App Context API for C# SDK

This page describes App Context (formerly Objects v2). To upgrade from Objects v1, refer to the migration guide.

App Context provides easy-to-use, serverless storage for user and channel data that you need to build reliable, scalable applications. Use App Context to store metadata about your application users and channels, and their membership associations, without the need to run your own databases.

PubNub triggers events when object data is set, updated, or removed. Setting the same data that already exists does not trigger an event. Clients can receive these events in real time and update the front end accordingly.

Request execution

Use try/catch when working with the C# SDK.

If a request has invalid parameters (for example, a missing required field), the SDK throws an exception. If the request reaches the server but fails (server error or network issue), the error details are available in the returned status.

1try
2{
3    PNResult<PNPublishResult> publishResponse = await pubnub.Publish()
4        .Message("Why do Java developers wear glasses? Because they can't C#.")
5        .Channel("my_channel")
6        .ExecuteAsync();
7

8    PNStatus status = publishResponse.Status;
9

10    Console.WriteLine("Server status code : " + status.StatusCode.ToString());
11}
12catch (Exception ex)
13{
14    Console.WriteLine($"Request can't be executed due to error: {ex.Message}");
15}

User

Get metadata for all users

Returns a paginated list of UUID Metadata objects, optionally including the custom data object for each.

Method(s)

To Get All UUID Metadata you can use the following method(s) in the C# SDK:

1pubnub.GetAllUuidMetadata()
2        .IncludeCustom(bool)
3        .IncludeCount(bool)
4        .Page(PNPageObject)
5        .Sort(List<string>)
6        .Filter(string)
7        .Limit(int)

* required

Parameter	Description
IncludeCustom Type: bool	Whether to include the Custom object in the response.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1

Response

1{
2    "Uuids": [
3        {
4            "Uuid": "uuid-1",
5            "Name": "John Doe",
6            "Email": "jack@twitter.com",
7            "ExternalId": null,
8            "ProfileUrl": null,
9            "Custom": null,
10            "Updated": "2020-06-17T16:28:14.060718Z"
11        },
12        {
13            "Uuid": "uuid-2",
14            "Name": "Bob Cat",
15            "Email": "bobc@example.com",
16            "ExternalId": null,
17            "ProfileUrl": null,
18            "Custom": {
19                "phone": "999-999-9999"
20            },
21            "Updated": "2020-06-17T16:42:22.906768Z"
22        }
23    ],
24    "TotalCount": 2,
25    "Page": {
26        "Next": "MTI",
27        "Prev": ""
28    }
29}

show all 29 lines

Get user metadata

Returns metadata for the specified UUID, optionally including the custom data object for each.

Method(s)

To Get UUID Metadata you can use the following method(s) in the C# SDK:

1pubnub.GetUuidMetadata()
2        .Uuid(string)
3        .IncludeCustom(bool)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
IncludeCustom Type: bool	Whether to include the Custom object in the response.

Sample code

1

Response

1{
2    "Uuid": "uuid-1",
3    "Name": "John Doe",
4    "Email": "jack@twitter.com",
5    "ExternalId": null,
6    "ProfileUrl": null,
7    "Custom": null,
8    "Updated": "2020-06-17T16:28:14.060718Z"
9}

Set user metadata

Unsupported partial updates of custom metadata

The value of the custom metadata parameter sent in this method always overwrites the value stored on PubNub servers. If you want to add new custom data to an existing one, you must:

1. Get the existing metadata and store it locally.
2. Append the new custom metadata to the existing one.
3. Set the entire updated custom object.

Set metadata for a UUID in the database, optionally including the custom data object for each.

Method(s)

To Set UUID Metadata you can use the following method(s) in the C# SDK:

1pubnub.SetUuidMetadata()
2        .Uuid(string)
3        .Name(string)
4        .Email(string)
5        .ExternalId(string)
6        .ProfileUrl(string)
7        .Custom(Dictionary<string, object>)
8        .IncludeCustom(bool)
9        .IfMatchesEtag(string)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
Name * Type: string	Display name for the user.
Email Type: string	The user's email address.
ExternalId Type: string	User's identifier in an external system.
ProfileUrl Type: string	The URL of the user's profile picture.
Custom Type: Dictionary<string, object>	Custom JSON values. Can be strings, numbers, or booleans. Filtering by Custom isn’t supported.
IncludeCustom Type: bool	Whether to include the Custom object in the response.
IfMatchesEtag Type: String	Use the eTag from an applicable get metadata call to ensure updates only apply if the object hasn’t changed. If the eTags differ, the server returns HTTP 412.

