Ways to upload pdf file in child notes via etapi

[tan-yong-sheng]

I wish to ask if there is any etapi endpoint which we can upload pdf file via etapi.

I did see an internal endpoint which seems to upload pdf file but it only accepts session token not etapi token.

# Upload PDF as attachment (INTERNAL API - not ETAPI)
curl -X POST "http://localhost:8080/api/notes/TARGET_NOTE_ID/attachments/upload" \
  -H "Authorization: Bearer SESSION_TOKEN" \
  -H "Content-Type: multipart/form-data" \
  -F "upload=@document.pdf;type=application/pdf"

Here are the operations currently seems to be supported by each authentication method:

Operation	ETAPI Token	Session Token	Requires Password
Create Notes	✅ Works	❌ No access	❌ No
Search Notes	✅ Works	❌ No access	❌ No
Upload Binary Files	❌ No access	✅ Works	✅ Yes
Import Archives	❌ No access	✅ Works	✅ Yes

See more here
tan-yong-sheng/triliumnext-mcp#11

[eliandoran]

For attachments, POST /etapi/attachments should do the trick.

[tan-yong-sheng]

Hi @eliandoran, thanks a lot for answering. I tried using the /etapi/attachments endpoint to perform a two-step file upload, but encountered an error when uploading the actual file content.

1. Create Attachment Metadata

curl -X POST "http://localhost:37740/etapi/attachments" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_ETAPI_TOKEN" \
  -d '{
    "ownerId": "NOTE_ID_HERE",
    "role": "file",
    "mime": "application/pdf",
    "title": "My Document.pdf",
    "position": 10
  }'

Response:

{
  "attachmentId": "ATTACHMENT_ID",
  "ownerId": "NOTE_ID_HERE",
  "role": "file",
  "mime": "application/pdf",
  "title": "My Document.pdf",
  "position": 1,
  "blobId": "...",
  "dateModified": "...",
  "utcDateModified": "..."
}

So far this step works fine — the metadata record is created successfully.

2. Upload PDF Content

curl -X PUT "http://localhost:37740/etapi/attachments/ATTACHMENT_ID_HERE/content" \
  -H "Content-Type: application/pdf" \
  -H "Authorization: Bearer YOUR_ETAPI_TOKEN" \
  --data-binary "@/path/to/your/document.pdf"

Error Response:

{"status":500,"code":"GENERIC","message":"Cannot set null content to attachmentId '9SISSW0ftKmx'"}

It seems the server rejects the binary upload with a “Cannot set null content” error.
I’m not sure if this endpoint actually supports binary content upload (like /etapi/notes/{noteId}/content does for text), or if there’s a missing step to link the uploaded blob.

Could you clarify whether /etapi/attachments/{id}/content is intended for direct binary uploads, and if so, what’s the correct way to send the file data?

Thanks a lot.

[eliandoran]

It should support binary content, according to this test for ETAPI:

    it("supports binary content", async() => {
        await supertest(app)
            .put(`/etapi/attachments/${createdAttachmentId}/content`)
            .auth(USER, token, { "type": "basic"})
            .set("Content-Type", "application/octet-stream")
            .set("Content-Transfer-Encoding", "binary")
            .send(Buffer.from("Hello world"))
            .expect(204);
    });

Notice the Content-Type and the Content-Transfer-Encoding.

[miraculix95]

Wow!! Thanks a lot for having a look!!