How to retrieve contents of an itemAttachment via the Microsoft Graph API
Use $expand option:
GET https://graph.microsoft.com/v1.0/me/messages('AAMkADA1M-zAAA=')/attachments('AAMkADA1M-CJKtzmnlcqVgqI=')/?$expand=microsoft.graph.itemattachment/item
Response:
HTTP/1.1 200 OK
Content-type: application/json
{
"@odata.context":"https://graph.microsoft.com/v1.0/$metadata#users('d1a2fae9-db66-4cc9-8133-2184c77af1b8')/messages('AAMkADA1M-zAAA%3D')/attachments/$entity",
"@odata.type":"#microsoft.graph.itemAttachment",
"id":"AAMkADA1MCJKtzmnlcqVgqI=",
"lastModifiedDateTime":"2017-07-21T00:20:34Z",
"name":"Reminder - please bring laptop",
"contentType":null,
"size":32005,
"isInline":false,
"[email protected]":"https://graph.microsoft.com/v1.0/$metadata#users('d1a2fae9-db66-4cc9-8133-2184c77af1b8')/messages('AAMkADA1M-zAAA%3D')/attachments('AAMkADA1M-CJKtzmnlcqVgqI%3D')/microsoft.graph.itemAttachment/item/$entity",
"item":{
"@odata.type":"#microsoft.graph.message",
"id":"",
"createdDateTime":"2017-07-21T00:20:41Z",
"lastModifiedDateTime":"2017-07-21T00:20:34Z",
"receivedDateTime":"2017-07-21T00:19:55Z",
"sentDateTime":"2017-07-21T00:19:52Z",
"hasAttachments":false,
"internetMessageId":"<BY2PR15MB05189A084C01F466709E414F9CA40@BY2PR15MB0518.namprd15.prod.outlook.com>",
"subject":"Reminder - please bring laptop",
"importance":"normal",
"conversationId":"AAQkADA1MzMyOGI4LTlkZDctNDkzYy05M2RiLTdiN2E1NDE3MTRkOQAQAMG_NSCMBqdKrLa2EmR-lO0=",
"isDeliveryReceiptRequested":false,
"isReadReceiptRequested":false,
"isRead":false,
"isDraft":false,
"webLink":"https://outlook.office365.com/owa/?ItemID=AAMkADA1M3MTRkOQAAAA%3D%3D&exvsurl=1&viewmodel=ReadMessageItem",
"body":{
"contentType":"html",
"content":"<html><head>\r\n</head>\r\n<body>\r\n</body>\r\n</html>"
},
"sender":{
"emailAddress":{
"name":"Adele Vance",
"address":"[email protected]"
}
},
"from":{
"emailAddress":{
"name":"Adele Vance",
"address":"[email protected]"
}
},
"toRecipients":[
{
"emailAddress":{
"name":"Alex Wilbur",
"address":"[email protected]"
}
}
],
"ccRecipients":[
{
"emailAddress":{
"name":"Adele Vance",
"address":"[email protected]"
}
}
]
}
}
Source: https://developer.microsoft.com/en-us/graph/docs/api-reference/v1.0/api/attachment_get#request-2