API limits

To learn about the maximum length of parameters used to set user metadata, refer to REST API docs.

Sample code

1

Response

1{
2    "Uuid": "uuid-1",
3    "Name": "John Doe",
4    "Email": "jack@twitter.com",
5    "ExternalId": null,
6    "ProfileUrl": null,
7    "Custom": null,
8    "Updated": "2020-06-17T16:28:14.060718Z"
9}

Remove user metadata

Removes the metadata from a specified UUID.

Method(s)

To Remove UUID Metadata you can use the following method(s) in the C# SDK:

1pubnub.RemoveUuidMetadata()
2        .Uuid(string)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.

Sample code

1

Response

1{}

Channel

Get metadata for all channels

Returns a paginated list of Channel Metadata objects, optionally including the custom data object for each.

Method(s)

To Get All Channel Metadata you can use the following method(s) in the C# SDK:

1pubnub.GetAllChannelMetadata()
2        .IncludeCustom(bool)
3        .IncludeCount(bool)
4        .Page(PNPageObject)
5        .Sort(List<string>)
6        .Filter(string)

* required

Parameter	Description
IncludeCustom Type: bool	Whether to include the Custom object in the response.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.

Sample code

1

Response

1{
2    "Channels": [
3        {
4            "Channel": "my-channel",
5            "Name": "My channel",
6            "Description": "A channel that is mine",
7            "Custom": null,
8            "Updated": "2020-06-17T16:52:19.562469Z"
9        },
10        {
11            "Channel": "main",
12            "Name": "Main channel",
13            "Description": "The main channel",
14            "Custom": {
15                "public": true,
16                "motd": "Always check your spelling!"
17            },
18            "Updated": "2020-06-17T16:52:19.562469Z"
19        }
20    ],
21    "TotalCount": 2,
22    "Page": {
23        "Next": "MTE",
24        "Prev": ""
25    }
26}

show all 26 lines

Get channel metadata

Returns metadata for the specified Channel, optionally including the custom data object for each.

Method(s)

To Get Channel Metadata you can use the following method(s) in the C# SDK:

1pubnub.GetChannelMetadata()
2        .Channel(string)
3        .IncludeCustom(bool)

* required

Parameter	Description
Channel * Type: string	Channel name.
IncludeCustom Type: bool	Whether to include the Custom object in the response.

Sample code

1

Response

1{
2    "Channel": "my-channel",
3    "Name": "My channel",
4    "Description": "A channel that is mine",
5    "Custom": null,
6    "Updated": "2020-06-17T16:52:19.562469Z"
7}

Set channel metadata

Unsupported partial updates of custom metadata

The value of the custom metadata parameter sent in this method always overwrites the value stored on PubNub servers. If you want to add new custom data to an existing one, you must:

1. Get the existing metadata and store it locally.
2. Append the new custom metadata to the existing one.
3. Set the entire updated custom object.

Set metadata for a Channel in the database, optionally including the custom data object for each.

Method(s)

To Set Channel Metadata you can use the following method(s) in the C# SDK:

1pubnub.SetChannelMetadata()
2        .Channel(string)
3        .Name(string)
4        .Description(string)
5        .Custom(Dictionary<string, object>)
6        .IncludeCustom(bool)
7        .IfMatchesEtag(string)

* required

Parameter	Description
Channel * Type: string	Channel name.
Name Type: string	Channel name.
Description Type: string	Channel description.
Custom Type: Dictionary<string, object>	Custom JSON values. Can be strings, numbers, or booleans. Filtering by Custom isn’t supported.
IncludeCustom Type: bool	Whether to include the Custom object in the response.
IfMatchesEtag Type: String	Use the eTag from an applicable get metadata call to ensure updates only apply if the object hasn’t changed. If the eTags differ, the server returns HTTP 412.

API limits

To learn about the maximum length of parameters used to set channel metadata, refer to REST API docs.

Sample code

1

Response

1{
2    "Channel": "my-channel",
3    "Name": "John Doe",
4    "Description": "sample description",
5    "Custom": {
6        "color": "blue"
7    },
8    "Updated": "2020-06-17T16:52:19.562469Z"
9}

Other examples

Iteratively update existing metadata

1

Remove channel metadata

Removes the metadata from a specified channel.

