multercf/README.md

NestJS module to parse incoming HTML form data in Firebase CloudFunctions projects

# MulterCF for NestJS

A NestJS module to handle `multipart/form-data` (file uploads) in environments like Firebase Cloud Functions where the raw request body is needed for other webhooks or handlers.

This module uses `multer` internally but is designed to work around the issue where `express.json()` or other body parsers can conflict with `multer`. It provides a custom interceptor that processes the form data directly from the request stream.

## Features

-   Seamless integration with NestJS.
-   Handles file uploads in serverless environments (Firebase Cloud Functions, etc.).
-   Avoids conflicts with global body parsers.
-   Provides a `FileInterceptorCF` similar to the standard `FileInterceptor`.

## Installation

```bash
npm install multercf
```

## Usage

Follow these steps to integrate `MulterCF` into your NestJS application.

### 1. Import `MultercfModule`

First, import the `MultercfModule` into your feature module or root `AppModule`.

```typescript
// src/app.module.ts
import { Module } from '@nestjs/common';
import { MultercfModule } from 'multercf';
import { AppController } from './app.controller';

@Module({
  imports: [
    MultercfModule, // Import the module
  ],
  controllers: [AppController],
})
export class AppModule {}
```

### 2. Use the `FileInterceptorCF`

Use the `FileInterceptorCF` in your controller to handle a file upload. It works similarly to NestJS's built-in `FileInterceptor`.

The first argument to the interceptor is the `fieldName` that corresponds to the file input in your HTML form.

```typescript
// src/app.controller.ts
import { Controller, Post, UploadedFile, UseInterceptors } from '@nestjs/common';
import { FileInterceptorCF } from 'multercf';
import { Express } from 'express';

@Controller('files')
export class AppController {
  @Post('upload')
  @UseInterceptors(FileInterceptorCF('file')) // 'file' is the field name for the uploaded file
  uploadFile(@UploadedFile() file: Express.Multer.File) {
    console.log(file);

    // Your logic here to handle the file
    // e.g., save to Google Cloud Storage, etc.

    return {
      message: 'File uploaded successfully!',
      fileName: file.originalname,
      size: file.size,
    };
  }
}
```

### 3. Client-Side Example

Here is a basic HTML form to test the endpoint:

```html
<form action="http://localhost:3000/files/upload" method="post" enctype="multipart/form-data">
  <input type="file" name="file" />
  <button type="submit">Upload</button>
</form>
```

## License

This project is licensed under the ISC License.