# Alamofire

* [1. Core](#1-core)
  * [1.1. Session](#11-session)
  * [1.2. Request](#12-request)
  * [1.3. URLRequestConvertible](#13-urlrequestconvertible)
  * [1.4. HTTPMethod](#14-httpmethod)
  * [1.5. HTTPHeaders](#15-httpheaders)
  * [1.6. ParameterEncoder](#16-parameterencoder)
  * [1.7. ParameterEncoding (Deprecated)](#17-parameterencoding-deprecated)
  * [1.8. Protected](#18-protected)
  * [1.9. typealias](#19-typealias)
* [2. Feature](#2-feature)
  * [2.1. CachedResponseHandler](#21-cachedresponsehandler)
  * [2.2. RedirectHandler](#22-redirecthandler)
  * [2.3. EventMonitor](#23-eventmonitor)
  * [2.4. RequestInterceptor](#24-requestinterceptor)
  * [2.5. Server Trust](#25-server-trust)
  * [2.6. AlamofireExtended](#26-alamofireextended)
    * [2.6.1. `AlamofireExtended` protocol](#261-alamofireextended-protocol)
    * [2.6.2. `AlamofireExtension` struct](#262-alamofireextension-struct)
    * [2.6.3. `AlamofireExtension+URLSessionConfiguration`](#263-alamofireextensionurlsessionconfiguration)
    * [2.6.4. `AlamofireExtension+Bundle`](#264-alamofireextensionbundle)
    * [2.6.5. `AlamofireExtension+SecTrust`](#265-alamofireextensionsectrust)
    * [2.6.6. `AlamofireExtension+SecPolicy`](#266-alamofireextensionsecpolicy)
    * [2.6.7. `AlamofireExtension+SecTrustResultType`](#267-alamofireextensionsectrustresulttype)
    * [2.6.8. `AlamofireExtension+SecCertificate`](#268-alamofireextensionseccertificate)
    * [2.6.9. `AlamofireExtension+Array`](#269-alamofireextensionarray)
    * [2.6.10. `AlamofireExtension+OSStatus`](#2610-alamofireextensionosstatus)
* [3. FAQ](#3-faq)
  * [3.1. Result](#31-result)

## 1. Core

### 1.1. Session

### 1.2. Request

### 1.3. URLRequestConvertible

`URLConvertible` & `URLRequestConvertible`

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-URLRequestConvertible.puml)

### 1.4. HTTPMethod

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-HTTPMethod.puml)

### 1.5. HTTPHeaders

`HTTPHeaders`: An **order-preserving** and **case-insensitive** representation of HTTP headers.

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-HTTPHeaders.puml)

### 1.6. ParameterEncoder

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-ParameterEncoder.puml)

### 1.7. ParameterEncoding (Deprecated)

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-ParameterEncoding.puml)

### 1.8. Protected

`Protected` is defined as a **Property Wrapper**:

```swift
@propertyWrapper
@dynamicMemberLookup
final class Protected<T> {
    ...
}
```

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-Protected.puml)

### 1.9. typealias

```swift
public typealias RequestModifier = (inout URLRequest) throws -> Void
public typealias Parameters = [String: Any]
```

## 2. Feature

### 2.1. CachedResponseHandler

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://raw.githubusercontent.com/Huang-Libo/Notebook/master/Diagram/Alamofire/Alamofire-CachedResponseHandler.puml)

### 2.2. RedirectHandler

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://raw.githubusercontent.com/Huang-Libo/Notebook/master/Diagram/Alamofire/Alamofire-RedirectHandler.puml)

### 2.3. EventMonitor

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://github.com/Huang-Libo/Notebook/raw/master/Diagram/Alamofire/Alamofire-EventMonitor.puml)

### 2.4. RequestInterceptor

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://raw.githubusercontent.com/Huang-Libo/Notebook/master/Diagram/Alamofire/Alamofire-RequestInterceptor.puml)

### 2.5. Server Trust

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://raw.githubusercontent.com/Huang-Libo/Notebook/master/Diagram/Alamofire/Alamofire-ServerTrust.puml)

`ServerTrustManager`: Responsible for managing the mapping of `ServerTrustEvaluating` values to given hosts.

### 2.6. AlamofireExtended

![Class Diagram](http://www.plantuml.com/plantuml/proxy?src=https://raw.githubusercontent.com/Huang-Libo/Notebook/master/Diagram/Alamofire/Alamofire-Extended.puml)

#### 2.6.1. `AlamofireExtended` protocol

The `AlamofireExtended` protocol is used as **namespace** of all `public` extensions.

**Note**: Since `AlamofireExtended` has default implementations, so the *class*/*struct* which conform to this protocol can use these default implementation of `af` directly without implement them.

```swift
/// Protocol describing the `af` extension points for Alamofire extended types.
public protocol AlamofireExtended {
    /// Type being extended.
    associatedtype ExtendedType

    /// Static Alamofire extension point.
    static var af: AlamofireExtension<ExtendedType>.Type { get set }
    /// Instance Alamofire extension point.
    var af: AlamofireExtension<ExtendedType> { get set }
}

/// Add default implementation of the protocol functions
extension AlamofireExtended {
    /// Static Alamofire extension point.
    public static var af: AlamofireExtension<Self>.Type {
        get { AlamofireExtension<Self>.self }
        set {}
    }

    /// Instance Alamofire extension point.
    public var af: AlamofireExtension<Self> {
        get { AlamofireExtension(self) }
        set {}
    }
}
```

#### 2.6.2. `AlamofireExtension` struct

All the `public` extension functions in Alamofire are implemented under the `AlamofireExtension` type.

