Files
django-anymail/anymail/backends/base.py
medmunds b72e0b0274 Internal: Hoist RequestsPayload.serialize_json to BasePayload
(Non-Requests payloads sometimes want to serialize json, too.)
2018-03-24 10:09:46 -07:00

521 lines
22 KiB
Python

import json
from datetime import date, datetime
import six
from django.conf import settings
from django.core.mail.backends.base import BaseEmailBackend
from django.utils.timezone import is_naive, get_current_timezone, make_aware, utc
from requests.structures import CaseInsensitiveDict
from ..exceptions import (
AnymailCancelSend, AnymailError, AnymailUnsupportedFeature, AnymailRecipientsRefused,
AnymailSerializationError)
from ..message import AnymailStatus
from ..signals import pre_send, post_send
from ..utils import (
Attachment, UNSET, combine, last, get_anymail_setting, parse_address_list, parse_single_address,
force_non_lazy, force_non_lazy_list, force_non_lazy_dict, is_lazy)
class AnymailBaseBackend(BaseEmailBackend):
"""
Base Anymail email backend
"""
def __init__(self, *args, **kwargs):
super(AnymailBaseBackend, self).__init__(*args, **kwargs)
self.ignore_unsupported_features = get_anymail_setting('ignore_unsupported_features',
kwargs=kwargs, default=False)
self.ignore_recipient_status = get_anymail_setting('ignore_recipient_status',
kwargs=kwargs, default=False)
# Merge SEND_DEFAULTS and <esp_name>_SEND_DEFAULTS settings
send_defaults = get_anymail_setting('send_defaults', default={}) # but not from kwargs
esp_send_defaults = get_anymail_setting('send_defaults', esp_name=self.esp_name,
kwargs=kwargs, default=None)
if esp_send_defaults is not None:
send_defaults = send_defaults.copy()
send_defaults.update(esp_send_defaults)
self.send_defaults = send_defaults
def open(self):
"""
Open and persist a connection to the ESP's API, and whether
a new connection was created.
Callers must ensure they later call close, if (and only if) open
returns True.
"""
# Subclasses should use an instance property to maintain a cached
# connection, and return True iff they initialize that instance
# property in _this_ open call. (If the cached connection already
# exists, just do nothing and return False.)
#
# Subclasses should swallow operational errors if self.fail_silently
# (e.g., network errors), but otherwise can raise any errors.
#
# (Returning a bool to indicate whether connection was created is
# borrowed from django.core.email.backends.SMTPBackend)
return False
def close(self):
"""
Close the cached connection created by open.
You must only call close if your code called open and it returned True.
"""
# Subclasses should tear down the cached connection and clear
# the instance property.
#
# Subclasses should swallow operational errors if self.fail_silently
# (e.g., network errors), but otherwise can raise any errors.
pass
def send_messages(self, email_messages):
"""
Sends one or more EmailMessage objects and returns the number of email
messages sent.
"""
# This API is specified by Django's core BaseEmailBackend
# (so you can't change it to, e.g., return detailed status).
# Subclasses shouldn't need to override.
num_sent = 0
if not email_messages:
return num_sent
created_session = self.open()
try:
for message in email_messages:
try:
sent = self._send(message)
except AnymailError:
if self.fail_silently:
sent = False
else:
raise
if sent:
num_sent += 1
finally:
if created_session:
self.close()
return num_sent
def _send(self, message):
"""Sends the EmailMessage message, and returns True if the message was sent.
This should only be called by the base send_messages loop.
Implementations must raise exceptions derived from AnymailError for
anticipated failures that should be suppressed in fail_silently mode.
"""
message.anymail_status = AnymailStatus()
if not self.run_pre_send(message): # (might modify message)
return False # cancel send without error
if not message.recipients():
return False
payload = self.build_message_payload(message, self.send_defaults)
response = self.post_to_esp(payload, message)
message.anymail_status.esp_response = response
recipient_status = self.parse_recipient_status(response, payload, message)
message.anymail_status.set_recipient_status(recipient_status)
self.run_post_send(message) # send signal before raising status errors
self.raise_for_recipient_status(message.anymail_status, response, payload, message)
return True
def run_pre_send(self, message):
"""Send pre_send signal, and return True if message should still be sent"""
try:
pre_send.send(self.__class__, message=message, esp_name=self.esp_name)
return True
except AnymailCancelSend:
return False # abort without causing error
def run_post_send(self, message):
"""Send post_send signal to all receivers"""
results = post_send.send_robust(
self.__class__, message=message, status=message.anymail_status, esp_name=self.esp_name)
for (receiver, response) in results:
if isinstance(response, Exception):
raise response
def build_message_payload(self, message, defaults):
"""Returns a payload that will allow message to be sent via the ESP.
