Start factoring out common backend functionality

This commit is contained in:
medmunds
2016-02-29 11:52:35 -08:00
parent 1c7fe8a759
commit ef971489cd
4 changed files with 297 additions and 164 deletions

248
anymail/backends/base.py Normal file
View File

@@ -0,0 +1,248 @@
import json
import requests
from django.core.mail.backends.base import BaseEmailBackend
from .._version import __version__
from ..exceptions import AnymailError, AnymailRequestsAPIError, AnymailSerializationError, AnymailImproperlyConfigured
class AnymailBaseBackend(BaseEmailBackend):
"""
Base Anymail email backend
"""
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 = None
esp_response_attr = "%s_response" % self.esp_name.lower() # e.g., message.mandrill_response
setattr(message, esp_response_attr, None) # until we have a response
if not message.recipients():
return False
payload = self.build_message_payload(message)
# FUTURE: if pre-send-signal OK...
response = self.post_to_esp(payload, message)
parsed_response = self.deserialize_response(response, payload, message)
setattr(message, esp_response_attr, parsed_response)
message.anymail_status = self.validate_response(parsed_response, response, payload, message)
# FUTURE: post-send signal
return True
def build_message_payload(self, message):
"""Return a payload with all message-specific options for ESP send call.
message is an EmailMessage, possibly with additional Anymail-specific attrs
Can raise AnymailUnsupportedFeature for unsupported options in message.
"""
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 build_message_payload" %
(self.__class__.__module__, self.__class__.__name__))
def deserialize_response(self, response, payload, message):
"""Deserialize a raw ESP response
Can raise AnymailAPIError (or derived exception) if response is unparsable
"""
raise NotImplementedError("%s.%s must implement build_message_payload" %
(self.__class__.__module__, self.__class__.__name__))
def validate_response(self, parsed_response, response, payload, message):
"""Validate parsed_response, raising exceptions for any problems, and return normalized status.
Extend this to provide your own validation checks.
Validation exceptions should inherit from anymail.exceptions.AnymailError
for proper fail_silently behavior.
If *all* recipients are refused or invalid, should raise AnymailRecipientsRefused
Returns one of "sent", "queued", "refused", "error" or "multi"
"""
raise NotImplementedError("%s.%s must implement validate_response" %
(self.__class__.__module__, self.__class__.__name__))
@property
def esp_name(self):
"""
Read-only name of the ESP for this backend.
(E.g., MailgunBackend will return "Mailgun")
"""
return self.__class__.__name__.replace("Backend", "")
class AnymailRequestsBackend(AnymailBaseBackend):
"""
Base Anymail email backend for ESPs that use an HTTP API via requests
"""
def __init__(self, api_url, **kwargs):
"""Init options from Django settings"""
self.api_url = api_url
super(AnymailRequestsBackend, self).__init__(**kwargs)
self.session = None
def open(self):
if self.session:
return False # already exists
try:
self.session = requests.Session()
except requests.RequestException:
if not self.fail_silently:
raise
else:
self.session.headers["User-Agent"] = "Anymail/%s %s" % (
__version__, self.session.headers.get("User-Agent", ""))
return True
def close(self):
if self.session is None:
return
try:
self.session.close()
except requests.RequestException:
if not self.fail_silently:
raise
finally:
self.session = None
def _send(self, message):
if self.session is None:
class_name = self.__class__.__name__
raise RuntimeError(
"Session has not been opened in {class_name}._send. "
"(This is either an implementation error in {class_name}, "
"or you are incorrectly calling _send directly.)".format(class_name=class_name))
return super(AnymailRequestsBackend, self)._send(message)
def get_api_url(self, payload, message):
"""Return the correct ESP url for sending payload
Override this to substitute your own logic for determining API endpoint.
"""
return self.api_url
def serialize_payload(self, payload, message):
"""Return payload serialized to post data.
Should raise AnymailSerializationError if payload is not serializable
"""
try:
return json.dumps(payload)
except TypeError as err:
# Add some context to the "not JSON serializable" message
raise AnymailSerializationError(orig_err=err, email_message=message, payload=payload)
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 requests.Response
Can raise AnymailRequestsAPIError for HTTP errors in the post
"""
api_url = self.get_api_url(payload, message)
post_data = self.serialize_payload(payload, message)
response = self.session.post(api_url, data=post_data)
if response.status_code != 200:
raise AnymailRequestsAPIError(email_message=message, payload=payload, response=response)
return response
def deserialize_response(self, response, payload, message):
"""Return parsed ESP API response
Can raise AnymailRequestsAPIError if response is unparsable
"""
try:
return response.json()
except ValueError:
raise AnymailRequestsAPIError("Invalid JSON in %s API response" % self.esp_name,
email_message=message, payload=payload, response=response)