Definition of `AlamofireExtension`:

```swift
/// Type that acts as a generic extension point for all `AlamofireExtended` types.
public struct AlamofireExtension<ExtendedType> {
    /// Stores the type or meta-type of any extended type.
    public private(set) var type: ExtendedType

    /// Create an instance from the provided value.
    ///
    /// - Parameter type: Instance being extended.
    public init(_ type: ExtendedType) {
        self.type = type
    }
}
```

#### 2.6.3. `AlamofireExtension+URLSessionConfiguration`

**Use case 1**, adding extension for `URLSessionConfiguration`:

```swift
extension URLSessionConfiguration: AlamofireExtended {}
extension AlamofireExtension where ExtendedType: URLSessionConfiguration {
    /// Alamofire's default configuration. Same as `URLSessionConfiguration.default` but adds Alamofire default
    /// `Accept-Language`, `Accept-Encoding`, and `User-Agent` headers.
    public static var `default`: URLSessionConfiguration {
        let configuration = URLSessionConfiguration.default
        configuration.headers = .default

        return configuration
    }

    /// `.ephemeral` configuration with Alamofire's default `Accept-Language`, `Accept-Encoding`, and `User-Agent`
    /// headers.
    public static var ephemeral: URLSessionConfiguration {
        let configuration = URLSessionConfiguration.ephemeral
        configuration.headers = .default

        return configuration
    }
}
```

Call the extension functions:

```swift
URLSessionConfiguration.af.default
```

**Note**: As you can see in this example, extension functions are implemented under the `AlamofireExtension`, `af` returns an instance of `AlamofireExtension`.

Other `public` extensions defined in Alamofire are listed below.

#### 2.6.4. `AlamofireExtension+Bundle`

```swift
extension Bundle: AlamofireExtended {}
extension AlamofireExtension where ExtendedType: Bundle {

    public var certificates: [SecCertificate] {
        ...
    }

    public var publicKeys: [SecKey] {
        ...
    }

    public func paths(forResourcesOfTypes types: [String]) -> [String] {
        ...
    }

}
```

#### 2.6.5. `AlamofireExtension+SecTrust`

```swift
extension SecTrust: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == SecTrust {

    public func evaluate(afterApplying policy: SecPolicy) throws {
        ...
    }

    public func validate(policy: SecPolicy, errorProducer: (_ status: OSStatus, _ result: SecTrustResultType) -> Error) throws {
        ...
    }

    public func apply(policy: SecPolicy) throws -> SecTrust {
        ...
    }

    public func evaluate() throws {
        ...
    }

    public func validate(errorProducer: (_ status: OSStatus, _ result: SecTrustResultType) -> Error) throws {
        ...
    }

    public func setAnchorCertificates(_ certificates: [SecCertificate]) throws {
        ...
    }

    public var publicKeys: [SecKey] {
        ...
    }

    public var certificates: [SecCertificate] {
        ...
    }

    public var certificateData: [Data] {
        ...
    }

    public func performDefaultValidation(forHost host: String) throws {
        ...
    }

    public func performValidation(forHost host: String) throws {
        ...
    }

}
```

#### 2.6.6. `AlamofireExtension+SecPolicy`

```swift
extension SecPolicy: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == SecPolicy {

    public static let `default` = SecPolicyCreateSSL(true, nil)

    public static func hostname(_ hostname: String) -> SecPolicy {
        ...
    }

    public static func revocation(options: RevocationTrustEvaluator.Options) throws -> SecPolicy {
        ...
    }

}
```

#### 2.6.7. `AlamofireExtension+SecTrustResultType`

```swift
extension SecTrustResultType: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == SecTrustResultType {
    public var isSuccess: Bool {
        ...
    }
}
```

#### 2.6.8. `AlamofireExtension+SecCertificate`

```swift
extension SecCertificate: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == SecCertificate {
    public var publicKey: SecKey? {
        ...
    }
}
```

#### 2.6.9. `AlamofireExtension+Array`

```swift
extension Array: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == [SecCertificate] {

    public var data: [Data] {
        ...
    }

    public var publicKeys: [SecKey] {
        ...
    }
}
```

#### 2.6.10. `AlamofireExtension+OSStatus`

```swift
extension OSStatus: AlamofireExtended {}
extension AlamofireExtension where ExtendedType == OSStatus {
    public var isSuccess: Bool { ... }
}
```

## 3. FAQ

### 3.1. Result

Where does the `Result` instance construct from?

`URLEncodedFormParameterEncoder` -> `open func encode<Parameters: Encodable>(...)` :

```swift
let query: String = try Result<String, Error> { try encoder.encode(parameters) }
    .mapError { AFError.parameterEncoderFailed(reason: .encoderFailed(error: $0)) }.get()
```