Derived classes must implement, and should subclass :class:BasePayload
to get standard Anymail options.
Raises :exc:AnymailUnsupportedFeature for message options that
cannot be communicated to the ESP.
:param message: :class:EmailMessage
:param defaults: dict
:return: :class:BasePayload
"""
raise NotImplementedError("%s.%s must implement build_message_payload" %
(self.__class__.__module__, self.__class__.__name__))
def post_to_esp(self, payload, message):
"""Post payload to ESP send API endpoint, and return the raw response.
payload is the result of build_message_payload
message is the original EmailMessage
return should be a raw response
Can raise AnymailAPIError (or derived exception) for problems posting to the ESP
"""
raise NotImplementedError("%s.%s must implement post_to_esp" %
(self.__class__.__module__, self.__class__.__name__))
def parse_recipient_status(self, response, payload, message):
"""Return a dict mapping email to AnymailRecipientStatus for each recipient.
Can raise AnymailAPIError (or derived exception) if response is unparsable
"""
raise NotImplementedError("%s.%s must implement parse_recipient_status" %
(self.__class__.__module__, self.__class__.__name__))
def raise_for_recipient_status(self, anymail_status, response, payload, message):
"""If *all* recipients are refused or invalid, raises AnymailRecipientsRefused"""
if not self.ignore_recipient_status:
# Error if *all* recipients are invalid or refused
# (This behavior parallels smtplib.SMTPRecipientsRefused from Django's SMTP EmailBackend)
if anymail_status.status.issubset({"invalid", "rejected"}):
raise AnymailRecipientsRefused(email_message=message, payload=payload, response=response,
backend=self)
@property
def esp_name(self):
"""
Read-only name of the ESP for this backend.
Concrete backends must override with class attr. E.g.:
esp_name = "Postmark"
esp_name = "SendGrid" # (use ESP's preferred capitalization)
"""
raise NotImplementedError("%s.%s must declare esp_name class attr" %
(self.__class__.__module__, self.__class__.__name__))
class BasePayload(object):
# Listing of EmailMessage/EmailMultiAlternatives attributes
# to process into Payload. Each item is in the form:
# (attr, combiner, converter)
# attr: the property name
# combiner: optional function(default_value, value) -> value
# to combine settings defaults with the EmailMessage property value
# (usually `combine` to merge, or `last` for message value to override default;
# use `None` if settings defaults aren't supported)
# converter: optional function(value) -> value transformation
# (can be a callable or the string name of a Payload method, or `None`)
# The converter must force any Django lazy translation strings to text.
# The Payload's `set_<attr>` method will be called with
# the combined/converted results for each attr.
base_message_attrs = (
# Standard EmailMessage/EmailMultiAlternatives props
('from_email', last, parse_address_list), # multiple from_emails are allowed
('to', combine, parse_address_list),
('cc', combine, parse_address_list),
('bcc', combine, parse_address_list),
('subject', last, force_non_lazy),
('reply_to', combine, parse_address_list),
('extra_headers', combine, force_non_lazy_dict),
('body', last, force_non_lazy), # special handling below checks message.content_subtype
('alternatives', combine, 'prepped_alternatives'),
('attachments', combine, 'prepped_attachments'),
)
anymail_message_attrs = (
# Anymail expando-props
('envelope_sender', last, parse_single_address),
('metadata', combine, force_non_lazy_dict),
('send_at', last, 'aware_datetime'),
('tags', combine, force_non_lazy_list),
('track_clicks', last, None),
('track_opens', last, None),
('template_id', last, force_non_lazy),
('merge_data', combine, force_non_lazy_dict),
('merge_global_data', combine, force_non_lazy_dict),
('esp_extra', combine, force_non_lazy_dict),
)
esp_message_attrs = () # subclasses can override
def __init__(self, message, defaults, backend):
self.message = message
self.defaults = defaults
self.backend = backend
self.esp_name = backend.esp_name
self.init_payload()
# we should consider hoisting the first text/html out of alternatives into set_html_body
message_attrs = self.base_message_attrs + self.anymail_message_attrs + self.esp_message_attrs
for attr, combiner, converter in message_attrs:
value = getattr(message, attr, UNSET)
if attr in ('to', 'cc', 'bcc', 'reply_to') and value is not UNSET:
self.validate_not_bare_string(attr, value)
if combiner is not None:
default_value = self.defaults.get(attr, UNSET)
value = combiner(default_value, value)
if value is not UNSET:
if converter is not None:
if not callable(converter):
converter = getattr(self, converter)
value = converter(value)
if value is not UNSET:
if attr == 'body':
setter = self.set_html_body if message.content_subtype == 'html' else self.set_text_body
elif attr == 'from_email':
setter = self.set_from_email_list
elif attr == 'extra_headers':
setter = self.process_extra_headers
else:
# AttributeError here? Your Payload subclass is missing a set_<attr> implementation
setter = getattr(self, 'set_%s' % attr)
setter(value)
def unsupported_feature(self, feature):
if not self.backend.ignore_unsupported_features:
raise AnymailUnsupportedFeature("%s does not support %s" % (self.esp_name, feature),
email_message=self.message, payload=self, backend=self.backend)
def process_extra_headers(self, headers):
