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.

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

    PNStatus status = publishResponse.Status;

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

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:

pubnub.GetAllUuidMetadata()
        .IncludeCustom(bool)
        .IncludeCount(bool)
        .Page(PNPageObject)
        .Sort(List<string>)
        .Filter(string)
        .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.

Response

{
    "Uuids": [
        {
            "Uuid": "uuid-1",
            "Name": "John Doe",
            "Email": "jack@twitter.com",
            "ExternalId": null,
            "ProfileUrl": null,
            "Custom": null,
            "Updated": "2020-06-17T16:28:14.060718Z"
        },
        {
            "Uuid": "uuid-2",
            "Name": "Bob Cat",
            "Email": "bobc@example.com",
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:

pubnub.GetUuidMetadata()
        .Uuid(string)
        .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

Response

{
    "Uuid": "uuid-1",
    "Name": "John Doe",
    "Email": "jack@twitter.com",
    "ExternalId": null,
    "ProfileUrl": null,
    "Custom": null,
    "Updated": "2020-06-17T16:28:14.060718Z"
}

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:

Get the existing metadata and store it locally.
Append the new custom metadata to the existing one.
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:

pubnub.SetUuidMetadata()
        .Uuid(string)
        .Name(string)
        .Email(string)
        .ExternalId(string)
        .ProfileUrl(string)
        .Custom(Dictionary<string, object>)
        .IncludeCustom(bool)
        .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

Response

{
    "Uuid": "uuid-1",
    "Name": "John Doe",
    "Email": "jack@twitter.com",
    "ExternalId": null,
    "ProfileUrl": null,
    "Custom": null,
    "Updated": "2020-06-17T16:28:14.060718Z"
}

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:

pubnub.RemoveUuidMetadata()
        .Uuid(string)

* required

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

Sample code

Response

{}

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:

pubnub.GetAllChannelMetadata()
        .IncludeCustom(bool)
        .IncludeCount(bool)
        .Page(PNPageObject)
        .Sort(List<string>)
        .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

Response

{
    "Channels": [
        {
            "Channel": "my-channel",
            "Name": "My channel",
            "Description": "A channel that is mine",
            "Custom": null,
            "Updated": "2020-06-17T16:52:19.562469Z"
        },
        {
            "Channel": "main",
            "Name": "Main channel",
            "Description": "The main channel",
            "Custom": {
                "public": true,
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:

pubnub.GetChannelMetadata()
        .Channel(string)
        .IncludeCustom(bool)

* required

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

Sample code

Response

{
    "Channel": "my-channel",
    "Name": "My channel",
    "Description": "A channel that is mine",
    "Custom": null,
    "Updated": "2020-06-17T16:52:19.562469Z"
}

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:

Get the existing metadata and store it locally.
Append the new custom metadata to the existing one.
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:

pubnub.SetChannelMetadata()
        .Channel(string)
        .Name(string)
        .Description(string)
        .Custom(Dictionary<string, object>)
        .IncludeCustom(bool)
        .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

Response

{
    "Channel": "my-channel",
    "Name": "John Doe",
    "Description": "sample description",
    "Custom": {
        "color": "blue"
    },
    "Updated": "2020-06-17T16:52:19.562469Z"
}

Other examples

Iteratively update existing metadata

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:

pubnub.RemoveChannelMetadata()
        .Channel(string)

* required

Parameter	Description
`Channel` * Type: string	Channel name.

Sample code

Response

{}

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:

pubnub.GetMemberships()
        .Uuid(string)
        .Include(PNMembershipField[])
        .IncludeCount(bool)
        .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

Response

{
    "Memberships": [
        {
            "ChannelMetadata": {
                "Channel": "my-channel",
                "Name": "My channel",
                "Description": "A channel that is mine",
                "Custom": null,
                "Updated": "2020-06-17T16:55:44.632042Z"
            },
            "Custom": {
                "starred": false
            },
            "Updated": "2020-06-17T17:05:25.987964Z"
        },
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:

pubnub.SetMemberships()
        .Uuid(string)
        .Channels(List<PNMembership>)
        .Include(PNMembershipField[])
        .IncludeCount(bool)
        .Page(PNPageObject)
        .Sort(List<string>)
        .Filter(string)
        .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

Response

{
    "Memberships": [
        {
            "ChannelMetadata": {
                "Channel": "my-channel",
                "Name": "My channel",
                "Description": "A channel that is mine",
                "Custom": null,
                "Updated": "2020-06-17T16:55:44.632042Z"
            },
            "Custom": {
                "starred": false
            },
            "Updated": "2020-06-17T17:05:25.987964Z"
        },
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:

pubnub.RemoveMemberships()
        .Uuid(string)
        .Channels(List<string>)
        .Include(PNMembershipField[])
        .IncludeCount(bool)
        .Page(PNPageObject)
        .Sort(List<string>)
        .Filter(string)
        .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

