holochain_roles

Generic holochain mixin to include administrator and dynamic roles in any holochain application, using the progenitor pattern.

This mixin is built to target hc v0.0.42-alpha3. It also depends on the holochain_anchors to be present and configured.

Design

Here is the design for this mixin: https://hackmd.io/6xfwfSVYSGeZe3vQ_-1cWw?view.

Documentation

Here you can find the documentation for this mixin: https://docs.rs/holochain_roles.

Installation

Add the following to your zomes cargo toml.

holochain_anchors = "0.2.1"
holochain_roles = "0.1.7"

Usage

Setup

Add the anchor entry definition to your zome.

 #[entry_def]
fn anchor_def() -> ValidatingEntryType {
    holochain_anchors::anchor_definition()
}

Add the roles entry definition to your zome.

 #[entry_def]
fn roles_def() -> ValidatingEntryType {
    holochain_roles::role_assignment_entry_def()
}

Assign a role

To assign a role, simply call the assign_role function:

#[zome_fn("hc_public")]
fn some_other_public_function(agent_address: Address) {
    let my_role_name = String::from("editor");

    holochain_roles::handlers::assign_role(&my_role_name, &agent_address)?;
    ...
}

Assign an administrator

Only agents that have the administrator role or the progenitor of the DNA can assign or unassign roles. To assign an administrator role, call the assign_role function with the imported administrator role name:

#[zome_fn("hc_public")]
fn some_other_public_function(agent_address: Address) {
    let my_role_name = String::from(holochain_roles::ADMIN_ROLE_NAME);

    holochain_roles::handlers::assign_role(&my_role_name, &agent_address)?;
    ...
}

Check if user currently has a certain role

To check if a user has a certain role, you can use the validation has_agent_role function:

validation: | _validation_data: hdk::EntryValidationData<MyEntry>| {
    match _validation_data {
        hdk::EntryValidationData::Create { entry, validation_data } => {
            let agent_address = &validation_data.sources()[0];
            let is_agent_permitted_to_create_this_entry = holochain_roles::validaton::has_agent_role(&agent_address, String::from("editor"))?;

            if !is_agent_permitted_to_create_this_entry {
                return Err(String::from("Only editors can create a new entry"));
            }
            ...

        }
    }
}

Check if user had a certain role in a certain moment in time

To check if a user has a certain role, you have two options:

• Use the validation validate_required_role function, which will return and error in case the user did not have the given role at the time they committed the entry:

validation: | _validation_data: hdk::EntryValidationData<MyEntry>| {
    match _validation_data {
        hdk::EntryValidationData::Create { validation_data } => {
            holochain_roles::validaton::validate_require_role(&validation_data, String::from("editor"))?;

            ...
        }
    }
}

• Use the validation has_agent_role function:

validation: | _validation_data: hdk::EntryValidationData<MyEntry>| {
    match _validation_data {
        hdk::EntryValidationData::Create { entry, validation_data } => {
            let agent_address = &validation_data.sources()[0];
            let timestamp = &validation_data.package.chain_header.timestamp();
            let is_agent_permitted_to_create_this_entry = holochain_roles::validaton::had_agent_role(&agent_address, String::from("editor"), timestamp)?;

            if !is_agent_permitted_to_create_this_entry {
                return Err(String::from("Only editors can create a new entry"));
            }
            ...

        }
    }
}

Get all role assignments for an agent

To get all role assignments for a certain agent, you can use the validation get_agent_roles function:

#[zome_fn("hc_public")]
fn some_public_function(agent_address: Address) {
    let roles: Vec<String> = holochain_roles::handlers::get_agent_roles(&agent_address)?;
}

Get all agents that have a certain role assigned

To get all role assignments for a certain agent, you can use the validation get_role_agents function:

#[zome_fn("hc_public")]
fn some_public_function(role_name: String) {
    let agents: Vec<Address> = holochain_roles::handlers::get_role_agents(&role_name)?;
}

Unassign a role

To unassign a role, simply call the unassign_role function:

#[zome_fn("hc_public")]
fn some_other_public_function(agent_address: Address) {
    let my_role_name = String::from("editor");

    holochain_roles::handlers::unassign_role(&my_role_name, &agent_address)?;
    ...
}