# Handle some special-case headers, and pass the remainder to set_extra_headers.
# (Subclasses shouldn't need to override this.)
headers = CaseInsensitiveDict(headers) # email headers are case-insensitive per RFC-822 et seq
reply_to = headers.pop('Reply-To', None)
if reply_to:
# message.extra_headers['Reply-To'] will override message.reply_to
# (because the extra_headers attr is processed after reply_to).
# This matches the behavior of Django's EmailMessage.message().
self.set_reply_to(parse_address_list([reply_to]))
if 'From' in headers:
# If message.extra_headers['From'] is supplied, it should override message.from_email,
# but message.from_email should be used as the envelope_sender. See:
# - https://code.djangoproject.com/ticket/9214
# - https://github.com/django/django/blob/1.8/django/core/mail/message.py#L269
# - https://github.com/django/django/blob/1.8/django/core/mail/backends/smtp.py#L118
header_from = parse_address_list(headers.pop('From'))
envelope_sender = parse_single_address(self.message.from_email) # must be single address
self.set_from_email_list(header_from)
self.set_envelope_sender(envelope_sender)
if 'To' in headers:
# If message.extra_headers['To'] is supplied, message.to is used only as the envelope
# recipients (SMTP.sendmail to_addrs), and the header To is spoofed. See:
# - https://github.com/django/django/blob/1.8/django/core/mail/message.py#L270
# - https://github.com/django/django/blob/1.8/django/core/mail/backends/smtp.py#L119-L120
# No current ESP supports this, so this code is mainly here to flag
# the SMTP backend's behavior as an unsupported feature in Anymail:
header_to = headers.pop('To')
self.set_spoofed_to_header(header_to)
if headers:
self.set_extra_headers(headers)
#
# Attribute validators
#
def validate_not_bare_string(self, attr, value):
"""EmailMessage to, cc, bcc, and reply_to are specced to be lists of strings.
This catches the common error where a single string is used instead.
(See also checks in EmailMessage.__init__.)
"""
# Note: this actually only runs for reply_to. If to, cc, or bcc are
# set to single strings, you'll end up with an earlier cryptic TypeError
# from EmailMesssage.recipients (called from EmailMessage.send) before
# the Anymail backend even gets involved:
# TypeError: must be str, not list
# TypeError: can only concatenate list (not "str") to list
# TypeError: Can't convert 'list' object to str implicitly
if isinstance(value, six.string_types) or is_lazy(value):
raise TypeError('"{attr}" attribute must be a list or other iterable'.format(attr=attr))
#
# Attribute converters
#
def prepped_alternatives(self, alternatives):
return [(force_non_lazy(content), mimetype)
for (content, mimetype) in alternatives]
def prepped_attachments(self, attachments):
str_encoding = self.message.encoding or settings.DEFAULT_CHARSET
return [Attachment(attachment, str_encoding) # (handles lazy content, filename)
for attachment in attachments]
def aware_datetime(self, value):
"""Converts a date or datetime or timestamp to an aware datetime.
Naive datetimes are assumed to be in Django's current_timezone.
Dates are interpreted as midnight that date, in Django's current_timezone.
Integers are interpreted as POSIX timestamps (which are inherently UTC).
Anything else (e.g., str) is returned unchanged, which won't be portable.
