Access Manager API for PubNub Python-Tornado SDK

Python version support

Python SDK versions 5.0.0 and higher no longer support Python v2.7 and the Twisted and Tornado frameworks. If you require support for any of these, use SDK version 4.8.1.

Note that PubNub will stop supporting versions of Python lower than 3.7 by the end of 2021.

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.

Grant

Requires Access Manager add-on Requires 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 subscribe_key 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

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 channels
a.* grants access on all channels that begin with a.
a.b.* doesn't work. If you grant on a.b.*, the grant treats a.b.* as a channel name, not a wildcard

Grant Levels

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 either read or write attribute is set to True for a subscribe_key, PAM will immediately grant access for that attribute without proceeding to check permissions at either Channel or User levels. If an attribute is set to False 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 of subscribe_key, and channel, PAM grants access for that attribute at the Channel level without proceeding to check whether there may be user level permissions.
User Level (Recommended) - As a final step PAM evaluates the attributes at the User level. If an attribute is set to True for subscribe_key, channel and auth_key, access is granted for that attribute. Similarly, user level grants also allow you granting an auth_key access to channelGroups and uuids. User level grants require auth_key and are the recommended approach if you need to manage permissions for individual users within your application. Each user should be assigned a unique auth_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 Python-Tornado SDK:

pubnub.grant().auth_keys(String|List|Tuple).channels(String|List|Tuple).channel_groups(String|List|Tuple).read(Boolean).write(Boolean).manage(Boolean).delete(Boolean).ttl(Int)

Parameter	Type	Required	Defaults	Description
`auth_keys`	String \| List \| Tuple	Optional		Specifies `auth` Key to grant permissions. It is possible to specify multiple `auth` keys as comma separated list in combination with a single `channel` name. You can also grant access to a single `auth` key for multiple `channels` at the same time. Zero or more `channels` with zero or more `auth` tokens are allowed.
`channels`	String \| List \| Tuple	Optional		Specifies the `channels` on which to `grant` permissions. If no `channels/channelGroups` are specified, then the `grant` applies to any and 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 is possible to `grant` permissions to multiple `channels` simultaneously by specifying the `channels` as a comma separated list.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 will not work on this. If you grant on `a.b.`, the grant will treat `a.b.` as a single channel with name `a.b.`.
`channel_groups`	String \| List \| Tuple	Optional		Specifies the `channelGroups` to `grant` permissions. If no `channels/channelGroups` are specified, then the `grant` applies to any and 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 is possible to `grant` permissions to multiple `channelGroups` simultaneously by specifying the `channelGroups` as a comma separated list.
`read`	Boolean	Optional	`False`	`Read` permissions.
`write`	Boolean	Optional	`False`	`Write` permissions.
`manage`	Boolean	Optional	`False`	`Manage` permissions.
`delete`	Boolean	Optional	`False`	`Delete` permissions.
`ttl`	Int	Optional	`None`	`Time to live` for permission to be valid.

Basic Usage

Grant PAM Permissions for channel and auth_key

envelope = yield pubnub.grant().channels(["ch1", "ch2", "ch3"]).\
    channel_groups(["cg1", "cg2"]).\
    auth_keys(["key1", "key2"]).\
    read(True).write(True).manage(True).\
    future()

Returns

The grant() operation returns a PNAccessManagerGrantResult which contains the following fields:

Field	Type	Description
`level`	String	Permissions level, one of `subkey`, `subkey`+`auth`, `channel`, `channel-group`, `channel-group`+`auth` level.
`ttl`	Int	`ttl` of grant
`subscribe_key`	String	The `subscribe key`.
`channels`	Dict	Access rights per channel. See PNAccessManagerChannelData for more details.
`groups`	Dict	Access rights per group. See PNAccessManagerGroupData for more details.
`read_enabled`	Boolean	subkey level `read` permissions.
`write_enabled`	Boolean	subkey level `write` permissions.
`manage_enabled`	Boolean	subkey level `manage` permissions.
`delete_enabled`	Boolean	subkey level `delete` permissions.
`ttl`	Int	Time to live value.

