Working with Inboxes

Inboxes provide a secure way to receive entries from both internal and external sources.

• Entries can contain binary data and files.
• Each Context can contain any number of Inboxes with unique identifiers (inboxId) used to distinguish them.
• Everyone with access to inboxID, solutionID, and Bridge URL can send an entry, but only the users who are added to given Inbox can read them.

Permissions

The user list in Inbox is designed to be flexible, accommodating a wide range of use cases.

Inboxes differentiate three types of users: Regular Users, Managers, and External Users. The table below shows what actions can be performed by each type of users:

The values above are the default policy values defined by PrivMX. To read more about Policies and learn how to modify them, go to Policies.

Working with Inboxes

To access Threads methods, get the field inboxApi from active connection. Connection should be initialized with Modules.INBOX and passed to PrivmxEndpoint().

val inboxApi = endpointSession.inboxApi

Creating Inboxes

To create an Inbox, you need to name it and provide a list of public key - userID pairs. Due to the fact that each Inbox is inside a Context, all the public keys have to be registered inside the given Context. You can do it using Bridge API context/addUserToContext method.

While creating an Inbox, you can also provide additional information:

• publicMeta contains additional info about the Inbox. It is not encrypted before sending to PrivMX Bridge. Inbox API provides methods for accessing this field as publicView. For more information about Inbox publicView and its common use cases go to Using Public View.

• privateMeta this field will be encrypted by PrivMX Endpoint before sending to PrivMX Bridge. It's meant to store additional sensitive information about the Inbox. privateMeta is accessible only for users registered to the given Inbox.

• filesConfig you can specify up front file requirements for each entry submitted to the Inbox. This config includes min and max count of files in an entry, their max size, but also max size of whole upload.

• policy determines what actions will be available to specific users. For more information and use cases, go to Policies.

Public and private metadata is sent in binary format.

After creating an Inbox, all the users with management rights will be able to edit it. Skip to Modifying Inboxes for more info.

val users : List<UserWithPubKey> = listOf(
    UserWithPubKey(user1Id, user1PublicKey),
    UserWithPubKey(user2Id, user2PublicKey)
)
val managers : List<UserWithPubKey> = listOf(
    UserWithPubKey(user1Id, user1PublicKey)
)
val publicMeta = ByteArray(0)
val privateMeta = ByteArray(0)

val inboxId = inboxApi.createInbox(
    contextId,
    users,
    managers,
    publicMeta,
    privateMeta
)

Listing Inboxes

Your application may include multiple Inboxes, each associated with different Contexts. You can retrieve a list of all Inboxes within a given Context. This list, alongside the metadata you sent while creating the Inbox, will include useful metadata about the Inbox, such as the creation date, last file upload date, user list, and information about the last modification.

PrivMX Endpoint takes care of decrypting received data, which means you only have to take care of decoding them from binary format.

Define Inbox item class with decoded publicMeta and privateMeta:

data class InboxItem(
    val inbox: Inbox,
    val decodedPrivateMeta: String,
    val decodedPublicMeta: InboxPublicMeta
)

val startIndex = 0L
val pageSize = 100L

val inboxesPagingList = inboxApi.listInboxes(
    contextId,
    startIndex,
    pageSize,
    SortOrder.DESC
)

val inboxes = inboxesPagingList.readItems.map {
    InboxItem(
        it,
        it.privateMeta.decodeToString(),
        Json.decodeFromString(it.publicMeta.decodeToString())
    )
}

Using Public View

Users with public connection (created by Connection.connectPublic) have access to the Public View which shares not encrypted fields of the Inbox, such as publicMeta.

val inboxID = "INBOX_ID"
val inboxPublicView = inboxApi.getInboxPublicView(inboxID)
val inboxPublicMeta: InboxPublicMeta = Json.decodeFromString(
    inboxPublicView.publicMeta.decodeToString()
)

Modifying Inboxes

Depending on your project's specification, it may be necessary to modify an Inbox. It could be, for example, changing the name or adding/removing users. Each user with management rights is able to modify Inboxes, delete them as a whole or only particular entries.

Three additional options are available when changing the list of users inside an Inbox:

• force - applies an update, without checking the current version.
• forceGenerateNewKey - re-encrypts entries in the Inbox. It's useful when a user is removed, and you want to prevent them from accessing the Inbox.
• policy - you can also pass a new policy object as the last optional argument.

Updating an Inbox means overwriting it with the provided data. To successfully update an Inbox, you must specify its current version. The version field is mandatory to handle multiple updates on the server, and it is incremented by 1 with each update.

val inboxID = "INBOX_ID"
val inbox: Inbox = inboxApi.getInbox(inboxID)
val users = inbox
    .users
    .map { userId ->
        //Your application must provide a way,
        //to get user's public key from their userId.
        UserWithPubKey(
            userId,
            "USER_PUBLIC_KEY"
        )
    }
val managers = inbox
    .managers
    .map { userId ->
        //Your application must provide a way,
        //to get user's public key from their userId.
        UserWithPubKey(
            userId,
            "USER_PUBLIC_KEY"
        )
    }
val newInboxNameAsPrivateMeta = "New inbox name"

inboxApi.updateInbox(
    inboxID,
    users,
    managers,
    inbox.publicMeta,
    newInboxNameAsPrivateMeta.encodeToByteArray(),
    inbox.filesConfig,
    inbox.version,
    false
)