Files
django-anymail/anymail/backends/mailgun.py
Mike Edmunds fd558e904e Mailgun: disable non-ASCII attachment filename workaround when not needed
urllib3 v1.25 fixes non-ASCII filenames in multipart form data to be
RFC 5758 compliant by default, so our earlier workaround is no longer
needed. Disable the workaround if we detect that Requests is using a
fixed version of urllib3.

Closes #157
2019-09-03 18:04:27 -07:00

376 lines
18 KiB
Python

from datetime import datetime
from email.utils import encode_rfc2231
from six.moves.urllib.parse import quote
from requests import Request
from ..exceptions import AnymailRequestsAPIError, AnymailError
from ..message import AnymailRecipientStatus
from ..utils import get_anymail_setting, rfc2822date
from .base_requests import AnymailRequestsBackend, RequestsPayload
# Feature-detect whether requests (urllib3) correctly uses RFC 7578 encoding for non-
# ASCII filenames in Content-Disposition headers. (This was fixed in urllib3 v1.25.)
# See MailgunPayload.get_request_params for info (and a workaround on older versions).
# (Note: when this workaround is removed, please also remove the "old_urllib3" tox envs.)
def is_requests_rfc_5758_compliant():
request = Request(method='POST', url='https://www.example.com',
files=[('attachment', (u'\N{NOT SIGN}.txt', 'test', 'text/plain'))])
prepared = request.prepare()
form_data = prepared.body # bytes
return b'filename*=' not in form_data
REQUESTS_IS_RFC_7578_COMPLIANT = is_requests_rfc_5758_compliant()
class EmailBackend(AnymailRequestsBackend):
"""
Mailgun API Email Backend
"""
esp_name = "Mailgun"
def __init__(self, **kwargs):
"""Init options from Django settings"""
esp_name = self.esp_name
self.api_key = get_anymail_setting('api_key', esp_name=esp_name, kwargs=kwargs, allow_bare=True)
self.sender_domain = get_anymail_setting('sender_domain', esp_name=esp_name, kwargs=kwargs,
allow_bare=True, default=None)
api_url = get_anymail_setting('api_url', esp_name=esp_name, kwargs=kwargs,
default="https://api.mailgun.net/v3")
if not api_url.endswith("/"):
api_url += "/"
super(EmailBackend, self).__init__(api_url, **kwargs)
def build_message_payload(self, message, defaults):
return MailgunPayload(message, defaults, self)
def parse_recipient_status(self, response, payload, message):
# The *only* 200 response from Mailgun seems to be:
# {
# "id": "<20160306015544.116301.25145@example.org>",
# "message": "Queued. Thank you."
# }
#
# That single message id applies to all recipients.
# The only way to detect rejected, etc. is via webhooks.
# (*Any* invalid recipient addresses will generate a 400 API error)
parsed_response = self.deserialize_json_response(response, payload, message)
try:
message_id = parsed_response["id"]
mailgun_message = parsed_response["message"]
except (KeyError, TypeError):
raise AnymailRequestsAPIError("Invalid Mailgun API response format",
email_message=message, payload=payload, response=response,
backend=self)
if not mailgun_message.startswith("Queued"):
raise AnymailRequestsAPIError("Unrecognized Mailgun API message '%s'" % mailgun_message,
email_message=message, payload=payload, response=response,
backend=self)
# Simulate a per-recipient status of "queued":
status = AnymailRecipientStatus(message_id=message_id, status="queued")
return {recipient.addr_spec: status for recipient in payload.all_recipients}
class MailgunPayload(RequestsPayload):
def __init__(self, message, defaults, backend, *args, **kwargs):
auth = ("api", backend.api_key)
self.sender_domain = backend.sender_domain
self.all_recipients = [] # used for backend.parse_recipient_status
# late-binding of recipient-variables:
self.merge_data = {}
self.merge_global_data = {}
self.metadata = {}
self.merge_metadata = {}
self.to_emails = []
super(MailgunPayload, self).__init__(message, defaults, backend, auth=auth, *args, **kwargs)
def get_api_endpoint(self):
if self.sender_domain is None:
raise AnymailError("Cannot call Mailgun unknown sender domain. "
"Either provide valid `from_email`, "
"or set `message.esp_extra={'sender_domain': 'example.com'}`",
backend=self.backend, email_message=self.message, payload=self)
if '/' in self.sender_domain or '%2f' in self.sender_domain.lower():
