How to Use React to Send Emails with Attachments

Backend Script to Use Resend to Send Email with Attachment

Next's backend script.JavaScript using Resend

import type { NextApiRequest, NextApiResponse } from 'next';
import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);

const send = async (req: NextApiRequest, res: NextApiResponse) => {
  const { method } = req;
  const { content, filename } = req.body;

  switch (method) {
    case 'POST': {
      try {
        const { data } = await resend.emails.send({
          from: 'onboarding@resend.dev',
          to: ['XXXXXXXXXX@gmail.com'],
          subject: 'Email with attachment',
          html: '<p>See attachment</p>',
          attachments: [{
            content,
            filename,
          }],
        });
        return res.status(200).send({ data: data?.id });
      } catch (error) {
        return res.status(500).json({ error: 'Internal Server Error' });
      }
    }
    default: {
      res.setHeader('Allow', ['POST']);
      res.status(405).end(`Method ${method} Not Allowed`);
    }
  }
};

export default send;

Contact Form Frontend Component with File Attachment

Frontend component in React.js

import * as React from 'react';

const ContactForm: React.FC = () => {
  const [content, setContent] = React.useState<string | null>(null);
  const [filename, setFilename] = React.useState('');

  const onSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    if (content === null) {
      alert('Please select a file to upload');
      return;
    }
    const base64Content = content.split(',')[1];
    try {
      await fetch('/api/send', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ content: base64Content, filename }),
      });
      alert('Request sent');
    } catch (e) {
      alert('Something went wrong');
    }
  };

  const onAddFileAction = (e: React.ChangeEvent<HTMLInputElement>) => {
    const reader = new FileReader();
    const files = e.target.files;
    if (files && files.length > 0) {
      reader.onload = (r) => {
        if (r.target?.result) {
          setContent(r.target.result.toString());
          setFilename(files[0].name);
        }
      };
      reader.readAsDataURL(files[0]);
    }
  };

  return (
    <form onSubmit={onSubmit} style={{ display: 'flex', flexDirection: 'column', gap: '20px', width: 200 }}> 
      <input type="file" name="file" onChange={onAddFileAction} accept="image/*" /> 
      <input type="submit" value="Send Email" /> 
    </form> 
  );
};

export default ContactForm;

Frequently Asked Questions and Responses regarding Emailing with Attachments in React

1. Why is FileReader being used in file uploads?
2. Asynchronous file contents can be read and encoded as a base64 string for transmission via HTTP requests using the FileReader API.
3. How can I make sure the files I upload are safe?
4. Make sure that the input field's accept property is being used to accept just particular file formats. Furthermore, verify the content of files via server-side validation.
5. What role does the onload incident play in FileReader?
6. When the file reading process is finished, the onload event is triggered, enabling you to view the contents of the file and take additional actions.
7. How can I use React to manage big files?
8. To get above browser memory restrictions and give the user progress reports, think about using chunked file uploads for huge files.
9. Why is JSON.stringify required for file data transmission?
10. JSON.stringify transforms the file data-containing JavaScript object into a JSON string, which is the format used for the request body in API requests.
11. When sending emails, what does a 500 (Internal Server Error) mean?
12. A 500 error usually points to a server-side problem, like a misconfigured API endpoint or problems with the email sending service.
13. How can a 500 error in my API calls be troubleshooted?
14. In addition to making that the API endpoint and request payload are configured appropriately, check the server logs for detailed error messages.
15. What function does the backend script's res.setHeader method serve?
16. The HTTP response header is set using the res.setHeader method, which indicates the permitted HTTP methods (such as 'POST').
17. How can I solicit user input while a file is being uploaded?
18. To let users know about the upload status and any errors that have occurred, utilize alert messages, progress bars, or status indicators.
19. Can I use this arrangement to upload numerous files at once?
20. Uploads of a single file are handled by this configuration. You must edit the code to handle arrays of file data for many files and send them in the API call.

Concluding React Contact Form Thoughts

React contact form file attachment implementation with Resend requires both front-end and back-end setups. The back-end uses Resend's API to send the email with the attachment, while the front-end selects, reads, and encodes the file to base64. For a seamless user experience, effective error management and user feedback methods are essential. Avoiding frequent hazards like server issues can be achieved by adhering to best practices and making sure all configurations are proper.