Method(s)

To Remove Channel Metadata you can use the following method(s) in the C# SDK:

1pubnub.RemoveChannelMetadata()
2        .Channel(string)

* required

Parameter	Description
Channel * Type: string	Channel name.

Sample code

1

Response

1{}

Channel memberships

Get channel memberships

This method returns a list of channel memberships for a user. This method doesn't return subscriptions.

Method(s)

To Get Memberships you can use the following method(s) in the C# SDK:

1pubnub.GetMemberships()
2        .Uuid(string)
3        .Include(PNMembershipField[])
4        .IncludeCount(bool)
5        .Page(PNPageObject)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
Include Type: PNMembershipField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.

Sample code

1

Response

1{
2    "Memberships": [
3        {
4            "ChannelMetadata": {
5                "Channel": "my-channel",
6                "Name": "My channel",
7                "Description": "A channel that is mine",
8                "Custom": null,
9                "Updated": "2020-06-17T16:55:44.632042Z"
10            },
11            "Custom": {
12                "starred": false
13            },
14            "Updated": "2020-06-17T17:05:25.987964Z"
15        },
16        {
17            "ChannelMetadata": {
18                "Channel": "main",
19                "Name": "Main channel",
20                "Description": "The main channel",
21                "Custom": {
22                    "public": true,
23                    "motd": "Always check your spelling!"
24                },
25                "Updated": "2020-06-17T16:55:44.632042Z"
26            },
27            "Custom": {
28                "item": "book"
29            },
30            "Updated": "2020-06-17T17:05:25.987964Z"
31        }
32    ],
33    "TotalCount": 2,
34    "Page": {
35        "Next": "MQ",
36        "Prev": ""
37    }
38}

show all 38 lines

Set channel memberships

Set channel memberships for a UUID.

Method(s)

To Set Memberships you can use the following method(s) in the C# SDK:

1pubnub.SetMemberships()
2        .Uuid(string)
3        .Channels(List<PNMembership>)
4        .Include(PNMembershipField[])
5        .IncludeCount(bool)
6        .Page(PNPageObject)
7        .Sort(List<string>)
8        .Filter(string)
9        .Limit(int)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
Channels * Type: List<PNMembership>	Channels to add to the membership. Accepts channel names (strings) or objects (with optional custom data).
Include Type: PNMembershipField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

API limits

To learn about the maximum length of parameters used to set channel membership metadata, refer to REST API docs.

PNMembership

* required

Property	Description
Channel * Type: string	The name of the channel associated with this membership.
Custom Type: Dictionary<string, object>	A dictionary that stores custom metadata related to the membership, allowing for additional context or information. Values can be strings, numbers, or booleans.
Status Type: string	The status of the membership, for example: "active" or "inactive"
Type Type: string	The type of membership for categorization purposes.

Sample code

1

Response

1{
2    "Memberships": [
3        {
4            "ChannelMetadata": {
5                "Channel": "my-channel",
6                "Name": "My channel",
7                "Description": "A channel that is mine",
8                "Custom": null,
9                "Updated": "2020-06-17T16:55:44.632042Z"
10            },
11            "Custom": {
12                "starred": false
13            },
14            "Updated": "2020-06-17T17:05:25.987964Z"
15        },
16        {
17            "ChannelMetadata": {
18                "Channel": "main",
19                "Name": "Main channel",
20                "Description": "The main channel",
21                "Custom": {
22                    "public": true,
23                    "motd": "Always check your spelling!"
24                },
25                "Updated": "2020-06-17T16:55:44.632042Z"
26            },
27            "Custom": {
28                "item": "book"
29            },
30            "Updated": "2020-06-17T17:05:25.987964Z"
31        }
32    ],
33    "TotalCount": 2,
34    "Page": {
35        "Next": "MQ",
36        "Prev": ""
37    }
38}

show all 38 lines

Remove channel memberships

Remove channel memberships for a UUID.

