feat: Inline attachment support

examples/with_inline_attachments.py

@@ -0,0 +1,51 @@
+import os
+
+import resend
+
+if not os.environ["RESEND_API_KEY"]:
+    raise EnvironmentError("RESEND_API_KEY is missing")
+
+f: bytes = open(
+    os.path.join(os.path.dirname(__file__), "../resources/resend-wordmark-black.png"),
+    "rb",
+).read()
+
+# Send email with local inline attachment
+local_attachment: resend.Attachment = {
+    "filename": "resend-wordmark-black.png",
+    "content": list(f),
+    "content_type": "image/png",
+    # This is the content ID that will be used in the HTML to reference the image
+    "inline_content_id": "my-test-image",
+}
+
+local_params: resend.Emails.SendParams = {
+    "from": "onboarding@resend.dev",
+    "to": ["delivered@resend.dev"],
+    "subject": "Local inline attachment test from Resend's python SDK",
+    "html": '<p>This email contains a local inline attachment: <img width=100 height=40 src="cid:my-test-image" /></p>',
+    "attachments": [local_attachment],
+}
+
+local_email: resend.Email = resend.Emails.send(local_params)
+print("Sent email with local inline attachment")
+print(local_email)
+
+# Send email with remote inline attachment
+remote_attachment: resend.RemoteAttachment = {
+    "filename": "remote-resend-wordmark-black.png",
+    "path": "https://resend.com/static/brand/resend-wordmark-black.png",
+    "inline_content_id": "my-test-image",
+}
+
+remote_params: resend.Emails.SendParams = {
+    "from": "onboarding@resend.dev",
+    "to": ["delivered@resend.dev"],
+    "subject": "Remote inline attachment test from Resend's python SDK",
+    "html": '<p>This email contains a remote inline attachment: <img width=100 height=40 src="cid:my-test-image" /></p>',
+    "attachments": [remote_attachment],
+}
+
+remote_email: resend.Email = resend.Emails.send(remote_params)
+print("Sent email with remote inline attachment")
+print(remote_email)

resend/__init__.py

@@ -10,7 +10,7 @@
 from .contacts._contacts import Contacts
 from .domains._domain import Domain
 from .domains._domains import Domains
-from .emails._attachment import Attachment
+from .emails._attachment import Attachment, RemoteAttachment
 from .emails._batch import Batch
 from .emails._email import Email
 from .emails._emails import Emails
@@ -48,6 +48,7 @@
     "ApiKey",
     "Email",
     "Attachment",
+    "RemoteAttachment",
     "Tag",
     "Broadcast",
     # Default HTTP Client

resend/emails/_attachment.py

@@ -23,3 +23,22 @@ class Attachment(TypedDict):
     """
     Content type for the attachment, if not set will be derived from the filename property
     """
+    inline_content_id: NotRequired[str]
+    """
+    Content ID for inline attachments used in HTML content with cid: references
+    """
+
+
+class RemoteAttachment(TypedDict):
+    path: str
+    """
+    Path where the remote attachment file is hosted
+    """
+    filename: NotRequired[str]
+    """
+    Name of attached file.
+    """
+    inline_content_id: NotRequired[str]
+    """
+    Content ID for inline attachments used in HTML content with cid: references
+    """

resend/emails/_emails.py

@@ -3,7 +3,7 @@
 from typing_extensions import NotRequired, TypedDict
 
 from resend import request
-from resend.emails._attachment import Attachment
+from resend.emails._attachment import Attachment, RemoteAttachment
 from resend.emails._email import Email
 from resend.emails._tag import Tag
 
@@ -95,7 +95,7 @@ class _SendParamsDefault(_SendParamsFrom):
     """
     Custom headers to be added to the email.
     """
-    attachments: NotRequired[List[Attachment]]
+    attachments: NotRequired[List[Union[Attachment, RemoteAttachment]]]
     """
     List of attachments to be added to the email.
     """
@@ -153,7 +153,7 @@ class SendParams(_SendParamsDefault):
             html (NotRequired[str]): The HTML content of the email.
             text (NotRequired[str]): The text content of the email.
             headers (NotRequired[Dict[str, str]]): Custom headers to be added to the email.
-            attachments (NotRequired[List[Attachment]]): List of attachments to be added to the email.
+            attachments (NotRequired[List[Union[Attachment, RemoteAttachment]]]): List of attachments to be added to the email.
             tags (NotRequired[List[Tag]]): List of tags to be added to the email.
         """
 

tests/emails_test.py

@@ -109,3 +109,50 @@ def test_cancel_scheduled_email(self) -> None:
             email_id="49a3999c-0ce1-4ea6-ab68-afcd6dc2e794"
         )
         assert email["id"] == "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794"
+
+    def test_email_send_with_attachment(self) -> None:
+        self.set_mock_json(
+            {
+                "id": "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794",
+            }
+        )
+
+        attachment: resend.Attachment = {
+            "filename": "test.pdf",
+            "content": [1, 2, 3, 4, 5],
+            "content_type": "application/pdf",
+        }
+
+        params: resend.Emails.SendParams = {
+            "to": "to@email.com",
+            "from": "from@email.com",
+            "subject": "subject",
+            "html": "html",
+            "attachments": [attachment],
+        }
+        email: resend.Email = resend.Emails.send(params)
+        assert email["id"] == "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794"
+
+    def test_email_send_with_inline_attachment(self) -> None:
+        self.set_mock_json(
+            {
+                "id": "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794",
+            }
+        )
+
+        attachment: resend.Attachment = {
+            "filename": "image.png",
+            "content": [1, 2, 3, 4, 5],
+            "content_type": "image/png",
+            "inline_content_id": "my-image",
+        }
+
+        params: resend.Emails.SendParams = {
+            "to": "to@email.com",
+            "from": "from@email.com",
+            "subject": "subject",
+            "html": '<img src="cid:my-image" />',
+            "attachments": [attachment],
+        }
+        email: resend.Email = resend.Emails.send(params)
+        assert email["id"] == "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794"