From 1cb98efe176aff176b9d1cbe61a4594359db44c2 Mon Sep 17 00:00:00 2001
From: John Rei Enriquez <johnrei.enriquez@gmail.com>
Date: Sun, 4 Feb 2024 22:11:18 +0800
Subject: [PATCH] feature: base64 image convert to attachments

fix: removed <>

fix: removing non alphanumeric characters

fix: use inline type for disposition
---
 django_email_verification/confirm.py | 10 +++++-
 django_email_verification/utils.py   | 51 ++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 django_email_verification/utils.py

diff --git a/django_email_verification/confirm.py b/django_email_verification/confirm.py
index 05cea0f..b70981b 100644
--- a/django_email_verification/confirm.py
+++ b/django_email_verification/confirm.py
@@ -13,6 +13,7 @@
 
 from .errors import InvalidUserModel, NotAllFieldCompiled
 from .token_utils import default_token_generator
+from .utils import convert_base64_images
 
 logger = logging.getLogger('django_email_verification')
 DJANGO_EMAIL_VERIFICATION_MORE_VIEWS_ERROR = 'ERROR: more than one verify view found'
@@ -81,13 +82,20 @@ def has_decorator(k):
         if not validators.url(context['link']):
             logger.warning(f'{DJANGO_EMAIL_VERIFICATION_MALFORMED_URL} - {context["link"]}')
 
+    do_convert_base64_images = _get_validated_field(f'EMAIL_CONVERT_BASE64_IMAGES', default=False, use_default=True, default_type=bool)
+
+    attachments = []
+    if do_convert_base64_images:
+        # Look for inline base64 images and converts them to attachments for email providers that require them i.e. Gmail
+        mail_html, attachments = convert_base64_images(mail_html, attachments)
+
     subject = Template(subject).render(Context(context))
 
     text = render_to_string(mail_plain, context)
 
     html = render_to_string(mail_html, context)
 
-    msg = EmailMultiAlternatives(subject, text, sender, [user.email])
+    msg = EmailMultiAlternatives(subject, text, sender, [user.email], attachments=attachments)
 
     if debug:
         msg.extra_headers['LINK'] = context['link']
diff --git a/django_email_verification/utils.py b/django_email_verification/utils.py
new file mode 100644
index 0000000..84e7c1b
--- /dev/null
+++ b/django_email_verification/utils.py
@@ -0,0 +1,51 @@
+
+import base64
+import hashlib
+import random
+import re
+import string
+
+from email.mime.image import MIMEImage
+
+def random_string(length, case="lowercase"):
+    return "".join(random.choices(getattr(string, f"ascii_{case}") + string.digits, k=length))
+
+def convert_base64_images(body, attachments):
+
+    def repl(match):
+        # Capture subtype in case MIMEImage's use of imghdr.what bugs out in guesesing the file type
+        subtype = match.group("subtype")
+        key = hashlib.md5(base64.b64decode(match.group("data"))).hexdigest().replace("-", "")
+        if key not in base64_images:
+           base64_images[key] = {
+                "data": match.group("data"),
+                "subtype": subtype,
+            }
+        return ' src="cid:image-%s"' % key
+
+    # Compile pattern for base64 inline images
+    RE_BASE64_SRC = re.compile(
+        r' src="data:image/(?P<subtype>gif|png|jpeg|bmp|webp)(?:;charset=utf-8)?;base64,(?P<data>[A-Za-z0-9|+ /]+={0,2})"',
+        re.MULTILINE)
+
+    base64_images = {}
+
+    # Replace and add base64 data to base64_images via repl
+    body = re.sub(RE_BASE64_SRC, repl, body)
+    for key, image_data in base64_images.items():
+        try:
+            image = MIMEImage(base64.b64decode(image_data["data"]))
+        except TypeError:
+            # Check for subtype if checking fails
+            if image_data["subtype"]:
+                image = MIMEImage(
+                    base64.b64decode(image_data["data"]),
+                    _subtype=image_data["subtype"]
+                )
+            else:
+                raise
+        image.add_header('Content-ID', '<image-%s>' % key)
+        image.add_header('Content-Disposition', "inline; filename=%s" % f'image_{random_string(length=6)}')
+        attachments.append(image)
+
+    return body, attachments