attachment: createUploadSession

Namespace: microsoft.graph

Create an upload session that allows an app to iteratively upload ranges of a file, so as to attach the file to the specified Outlook item. The item can be a message or event.

Use this approach to attach a file if the file size is between 3 MB and 150 MB. To attach a file that's smaller than 3 MB, do a POST operation on the attachments navigation property of the Outlook item; see how to do this for a message or for an event.

As part of the response, this action returns an upload URL that you can use in subsequent sequential PUT queries. Request headers for each PUT operation let you specify the exact range of bytes to be uploaded. This allows transfer to be resumed, in case the network connection is dropped during upload.

The following are the steps to attach a file to an Outlook item using an upload session:

1. Create an upload session.
2. Within that upload session, iteratively upload ranges of bytes (up to 4 MB each time) until all the bytes of the file have been uploaded, and the file is attached to the specified item.
3. Save the ID for the attachment for future access.
4. Optional: Delete the upload session.

See attach large files to Outlook messages or events for an example.

Tip

Exchange Online lets administrators customize the message size limit for Microsoft 365 mailboxes, including any message attachments. By default, this message size limit is 35 MB. Find out how to customize the maximum message size to support attachments larger than the default limit for your tenant.

Important

Be aware of a known issue if you're attaching a large file to a message or event in a shared or delegated mailbox.

This API is available in the following national cloud deployments.

Global service	US Government L4	US Government L5 (DOD)	China operated by 21Vianet
✅	❌	❌	✅

Permissions

Choose the permission or permissions marked as least privileged for this API. Use a higher privileged permission or permissions only if your app requires it. For details about delegated and application permissions, see Permission types. To learn more about these permissions, see the permissions reference.

Permission type	Least privileged permissions	Higher privileged permissions
Delegated (work or school account)	Calendars.ReadWrite	Mail.ReadWrite
Delegated (personal Microsoft account)	Calendars.ReadWrite	Mail.ReadWrite
Application	Calendars.ReadWrite	Mail.ReadWrite

HTTP request

To create an upload session for attaching a file to an event:

POST /me/events/{id}/attachments/createUploadSession
POST /users/{id | userPrincipalName}/events/{id}/attachments/createUploadSession

To create an upload session for attaching a file to a message:

POST /me/messages/{id}/attachments/createUploadSession
POST /users/{id | userPrincipalName}/messages/{id}/attachments/createUploadSession

Request headers

Name	Description
Authorization	Bearer {token}. Required. Learn more about authentication and authorization.

Request body

In the request body, provide a JSON object with the following parameters.

Parameter	Type	Description
AttachmentItem	attachmentItem	Represents attributes of the item to be uploaded and attached. At minimum, specify the attachment type (file), a name, and the size of the file.

Response

If successful, this method returns a 201 Created response code and a new uploadSession object in the response body.

Note:

The uploadUrl property returned as part of the uploadSession response object is an opaque URL for subsequent PUT queries to upload byte ranges of the file. It contains the appropriate auth token for subsequent PUT queries that expire by expirationDateTime. Do not customize this URL.

The nextExpectedRanges property specifies the next file byte location to upload from, for example, "NextExpectedRanges":["2097152"]. You must upload bytes in a file in order.

Examples

Example 1: Create an upload session to add a large attachment to a draft message

The following example shows how to create an upload session that you can use in subsequent file upload operations to the specified message.

Request

HTTP

POST https://graph.microsoft.com/v1.0/me/messages/AAMkADI5MAAIT3drCAAA=/attachments/createUploadSession
Content-type: application/json

{
  "AttachmentItem": {
    "attachmentType": "file",
    "name": "flower",
    "size": 3483322
  }
}

C#

// Code snippets are only available for the latest version. Current version is 5.x

// Dependencies
using Microsoft.Graph.Me.Messages.Item.Attachments.CreateUploadSession;
using Microsoft.Graph.Models;

var requestBody = new CreateUploadSessionPostRequestBody
{
	AttachmentItem = new AttachmentItem
	{
		AttachmentType = AttachmentType.File,
		Name = "flower",
		Size = 3483322L,
	},
};

// To initialize your graphClient, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=csharp
var result = await graphClient.Me.Messages["{message-id}"].Attachments.CreateUploadSession.PostAsync(requestBody);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

