Change sendmail functions into classes that can be overriden from a plugin (#2221)

* Change sendmail functions into classes that can be overriden from a plugin
* Deprecate `CTFd.utils.email.mailgun.sendmail`
* Deprecate `CTFd.utils.email.smtp.sendmail`

CTFd/config.ini

@@ -102,6 +102,12 @@ MAILGUN_API_KEY =
 # Installations using the Mailgun API should migrate over to SMTP settings.
 MAILGUN_BASE_URL =
 
+# MAIL_PROVIDER
+# Specifies the email provider that CTFd will use to send email.
+# By default CTFd will automatically detect the correct email provider based on the other settings 
+# specified here or in the configuration panel. This setting can be used to force a specific provider.
+MAIL_PROVIDER =
+
 [uploads]
 # UPLOAD_PROVIDER
 # Specifies the service that CTFd should use to store files.

CTFd/config.py

@@ -154,6 +154,8 @@ class ServerConfig(object):
 
     MAILGUN_BASE_URL: str = empty_str_cast(config_ini["email"]["MAILGUN_API_KEY"])
 
+    MAIL_PROVIDER: str = empty_str_cast(config_ini["email"].get("MAIL_PROVIDER"))
+
     # === LOGS ===
     LOG_FOLDER: str = empty_str_cast(config_ini["logs"]["LOG_FOLDER"]) \
         or os.path.join(os.path.dirname(os.path.abspath(__file__)), "logs")

CTFd/utils/config/__init__.py

@@ -60,6 +60,9 @@ def can_send_mail():
 
 
 def get_mail_provider():
+    mail_provider = app.config.get("MAIL_PROVIDER")
+    if mail_provider:
+        return mail_provider
     if get_config("mail_server") and get_config("mail_port"):
         return "smtp"
     if get_config("mailgun_api_key") and get_config("mailgun_base_url"):

CTFd/utils/email/__init__.py

@@ -2,10 +2,13 @@ from flask import url_for
 
 from CTFd.utils import get_config
 from CTFd.utils.config import get_mail_provider
-from CTFd.utils.email import mailgun, smtp
+from CTFd.utils.email.providers.mailgun import MailgunEmailProvider
+from CTFd.utils.email.providers.smtp import SMTPEmailProvider
 from CTFd.utils.formatters import safe_format
 from CTFd.utils.security.signing import serialize
 
+PROVIDERS = {"smtp": SMTPEmailProvider, "mailgun": MailgunEmailProvider}
+
 DEFAULT_VERIFICATION_EMAIL_SUBJECT = "Confirm your account for {ctf_name}"
 DEFAULT_VERIFICATION_EMAIL_BODY = (
     "Welcome to {ctf_name}!\n\n"
@@ -42,11 +45,10 @@ DEFAULT_PASSWORD_CHANGE_ALERT_BODY = (
 def sendmail(addr, text, subject="Message from {ctf_name}"):
     subject = safe_format(subject, ctf_name=get_config("ctf_name"))
     provider = get_mail_provider()
-    if provider == "smtp":
-        return smtp.sendmail(addr, text, subject)
-    if provider == "mailgun":
-        return mailgun.sendmail(addr, text, subject)
-    return False, "No mail settings configured"
+    EmailProvider = PROVIDERS.get(provider)
+    if EmailProvider is None:
+        return False, "No mail settings configured"
+    return EmailProvider.sendmail(addr, text, subject)
 
 
 def password_change_alert(email):

CTFd/utils/email/mailgun.py

@@ -1,40 +1,8 @@
-from email.utils import formataddr
-
-import requests
-
-from CTFd.utils import get_app_config, get_config
+from CTFd.utils.email.providers.mailgun import MailgunEmailProvider
 
