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# Provider

The `Provider` protocol creates a simple and predictable way for adding functionality and third party packages to your Vapor project.

## Adding a Provider

Adding a provider to your application takes 2-3 steps.

### Add Package

All of Vapor's providers end with the `-provider` syntax. You can see a list of available providers by searching on our GitHub.

To add the provider to your package, add it as a dependency in your `Package.swift` file.

    let package = Package(
        name: "MyApp",
        dependencies: [
            .Package(url: "https://github.com/vapor/vapor.git", majorVersion: 2),
            .Package(url: "https://github.com/vapor/mysql-provider.git", majorVersion: 2)
        ]
    )

Warning

Always run `vapor update` or `vapor clean` after editing your `Package.swift` file.

### Import

Once the provider has been added, you can import it using `import VaporFoo` where `Foo` is the name of the provider.

Here is what importing the MySQL provider looks like:

    import Vapor
    import MySQLProvider

### Add to Droplet

Every provider comes with a class named `Provider`. Add this class to your Droplet using the `addProvider` method.

    let config = try Config()
    try config.addProvider(MySQLProvider.Provider.self)

    let drop = try Droplet(config)

    // ...

    drop.run()

### Configuration

Some drivers may require a configuration file. For example, `MySQLProvider` requires a `Config/mysql.json` file like the following:

    {
        "hostname": "localhost",
        "user": "root",
        "password": "",
        "database": "vapor"
    }

You will receive an error during the `Droplet`'s initialization if a configuration file is required.

Tip

Storing sensitive configuration files (ones that contain passwords) in the `Config/secrets` folder will prevent them from being tracked by git.

### Manual

Some providers can be configured manually by using the Provider's init method. This method can be used instead of configuration files.

    let mysqlProvider = VaporMySQL.Provider(host: "localhost", user: "root", password: "", database: "vapor")
    try config.addProvider(mysqlProvider)

## Create a Provider

Creating a provider is easy, you just need to create a package with a class `Provider` that conforms to `Vapor.Provider`.

### Example

Here is what a provider for an example `Foo` package would look like. All the provider does is take a message, then print the message when the `Droplet` starts.

    import Vapor

    public final class Provider: Vapor.Provider {
        public let message: String

        public convenience init(config: Config) throws {
            guard let message = config["foo", "message"].string else {
                throw ConfigError.missing(key: ["message"], file: "foo", desiredType: String.self)
            }

            self.init(message: message)
        }

        public init(message: String) {
            self.message = message
        }

        public func boot(_ drop: Droplet) { }

        public func beforeRun(_ drop: Droplet) {
            drop.console.info(message)
        }
    }

This provider wil require a `Config/foo.json` file that looks like:

    {
        "message": "The message to output"
    }

The provider can also be initialized manually with the `init(message: String)` init.