Kotlin Access Manager API Reference for Realtime Apps
PubNub Access Manager (PAM) allows you to enforce secure controls for client access to resources within the PubNub network. With PAM, your servers can grant their clients access to individual PubNub resources for a limited duration, with the ability to extend access or add permissions for additional resources.
As soon as PAM is enabled, no publish/subscribe operations can be done without first explicitly providing an authorization token to the PubNub object. If an invalid token is provided, the requesting client will receive a Forbidden error.
For more information about PAM, refer to Managing Permissions with Access Manager.
Calling Kotlin methods
Most PubNub Kotlin SDK method invocations return an Endpoint
object, which allows you to decide whether to perform the operation synchronously or asynchronously. You must choose one of these or the operation will not be performed at all.
For example, the following code is valid and will compile, but the publish won't be performed:
pubnub.publish(
message = "this sdk rules!",
channel = "my_channel"
)
To successfully publish a message, you must follow the actual method invocation with whether to perform it synchronously or asynchronously, for example:
pubnub.publish(
message = "this sdk rules!",
channel = "my_channel"
).async { result, status ->
if (status.error) {
// handle error
} else {
// handle successful method result
}
}
Grant
Requires Access Manager add-onRequires that the Access Manager add-on is enabled for your key. See this page on enabling add-on features on your keys:
https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-
The grant
method allows you to grant permissions for one or more resources to one or more authKeys
. You may need to make multiple grant calls with an authKey
so that you can specify explicit permissions for each channel
, channelGroup
and uuid
resources. For common permissions, you can normally use a single request.
Privileges specifically granted to an application's subscribeKey
always take precedence over privileges granted to channel
or auth_key
. Therefore an application that requires authentication at the user level should not grant access at either the Application or Channel levels. View the Grant Levels section for more details.
The grant request allows your server to securely grant access for your clients on the following resources within the platform. Each resource allows a limited set of permissions that control the operations that can be performed by the clients. For permissions and API operations mapping information, refer to Managing Permissions with Access Manager
Resource | Permissions |
---|---|
channel | read , write , get , manage , update , join , delete |
uuid | get , update , delete |
channelGroup | read , manage |
To make granting access on multiple channels and channel groups more efficient, you can use the wildcard notation. It doesn't, however, apply to the uuid
resource and you can only go one level deep using wildcards.
*
grants access on all channelsa.*
grants access on all channels that begin witha.
a.b.*
doesn't work. If you grant ona.b.*
, the grant treatsa.b.*
as a channel name, not a wildcard
When a user attempts to access a PubNub resource, PAM will evaluate any existing rules using the following order of precedence before access to a channel is granted to the user:
- Application Level - PAM privileges are always evaluated first at the
Application
level. If eitherread
orwrite
attribute is set totrue
for asubscribeKey
, PAM will immediately grant access for that attribute without proceeding to check permissions at eitherChannel
orUser
levels. If an attribute is set tofalse
at the Application level, PAM proceeds to evaluate the attribute at the next most granular level. - Channel Level - After first verifying an attribute at the Application level, PAM evaluates the attribute at the Channel level. If an attribute is set to
true
for a combination ofsubscribeKey
, andchannel
, PAM grants access for that attribute at theChannel
level without proceeding to check whether there may beuser
level permissions. - User Level (Recommended) - As a final step PAM evaluates the attributes at the
User
level. If an attribute is set totrue
forsubscribeKey
,channel
andauth_key
, access is granted for that attribute. Similarly, user level grants also allow you granting anauth_key
access tochannelGroups
anduuids
. User level grants requireauth_key
and are the recommended approach if you need to manage permissions for individual users within your application. Each user should be assigned a uniqueauth_key
and securely passed back to the user to perform operations on the platform.