# Mailgun returns a cryptic 200-OK "Mailgun Magnificent API" response
# if '/' (or even %-encoded '/') confuses it about the API endpoint.
raise AnymailError("Invalid '/' in sender domain '%s'" % self.sender_domain,
backend=self.backend, email_message=self.message, payload=self)
return "%s/messages" % quote(self.sender_domain, safe='')
def get_request_params(self, api_url):
params = super(MailgunPayload, self).get_request_params(api_url)
non_ascii_filenames = [filename
for (field, (filename, content, mimetype)) in params["files"]
if filename is not None and not isascii(filename)]
if non_ascii_filenames and not REQUESTS_IS_RFC_7578_COMPLIANT:
# Workaround https://github.com/requests/requests/issues/4652:
# Mailgun expects RFC 7578 compliant multipart/form-data, and is confused
# by Requests/urllib3's improper use of RFC 2231 encoded filename parameters
# ("filename*=utf-8''...") in Content-Disposition headers.
# The workaround is to pre-generate the (non-compliant) form-data body, and
# replace 'filename*={RFC 2231 encoded}' with 'filename="{UTF-8 bytes}"'.
# Replace _only_ the filenames that will be problems (not all "filename*=...")
# to minimize potential side effects--e.g., in attached messages that might
# have their own attachments with (correctly) RFC 2231 encoded filenames.
prepared = Request(**params).prepare()
form_data = prepared.body # bytes
for filename in non_ascii_filenames: # text
rfc2231_filename = encode_rfc2231( # wants a str (text in PY3, bytes in PY2)
filename if isinstance(filename, str) else filename.encode("utf-8"),
charset="utf-8")
form_data = form_data.replace(
b'filename*=' + rfc2231_filename.encode("utf-8"),
b'filename="' + filename.encode("utf-8") + b'"')
params["data"] = form_data
params["headers"]["Content-Type"] = prepared.headers["Content-Type"] # multipart/form-data; boundary=...
params["files"] = None # these are now in the form_data body
return params
def serialize_data(self):
self.populate_recipient_variables()
