Form

jin-frame supports form data submission, which can be handled in two main ways:

• application/x-www-form-urlencoded
• multipart/form-data

These formats make it easy to handle file uploads or form field submissions.

application/x-www-form-urlencoded

The application/x-www-form-urlencoded format serializes form fields into URL-encoded key-value pairs using the native URLSearchParams API. Set the contentType option to application/x-www-form-urlencoded and annotate each field with @Body().

@Post({
  host: 'http://some.api.google.com/jinframe/:passing',
  contentType: 'application/x-www-form-urlencoded',
})
class TestUrlencodedPostFrame extends JinFrame {
  @Param()
  declare public readonly passing: string;

  @Body()
  declare public readonly username: string;

  @Body()
  declare public readonly password: string;
}

jin-frame encodes all @Body() fields into application/x-www-form-urlencoded format automatically — no extra configuration needed.

multipart/form-data

The multipart/form-data format is mainly used for file uploads or complex data submissions. jin-frame uses the native FormData API to build the request body. Use JinFile to wrap file data and annotate fields with @Body().

Supported HTTP methods: POST, PUT, PATCH.

@Post({
  host: 'http://some.api.google.com/fileupload-case04',
  contentType: 'multipart/form-data',
})
class UploadFrame extends JinFrame {
  @Body()
  declare public readonly description: string;

  @Body()
  declare public readonly myFile: JinFile<Buffer>;

  @Body()
  declare public readonly myFiles: JinFile<Buffer>[];
}

• When contentType is set to multipart/form-data, jin-frame uses the native FormData API to build the request body automatically.
• The Content-Type header (including the multipart boundary) is set by the runtime — do not set it manually.

This makes it simple to upload a variety of data types, including images, documents, and binary files.

Summary

• Use application/x-www-form-urlencoded for simple key-value data submissions.
• Use multipart/form-data when uploading files or sending complex structured data.