Send file/image as a message from local system in Microsoft Team Channel - microsoft-graph-api

Question

How can I send the local file/image in Microsoft Teams Channel using Send Message of Microsoft Graph API?
I have followed a document https://learn.microsoft.com/en-us/graph/api/resources/chatmessageattachment?view=graph-rest-1.0 to attach an image when creating a message to send the team channel. I am trying to send the base64 format of an image. But I am getting an error.
{
"error": {
"code": "InternalServerError",
"message": "Failed to process request.",
"innerError": {
"date": "2020-09-25T11:43:02",
"request-id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
"client-request-id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
}
}
}

Answer 1

It seems there is no appropriate API for you to send local file as message directly.
Creating chatMessage in a channel just supports send the file that has been in SharePoint. So, there are two steps to send the local file: first, upload file to SharePoint, then create chatMessage.
1. Upload file to SharePoint:
File smaller than 4MB:
PUT https://graph.microsoft.com/v1.0/drives/{{drive-id}}/items/root:/{{file-name}}:/content
Header:
"Authorization" : "Bearer <access-token>"
Body: binary (select binary option in body in postman)
Upload a file using select file option
file-name: is file name along with extension example: test.txt
File greater than 4MB:
GET: https://graph.microsoft.com/v1.0/drives/{{drive-id}}/items/root:/{{file-name}}:/createUploadSession
Header:
"Authorization" : "Bearer <access-token>"
The Get request will return upload url.
PUT <upload url>
Header:
"Authorization" : "Bearer <access-token>"
Body: binary (select binary option in body in postman)
For more details, see here.
2. Create chatMessage:
POST https://graph.microsoft.com/v1.0/teams/{id}/channels/{id}/messages
Content-type: application/json
{
"body": {
"contentType": "html",
"content": "Here's the latest budget. <attachment id=\"153fa47d-18c9-4179-be08-9879815a9f90\"></attachment>"
},
"attachments": [
{
"id": "153fa47d-18c9-4179-be08-9879815a9f90",
"contentType": "reference",
"contentUrl": "https://m365x987948.sharepoint.com/sites/test/Shared%20Documents/General/test%20doc.docx",
"name": "Budget.docx"
}
]
}