return self.data
# A not-so-brief digression about Mailgun's batch sending, template personalization,
# and metadata tracking capabilities...
#
# Mailgun has two kinds of templates:
# * ESP-stored templates (handlebars syntax), referenced by template name in the
# send API, with substitution data supplied as "custom data" variables.
# Anymail's `template_id` maps to this feature.
# * On-the-fly templating (`%recipient.KEY%` syntax), with template variables
# appearing directly in the message headers and/or body, and data supplied
# as "recipient variables" per-recipient personalizations. Mailgun docs also
# sometimes refer to this data as "template variables," but it's distinct from
# the substitution data used for stored handelbars templates.
#
# Mailgun has two mechanisms for supplying additional data with a message:
# * "Custom data" is supplied via `v:KEY` and/or `h:X-Mailgun-Variables` fields.
# Custom data is passed to tracking webhooks (as 'user-variables') and is
# available for `{{substitutions}}` in ESP-stored handlebars templates.
# Normally, the same custom data is applied to every recipient of a message.
# * "Recipient variables" are supplied via the `recipient-variables` field, and
# provide per-recipient data for batch sending. The recipient specific values
# are available as `%recipient.KEY%` virtually anywhere in the message
# (including header fields and other parameters).
#
# Anymail needs both mechanisms to map its normalized metadata and template merge_data
# features to Mailgun:
# (1) Anymail's `metadata` maps directly to Mailgun's custom data, where it can be
# accessed from webhooks.
# (2) Anymail's `merge_metadata` (per-recipient metadata for batch sends) maps
# *indirectly* through recipient-variables to Mailgun's custom data. To avoid
# conflicts, the recipient-variables mapping prepends 'v:' to merge_metadata keys.
# (E.g., Mailgun's custom-data "user" is set to "%recipient.v:user", which picks
# up its per-recipient value from Mailgun's `recipient-variables[to_email]["v:user"]`.)
# (3) Anymail's `merge_data` (per-recipient template substitutions) maps directly to
# Mailgun's `recipient-variables`, where it can be referenced in on-the-fly templates.
# (4) Anymail's `merge_global_data` (global template substitutions) is copied to
# Mailgun's `recipient-variables` for every recipient, as the default for missing
# `merge_data` keys.
# (5) Only if a stored template is used, `merge_data` and `merge_global_data` are
# *also* mapped *indirectly* through recipient-variables to Mailgun's custom data,
# where they can be referenced in handlebars {{substitutions}}.
# (E.g., Mailgun's custom-data "name" is set to "%recipient.name%", which picks
# up its per-recipient value from Mailgun's `recipient-variables[to_email]["name"]`.)
#
# If Anymail's `merge_data`, `template_id` (stored templates) and `metadata` (or
# `merge_metadata`) are used together, there's a possibility of conflicting keys in
# Mailgun's custom data. Anymail treats that conflict as an unsupported feature error.
def populate_recipient_variables(self):
"""Populate Mailgun recipient-variables and custom data from merge data and metadata"""
# (numbers refer to detailed explanation above)
# Mailgun parameters to construct:
recipient_variables = {}
custom_data = {}
# (1) metadata --> Mailgun custom_data
custom_data.update(self.metadata)
# (2) merge_metadata --> Mailgun custom_data via recipient_variables
if self.merge_metadata:
def vkey(key): # 'v:key'
return 'v:{}'.format(key)
merge_metadata_keys = flatset( # all keys used in any recipient's merge_metadata
recipient_data.keys() for recipient_data in self.merge_metadata.values())
custom_data.update({ # custom_data['key'] = '%recipient.v:key%' indirection
key: '%recipient.{}%'.format(vkey(key))
for key in merge_metadata_keys})
base_recipient_data = { # defaults for each recipient must cover all keys
vkey(key): self.metadata.get(key, '')
for key in merge_metadata_keys}
for email in self.to_emails:
this_recipient_data = base_recipient_data.copy()
this_recipient_data.update({
vkey(key): value
for key, value in self.merge_metadata.get(email, {}).items()})
recipient_variables.setdefault(email, {}).update(this_recipient_data)
# (3) and (4) merge_data, merge_global_data --> Mailgun recipient_variables
if self.merge_data or self.merge_global_data:
merge_data_keys = flatset( # all keys used in any recipient's merge_data
recipient_data.keys() for recipient_data in self.merge_data.values())
merge_data_keys = merge_data_keys.union(self.merge_global_data.keys())
base_recipient_data = { # defaults for each recipient must cover all keys
key: self.merge_global_data.get(key, '')
for key in merge_data_keys}
for email in self.to_emails:
this_recipient_data = base_recipient_data.copy()
