如何通过 Microsoft Graph API 添加内嵌图像？

Question

Background

When I use Outlook client to send a mail with inline image.

The image in html email looks like this, which has cid :

<img size="100" src="cid:3bb599fc-f3eb-465b-af83-aa6a495f563a" style="max-width:100%">

When I use

GET /me/messages/{messageId}/attachments

The contentId in the result returned matched the cid in html.

{
    "value": [
        {
            "@odata.type": "#microsoft.graph.fileAttachment",
            "id": "aaa",
            "lastModifiedDateTime": "2017-11-30T09:32:09Z",
            "name": "image.png",
            "contentType": "image/png",
            "size": 100,
            "isInline": true,
            "contentId": "3bb599fc-f3eb-465b-af83-aa6a495f563a",
            "contentLocation": null,
            "contentBytes": "validBase64Bytes"
        }
    ]
}

Using Microsoft Graph API

Now I am trying to use Microsoft Graph API to add inline image.

POST /me/messages/{messageId}/attachments
{
  "@odata.type": "#microsoft.graph.fileAttachment",
  "name": "1.jpg",
  "isInline": true,
  "contentBytes": "validBase64Bytes"
}

However, the contentId is null in the result returned.

{
    "@odata.type": "#microsoft.graph.fileAttachment",
    "id": "aaa",
    "lastModifiedDateTime": "2017-11-30T09:35:50Z",
    "name": "1.jpg",
    "contentType": "image/jpeg",
    "size": 100,
    "isInline": true,
    "contentId": null,
    "contentLocation": null,
    "contentBytes": "validBase64Bytes"
}

And if I set contentId manually in POST

POST /me/messages/{messageId}/attachments
{
  "@odata.type": "#microsoft.graph.fileAttachment",
  "name": "1.jpg",
  "isInline": true,
  "contentId": "myContentId",
  "contentBytes": "validBase64Bytes"
}

It will return the error

{
    "error": {
        "code": "BadRequest",
        "message": "Unable to read JSON request payload. Please ensure Content-Type header is set and payload is of valid JSON format.",
        "innerError": {
            "request-id": "36e95f0a-ad75-46c6-b86c-d585a150b96d",
            "date": "2017-11-30T09:37:41"
        }
    }
}

So how to add inline image correctly?

Answer 1

Weird, I tried to run the exact same code again, it won't give me any error now.

POST /me/messages/{messageId}/attachments
{
  "@odata.type": "#microsoft.graph.fileAttachment",
  "name": "1.jpg",
  "isInline": true,
  "contentId": "myContentId",
  "contentBytes": "validBase64Bytes"
}

Not sure whether it is a temporary issue. I will inform Microsoft team to check the log.

If I am wrong for how to use the API, please definitely point out. Thanks.

I will leave it here for future people to save some time to implement adding inline image.