PNAccessManagerChannelData and PNAccessManagerGroupData has the same fields structure:

Field	Type	Description
`auth_keys`	List	Access rights per `auth-key`. See PNAccessManagerKeyData for more details.
`name`	String	Channel or group `name`.
`read_enabled`	Boolean	Channel or group level `read` permissions.
`write_enabled`	Boolean	Channel or group level `write` permissions.
`manage_enabled`	Boolean	Channel or group level `manage` permissions.
`delete_enabled`	Boolean	Channel or group level `delete` permissions.
`ttl`	Int	Time to live value.

PNAccessManagerKeyData:

Field	Type	Description
`read_enabled`	Boolean	`read` permissions
`write_enabled`	Boolean	`write` permissions
`manage_enabled`	Boolean	`manage` permissions
`delete_enabled`	Boolean	`delete` permissions
`ttl`	Int	Time to live value

read, write, manage, and delete permissions have 3 states:

True if enabled.
False if disabled.
None if not explicitly set.

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.

https://support.pubnub.com/hc/en-us/articles/360051973331-Why-do-I-get-Invalid-Timestamp-when-I-try-to-grant-permission-using-Access-Manager-

Other Examples

Grant subscribe privileges to all users on all channel(s) with default ttl (1440 minutes):
```
envelope = yield pubnub.grant().read(True).write(True).future()
```
Allow subscribe and publish to a specific Grant subscribe and publish to a specific channel for all users (no auth_key required) with default ttl (1440 minutes):
```
envelope = yield pubnub.grant().channels("my_channel").read(True).write(True).future()
```

Grant subscribe access to a channel only for clients with a specific auth_key with a 5 minute ttl:

envelope = yield pubnub.grant().channels("my_channel").read(True).write(False).\
    auth_keys("my_ro_authkey").ttl(5).future()

The above code would return the following response to the client:

{
    "status" : 200,
    "message" : "Success",
    "payload" : {
        "ttl" : 5,
        "auths" : {
            "my_ro_authkey" : {
                "r" : 1,
                "w" : 0,
                "d" : 0
            }
        },
        "subscribe_key" : "my_subkey",
        "level" : "user",
        "channel" : "my_channel"
    },
    "service" : "Access Manager"
}

Allow access to a specific channel for Presence:

envelope = yield pubnub.grant().\
    channels("my_channel-pnpres").read(True).write(True).future()

Grant PAM Permissions for channel group:

envelope = yield pubnub.grant().\
    channel_groups(["cg1", "cg2", "cg3"]).\
    auth_keys(["auth1", "auth2", "auth3"]).\
    read(True).write(True).manage(True).\
    ttl(12237).\
    .future()

The above code would return the following response to the client:

{
    "status":200,
    "message":"Success",
    "payload":{
        "ttl":5,
        "auths":{
            "my_rw_authkey":{
                "r":1,
                "w":1,
                "d":1
            }
        },
        "subscribe_key":"my_subkey",
        "level":"user",
        "channel":"my_channel"
    },
    "service":"Access Manager"
}

Grant Permissions on Multiple Channels:

envelope = pubnub.grant().\
    auth_keys("my_rw_authkey").\
    channels(["girish", "girish2"]).\
    read(True).\
    write(True).\
    ttl(5).\
    sync()

Note

The limit on the total amount of channels that you can pass at once when using grant() is 200.

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 for channel_groups. This will ensure that users can read or manage all channel groups.
```
yield pubnub.grant().channel_groups(":").future()
```
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.
```
envelope = yield pubnub.grant().\
               read(True).write(True).\
               .future()
```

Channel Level Grant

envelope = yield pubnub.grant().channels("my_channel").\
               read(True).write(True).\
               .future()

User Level Grant

envelope = yield pubnub.grant().channels("my_channel").\
               auth_keys("my_authkey").\
               read(True).write(True).\
               ttl(5).\
               .future()