Method(s)

To Remove Memberships you can use the following method(s) in the C# SDK:

1pubnub.RemoveMemberships()
2        .Uuid(string)
3        .Channels(List<string>)
4        .Include(PNMembershipField[])
5        .IncludeCount(bool)
6        .Page(PNPageObject)
7        .Sort(List<string>)
8        .Filter(string)
9        .Limit(int)

* required

Parameter	Description
Uuid Type: String	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
Channels * Type: List<string>	Channels to remove from membership.
Include Type: PNMembershipField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

Sample code

1

Response

1{
2    "Memberships": [
3        {
4            "ChannelMetadata": {
5                "Channel": "my-channel",
6                "Name": "My channel",
7                "Description": "A channel that is mine",
8                "Custom": null,
9                "Updated": "2020-06-17T16:55:44.632042Z"
10            },
11            "Custom": {
12                "starred": false
13            },
14            "Updated": "2020-06-17T17:05:25.987964Z"
15        },
16        {
17            "ChannelMetadata": {
18                "Channel": "main",
19                "Name": "Main channel",
20                "Description": "The main channel",
21                "Custom": {
22                    "public": true,
23                    "motd": "Always check your spelling!"
24                },
25                "Updated": "2020-06-17T16:55:44.632042Z"
26            },
27            "Custom": {
28                "item": "book"
29            },
30            "Updated": "2020-06-17T17:05:25.987964Z"
31        }
32    ],
33    "TotalCount": 2,
34    "Page": {
35        "Next": "MQ",
36        "Prev": ""
37    }
38}

show all 38 lines

Manage channel memberships

Set and remove channel memberships for a user.

Method(s)

To Manage Memberships you can use the following method(s) in the C# SDK:

1pubnub.ManageMemberships()
2        .Uuid(string)
3        .Set(List<PNMembership>)
4        .Remove(List<string>)
5        .Include(PNMembershipField[])
6        .IncludeCount(bool)
7        .Page(PNPageObject)
8        .Sort(List<string>)

* required

Parameter	Description
Uuid * Type: string	Unique user identifier (UUID). If not supplied, the current user's UUID is used.
Set Type: List<PNMembership>	Set channel memberships for the user.
Remove Type: List<string>	Remove channel memberships for the user.
Include Type: PNMembershipField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).

Sample code

1

Response

1{
2    "Memberships": [
3        {
4            "ChannelMetadata": {
5                "Channel": "my-channel",
6                "Name": "My channel",
7                "Description": "A channel that is mine",
8                "Custom": null,
9                "Updated": "2020-06-17T16:55:44.632042Z"
10            },
11            "Custom": {
12                "starred": false
13            },
14            "Updated": "2020-06-17T17:05:25.987964Z"
15        },
16        {
17            "ChannelMetadata": {
18                "Channel": "main",
19                "Name": "Main channel",
20                "Description": "The main channel",
21                "Custom": {
22                    "public": true,
23                    "motd": "Always check your spelling!"
24                },
25                "Updated": "2020-06-17T16:55:44.632042Z"
26            },
27            "Custom": {
28                "item": "book"
29            },
30            "Updated": "2020-06-17T17:05:25.987964Z"
31        }
32    ],
33    "TotalCount": 2,
34    "Page": {
35        "Next": "MQ",
36        "Prev": ""
37    }
38}

show all 38 lines

Channel members

Get channel members

This method returns a list of members in a channel. The list includes user metadata for members that have additional metadata stored in the database.

Method(s)

To Get Channel Members you can use the following method(s) in the C# SDK:

1pubnub.GetChannelMembers()
2        .Channel(string)
3        .Include(PNChannelMemberField[])
4        .IncludeCount(bool)
5        .Page(PNPageObject)
6        .Sort(List<string>)
7        .Filter(string)
8        .Limit(int)

* required

Parameter	Description
Channel * Type: string	Channel name.
Include Type: PNChannelMemberField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

Sample code

1

Response

1{
2    "ChannelMembers": [
3        {
4            "UuidMetadata": {
5                "Uuid": "uuid-1",
6                "Name": "John Doe",
7                "Email": "jack@twitter.com",
8                "ExternalId": "",
9                "ProfileUrl": "",
10                "Custom": null,
11                "Updated": "2019-02-20T23:11:20.89375"
12            },
13            "Custom": {
14                "role": "admin"
15            },
16            "Updated": "2020-06-17T17:05:25.987964Z"
17        },
18        {
19            "UuidMetadata": {
20                "Uuid": "uuid-2",
21                "Name": "Bob Cat",
22                "Email": "bobc@example.com",
23                "ExternalId": "",
24                "ProfileUrl": "",
25                "Custom": {
26                    "phone": "999-999-9999"
27                },
28                "Updated": "2019-02-20T23:11:20.89375"
29            },
30            "Custom": null,
31            "Updated": "2020-06-17T17:05:25.987964Z"
32        }
33    ],
34    "TotalCount": 2,
35    "Page": {
36        "Next": "MQ",
37        "Prev": ""
38    }
39}

show all 39 lines

Set channel members

This method sets members in a channel.