CLI

mgc users messages attachments create-upload-session post --user-id {user-id} --message-id {message-id} --body '{\
  "AttachmentItem": {\
    "attachmentType": "file",\
    "name": "flower",\
    "size": 3483322\
  }\
}\
'

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Go

// Code snippets are only available for the latest major version. Current major version is $v1.*

// Dependencies
import (
	  "context"
	  msgraphsdk "github.com/microsoftgraph/msgraph-sdk-go"
	  graphusers "github.com/microsoftgraph/msgraph-sdk-go/users"
	  graphmodels "github.com/microsoftgraph/msgraph-sdk-go/models"
	  //other-imports
)

requestBody := graphusers.NewItemCreateUploadSessionPostRequestBody()
attachmentItem := graphmodels.NewAttachmentItem()
attachmentType := graphmodels.FILE_ATTACHMENTTYPE 
attachmentItem.SetAttachmentType(&attachmentType) 
name := "flower"
attachmentItem.SetName(&name) 
size := int64(3483322)
attachmentItem.SetSize(&size) 
requestBody.SetAttachmentItem(attachmentItem)

// To initialize your graphClient, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=go
createUploadSession, err := graphClient.Me().Messages().ByMessageId("message-id").Attachments().CreateUploadSession().Post(context.Background(), requestBody, nil)

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Java

// Code snippets are only available for the latest version. Current version is 6.x

GraphServiceClient graphClient = new GraphServiceClient(requestAdapter);

com.microsoft.graph.users.item.messages.item.attachments.createuploadsession.CreateUploadSessionPostRequestBody createUploadSessionPostRequestBody = new com.microsoft.graph.users.item.messages.item.attachments.createuploadsession.CreateUploadSessionPostRequestBody();
AttachmentItem attachmentItem = new AttachmentItem();
attachmentItem.setAttachmentType(AttachmentType.File);
attachmentItem.setName("flower");
attachmentItem.setSize(3483322L);
createUploadSessionPostRequestBody.setAttachmentItem(attachmentItem);
var result = graphClient.me().messages().byMessageId("{message-id}").attachments().createUploadSession().post(createUploadSessionPostRequestBody);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

JavaScript

const options = {
	authProvider,
};

const client = Client.init(options);

const uploadSession = {
  AttachmentItem: {
    attachmentType: 'file',
    name: 'flower',
    size: 3483322
  }
};

await client.api('/me/messages/AAMkADI5MAAIT3drCAAA=/attachments/createUploadSession')
	.post(uploadSession);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

PHP

<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Users\Item\Messages\Item\Attachments\CreateUploadSession\CreateUploadSessionPostRequestBody;
use Microsoft\Graph\Generated\Models\AttachmentItem;
use Microsoft\Graph\Generated\Models\AttachmentType;


$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);

$requestBody = new CreateUploadSessionPostRequestBody();
$attachmentItem = new AttachmentItem();
$attachmentItem->setAttachmentType(new AttachmentType('file'));
$attachmentItem->setName('flower');
$attachmentItem->setSize(3483322);
$requestBody->setAttachmentItem($attachmentItem);

$result = $graphServiceClient->me()->messages()->byMessageId('message-id')->attachments()->createUploadSession()->post($requestBody)->wait();

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

PowerShell

Import-Module Microsoft.Graph.Users.Actions

$params = @{
	AttachmentItem = @{
		attachmentType = "file"
		name = "flower"
		size = 3483322
	}
}

# A UPN can also be used as -UserId.
New-MgUserMessageAttachmentUploadSession -UserId $userId -MessageId $messageId -BodyParameter $params

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Python

# Code snippets are only available for the latest version. Current version is 1.x
from msgraph import GraphServiceClient
from msgraph.generated.users.item.messages.item.attachments.create_upload_session.create_upload_session_post_request_body import CreateUploadSessionPostRequestBody
from msgraph.generated.models.attachment_item import AttachmentItem
from msgraph.generated.models.attachment_type import AttachmentType
# To initialize your graph_client, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=python
request_body = CreateUploadSessionPostRequestBody(
	attachment_item = AttachmentItem(
		attachment_type = AttachmentType.File,
		name = "flower",
		size = 3483322,
	),
)

result = await graph_client.me.messages.by_message_id('message-id').attachments.create_upload_session.post(request_body)

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Response

Note: The response object shown here might be shortened for readability.

