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 you need to build innovative, reliable, scalable applications. Use App Context to easily store metadata about your application users and channels, and their membership associations, without the need to stand up your own databases.

PubNub also triggers events when object data is changed: set, updated, or removed from the database. At the same time, making a request to set the same data that already exist, doesn't trigger any event. Clients can receive these events in real time and update their front-end application accordingly.

Request execution

We recommend using try and catch statements when working with the C# SDK.

If there's an issue with the provided API parameter values, like missing a required parameter, the SDK throws an exception. However, if there is a server-side API execution issue or a network problem, the error details are contained within the 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 fetch Custom fields or not.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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",

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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. If not supplied then current user's Uuid is used.
IncludeCustom Type: bool	Whether to fetch Custom fields or not.

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:

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:

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. If not supplied then 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>	JSON object of key-value pairs with supported data types. App Context filtering language doesn’t support filtering by custom properties.
IncludeCustom Type: bool	Whether to fetch Custom fields or not.
IfMatchesEtag Type: String	The entity tag to be used to ensure updates only happen if the object hasn't been modified since it was read. Use the eTag you received from an applicable get metadata method to check against the server entity tag. If the eTags don't match, an HTTP 412 error is thrown.

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. If not supplied then 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 fetch Custom fields or not.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.

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,

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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 fetch Custom fields or not.

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:

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:

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	Name of a channel.
Description Type: string	Description of a channel.
Custom Type: Dictionary<string, object>	Include respective additional fields in the response. App Context filtering language doesn’t support filtering by custom properties.
IncludeCustom Type: bool	Whether to fetch custom fields or not.
IfMatchesEtag Type: String	The entity tag to be used to ensure updates only happen if the object hasn't been modified since it was read. Use the eTag you received from an applicable get metadata method to check against the server entity tag. If the eTags don't match, an HTTP 412 error is thrown.

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

The method returns a list of channel memberships for a user. This method doesn't return a user's 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. If not supplied then current user's Uuid is used.
Include Type: PNMembershipField[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for 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"
        },

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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. If not supplied then current user's Uuid is used.
Channels * Type: List<PNMembership>	List of Channels to add to membership. List can contain strings (channel-name only) or objects (which can include custom data).
Include Type: PNMembershipField[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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.
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"
        },

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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. If not supplied then current user's Uuid is used.
Channels * Type: List<string>	Channels to remove from membership.
Include Type: PNMembershipField[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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"
        },

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Manage channel memberships

The method 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. If not supplied then 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[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. 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"
        },

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Channel members

Get channel members

The method returns a list of members in a channel. The list will include 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[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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"
            },

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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>	List of members to add to the channel. List can contain strings (Uuids only) or objects (which can include custom data).
Include Type: PNChannelMemberField[]	Include respective additional fields in the response.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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"
            },

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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 channel.
Include Type: PNChannelMemberField[]	Include respective additional fields in the response.
IncludeCount Type: bool	Request IncludeCount to be included in paginated response. By default, IncludeCount is omitted.
Page Type: PNPageObject	Use for pagination.
Sort Type: List<string>	List of properties to sort by. Available options are id, name, and updated. Use asc or desc to specify sort direction. For example: {name: 'asc'}
Filter Type: string	Expression used to filter the results. Only objects whose properties satisfy the given expression are returned. The filter language is defined here.
Limit Type: int	Number of objects to return in response. Default is 100, which is also the maximum value.

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"
            },

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