"""
if isinstance(value, datetime):
dt = value
else:
if isinstance(value, date):
dt = datetime(value.year, value.month, value.day) # naive, midnight
else:
try:
dt = datetime.utcfromtimestamp(value).replace(tzinfo=utc)
except (TypeError, ValueError):
return value
if is_naive(dt):
dt = make_aware(dt, get_current_timezone())
return dt
#
# Abstract implementation
#
def init_payload(self):
raise NotImplementedError("%s.%s must implement init_payload" %
(self.__class__.__module__, self.__class__.__name__))
def set_from_email_list(self, emails):
# If your backend supports multiple from emails, override this to handle the whole list;
# otherwise just implement set_from_email
if len(emails) > 1:
self.unsupported_feature("multiple from emails")
# fall through if ignoring unsupported features
if len(emails) > 0:
self.set_from_email(emails[0])
def set_from_email(self, email):
raise NotImplementedError("%s.%s must implement set_from_email or set_from_email_list" %
(self.__class__.__module__, self.__class__.__name__))
def set_to(self, emails):
return self.set_recipients('to', emails)
def set_cc(self, emails):
return self.set_recipients('cc', emails)
def set_bcc(self, emails):
return self.set_recipients('bcc', emails)
def set_recipients(self, recipient_type, emails):
for email in emails:
self.add_recipient(recipient_type, email)
def add_recipient(self, recipient_type, email):
raise NotImplementedError("%s.%s must implement add_recipient, set_recipients, or set_{to,cc,bcc}" %
(self.__class__.__module__, self.__class__.__name__))
def set_subject(self, subject):
raise NotImplementedError("%s.%s must implement set_subject" %
(self.__class__.__module__, self.__class__.__name__))
def set_reply_to(self, emails):
self.unsupported_feature('reply_to')
def set_extra_headers(self, headers):
# headers is a CaseInsensitiveDict, and is a copy (so is safe to modify)
self.unsupported_feature('extra_headers')
def set_text_body(self, body):
raise NotImplementedError("%s.%s must implement set_text_body" %
(self.__class__.__module__, self.__class__.__name__))
def set_html_body(self, body):
raise NotImplementedError("%s.%s must implement set_html_body" %
(self.__class__.__module__, self.__class__.__name__))
def set_alternatives(self, alternatives):
for content, mimetype in alternatives:
if mimetype == "text/html":
# This assumes that there's at most one html alternative,
# and so it should be the html body. (Most ESPs don't
# support multiple html alternative parts anyway.)
self.set_html_body(content)
else:
self.add_alternative(content, mimetype)
def add_alternative(self, content, mimetype):
self.unsupported_feature("alternative part with type '%s'" % mimetype)
def set_attachments(self, attachments):
for attachment in attachments:
self.add_attachment(attachment)
def add_attachment(self, attachment):
raise NotImplementedError("%s.%s must implement add_attachment or set_attachments" %
(self.__class__.__module__, self.__class__.__name__))
def set_spoofed_to_header(self, header_to):
# In the unlikely case an ESP supports *completely replacing* the To message header
# without altering the actual envelope recipients, the backend can implement this.
self.unsupported_feature("spoofing `To` header")
# Anymail-specific payload construction
def set_envelope_sender(self, email):
self.unsupported_feature("envelope_sender")
def set_metadata(self, metadata):
self.unsupported_feature("metadata")
def set_send_at(self, send_at):
self.unsupported_feature("send_at")
def set_tags(self, tags):
self.unsupported_feature("tags")
def set_track_clicks(self, track_clicks):
self.unsupported_feature("track_clicks")
def set_track_opens(self, track_opens):
self.unsupported_feature("track_opens")
def set_template_id(self, template_id):
self.unsupported_feature("template_id")
def set_merge_data(self, merge_data):
self.unsupported_feature("merge_data")
def set_merge_global_data(self, merge_global_data):
self.unsupported_feature("merge_global_data")
# ESP-specific payload construction
def set_esp_extra(self, extra):
self.unsupported_feature("esp_extra")
#
# Helpers for concrete implementations
#
def serialize_json(self, data):
"""Returns data serialized to json, raising appropriate errors.
Essentially json.dumps with added context in any errors.
Useful for implementing, e.g., serialize_data in a subclass,
"""
try:
return json.dumps(data, default=self._json_default)
except TypeError as err:
# Add some context to the "not JSON serializable" message
raise AnymailSerializationError(orig_err=err, email_message=self.message,
backend=self.backend, payload=self)
@staticmethod
def _json_default(o):
"""json.dump default function that handles some common Payload data types"""
if isinstance(o, CaseInsensitiveDict): # used for headers
return dict(o)
raise TypeError("Object of type '%s' is not JSON serializable" %
o.__class__.__name__)