# Web API

## Description

The API is very important part of ReCodEx project. It provides common interface for usage in different user frontends such as default web application, mobile applications, commandline tools and possibly others. The communication goes as HTTP(S) requests in predefined format, nowadays mostly known as [REST](https://en.wikipedia.org/wiki/Representational_state_transfer) format. Results from the API are in plain text in JSON format to be easily parsed in various languages (notably JavaScript).

This component must be publicly visible in the internet, so it's important to care about security and follow our recommendations. We have really focused on security aspect of the project, so proper roles with permission separation are introduced and maintained. Also some additional checks are made directly in the code, so user can't access informations which are out of his authorization.

## Architecture

## Installation

The web API requires a PHP runtime version at least 7. Which one depends on actual configuration, there is a choice between _mod_php_ inside Apache, _php-fpm_ with Apache or Nginx proxy or running it as standalone uWSGI script. Common thing is, that there are some PHP extensions, that have to be installed on the system. It's ZeroMQ binding (`php-zmq` package or similar), MySQL module (`php-mysqlnd` package) and ldap extension module for CAS authentication (`php-ldap` package). Make sure that the extensions are loaded in your `php.ini` file (`/etc/php.ini` or files in `/etc/php.d/`).

The API depends on some other projects and libraries. For managing them is used [Composer](https://getcomposer.org/). It can be installed from system repositories or downloaded from the website, where are also detailed instructions. Composer reads `composer.json` file in project root and install dependencies to `vendor/` subdirectory. To do that, run
```
$ composer install
```

## Configuration and usage

The API can be configured in `config.neon` and `config.local.neon` files in `app/config` directory. The first file is predefined by authors and should not be modified. The second one is not present and could be created from template `config.local.neon.example` in the config directory. Local configuration have higher precedence, so it will override default values from `config.neon`.

### Configurable items

Description of configurable items. All timeouts are in milliseconds if not stated otherwise.

- accessManager -- configuration of access token in [JWT standard](https://www.rfc-editor.org/rfc/rfc7519.txt). Do **not** modify unless you really know what are you doing.
- fileServer -- connection to fileserver
	- address -- URI of fileserver
	- auth -- _username_ and _password_ for HTTP basic authentication
	- timeouts -- _connection_ timeout for establishing new connection and _request_ timeout for completing one request
- broker -- connection to broker
	- address -- URI of broker
	- auth -- _username_ and _password_ for broker callback authentication back to API
	- timeouts -- _ack_ timeout for first response that broker receives the message, _send_ timeout how long try to send new job to the broker and _result_ timeout how long to wait for confirmation if job can be processed or not
- monitor -- connection to monitor
	- address -- URI of monitor
- CAS -- CAS external authentication
	- serviceId -- identifier of this service for public
	- ldapConnection -- parameters for connecting to LDAP, _hostname_, _base_dn_, _port_, _security_ and _bindName_
	- fields -- names of LDAP keys for informations as _email_, _firstName_ and _lastName_
- emails -- common configuration for sending email (addresses and template variables)
	- apiUrl -- base URL of api server including port (for referencing pictures in messages)
	- footerUrl -- link in the message footer
	- siteName -- name of frontend (ReCodEx, or KSP for unique instance for KSP course)
	- githubUrl -- URL to GitHub repository of this project
	- from -- sending email address
- failures -- admin messages on errors
	- emails -- additional info for sending mails, _to_ is admin mail address, _from_ is source address, _subjectPrefix_ is prefix of mail subject
- forgottenPassword -- user messages for changing passwords
	- redirectUrl -- URL of web application where the password can be changed
	- tokenExpiration -- expiration timeout of temporary token (in seconds)
	- emails -- additional info for sending mails, _from_ is source address and _subjectPrefix_ is prefix of mail subject
- mail -- configuration of sending mails
	- smtp -- using SMTP server, have to be "true"
	- host -- address of the server
	- port -- sending port (common values are 25, 465, 587)
	- username -- login to the server
	- password -- password to the server
	- secure -- security, values are empty for no security, "ssl" or "tls"
	- context -- additional parameters, depending on used mail engine. For examle self-signed certificates can be allowed as _verify_peer_ and _verify_peer_name_ to false and _allow_self_signed_ to true under _ssl_ key (see example).

