Parse'ing Sendgrid inbound messages via webhook in python and fastapi

README.md

Sendgrid inbound parse'ing in python and fastapi

This took me far too long to figure out how to parse emails coming in from sendgrid's "inbound parse" tool to receive an email via webhook, so I saved it for others to view if they stumble upon it.

The key to this is to check off the setting "POST the raw, full MIME message" in the inbound parse webhook address options.

api.py

import logging
from fastapi import Form, FastAPI
from email import message_from_string

app = FastAPI()
LOG = logging.getLogger()

@app.post("/sendgrid-inbound-parse")
async def parse_sendgrid_email(email: str = Form()):
    message = message_from_string(email)
    subject = message.get('subject')
    from_ = message.get('from')

    body = ""
    if message.is_multipart():
        for part in message.walk():
            ctype = part.get_content_type()
            cdispo = str(part.get('Content-Disposition'))

            # skip any text/plain (txt) attachments
            if ctype == 'text/plain' and 'attachment' not in cdispo:
                body = part.get_payload(decode=True).decode()
                break
    # not multipart - i.e. plain text, no attachments, keeping fingers crossed
    else:
        body = message.get_payload(decode=True).decode()

    LOG.info(f'{subject=} {from_=} {body=}')