Sample plugability in Context

context-plugin

// oae-context/lib/api.js

/**
 * A generic context object that represents a user execution context.
 *
 * @param {String} tenantId    The unique id of the tenant in the context (e.g., 'cam')
 * @param {String} userUuid    The UUID of the active user in the context (e.g., 'u:cam:nicolaas')
 */
var Context = module.exports.Context = function(tenantId, userUuid) {

    /**
     * Get the tenant associated to the current context
     */
    this.tenantId = function() {
        return tenantId;
    };

    /**
     * Get the user associated to the current context
     */
    this.userUuid = function() {
        return userUuid;
    };

}


// oae-authz/lib/some-file.js
// oae-authz module would like to plug in context-aware functionality

Context.prototype.authz = function() {
    var that = {};

    // determine if the current user is allowed to do something
    that.isAllowed = function(action, resourceUuid, callback) {
        api.isAllowed(this.userUuid(), action, resourceUuid, callback);
    };

    return that;
}

// Usage:
var getContent = function(ctx, contentUuid, callback) {
    ctx.authz().isAllowed('viewer', contentUuid, function(err, isAllowed) {
        if (isAllowed) .....
    }
}