 
 def sendmail(addr, text, subject):
-    ctf_name = get_config("ctf_name")
-    mailfrom_addr = get_config("mailfrom_addr") or get_app_config("MAILFROM_ADDR")
-    mailfrom_addr = formataddr((ctf_name, mailfrom_addr))
-
-    mailgun_base_url = get_config("mailgun_base_url") or get_app_config(
-        "MAILGUN_BASE_URL"
+    print(
+        "CTFd.utils.email.mailgun.sendmail will raise an exception in a future minor release of CTFd and then be removed in CTFd v4.0"
     )
-    mailgun_api_key = get_config("mailgun_api_key") or get_app_config("MAILGUN_API_KEY")
-    try:
-        r = requests.post(
-            mailgun_base_url + "/messages",
-            auth=("api", mailgun_api_key),
-            data={
-                "from": mailfrom_addr,
-                "to": [addr],
-                "subject": subject,
-                "text": text,
-            },
-            timeout=1.0,
-        )
-    except requests.RequestException as e:
-        return (
-            False,
-            "{error} exception occured while handling your request".format(
-                error=type(e).__name__
-            ),
-        )
-
-    if r.status_code == 200:
-        return True, "Email sent"
-    else:
-        return False, "Mailgun settings are incorrect"
+    return MailgunEmailProvider.sendmail(addr, text, subject)

CTFd/utils/email/providers/__init__.py

@@ -0,0 +1,4 @@
+class EmailProvider:
+    @staticmethod
+    def sendmail(addr, text, subject):
+        raise NotImplementedError

CTFd/utils/email/providers/mailgun.py

@@ -0,0 +1,45 @@
+from email.utils import formataddr
+
+import requests
+
+from CTFd.utils import get_app_config, get_config
+from CTFd.utils.email.providers import EmailProvider
+
+
+class MailgunEmailProvider(EmailProvider):
+    @staticmethod
+    def sendmail(addr, text, subject):
+        ctf_name = get_config("ctf_name")
+        mailfrom_addr = get_config("mailfrom_addr") or get_app_config("MAILFROM_ADDR")
+        mailfrom_addr = formataddr((ctf_name, mailfrom_addr))
+
+        mailgun_base_url = get_config("mailgun_base_url") or get_app_config(
+            "MAILGUN_BASE_URL"
+        )
+        mailgun_api_key = get_config("mailgun_api_key") or get_app_config(
+            "MAILGUN_API_KEY"
+        )
+        try:
+            r = requests.post(
+                mailgun_base_url + "/messages",
+                auth=("api", mailgun_api_key),
+                data={
+                    "from": mailfrom_addr,
+                    "to": [addr],
+                    "subject": subject,
+                    "text": text,
+                },
+                timeout=1.0,
+            )
+        except requests.RequestException as e:
+            return (
+                False,
+                "{error} exception occured while handling your request".format(
+                    error=type(e).__name__
+                ),
+            )
+
+        if r.status_code == 200:
+            return True, "Email sent"
+        else:
+            return False, "Mailgun settings are incorrect"

CTFd/utils/email/providers/smtp.py

@@ -0,0 +1,79 @@
+import smtplib
+from email.message import EmailMessage
+from email.utils import formataddr
+from socket import timeout
+
+from CTFd.utils import get_app_config, get_config
+from CTFd.utils.email.providers import EmailProvider
+
+
+class SMTPEmailProvider(EmailProvider):
+    @staticmethod
+    def sendmail(addr, text, subject):
+        ctf_name = get_config("ctf_name")
+        mailfrom_addr = get_config("mailfrom_addr") or get_app_config("MAILFROM_ADDR")
+        mailfrom_addr = formataddr((ctf_name, mailfrom_addr))
+
+        data = {
+            "host": get_config("mail_server") or get_app_config("MAIL_SERVER"),
+            "port": int(get_config("mail_port") or get_app_config("MAIL_PORT")),
+        }
+        username = get_config("mail_username") or get_app_config("MAIL_USERNAME")
+        password = get_config("mail_password") or get_app_config("MAIL_PASSWORD")
+        TLS = get_config("mail_tls") or get_app_config("MAIL_TLS")
+        SSL = get_config("mail_ssl") or get_app_config("MAIL_SSL")
+        auth = get_config("mail_useauth") or get_app_config("MAIL_USEAUTH")
+
+        if username:
+            data["username"] = username
+        if password:
+            data["password"] = password
+        if TLS:
+            data["TLS"] = TLS
+        if SSL:
+            data["SSL"] = SSL
+        if auth:
+            data["auth"] = auth
+
+        try:
+            smtp = get_smtp(**data)
+
+            msg = EmailMessage()
+            msg.set_content(text)
+
+            msg["Subject"] = subject
+            msg["From"] = mailfrom_addr
+            msg["To"] = addr
+
+            # Check whether we are using an admin-defined SMTP server
+            custom_smtp = bool(get_config("mail_server"))
+
+            # We should only consider the MAILSENDER_ADDR value on servers defined in config
+            if custom_smtp:
+                smtp.send_message(msg)
+            else:
+                mailsender_addr = get_app_config("MAILSENDER_ADDR")
+                smtp.send_message(msg, from_addr=mailsender_addr)
+
+            smtp.quit()
+            return True, "Email sent"
+        except smtplib.SMTPException as e:
+            return False, str(e)
+        except timeout:
+            return False, "SMTP server connection timed out"
+        except Exception as e:
+            return False, str(e)
+
+
+def get_smtp(host, port, username=None, password=None, TLS=None, SSL=None, auth=None):
+    if SSL is None:
+        smtp = smtplib.SMTP(host, port, timeout=3)
+    else:
+        smtp = smtplib.SMTP_SSL(host, port, timeout=3)
+
+    if TLS:
+        smtp.starttls()
+
+    if auth:
+        smtp.login(username, password)
+    return smtp