View File

@@ -1,6 +1,4 @@
import json
import mimetypes
import requests
from base64 import b64encode
from datetime import date, datetime
from email.mime.base import MIMEBase
@@ -11,32 +9,32 @@ except ImportError:
from urllib.parse import urljoin # python 3
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.core.mail.backends.base import BaseEmailBackend
from django.core.mail.message import sanitize_address, DEFAULT_ATTACHMENT_MIME_TYPE
from .._version import __version__
from ..exceptions import (AnymailError, AnymailRequestsAPIError, AnymailRecipientsRefused,
AnymailSerializationError, AnymailUnsupportedFeature)
from ..exceptions import (AnymailImproperlyConfigured,
AnymailRequestsAPIError, AnymailRecipientsRefused,
AnymailUnsupportedFeature)
from .base import AnymailRequestsBackend
class MandrillBackend(BaseEmailBackend):
class MandrillBackend(AnymailRequestsBackend):
"""
Mandrill API Email Backend
"""
def __init__(self, **kwargs):
"""Init options from Django settings"""
super(MandrillBackend, self).__init__(**kwargs)
api_url = getattr(settings, "MANDRILL_API_URL", "https://mandrillapp.com/api/1.0")
if not api_url.endswith("/"):
api_url += "/"
super(MandrillBackend, self).__init__(api_url, **kwargs)
try:
self.api_key = settings.MANDRILL_API_KEY
except AttributeError:
raise ImproperlyConfigured("Set MANDRILL_API_KEY in settings.py to use Djrill")
self.api_url = getattr(settings, "MANDRILL_API_URL", "https://mandrillapp.com/api/1.0")
if not self.api_url.endswith("/"):
self.api_url += "/"
raise AnymailImproperlyConfigured("Set MANDRILL_API_KEY in settings.py to use Anymail Mandrill backend")
self.global_settings = {}
try:
@@ -44,7 +42,7 @@ class MandrillBackend(BaseEmailBackend):
except AttributeError:
pass # no MANDRILL_SETTINGS setting
except (TypeError, ValueError): # e.g., not enumerable
raise ImproperlyConfigured("MANDRILL_SETTINGS must be a dict or mapping")
raise AnymailImproperlyConfigured("MANDRILL_SETTINGS must be a dict or mapping")
try:
self.global_settings["subaccount"] = settings.MANDRILL_SUBACCOUNT
@@ -54,100 +52,7 @@ class MandrillBackend(BaseEmailBackend):
self.ignore_recipient_status = getattr(settings, "MANDRILL_IGNORE_RECIPIENT_STATUS", False)
self.session = None
def open(self):
"""
Ensure we have a requests Session to connect to the Mandrill API.
Returns True if a new session was created (and the caller must close it).
"""
if self.session:
return False # already exists
try:
self.session = requests.Session()
except requests.RequestException:
if not self.fail_silently:
raise
else:
self.session.headers["User-Agent"] = "Djrill/%s %s" % (
__version__, self.session.headers.get("User-Agent", ""))
return True
def close(self):
"""
Close the Mandrill API Session unconditionally.
(You should call this only if you called open and it returned True;
else someone else created the session and will clean it up themselves.)
"""
if self.session is None:
return
try:
self.session.close()
except requests.RequestException:
if not self.fail_silently:
raise
finally:
self.session = None
def send_messages(self, email_messages):
"""
Sends one or more EmailMessage objects and returns the number of email
messages sent.
"""
if not email_messages:
return 0
created_session = self.open()
if not self.session:
return 0 # exception in self.open with fail_silently
num_sent = 0
try:
for message in email_messages:
sent = self._send(message)
if sent:
num_sent += 1
finally:
if created_session:
self.close()
return num_sent
def _send(self, message):
message.mandrill_response = None # until we have a response
if not message.recipients():
return False
try:
payload = self.get_base_payload()
self.build_send_payload(payload, message)
response = self.post_to_mandrill(payload, message)
# add the response from mandrill to the EmailMessage so callers can inspect it
message.mandrill_response = self.parse_response(response, payload, message)
self.validate_response(message.mandrill_response, response, payload, message)
except AnymailError:
# every *expected* error is derived from AnymailError;
# we deliberately don't silence unexpected errors
if not self.fail_silently:
raise
return False
return True
def get_base_payload(self):
"""Return non-message-dependent payload for Mandrill send call
(The return value will be modified for the send, so must be a copy
of any shared state.)
"""
payload = {
"key": self.api_key,
}
return payload
def build_send_payload(self, payload, message):
def build_message_payload(self, message):
"""Modify payload to add all message-specific options for Mandrill send call.
payload is a dict that will become the Mandrill send data
@@ -160,12 +65,17 @@ class MandrillBackend(BaseEmailBackend):
if getattr(message, 'alternatives', None):
self._add_alternatives(message, msg_dict)
self._add_attachments(message, msg_dict)
payload.setdefault('message', {}).update(msg_dict)
payload = {
"key": self.api_key,
"message": msg_dict,
}
if hasattr(message, 'template_name'):
payload['template_name'] = message.template_name
payload['template_content'] = \
self._expand_merge_vars(getattr(message, 'template_content', {}))
self._add_mandrill_toplevel_options(message, payload)
return payload
def get_api_url(self, payload, message):
"""Return the correct Mandrill API url for sending payload
@@ -178,67 +88,28 @@ class MandrillBackend(BaseEmailBackend):
api_method = "messages/send.json"
return urljoin(self.api_url, api_method)
def serialize_payload(self, payload, message):
"""Return payload serialized to a json str.
Override this to substitute your own JSON serializer (e.g., to handle dates)
"""
return json.dumps(payload)
def post_to_mandrill(self, payload, message):
"""Post payload to correct Mandrill send API endpoint, and return the response.
payload is a dict to use as Mandrill send data
message is the original EmailMessage
return should be a requests.Response
Can raise AnymailSerializationError if payload is not serializable
Can raise AnymailRequestsAPIError for HTTP errors in the post
"""
api_url = self.get_api_url(payload, message)
try:
json_payload = self.serialize_payload(payload, message)
except TypeError as err:
# Add some context to the "not JSON serializable" message
raise AnymailSerializationError(
orig_err=err, email_message=message, payload=payload)
response = self.session.post(api_url, data=json_payload)
if response.status_code != 200:
raise AnymailRequestsAPIError(email_message=message, payload=payload, response=response)
return response
def parse_response(self, response, payload, message):
"""Return parsed json from Mandrill API response
Can raise AnymailRequestsAPIError if response is not valid JSON
"""
try:
return response.json()
except ValueError:
raise AnymailRequestsAPIError("Invalid JSON in Mandrill API response",
email_message=message, payload=payload, response=response)
def validate_response(self, parsed_response, response, payload, message):
"""Validate parsed_response, raising exceptions for any problems.
Extend this to provide your own validation checks.
Validation exceptions should inherit from anymail.exceptions.DjrillException
for proper fail_silently behavior.
The base version here checks for invalid or refused recipients.
"""
if self.ignore_recipient_status:
return
try:
recipient_status = [item["status"] for item in parsed_response]
unique_statuses = set([item["status"] for item in parsed_response])
except (KeyError, TypeError):
raise AnymailRequestsAPIError("Invalid Mandrill API response format",
email_message=message, payload=payload, response=response)
# Error if *all* recipients are invalid or refused
# (This behavior parallels smtplib.SMTPRecipientsRefused from Django's SMTP EmailBackend)
if all([status in ('invalid', 'rejected') for status in recipient_status]):
raise AnymailRecipientsRefused(email_message=message, payload=payload, response=response)
if unique_statuses == {"sent"}:
return "sent"
elif unique_statuses == {"queued"}:
return "queued"
elif unique_statuses.issubset({"invalid", "rejected"}):
if self.ignore_recipient_status:
return "refused"
else:
# Error if *all* recipients are invalid or refused
# (This behavior parallels smtplib.SMTPRecipientsRefused from Django's SMTP EmailBackend)
raise AnymailRecipientsRefused(email_message=message, payload=payload, response=response)
else:
return "multi"
#
# Payload construction