Response

{
    "Memberships": [
        {
            "ChannelMetadata": {
                "Channel": "my-channel",
                "Name": "My channel",
                "Description": "A channel that is mine",
                "Custom": null,
                "Updated": "2020-06-17T16:55:44.632042Z"
            },
            "Custom": {
                "starred": false
            },
            "Updated": "2020-06-17T17:05:25.987964Z"
        },
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:

pubnub.ManageMemberships()
        .Uuid(string)
        .Set(List<PNMembership>)
        .Remove(List<string>)
        .Include(PNMembershipField[])
        .IncludeCount(bool)
        .Page(PNPageObject)
        .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

Response

{
    "Memberships": [
        {
            "ChannelMetadata": {
                "Channel": "my-channel",
                "Name": "My channel",
                "Description": "A channel that is mine",
                "Custom": null,
                "Updated": "2020-06-17T16:55:44.632042Z"
            },
            "Custom": {
                "starred": false
            },
            "Updated": "2020-06-17T17:05:25.987964Z"
        },
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:

pubnub.GetChannelMembers()
        .Channel(string)
        .Include(PNChannelMemberField[])
        .IncludeCount(bool)
        .Page(PNPageObject)
        .Sort(List<string>)
        .Filter(string)
        .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

Response

{
    "ChannelMembers": [
        {
            "UuidMetadata": {
                "Uuid": "uuid-1",
                "Name": "John Doe",
                "Email": "jack@twitter.com",
                "ExternalId": "",
                "ProfileUrl": "",
                "Custom": null,
                "Updated": "2019-02-20T23:11:20.89375"
            },
            "Custom": {
                "role": "admin"
            },
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:

pubnub.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

Response

{
    "ChannelMembers": [
        {
            "UuidMetadata": {
                "Uuid": "uuid-1",
                "Name": "John Doe",
                "Email": "jack@twitter.com",
                "ExternalId": "",
                "ProfileUrl": "",
                "Custom": null,
                "Updated": "2019-02-20T23:11:20.89375"
            },
            "Custom": {
                "role": "admin"
            },
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:

pubnub.RemoveChannelMembers()
        .Channel(string)
        .Remove( List)
        .Include(PNChannelMembersInclude[])
        .Limit(int)
        .Count(bool)
        .Start(string)
        .End(string)
        .Sort(List)
        .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

Response

{
    "ChannelMembers": [
        {
            "UuidMetadata": {
                "Uuid": "uuid-1",
                "Name": "John Doe",
                "Email": "jack@twitter.com",
                "ExternalId": "",
                "ProfileUrl": "",
                "Custom": null,
                "Updated": "2019-02-20T23:11:20.89375"
            },
            "Custom": {
                "role": "admin"
            },
show all 39 lines

Request execution

User​

Get metadata for all users​

Method(s)​

Sample code​

Reference code

Response​

Get user metadata​

Method(s)​

Sample code​

Response​

Set user metadata​

Unsupported partial updates of custom metadata

Method(s)​

API limits

Sample code​

Response​

Remove user metadata​

Method(s)​

Sample code​

Response​

Channel​

Get metadata for all channels​

Method(s)​

Sample code​

Response​

Get channel metadata​

Method(s)​

Sample code​

Response​

Set channel metadata​

Unsupported partial updates of custom metadata

Method(s)​

API limits

Sample code​

Response​

Other examples​

Iteratively update existing metadata​

Remove channel metadata​

Method(s)​

Sample code​

Response​

Channel memberships​

Get channel memberships​

Method(s)​

Sample code​

Response​

Set channel memberships​

Method(s)​

API limits

PNMembership​

Sample code​

Response​

Remove channel memberships​

Method(s)​

Sample code​

Response​

Manage channel memberships​

Method(s)​

Sample code​

Response​

Channel members​

Get channel members​

Method(s)​

Sample code​

Response​

Set channel members​

Method(s)​

API limits

Sample code​

Response​

Remove channel members​

Method(s)​

Sample code​

Response​

User

Get metadata for all users

Method(s)

Sample code

Response

Get user metadata

Method(s)

Sample code

Response

Set user metadata

Method(s)

Sample code

Response

Remove user metadata

Method(s)

Sample code

Response

Channel

Get metadata for all channels

Method(s)

Sample code

Response

Get channel metadata

Method(s)

Sample code

Response

Set channel metadata

Method(s)

Sample code

Response

Other examples

Iteratively update existing metadata

Remove channel metadata

Method(s)

Sample code

Response

Channel memberships

Get channel memberships

Method(s)

Sample code

Response

Set channel memberships

Method(s)

PNMembership

Sample code

Response

Remove channel memberships

Method(s)

Sample code

Response

Manage channel memberships

Method(s)

Sample code

Response

Channel members

Get channel members

Method(s)

Sample code

Response

Set channel members

Method(s)

Sample code

Response

Remove channel members

Method(s)

Sample code

Response