this_recipient_data.update(self.merge_data.get(email, {}))
recipient_variables.setdefault(email, {}).update(this_recipient_data)
# (5) if template, also map Mailgun custom_data to per-recipient_variables
if self.data.get('template') is not None:
conflicts = merge_data_keys.intersection(custom_data.keys())
if conflicts:
self.unsupported_feature(
"conflicting merge_data and metadata keys (%s) when using template_id"
% ', '.join("'%s'" % key for key in conflicts))
custom_data.update({ # custom_data['key'] = '%recipient.key%' indirection
key: '%recipient.{}%'.format(key)
for key in merge_data_keys})
# populate Mailgun params
self.data.update({'v:%s' % key: value
for key, value in custom_data.items()})
if recipient_variables or self.is_batch():
self.data['recipient-variables'] = self.serialize_json(recipient_variables)
#
# Payload construction
#
def init_payload(self):
self.data = {} # {field: [multiple, values]}
self.files = [] # [(field, multiple), (field, values)]
self.headers = {}
def set_from_email_list(self, emails):
# Mailgun supports multiple From email addresses
self.data["from"] = [email.address for email in emails]
if self.sender_domain is None and len(emails) > 0:
# try to intuit sender_domain from first from_email
self.sender_domain = emails[0].domain or None
def set_recipients(self, recipient_type, emails):
assert recipient_type in ["to", "cc", "bcc"]
if emails:
self.data[recipient_type] = [email.address for email in emails]
self.all_recipients += emails # used for backend.parse_recipient_status
if recipient_type == 'to':
self.to_emails = [email.addr_spec for email in emails] # used for populate_recipient_variables
def set_subject(self, subject):
self.data["subject"] = subject
def set_reply_to(self, emails):
if emails:
reply_to = ", ".join([str(email) for email in emails])
self.data["h:Reply-To"] = reply_to
def set_extra_headers(self, headers):
for key, value in headers.items():
self.data["h:%s" % key] = value
def set_text_body(self, body):
self.data["text"] = body
def set_html_body(self, body):
if "html" in self.data:
# second html body could show up through multiple alternatives, or html body + alternative
self.unsupported_feature("multiple html parts")
self.data["html"] = body
def add_attachment(self, attachment):
# http://docs.python-requests.org/en/v2.4.3/user/advanced/#post-multiple-multipart-encoded-files
if attachment.inline:
field = "inline"
name = attachment.cid
if not name:
self.unsupported_feature("inline attachments without Content-ID")
else:
field = "attachment"
name = attachment.name
if not name:
self.unsupported_feature("attachments without filenames")
self.files.append(
(field, (name, attachment.content, attachment.mimetype))
)
def set_envelope_sender(self, email):
# Only the domain is used
self.sender_domain = email.domain
def set_metadata(self, metadata):
self.metadata = metadata # save for handling merge_metadata later
for key, value in metadata.items():
self.data["v:%s" % key] = value
def set_send_at(self, send_at):
# Mailgun expects RFC-2822 format dates
# (BasePayload has converted most date-like values to datetime by now;
# if the caller passes a string, they'll need to format it themselves.)
if isinstance(send_at, datetime):
send_at = rfc2822date(send_at)
self.data["o:deliverytime"] = send_at
def set_tags(self, tags):
self.data["o:tag"] = tags
def set_track_clicks(self, track_clicks):
# Mailgun also supports an "htmlonly" option, which Anymail doesn't offer
self.data["o:tracking-clicks"] = "yes" if track_clicks else "no"
def set_track_opens(self, track_opens):
self.data["o:tracking-opens"] = "yes" if track_opens else "no"
def set_template_id(self, template_id):
self.data["template"] = template_id
def set_merge_data(self, merge_data):
# Processed at serialization time (to allow merging global data)
self.merge_data = merge_data
def set_merge_global_data(self, merge_global_data):
# Processed at serialization time (to allow merging global data)
self.merge_global_data = merge_global_data
def set_merge_metadata(self, merge_metadata):
# Processed at serialization time (to allow combining with merge_data)
self.merge_metadata = merge_metadata
def set_esp_extra(self, extra):
self.data.update(extra)
# Allow override of sender_domain via esp_extra
# (but pop it out of params to send to Mailgun)
self.sender_domain = self.data.pop("sender_domain", self.sender_domain)
def isascii(s):
"""Returns True if str s is entirely ASCII characters.
(Compare to Python 3.7 `str.isascii()`.)
"""
try:
s.encode("ascii")
except UnicodeEncodeError:
return False
return True
def flatset(iterables):
"""Return a set of the items in a single-level flattening of iterables
>>> flatset([1, 2], [2, 3])
set(1, 2, 3)
"""
return set(item for iterable in iterables for item in iterable)