walnut.js/README.md

walnut
======

An opinionated, constrained, secure application framework with a hard shell - kinda like iOS, but for a server.

Applications are written in express, but instead of using `require` for generic packages,
they use `req.getSiteCapability(pkg)` and are restricted to packages that have been
allowed by app, device, site, or user permission. Any configuration for the capability
(external passwords, api keys, etc) will be set up beforehand so that they are not exposed
to the application.

Security Features
-----------------

* JSON-only APIs
* JWT (not cookie*) authentication
* no server-rendered html
* disallows urlencoded forms, except for secured webhooks
* disallows cookies, except for protected static assets
* api.* subdomain for apis
* assets.* subdomain for protected assets
* *must* sit behind a trusted https proxy (such as [Goldilocks](https://git.daplie.com/Daplie/goldilocks.js)
* HTTPS-only (checks for X-Forwarded-For)
* AES, RSA, and ECDSA encryption and signing
* Safe against CSRF, XSS, and SQL injection
* Safe against Compression attacks

\*Cookies are used only for GETs and only where using a token would be less secure -
such as images which would otherwise require the token to be passed into the img src.
They are also scoped such that CSRF attacks are not possible.

Application Features
--------------------

* JSON-only expressjs APIs
* Capability-based permissions system for (oauth3-discoverable) packages such as
  * large file access (files@daplie.com)
  * database access (data@daplie.com)
  * scheduling (for background tasks, alerts, alarms, calendars, reminders, etc) (events@daplie.com)
  * payments (credit card) (payments@daplie.com)
  * email (email@daplie.com)
  * SMS (texting) (tel@daplie.com)
  * voice (calls and answering machine) (tel@daplie.com)
  * lamba-style functions (functions@daplie.com)
* Per-app, per-site, and per-user configurations
* Multi-Tentated Application Management
* Built-in OAuth2 & OAuth3 support

Currently being tested with Ubuntu, Raspbian, and Debian on Digital Ocean, Raspberry Pi, and Heroku.

Installation
------------

See [INSTALL.md](https://git.daplie.com/Daplie/walnut.js/blob/master/INSTALL.md)

API
---

See [API.md](https://git.daplie.com/Daplie/walnut.js/blob/master/API.md)

Understanding Walnut
====================

```
/srv/walnut/
├── setup.sh (in-progress)
├── core
│   ├── bin
│   ├── boot
│   └── lib
├── etc
│   └── client-api-grants
├── node_modules
├── packages
│   ├── apis
|   ├── pages
│   └── services
└── var
    └── sites
```

* `core` contains all walnut code
* `node_modules` is a flat installation of all dependencies
* `certs` is a directory for Let's Encrypt (or custom) certificates
* `var` is a directory for database files and such
* `packages` contains 3 types of packages

Will install to
---------------

```
/srv/walnut/core/
/etc/walnut
/opt/walnut
/var/log/walnut
/etc/systemd/system/walnut.service
/etc/tmpfiles.d/walnut.conf
```

Initialization
--------------

needs to know its primary domain

```
POST https://api.<domain.tld>/api/walnut@daplie.com/init

{ "domain": "<domain.tld>" }
```

The following domains are required to point to WALNUT server

```
cloud.<domain.tld>
api.cloud.<domain.tld>
```

and

```
<domain.tld>
www.<domain.tld>

api.<domain.tld>
assets.<domain.tld>
```

The domains can be setup through the Daplie Desktop App or with `daplie-tools`

```bash
# set device address and attach primary domain
daplie devices:attach -d foodevice -n example.com -a 127.0.0.1

# attach all other domains with same device/address
daplie devices:attach -d foodevice -n www.example.com
daplie devices:attach -d foodevice -n api.example.com
daplie devices:attach -d foodevice -n assets.example.com
daplie devices:attach -d foodevice -n cloud.example.com
daplie devices:attach -d foodevice -n api.cloud.example.com
```

Example `/etc/goldilocks/goldilocks.yml`:
```yml
tls:
  email: domains@example.com
  servernames:
    - example.com
    - www.example.com
    - api.example.com
    - assets.example.com
    - cloud.example.com
    - api.cloud.example.com

http:
  trust_proxy: true
  modules:
    - name: proxy
      domains:
        - '*'
      address: '127.0.0.1:3000'
```

Resetting the Initialization
----------------------------

Once you run the app the initialization files will appear in these locations

```
/srv/walnut/var/com.daplie.walnut.config.sqlite3
/srv/walnut/config/<domain.tld>/config.json
```

Deleting those files and restarting walnut will reset it to its bootstrap state.

Accessing static apps
---------------------

Static apps are stored in `packages/pages`

```
# App ID as files with a list of packages they should load
# note that '#' is used in place of '/' because files and folders may not contain '/' in their names
/srv/walnut/packages/pages/<domain.tld#path>          # https://domain.tld/path
/srv/walnut/packages/pages/<domain.tld>               # https://domain.tld and https://domain.tld/foo match

# packages are directories with email-style name      # For the sake of debugging these packages can be accessed directly, without a site by
/srv/walnut/packages/pages/<package@domain.tld>       # matches apps.<domain.tld>/<package-name> and <domain.tld>/apps/<package-name>
```

Accessing REST APIs
-------------------

```
# Apps are granted access to use a package by listing it in the grants file by the name of the app url (domain.tld)
/srv/walnut/packages/client-api-grants/<domain.tld>   # matches api.<domain.tld>/api/ and contains a list of allowed REST APIs
                                                      # the REST apis themselves are submatched as api.<domain.tld>/api/<tld.domain.package>

# packages are directories with reverse dns name, a package.json, and an index.js
/srv/walnut/packages/rest/<tld.domain.package>
```

Example tree with contents:

Here `com.example.hello` is a package with a REST API and a static page
and `foobar.me` is a WALNUT-configured domain (smithfam.net, etc).


The packages:

```
/srv/walnut/packages/
├── api
├── rest
│   └── com.example.hello
│      ├── package.json
│      └── index.js
│           '''
│           'use strict';
│
│           module.exports.create = function (conf, deps, app) {
│
│             app.use('/', function (req, res) {
│               console.log('[com.example.hello] req.url', req.url);
│               res.send({ message: 'hello' });
│             });
│
│             return deps.Promise.resolve();
│           };
│
│           '''
│
└── services
```

```
/srv/walnut/packages/
└── pages
    └── demo@example.com
        └── index.html
              '''
              <html>
                <head><title>demo@example.com</title></head>
                <body>
                  <h1>demo@example.com</h1>
                </body>
              </html>
              '''
 
```

The permissions:

```
/srv/walnut/packages/
└── client-api-grants
    └── cloud.foobar.me
          '''
          hello@example.com     # refers to /srv/walnut/packages/rest/hello@example.com
          '''
```

```
/srv/walnut/var/
└── sites
    └── daplie.me
          '''
          seed@example.com      # refers to /srv/walnut/packages/pages/seed@example.com
          '''
```