CTFd/utils/email/smtp.py

@@ -1,76 +1,8 @@
-import smtplib
-from email.message import EmailMessage
-from email.utils import formataddr
-from socket import timeout
-
-from CTFd.utils import get_app_config, get_config
-
-
-def get_smtp(host, port, username=None, password=None, TLS=None, SSL=None, auth=None):
-    if SSL is None:
-        smtp = smtplib.SMTP(host, port, timeout=3)
-    else:
-        smtp = smtplib.SMTP_SSL(host, port, timeout=3)
-
-    if TLS:
-        smtp.starttls()
-
-    if auth:
-        smtp.login(username, password)
-    return smtp
+from CTFd.utils.email.providers.smtp import SMTPEmailProvider
 
 
 def sendmail(addr, text, subject):
-    ctf_name = get_config("ctf_name")
-    mailfrom_addr = get_config("mailfrom_addr") or get_app_config("MAILFROM_ADDR")
-    mailfrom_addr = formataddr((ctf_name, mailfrom_addr))
-
-    data = {
-        "host": get_config("mail_server") or get_app_config("MAIL_SERVER"),
-        "port": int(get_config("mail_port") or get_app_config("MAIL_PORT")),
-    }
-    username = get_config("mail_username") or get_app_config("MAIL_USERNAME")
-    password = get_config("mail_password") or get_app_config("MAIL_PASSWORD")
-    TLS = get_config("mail_tls") or get_app_config("MAIL_TLS")
-    SSL = get_config("mail_ssl") or get_app_config("MAIL_SSL")
-    auth = get_config("mail_useauth") or get_app_config("MAIL_USEAUTH")
-
-    if username:
-        data["username"] = username
-    if password:
-        data["password"] = password
-    if TLS:
-        data["TLS"] = TLS
-    if SSL:
-        data["SSL"] = SSL
-    if auth:
-        data["auth"] = auth
-
-    try:
-        smtp = get_smtp(**data)
-
-        msg = EmailMessage()
-        msg.set_content(text)
-
-        msg["Subject"] = subject
-        msg["From"] = mailfrom_addr
-        msg["To"] = addr
-
-        # Check whether we are using an admin-defined SMTP server
-        custom_smtp = bool(get_config("mail_server"))
-
-        # We should only consider the MAILSENDER_ADDR value on servers defined in config
-        if custom_smtp:
-            smtp.send_message(msg)
-        else:
-            mailsender_addr = get_app_config("MAILSENDER_ADDR")
-            smtp.send_message(msg, from_addr=mailsender_addr)
-
-        smtp.quit()
-        return True, "Email sent"
-    except smtplib.SMTPException as e:
-        return False, str(e)
-    except timeout:
-        return False, "SMTP server connection timed out"
-    except Exception as e:
-        return False, str(e)
+    print(
+        "CTFd.utils.email.smtp.sendmail will raise an exception in a future minor release of CTFd and then be removed in CTFd v4.0"
+    )
+    return SMTPEmailProvider.sendmail(addr, text, subject)