Access Manager v2 API for Kotlin SDK
Breaking changes in v9.0.0
PubNub Kotlin SDK version 9.0.0 unifies the codebases for Kotlin and Java SDKs, introduces a new way of instantiating the PubNub client, and changes asynchronous API callbacks and emitted status events. These changes can impact applications built with previous versions (< 9.0.0
) of the Kotlin SDK.
For more details about what has changed, refer to Java/Kotlin SDK migration guide.
Access Manager allows you to enforce secure controls for client access to resources within the PubNub network. With Access Manager, 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 Access Manager 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 Access Manager, refer to Managing Permissions with Access Manager.
Request execution
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 invoke the .sync()
or .async()
method on the Endpoint to execute the request, or the operation will not be performed.
val channel = pubnub.channel("channelName")
channel.publish("This SDK rules!").async { result ->
result.onFailure { exception ->
// Handle error
}.onSuccess { value ->
// Handle successful method result
}
}
Grant
Requires Access Manager add-on
This method requires that the Access Manager add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your 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.
Permissions
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 |
Wildcard Permissions
Wildcard notation allows you to grant permissions to multiple channels at a time and later revoke these permissions in the same manner. You can only go one level deep using wildcards. In other words:
a.*
grants access on all channels that begin witha.
.*
ora.b.*
won't work this way. If you grant on*
ora.b.*
, the grant treats*
ora.b.*
as a channel name, not a wildcard.
Wildcard revokes
You can revoke permissions with wildcards from one level deep, like a.*
, only when you initially used wildcards to grant permissions to a.*
.
Grant Levels
When a user attempts to access a PubNub resource, Access Manager will evaluate any existing rules using the following order of precedence before access to a channel is granted to the user:
- Application Level - Access Manager privileges are always evaluated first at the
Application
level. If eitherread
orwrite
attribute is set totrue
for asubscribeKey
, Access Manager 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, Access Manager proceeds to evaluate the attribute at the next most granular level. - Channel Level - After first verifying an attribute at the Application level, Access Manager evaluates the attribute at the Channel level. If an attribute is set to
true
for a combination ofsubscribeKey
, andchannel
, Access Manager 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 Access Manager 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 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 -> }
Parameter | Description |
---|---|
authKeys Type: List<String> Default: n/a | 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 Type: List<String> Default: n/a | 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.- * and a.b.* - grant will not work on these levels. If you grant on * or a.b.* , the grant will treat * or a.b.* as a single channel named either * or a.b.* . |
channelGroups Type: List<String> Default: n/a | 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 Type: Boolean Default: false | Write permission |
read Type: Boolean Default: false | Read permission |
manage Type: Boolean Default: false | Manage permission |
delete Type: Boolean Default: false | Delete permission |
ttl Type: Long Default: 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 Type: PNAccessManagerGrantResult? Default: n/a | Fires the request, locks the thread, and throws an exception if something goes wrong. |
async Type: {PNAccessManagerGrantResult?, PNStatus} -> Default: n/a | Fires the request asynchronously and reports back with a callback. |
Basic Usage
Grant Access Manager 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 ->
// result is a parsed and abstracted response from server
}
Returns
The grant()
operation returns a PNAccessManagerGrantResult?
which contains the following operations:
Method | Description |
---|---|
level Type: String | Permissions level, one of subkey , subkey+auth , channel , channel-group , channel-group+auth level. |
subscribeKey Type: String | The subscribeKey . |
channels Type: Map<String, Map<String, PNAccessManagerKeyData>?> | Access rights per channel. See PNAccessManagerKeyData for more details. |
channelGroups Type: Map<String, Map<String, PNAccessManagerKeyData>?> | Access rights per channel group. See PNAccessManagerKeyData for more details. |
PNAccessManagerKeyData
Method | Description |
---|---|
readEnabled Type: Boolean | Is true if read rights are granted |
writeEnabled Type: Boolean | Is true if write rights are granted |
manageEnabled Type: Boolean | Is true if manage rights are granted |
deleteEnabled Type: Boolean | Is true if delete rights are granted |
Size of revoke requests
Access Manager 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.
NTP configuration
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. Read the support article for more details.
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 -> }
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 -> }
Grant Access Manager 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 -> }
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()
}
Application Level Grant
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 -> }
Channel Level Grant
pubnub.grant(
channels = listOf("my_channel"),
write = true,
read = true
).async { result -> }
User Level Grant
pubnub.grant(
channels = listOf("my_channel"),
authKeys = listOf("my_authkey"),
write = true,
read = true,
ttl = 5
).async { result -> }