HTTP/1.1 201 Created
Content-type: application/json

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#microsoft.graph.uploadSession",
    "uploadUrl": "https://outlook.office.com/api/v1.0/Users('a8e8e219-4931-95c1-b73d-62626fd79c32@72aa88bf-76f0-494f-91ab-2d7cd730db47')/Messages('AAMkADI5MAAIT3drCAAA=')/AttachmentSessions('AAMkADI5MAAIT3k0uAAA=')?authtoken=eyJhbGciOiJSUzI1NiIsImtpZCI6IktmYUNIUlN6bllHMmNI",
    "expirationDateTime": "2019-09-25T01:09:30.7671707Z",
    "nextExpectedRanges": [
        "0-"
    ]
}

Example 2: Create an upload session to add a large in-line attachment to a draft message

The following example shows how to create an upload session that can be used to add a large inline attachment to a draft message.

For an inline attachment, set isInline property to true and use the contentId property to specify a CID for the attachment as shown below. In the body of the draft message, use the same CID value to indicate the position where you want to include the attachment using a CID HTML reference tag, for example <img src="cid:my_inline_picture">. Upon successfully uploading the file, the rendered message will include the attachment as part of the message body in the specified location.

Request

HTTP

POST https://graph.microsoft.com/v1.0/me/messages/AAMkAGUwNjQ4ZjIxLTQ3Y2YtNDViMi1iZjc4LTMA=/attachments/createUploadSession
Content-type: application/json

{
  "AttachmentItem": {
    "attachmentType": "file",
    "name": "scenary",
    "size": 7208534,
    "isInline": true,
    "contentId": "my_inline_picture"
  }
}

C#

// Code snippets are only available for the latest version. Current version is 5.x

// Dependencies
using Microsoft.Graph.Me.Messages.Item.Attachments.CreateUploadSession;
using Microsoft.Graph.Models;

var requestBody = new CreateUploadSessionPostRequestBody
{
	AttachmentItem = new AttachmentItem
	{
		AttachmentType = AttachmentType.File,
		Name = "scenary",
		Size = 7208534L,
		IsInline = true,
		ContentId = "my_inline_picture",
	},
};

// To initialize your graphClient, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=csharp
var result = await graphClient.Me.Messages["{message-id}"].Attachments.CreateUploadSession.PostAsync(requestBody);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

CLI

mgc users messages attachments create-upload-session post --user-id {user-id} --message-id {message-id} --body '{\
  "AttachmentItem": {\
    "attachmentType": "file",\
    "name": "scenary",\
    "size": 7208534,\
    "isInline": true,\
    "contentId": "my_inline_picture"\
  }\
}\
'

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Go

// Code snippets are only available for the latest major version. Current major version is $v1.*

// Dependencies
import (
	  "context"
	  msgraphsdk "github.com/microsoftgraph/msgraph-sdk-go"
	  graphusers "github.com/microsoftgraph/msgraph-sdk-go/users"
	  graphmodels "github.com/microsoftgraph/msgraph-sdk-go/models"
	  //other-imports
)

requestBody := graphusers.NewItemCreateUploadSessionPostRequestBody()
attachmentItem := graphmodels.NewAttachmentItem()
attachmentType := graphmodels.FILE_ATTACHMENTTYPE 
attachmentItem.SetAttachmentType(&attachmentType) 
name := "scenary"
attachmentItem.SetName(&name) 
size := int64(7208534)
attachmentItem.SetSize(&size) 
isInline := true
attachmentItem.SetIsInline(&isInline) 
contentId := "my_inline_picture"
attachmentItem.SetContentId(&contentId) 
requestBody.SetAttachmentItem(attachmentItem)

// To initialize your graphClient, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=go
createUploadSession, err := graphClient.Me().Messages().ByMessageId("message-id").Attachments().CreateUploadSession().Post(context.Background(), requestBody, nil)

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Java

// Code snippets are only available for the latest version. Current version is 6.x