View File

@@ -1,3 +1,4 @@
from django.core.exceptions import ImproperlyConfigured
import json
from requests import HTTPError
@@ -67,6 +68,10 @@ class AnymailError(Exception):
return description
class AnymailImproperlyConfigured(AnymailError, ImproperlyConfigured):
"""Exception for configuration problems"""
class AnymailAPIError(AnymailError):
"""Exception for unsuccessful response from ESP's API."""

View File

@@ -525,7 +525,10 @@ class DjrillMandrillFeatureTests(DjrillBackendMockAPITestCase):
msg = mail.EmailMessage('Subject', 'Message', 'from@example.com', ['to1@example.com'],)
sent = msg.send()
self.assertEqual(sent, 1)
# noinspection PyUnresolvedReferences
self.assertEqual(msg.mandrill_response, response)
# noinspection PyUnresolvedReferences
self.assertEqual(msg.anymail_status, "sent")
def test_send_failed_mandrill_response(self):
""" If the send fails, mandrill_response should be set to None """
@@ -533,7 +536,10 @@ class DjrillMandrillFeatureTests(DjrillBackendMockAPITestCase):
msg = mail.EmailMessage('Subject', 'Message', 'from@example.com', ['to1@example.com'],)
sent = msg.send(fail_silently=True)
self.assertEqual(sent, 0)
# noinspection PyUnresolvedReferences
self.assertIsNone(msg.mandrill_response)
# noinspection PyUnresolvedReferences
self.assertIsNone(msg.anymail_status)
def test_send_unparsable_mandrill_response(self):
"""If the send succeeds, but a non-JSON API response, should raise an API exception"""
@@ -541,7 +547,10 @@ class DjrillMandrillFeatureTests(DjrillBackendMockAPITestCase):
msg = mail.EmailMessage('Subject', 'Message', 'from@example.com', ['to1@example.com'],)
with self.assertRaises(AnymailAPIError):
msg.send()
# noinspection PyUnresolvedReferences
self.assertIsNone(msg.mandrill_response)
# noinspection PyUnresolvedReferences
self.assertIsNone(msg.anymail_status)
def test_json_serialization_errors(self):
"""Try to provide more information about non-json-serializable data"""