How to send an attachment file from Application to teams channel or user using Graph API

Question

Hi,

I would like to send an attachment to teams channel or 1:1 chat from my application using Graph API delegate permissions.

I can not use the "contentURL" here.

I have to generate the file from app itself and send to teams.

How can I achieve this using Graph API?

or any other solution for this?

Please advise.

Thanks!

Answer 1

Hello GP,

Thanks for reaching out. You can achieve sending an app generated file attachment using the Graph APIs 'fileAttachment' resource's 'contentBytes' property. The property takes a Base64 string as input so you will need to convert the file contents to Base64 first before sending the attachment. You can find more information in article [https://learn.microsoft.com/en-us/graph/api/resources/fileattachment?view=graph-rest-1.0](https://learn.microsoft.com/en-us/graph/api/resources/fileattachment?view=graph-rest-1.0) and example of sending a message using fileAttachment and 'contentBytes' in article [https://learn.microsoft.com/en-us/graph/api/user-sendmail?view=graph-rest-1.0&tabs=http](https://learn.microsoft.com/en-us/graph/api/user-sendmail?view=graph-rest-1.0&tabs=http).

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Thanks.

Answer 2

• If you want to send the attachment trough Graph API-
  The file must already be in SharePoint. To find the file properties, GET the driveItem for the file. For example, /drives/{id}/items/{id}. Your attachment ID is the GUID in the eTag of the driveItem, your attachment contentURL is the webUrl of the driveItem's folder plus the driveItem's name, and your attachment name is the driveItem's name.

Post messages with card attachments that refer to existing SharePoint files, using the Graph APIs for OneDrive and SharePoint. To use the Graph APIs, obtain access to either of the following through the standard OAuth 2.0 authorization flow:

• A user's OneDrive folder for personal and groupchat files.
  • The files in a team's channel for channel files.
  Graph APIs work in all Teams scopes. For more information, see send chat message file attachments. Alternately, you can send files to and receive files from a bot using the Teams bot APIs.

      POST https://graph.microsoft.com/beta/teams/fbe2bf47-16c8-47cf-b4a5-4b9b187c508b/channels/19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2/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"
              }
          ]
      }
      
      ```