Outside the parameters section of configuration is configuration for Doctrine. It's ORM framework which mappes PHP objects (entities) into database tables and rows. The configuration is simple, required items are only _user_, _password_ and _host_ with _dbname_, i.e. address of database computer (mostly localhost) with name of ReCodEx database.

### Example local configuration file

```{.yml}
parameters:
  accessManager:
    leeway: 60
    issuer: https://recodex.projekty.ms.mff.cuni.cz
    audience: https://recodex.projekty.ms.mff.cuni.cz
    expiration: 86400  # 24 hours in seconds
    usedAlgorithm: HS256
    allowedAlgorithms:
      - HS256
    verificationKey: "recodex-123"
  fileServer:
    address: http://127.0.0.1:9999
    auth:
      username: "user"
      password: "pass"
    timeouts:
      connection: 500
  broker:
    address: tcp://127.0.0.1:9658
    auth:
      username: "user"
      password: "pass"
    timeouts:
      ack: 100
      send: 5000
      result: 1000
  monitor:
    address: wss://recodex.projekty.ms.mff.cuni.cz:4443/ws
  CAS:
    serviceId: "cas-uk"
    ldapConnection:
      hostname: "ldap.cuni.cz"
      base_dn: "ou=people,dc=cuni,dc=cz"
      port: 389
      security: SSL
      bindName: "cunipersonalid"
    fields:
      email: "mail"
      firstName: "givenName"
      lastName: "sn"
  emails:
    apiUrl: https://recodex.projekty.ms.mff.cuni.cz:4000
    footerUrl: https://recodex.projekty.ms.mff.cuni.cz
    siteName: "ReCodEx"
    githubUrl: https://github.com/ReCodEx
    from: "ReCodEx <noreply@example.com>"
  failures:
    emails:
      to: "Admin Name <admin@example.com>"
      from: %emails.from%
      subjectPrefix: "ReCodEx Failure Report - "
  forgottenPassword:
    redirectUrl: "https://recodex.projekty.ms.mff.cuni.cz/
                  forgotten-password/change"
    tokenExpiration: 600 # 10 minues
    emails:
      from: %emails.from%
      subjectPrefix: "ReCodEx Forgotten Password Request - "
  mail:
    smtp: true
    host: "smtp.ps.stdin.cz"
    port: 587
    username: "user"
    password: "pass"
    secure: "tls"
    context:
      ssl:
        verify_peer: false
        verify_peer_name: false
        allow_self_signed: true
doctrine:
  user: "user"
  password: "pass"
  host: localhost
  dbname: "recodex-api"
```

### Database preparation

When the API is installed and configured (_doctrine_ section is sufficient here) the database schema can be generated. There is a prepared command to do that from command line:

```
$ php www/index.php orm:schema-tool:update --force
```

With API comes some initial values, for example default user roles with proper permissions. To fill your database with these values there is another command line command:

```
$ php www/index.php db:fill
```

Check the outputs of both commands for errors. If there are any, try to clean temporary API cache in `temp/cache/` directory and repeat the action.


### Webserver configuration

The simplest way to get started is to start the built-in PHP server in the root directory of your project:

```
$ php -S localhost:4000 -t www
```

Then visit `http://localhost:4000` in your browser to see the welcome page of API project.

For Apache or Nginx, setup a virtual host to point to the `www/` directory of the project and you should be ready to go. It is **critical** that whole `app/`, `log/` and `temp/` directories are not accessible directly via a web browser (see [security warning](https://nette.org/security-warning)). Also it's **highly recommended** to set up a HTTPS certificate for public access to the API.

### Troubleshooting

In case of any issues first remove the Nette cache directory `temp/cache/` and try again. This solves most of the errors. If it doesn't help, examine API logs from `log/` directory of the API source or logs of your webserver.