Method(s)
To Grant Permissions on a Channel
you can use the following method(s) in the Kotlin V4 SDK:
this.pubnub.grant(
authKeys: List<String>,
channels: List<String>,
channelGroups: List<String>,
write: Boolean,
read: Boolean,
manage: Boolean,
delete: Boolean,
ttl: Int
).async { result, status -> }
Parameter | Type | Required | Default | Description |
---|---|---|---|---|
authKeys | List<String> | Optional | Specifies authKey to grant permissions to.It's possible to specify multiple auth keys. You can also grant access to a single authKey for multiple channels at the same time. Zero or more channels with zero or more auth tokens are allowed. | |
channels | List<String> | Optional | Specifies the channels on which to grant permissions.If no channels /channelGroups are specified, then the grant applies to all channels /channelGroups that have been or will be created for that publish/subscribe key set.Furthermore, any existing or future grants on specific channels are ignored, until the all channels grant is revoked.It's possible to grant permissions to multiple channels simultaneously.Wildcard notation like a.* can be used to grant access on channels . You can grant one level deep.- a.* - you can grant on this.- a.b.* - grant won't work on this. If you grant on a.b.* , the grant will treat a.b.* as a single channel with name a.b.* . | |
channelGroups | List<String> | Optional | Specifies the channelGroups to grant permissions. If no channels /channelGroups are specified, then the grant applies to all channels /channelGroups that have been or will be created for that publish/subscribe key set.Furthermore, any existing or future grants on specific channelGroups are ignored, until the all channelGroups grant is revoked.It's possible to grant permissions to multiple channelGroups simultaneously. | |
write | Boolean | Optional | false | Write permission |
read | Boolean | Optional | false | Read permission |
manage | Boolean | Optional | false | Manage permission |
delete | Boolean | Optional | false | Delete permission |
ttl | Long | Optional | Not set | Time in minutes for which granted permissions are valid. Setting ttl to 0 will apply the grant indefinitely, which is also the default behavior. |
sync | PNAccessManagerGrantResult? | Optional | Fires the request, locks the thread, and throws an exception if something goes wrong. | |
async | {PNAccessManagerGrantResult?, PNStatus} -> | Optional | Fires the request asynchronously and reports back with a callback. |
Basic Usage
Grant PAM Permissions for channel and auth_key
pubnub.grant(
channels = listOf("ch1", "ch2", "ch3"), //channels to allow grant on
channelGroups = listOf("cg1", "cg2", "cg3"), // groups to allow grant on
authKeys = listOf("key1", "key2", "key3"), // the keys we are provisioning
write = true, // allow those keys to write (false by default)
manage = true, // allow those keys to manage channel groups (false by default)
read = true, // allow keys to read the subscribe feed (false by default)
delete = true, // allow keys to delete messages (false by default)
ttl = 12337 // how long those keys will remain valid (0 for eternity)
).async { result, status ->
// result is a parsed and abstracted response from server
}
Returns
The grant()
operation returns a PNAccessManagerGrantResult?
which contains the following operations:
Method | Type | Description |
---|---|---|
level | String | Permissions level, one of subkey , subkey+auth , channel , channel-group , channel-group+auth level. |
subscribeKey | String | The subscribeKey . |
channels | Map<String, Map<String, PNAccessManagerKeyData>?> | Access rights per channel. See PNAccessManagerKeyData for more details. |
channelGroups | Map<String, Map<String, PNAccessManagerKeyData>?> | Access rights per channel group. See PNAccessManagerKeyData for more details. |
PNAccessManagerKeyData
Method | Type | Description |
---|---|---|
readEnabled | Boolean | Is true if read rights are granted |
writeEnabled | Boolean | Is true if write rights are granted |
manageEnabled | Boolean | Is true if manage rights are granted |
deleteEnabled | Boolean | Is true if delete rights are granted |
Caution
PAM grant or revoke requests must be less than ~32KiB at a time, or the client will return an error. For requests greater than 32KiB, break them into smaller batched requests. When the message size exceeds 32KiB the server returns the HTTP Error code 500, instead of the correct error code 414.
Warning
For NTP synchronization, please ensure that you have configured NTP on your server to keep the clock in sync. This is to prevent system clock drift leading to 400 Invalid Timestamp
error response.
Other Examples
Grant subscribe access to a channel only for clients with a specific auth_key with a 5 minute ttl:
pubnub.grant( channels = listOf("my_channel"), write = false, read = true, authKeys = listOf("my_ro_authkey"), ttl = 5 ).async { result, status -> }
The above code returns the following response to the client:
if (!status.error) { result!!.ttl // 5 result.level // user } else { // handle error status.exception?.printStackTrace() }
Allow access to a specific channel for Presence:
pubnub.grant( channels = listOf("my_channel-pnpres"), write = true, read = true ).async { result, status -> }
Grant PAM Permissions for channel group:
pubnub.grant( channelGroups = listOf("cg1", "cg2", "cg3"), // groups to allow grant on authKeys = listOf("key1", "key2", "key3"), // the keys we are provisioning write = true, // allow those keys to write (false by default) manage = true, // allow those keys to manage channel groups (false by default) read = true, // allow keys to read the subscribe feed (false by default) ttl = 12337 // how long those keys will remain valid (0 for eternity) ).async { result, status -> }
The above code returns the following response to the client:
if (!status.error) { result!!.ttl // 12337 result.level // user } else { // handle error status.exception?.printStackTrace() }
Allow access to all channel groups using wildcard:
To perform a first level wildcard grant for channel groups you need to specify
:
(colon) as the parameter forchannelGroups
. This will ensure that users canread
ormanage
all channel groups.pubnub.grant( channelGroups = listOf(":"), read = true, manage = true ).async { result, status -> }
-
Use application level grants with caution
When access is granted on an application level,
all channels and users
will have access.Application level grants can also happen due to a bug in your code. For example, Null parameters for channels and auth-keys can cause accidental application level grants.
pubnub.grant( write = true, read = true ).async { result, status -> }
-
pubnub.grant( channels = listOf("my_channel"), write = true, read = true ).async { result, status -> }
-
pubnub.grant( channels = listOf("my_channel"), authKeys = listOf("my_authkey"), write = true, read = true, ttl = 5 ).async { result, status -> }