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# random
w

wide-midnight-78598

04/15/2023, 9:40 PM
Has anyone come across a local dev/e2e-centric SMTP server? I’m trying to create a full sign in/registration e2e workflow - and the missing piece is getting the forgot password link. I can create a custom mailbox, or outgoing mail thing on my server - but that’s already missing the point.
Something like Papercut, but for Mac and/or Linux. It’s not hard to write something like this, but 🤷 I’m also a bit lazy
n

narrow-vegetable-37489

04/15/2023, 10:00 PM
👍 1
w

wide-midnight-78598

04/15/2023, 10:13 PM
I looked at mail hog briefly, but I thought that’s more of an outgoing mail server? Not incoming?
I’ve also briefly considered using the gnu mail/mailx utilities built-in, but I just don’t know enough about them yet
Errr… Unix?
Python also has a deprecated smtpd which could be something
n

narrow-vegetable-37489

04/15/2023, 10:39 PM
MailHog is a local SMTP server that instead of sending your application's emails to the actual recipient, it stores them in memory and makes them available in a Web UI inbox. So I guess it could be either outgoing or incoming depending on how you look at it? :)
w

wide-midnight-78598

04/15/2023, 11:09 PM
Oh, yeah, then that could definitely be good. Thanks! I’ll look closer
b

broad-processor-92400

04/15/2023, 11:12 PM
We use mailhog for the email (and pseudo-SMS) parts of our e2e tests, and it works fine. The web UI is simple enough to easily clicking links etc in playwright
w

wide-midnight-78598

04/15/2023, 11:21 PM
Ah, great! I assume it has an API for that. I didn’t realize that python’s smtpd was so trivial to get started with.
python3 -m smtpd -c DebuggingServer -n localhost:2525
And that runs an SMTP server that prints to stdout. Pretty trivial to either pipe that to a shared file, or launch a FastAPI process that wraps the incoming messages into an API. Thanks for the help guys!
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from contextlib import asynccontextmanager
from threading import Lock
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from fastapi import FastAPI
from aiosmtpd.controller import Controller
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# Arguably the SMTP server should be either an asyncio task, or a separate process - but this is just for low-load e2e testing
# TODO: If the e2e tests run via multi-process, maybe it's worth making this a queue and being a bit smarter about it
lock = Lock()
mailbox: dict = {}
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@asynccontextmanager
async def lifespan(app: FastAPI):
    handler = CustomHandler()
    controller = Controller(handler, hostname="localhost", port=2525)
    controller.start()
    yield
    controller.stop()
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class CustomHandler:
    async def handle_DATA(self, server, session, envelope):
        mail_from = envelope.mail_from
        rcpt_tos = envelope.rcpt_tos
        data = envelope.content  # type: bytes
        print(f"{envelope}, {mail_from}, {rcpt_tos}, {data}")
        with lock:
            mailbox[mail_from] = {
                "from": mail_from,
                "to": rcpt_tos,
                "body": data.decode("utf-8"),
            }
        return "250 OK"
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app = FastAPI(lifespan=lifespan)
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@app.get("/")
async def root():
    with lock:
        return mailbox