Contact Form with NGINX, Lua, Python and SMTP

contact.lua

ngx.req.read_body()
local fp = assert(io.popen('/usr/local/bin/contact.py >> /var/log/nginx/contact-form.log 2>&1', 'w'))
fp:write(ngx.var.remote_addr)
fp:write('\r\n')
fp:write(ngx.req.get_body_data())
assert(fp:close())

contact.py

#!/usr/bin/env python3
import json
import smtplib
from email.mime.text import MIMEText
from sys import stdin, stdout
from urllib.parse import parse_qsl, urlencode
from urllib.request import Request, urlopen

ip, qs = stdin.read().split('\r\n', 1)
data = dict(parse_qsl(qs))
data['ip'] = ip
json.dump(data, stdout)
stdout.write('\n')

assert {'name', 'company', 'email', 'phone', 'message', 'g-recaptcha-response'} <= set(data)

with urlopen(Request(
        url='https://www.google.com/recaptcha/api/siteverify',
        data=urlencode({
            'secret': '0123456789ABCDEFGHIJK_LMNOPQRSTUVW_XYZab',
            'response': data.get('g-recaptcha-response')
        }).encode('utf-8'),
        headers={'content-type': 'application/x-www-form-urlencoded'}
)) as response:
    assert json.loads(response.read().decode('utf-8')).get('success')

template = "Name: {name}\r\nCompany: {company}\r\nEmail: {email}\r\nPhone: {phone}\r\nIP: {ip}\r\n\r\n{message}"

message = MIMEText(template.format(**data).encode('utf-8'), 'plain', 'utf-8')
message['Subject'] = 'Example Contact Form'
message['From'] = 'Example Contact Form <contact-form@example.com>'
message['To'] = 'sales@example.com'

with smtplib.SMTP('192.168.16.4') as smtp:
    smtp.send_message(message)

nginx.conf

location = /contact {
    default_type 'text/plain';
    content_by_lua_file /usr/local/bin/contact.lua;
}