GraphServiceClient graphClient = new GraphServiceClient(requestAdapter);

com.microsoft.graph.users.item.messages.item.attachments.createuploadsession.CreateUploadSessionPostRequestBody createUploadSessionPostRequestBody = new com.microsoft.graph.users.item.messages.item.attachments.createuploadsession.CreateUploadSessionPostRequestBody();
AttachmentItem attachmentItem = new AttachmentItem();
attachmentItem.setAttachmentType(AttachmentType.File);
attachmentItem.setName("scenary");
attachmentItem.setSize(7208534L);
attachmentItem.setIsInline(true);
attachmentItem.setContentId("my_inline_picture");
createUploadSessionPostRequestBody.setAttachmentItem(attachmentItem);
var result = graphClient.me().messages().byMessageId("{message-id}").attachments().createUploadSession().post(createUploadSessionPostRequestBody);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

JavaScript

const options = {
	authProvider,
};

const client = Client.init(options);

const uploadSession = {
  AttachmentItem: {
    attachmentType: 'file',
    name: 'scenary',
    size: 7208534,
    isInline: true,
    contentId: 'my_inline_picture'
  }
};

await client.api('/me/messages/AAMkAGUwNjQ4ZjIxLTQ3Y2YtNDViMi1iZjc4LTMA=/attachments/createUploadSession')
	.post(uploadSession);

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

PHP

<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Users\Item\Messages\Item\Attachments\CreateUploadSession\CreateUploadSessionPostRequestBody;
use Microsoft\Graph\Generated\Models\AttachmentItem;
use Microsoft\Graph\Generated\Models\AttachmentType;


$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);

$requestBody = new CreateUploadSessionPostRequestBody();
$attachmentItem = new AttachmentItem();
$attachmentItem->setAttachmentType(new AttachmentType('file'));
$attachmentItem->setName('scenary');
$attachmentItem->setSize(7208534);
$attachmentItem->setIsInline(true);
$attachmentItem->setContentId('my_inline_picture');
$requestBody->setAttachmentItem($attachmentItem);

$result = $graphServiceClient->me()->messages()->byMessageId('message-id')->attachments()->createUploadSession()->post($requestBody)->wait();

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

PowerShell

Import-Module Microsoft.Graph.Users.Actions

$params = @{
	AttachmentItem = @{
		attachmentType = "file"
		name = "scenary"
		size = 7208534
		isInline = $true
		contentId = "my_inline_picture"
	}
}

# A UPN can also be used as -UserId.
New-MgUserMessageAttachmentUploadSession -UserId $userId -MessageId $messageId -BodyParameter $params

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Python

# Code snippets are only available for the latest version. Current version is 1.x
from msgraph import GraphServiceClient
from msgraph.generated.users.item.messages.item.attachments.create_upload_session.create_upload_session_post_request_body import CreateUploadSessionPostRequestBody
from msgraph.generated.models.attachment_item import AttachmentItem
from msgraph.generated.models.attachment_type import AttachmentType
# To initialize your graph_client, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=python
request_body = CreateUploadSessionPostRequestBody(
	attachment_item = AttachmentItem(
		attachment_type = AttachmentType.File,
		name = "scenary",
		size = 7208534,
		is_inline = True,
		content_id = "my_inline_picture",
	),
)

result = await graph_client.me.messages.by_message_id('message-id').attachments.create_upload_session.post(request_body)

For details about how to add the SDK to your project and create an authProvider instance, see the SDK documentation.

Response

Note: The response object shown here might be shortened for readability.

HTTP/1.1 201 Created
Content-type: application/json

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#microsoft.graph.uploadSession",
    "uploadUrl": "https://outlook.office.com/api/gv1.0/users('a8e8e219-4931-95c1-b73d-62626fd79c32@72aa88bf-76f0-494f-91ab-2d7cd730db47')/messages('AAMkAGUwNjQ4ZjIxLTQ3Y2YtNDViMi1iZjc4LTMA=')/AttachmentSessions('AAMkAGUwNjQ4ZjIxLTAAA=')?authtoken=eyJhbGciOiJSUzI1NiIsImtpZCI6IjFTeXQ1bXdXYVh5UFJ",
    "expirationDateTime": "2021-12-27T14:20:12.9708933Z",
    "nextExpectedRanges": [
        "0-"
    ]
}