚨 File paths or streams also override the filename.~~
* ♻️ only work for buffer scence.
----------

> 当直接通过 Buffer 来上传文件时，无法自定义文件名，这在某些中间件会校验 filename，导致无法上传。

* 🤖 files 参数为 object 时，默认将 key 作为文件名传输
~~* 🚨 传入文件路径或 Readable 流时也同样覆盖~~
* ♻️ 仅处理 buffer 场景


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

## Summary by CodeRabbit

- **New Features**
- Enhanced file upload functionality to support optional custom file
names, allowing users to specify filenames when uploading files.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/HttpClient.ts

@@ -440,7 +440,7 @@ export class HttpClient extends EventEmitter {
           requestOptions.method = 'POST';
         }
         const formData = new FormData();
-        const uploadFiles: [string, string | Readable | Buffer][] = [];
+        const uploadFiles: [string, string | Readable | Buffer, string?][] = [];
         if (Array.isArray(args.files)) {
           for (const [ index, file ] of args.files.entries()) {
             const field = index === 0 ? 'file' : `file${index}`;
@@ -452,7 +452,8 @@ export class HttpClient extends EventEmitter {
           uploadFiles.push([ 'file', args.files ]);
         } else if (typeof args.files === 'object') {
           for (const field in args.files) {
-            uploadFiles.push([ field, args.files[field] ]);
+            // set custom fileName
+            uploadFiles.push([ field, args.files[field], field ]);
           }
         }
         // set normal fields first
@@ -461,7 +462,7 @@ export class HttpClient extends EventEmitter {
             formData.append(field, args.data[field]);
           }
         }
-        for (const [ index, [ field, file ]] of uploadFiles.entries()) {
+        for (const [ index, [ field, file, customFileName ]] of uploadFiles.entries()) {
           if (typeof file === 'string') {
             // FIXME: support non-ascii filename
             // const fileName = encodeURIComponent(basename(file));
@@ -470,9 +471,9 @@ export class HttpClient extends EventEmitter {
             const fileReadable = createReadStream(file);
             formData.append(field, new BlobFromStream(fileReadable, mime.lookup(fileName) || ''), fileName);
           } else if (Buffer.isBuffer(file)) {
-            formData.append(field, new Blob([ file ]), `bufferfile${index}`);
+            formData.append(field, new Blob([ file ]), customFileName || `bufferfile${index}`);
           } else if (file instanceof Readable || isReadable(file as any)) {
-            const fileName = getFileName(file) || `streamfile${index}`;
+            const fileName = getFileName(file) || customFileName || `streamfile${index}`;
             formData.append(field, new BlobFromStream(file, mime.lookup(fileName) || ''), fileName);
             isStreamingRequest = true;
           }

test/options.files.test.ts

@@ -120,7 +120,7 @@ describe('options.files.test.ts', () => {
     // console.log(response.data);
     assert.equal(response.data.method, 'POST');
     assert.match(response.data.headers['content-type'], /^multipart\/form-data;/);
-    assert.equal(response.data.files.hello.filename, 'bufferfile0');
+    assert.equal(response.data.files.hello.filename, 'hello');
     assert.equal(response.data.files.hello.mimeType, 'application/octet-stream');
     assert.equal(response.data.files.hello.encoding, '7bit');
     assert.equal(response.data.files.hello.size, 11);
@@ -268,4 +268,34 @@ describe('options.files.test.ts', () => {
     assert.equal(response.data.form.hello, 'hello world，😄😓');
     assert.equal(response.data.form.foo, 'bar');
   });
+
+  it('should support custom fileName when use files:object', async () => {
+    const rawData = JSON.stringify({ a: 1 });
+    const response = await urllib.request(`${_url}multipart`, {
+      files: {
+        'buffer.js': Buffer.from(rawData),
+        'readable.js': Readable.from([ rawData ]),
+      },
+      data: {
+        hello: 'hello world，😄😓',
+        foo: 'bar',
+      },
+      dataType: 'json',
+    });
+    assert.equal(response.status, 200);
+    // console.log(response.data);
+    assert.equal(response.data.method, 'POST');
+    assert.match(response.data.headers['content-type'], /^multipart\/form-data;/);
+
+    assert.equal(response.data.files['readable.js'].filename, 'readable.js');
+    // set mimeType by filename
+    assert.equal(response.data.files['readable.js'].mimeType, 'application/javascript');
+
+    assert.equal(response.data.files['buffer.js'].filename, 'buffer.js');
+    assert.equal(response.data.files['buffer.js'].mimeType, 'application/octet-stream');
+    assert.equal(response.data.files['buffer.js'].size, rawData.length);
+
+    assert.equal(response.data.form.hello, 'hello world，😄😓');
+    assert.equal(response.data.form.foo, 'bar');
+  });
 });