Method(s)

To Set Channel Members you can use the following method(s) in the C# SDK:

1pubnub.SetChannelMembers().Channel(string).Uuids(List<PNChannelMember>).Include(PNChannelMemberField[]).Page(PNPageObject).Sort(List<string>).Filter(string).Limit(int)

* required

Parameter	Description
Channel * Type: String	Channel name.
Uuids * Type: List<PNChannelMember>	Members to add to the channel. Accepts UUIDs (strings) or objects (with optional custom data).
Include Type: PNChannelMemberField[]	Whether to include additional fields.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

API limits

To learn about the maximum length of parameters used to set channel members metadata, refer to REST API docs.

Sample code

1

Response

1{
2    "ChannelMembers": [
3        {
4            "UuidMetadata": {
5                "Uuid": "uuid-1",
6                "Name": "John Doe",
7                "Email": "jack@twitter.com",
8                "ExternalId": "",
9                "ProfileUrl": "",
10                "Custom": null,
11                "Updated": "2019-02-20T23:11:20.89375"
12            },
13            "Custom": {
14                "role": "admin"
15            },
16            "Updated": "2020-06-17T17:05:25.987964Z"
17        },
18        {
19            "UuidMetadata": {
20                "Uuid": "uuid-2",
21                "Name": "Bob Cat",
22                "Email": "bobc@example.com",
23                "ExternalId": "",
24                "ProfileUrl": "",
25                "Custom": {
26                    "phone": "999-999-9999"
27                },
28                "Updated": "2019-02-20T23:11:20.89375"
29            },
30            "Custom": null,
31            "Updated": "2020-06-17T17:05:25.987964Z"
32        }
33    ],
34    "TotalCount": 2,
35    "Page": {
36        "Next": "MQ",
37        "Prev": ""
38    }
39}

show all 39 lines

Remove channel members

Remove members from a Channel.

Method(s)

To Remove Channel Members you can use the following method(s) in the C# SDK:

1pubnub.RemoveChannelMembers()
2        .Channel(string)
3        .Remove( List)
4        .Include(PNChannelMembersInclude[])
5        .Limit(int)
6        .Count(bool)
7        .Start(string)
8        .End(string)
9        .Sort(List)
10        .Async()

* required

Parameter	Description
Channel * Type: string	Channel name.
Uuids * Type: List<string>	Members to remove from the channel.
Include Type: PNChannelMemberField[]	Whether to include additional fields.
IncludeCount Type: bool	Whether to include the total count in the paginated response. Default is false.
Page Type: PNPageObject	Cursor-based pagination.
Sort Type: List<string>	Sort by id, name, updated with asc/desc (for example, {name: 'asc'}).
Filter Type: string	Filter expression. Only matching objects are returned. See filtering.
Limit Type: int	Number of objects to return. Default/Max: 100.

Sample code

1

Response

1{
2    "ChannelMembers": [
3        {
4            "UuidMetadata": {
5                "Uuid": "uuid-1",
6                "Name": "John Doe",
7                "Email": "jack@twitter.com",
8                "ExternalId": "",
9                "ProfileUrl": "",
10                "Custom": null,
11                "Updated": "2019-02-20T23:11:20.89375"
12            },
13            "Custom": {
14                "role": "admin"
15            },
16            "Updated": "2020-06-17T17:05:25.987964Z"
17        },
18        {
19            "UuidMetadata": {
20                "Uuid": "uuid-2",
21                "Name": "Bob Cat",
22                "Email": "bobc@example.com",
23                "ExternalId": "",
24                "ProfileUrl": "",
25                "Custom": {
26                    "phone": "999-999-9999"
27                },
28                "Updated": "2019-02-20T23:11:20.89375"
29            },
30            "Custom": null,
31            "Updated": "2020-06-17T17:05:25.987964Z"
32        }
33    ],
34    "TotalCount": 2,
35    "Page": {
36        "Next": "MQ",
37        "Prev": ""
38    }
39}

show all 39 lines