browsertrix/backend/btrixcloud/emailsender.py

""" Basic Email Sending Support"""

from datetime import datetime
import os
import smtplib
import ssl
from uuid import UUID
from typing import Optional, Union

from email.message import EmailMessage
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from fastapi import HTTPException
from fastapi.templating import Jinja2Templates

from .models import CreateReplicaJob, DeleteReplicaJob, Organization, InvitePending
from .utils import is_bool


# pylint: disable=too-few-public-methods, too-many-instance-attributes
class EmailSender:
    """SMTP Email Sender"""

    sender: str
    password: str
    reply_to: str
    smtp_server: Optional[str]
    smtp_port: int
    smtp_use_tls: bool
    support_email: str
    templates: Jinja2Templates

    def __init__(self):
        self.sender = os.environ.get("EMAIL_SENDER") or "Browsertrix admin"
        self.password = os.environ.get("EMAIL_PASSWORD") or ""
        self.reply_to = os.environ.get("EMAIL_REPLY_TO") or self.sender
        self.support_email = os.environ.get("EMAIL_SUPPORT") or self.reply_to
        self.smtp_server = os.environ.get("EMAIL_SMTP_HOST")
        self.smtp_port = int(os.environ.get("EMAIL_SMTP_PORT", 587))
        self.smtp_use_tls = is_bool(os.environ.get("EMAIL_SMTP_USE_TLS"))

        self.default_origin = os.environ.get("APP_ORIGIN")

        self.templates = Jinja2Templates(
            directory=os.path.join(os.path.dirname(__file__), "email-templates")
        )

    def _send_encrypted(self, receiver: str, name: str, **kwargs) -> None:
        """Send Encrypted SMTP Message using given template name"""

        full = self.templates.env.get_template(name).render(kwargs)
        parts = full.split("~~~")
        if len(parts) == 3:
            subject, html, text = parts
        elif len(parts) == 2:
            subject, text = parts
            html = None
        else:
            raise HTTPException(status_code=500, detail="invalid_email_template")

        print(full, flush=True)

        if not self.smtp_server:
            print("Email: No SMTP Server, not sending", flush=True)
            return

        msg: Union[EmailMessage, MIMEMultipart]

        if html:
            msg = MIMEMultipart("alternative")
            msg.attach(MIMEText(text.strip(), "plain"))
            msg.attach(MIMEText(html.strip(), "html"))
        else:
            msg = EmailMessage()
            msg.set_content(text.strip())

        msg["Subject"] = subject.strip()
        msg["From"] = self.reply_to
        msg["To"] = receiver
        msg["Reply-To"] = msg["From"]

        context = ssl.create_default_context()
        with smtplib.SMTP(self.smtp_server, self.smtp_port) as server:
            if self.smtp_use_tls:
                server.ehlo()
                server.starttls(context=context)
            server.ehlo()
            if self.password:
                server.login(self.sender, self.password)
            server.send_message(msg)
            # server.sendmail(self.sender, receiver, message)

    def get_origin(self, headers):
        """Return origin of the received request"""
        if not headers:
            return self.default_origin

        scheme = headers.get("X-Forwarded-Proto")
        host = headers.get("Host")
        if not scheme or not host:
            return self.default_origin

        return scheme + "://" + host

    def send_user_validation(
        self, receiver_email: str, token: str, headers: Optional[dict] = None
    ):
        """Send email to validate registration email address"""

        origin = self.get_origin(headers)

        self._send_encrypted(receiver_email, "validate", origin=origin, token=token)

    # pylint: disable=too-many-arguments
    def send_user_invite(
        self,
        invite: InvitePending,
        token: UUID,
        org_name: str,
        is_new: bool,
        headers: Optional[dict] = None,
    ):
        """Send email to invite new user"""

        origin = self.get_origin(headers)

        receiver_email = invite.email or ""

        invite_url = (
            f"{origin}/join/{token}?email={receiver_email}"
            if is_new
            else f"{origin}/invite/accept/{token}?email={receiver_email}"
        )

        self._send_encrypted(
            receiver_email,
            "invite",
            invite_url=invite_url,
            is_new=is_new,
            sender=invite.inviterEmail if not invite.fromSuperuser else "",
            org_name=org_name,
            support_email=self.support_email,
        )

    def send_user_forgot_password(self, receiver_email, token, headers=None):
        """Send password reset email with token"""
        origin = self.get_origin(headers)

        self._send_encrypted(
            receiver_email,
            "password_reset",
            origin=origin,
            token=token,
            support_email=self.support_email,
        )

    def send_background_job_failed(
        self,
        job: Union[CreateReplicaJob, DeleteReplicaJob],
        org: Organization,
        finished: datetime,
        receiver_email: str,
    ):
        """Send background job failed email to superuser"""
        self._send_encrypted(
            receiver_email, "failed_bg_job", job=job, org=org, finished=finished
        )