![Malibu logo](https://raw.githubusercontent.com/vadymmarkov/Malibu/master/Images/cover.png)

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## Description

Palm trees, coral reefs and breaking waves. Welcome to the surf club **Malibu**,
a networking library built on ***promises***. It's more than just a wrapper
around `URLSession`, but a powerful framework that helps to chain your
requests, validations and request processing.

Using [When](https://github.com/vadymmarkov/When) under the hood, **Malibu**
adds a lot of sugar helpers and moves your code up to the next level:

* No more "callback hell".
* Your requests are described in one place.
* Response processing could be easily broken down into multiple logical tasks.
* Data and errors are handled separately.
* Your networking code is much cleaner, readable and follows `DRY` principle.

Equip yourself with the necessary gears of **Malibu**, become a big wave surfer
and let the days of shark infested asynchronous networking be a thing of the
past. Enjoy the ride!

## Features

- [x] Multiple network stacks
- [x] Declarative requests
- [x] Chainable response callbacks built on ***promises***
- [x] All needed content types and parameter encodings
- [x] HTTP response validation
- [x] Response data serialization
- [x] Response mocking
- [x] Request, response and error logging
- [x] Synchronous and asynchronous modes
- [x] Request pre-processing and middleware
- [x] Request offline storage
- [x] Extensive unit test coverage

## Table of Contents

* [Catching the wave](#catching-the-wave)
* [RequestConvertible](#request-convertible)
* [Request](#request)
  * [Content types](#content-types)
  * [Encoding](#encoding)
  * [Cache policy](#cache-policy)
* [Networking](#networking)
  * [Initialization](#initialization)
  * [Mode](#mode)
  * [Mocks](#mocks)
  * [Session configuration](#session-configuration)
  * [Pre-processing](#pre-processing)
  * [Middleware](#middleware)
  * [Authentication](#authentication)
  * [Making a request](#making-a-request)
  * [Response and NetworkPromise](#response-and-networkpromise)
  * [Offline storage](#offline-storage)
  * [Backfoot surfer](#backfoot-surfer)
* [Response](#response)
  * [Serialization](#serialization)
  * [Validation](#validation)  
* [Logging](#logging)
* [Installation](#installation)
* [Author](#author)
* [Credits](#credits)
* [Contributing](#contributing)
* [License](#license)

## Catching the wave

You can start your ride straight away, not thinking about configurations:

```swift
// Create your request => GET http://sharkywaters.com/api/boards?type=1
let request = Request.get("http://sharkywaters.com/api/boards", parameters: ["type": 1])

// Make a call
Malibu.request(request)
  .validate()
  .toJsonDictionary()
  .then({ dictionary -> [Board] in
    // Let's say we use https://github.com/zenangst/Tailor for mapping
    return try dictionary.relationsOrThrow("boards") as [Board]
  })
  .done({ boards in
    // Handle response data
  })
  .fail({ error in
    // Handle errors
  })
  .always({ _ in
    // Hide progress bar
  })
```

If you still don't see any benefits, keep scrolling down and be ready for even
more magic 😉...

## RequestConvertible

Most of the time we need separate network stacks to work with multiple API
services. It's super easy to archive with **Malibu**. Create an
`enum` that conforms to **RequestConvertible** protocol and describe your
requests with all the properties:

```swift
enum SharkywatersEndpoint: RequestConvertible {
  // Describe requests
  case fetchBoards
  case showBoard(id: Int)
  case createBoard(type: Int, title: String)
  case updateBoard(id: Int, type: Int, title: String)
  case deleteBoard(id: Int)

  // Every request will be scoped by the base url
  // Base url is recommended, but optional
  static var baseUrl: URLStringConvertible? = "http://sharkywaters.com/api/"

  // Additional headers for every request
  static var headers: [String: String] = [
    "Accept" : "application/json"
  ]

  // Build requests
  var request: Request {
    switch self {
    case .fetchBoards:
      return Request.get("boards")
    case .showBoard(let id):
      return Request.get("boards/\(id)")
    case .createBoard(let type, let title):
      return Request.post("boards", parameters: ["type": type, "title": title])
    case .updateBoard(let id, let title):
      return Request.patch("boards/\(id)", parameters: ["title": title])
    case .deleteBoard(let id):
      return Request.delete("boards/\(id)")
    }
  }
}
```

**Note** that `Accept-Language`, `Accept-Encoding` and `User-Agent` headers are
included automatically.

## Request

Request is described with a struct in **Malibu**:

```swift
let request = Request(
  // HTTP method
  method: .get,
  // Request url or path
  resource: "boards",
  // Content type
  contentType: .query,
  // Request parameters
  parameters: ["type": 1, "text": "classic"],
  // Headers
  headers: ["custom": "header"],
  // Offline storage configuration
  storePolicy: .unspecified,
  // Cache policy
  cachePolicy: .useProtocolCachePolicy)
```

There are also multiple helper methods with default values for every HTTP method:

```swift
// GET request
let getRequest = Request.get("boards")

// POST request
let postRequest = Request.post(
  "boards",
  // Content type is set to `.json` by default for POST
  contentType: .formURLEncoded,
  parameters: ["type" : kind, "title" : title])

// PUT request
let putRequest = Request.put("boards/1", parameters: ["type" : kind, "title" : title])

// PATCH request
let patchRequest = Request.patch("boards/1", parameters: ["title" : title])

// DELETE request
let deleteRequest = Request.delete("boards/1")
```

`URLSessionDataTask` is default for executing requests. For uploading there
are two additional options that use `URLSessionUploadTask` instead of
`URLSessionDataTask`.

```swift
// Upload data to url
Request.upload(data: data, to: "boards")

// Upload multipart data with parameters
// You are responsible for constructing a proper value,
// which is normally a string created from data.
Request.upload(
  multipartParameters: ["key": "value"],
  to: "http:/api.loc/posts"
)
```

### Content types

* `query` - creates a query string to be appended to any existing url.
* `formURLEncoded` - uses `application/x-www-form-urlencoded` as a
`Content-Type` and formats your parameters with percent-encoding.
* `json` - sets the `Content-Type` to `application/json` and sends a JSON
representation of the parameters as the body of the request.
* `multipartFormData` - sends parameters encoded as `multipart/form-data`.
* `custom(String)` - uses given `Content-Type` string as a header.

### Encoding

**Malibu** comes with 3 parameter encoding implementations:
* `FormURLEncoder` - a percent-escaped encoding following RFC 3986.
* `JsonEncoder` - `JSONSerialization` based encoding.
* `MultipartFormEncoder` - multipart data builder.

You can extend default functionality by adding a custom parameter encoder
that conforms to `ParameterEncoding` protocol:

```swift
// Override default JSON encoder
Malibu.parameterEncoders[.json] = CustomJsonEncoder()

// Register encoder for the custom encoding type
Malibu.parameterEncoders[.custom("application/xml")] = CustomXMLEncoder()
```

### Cache policy

`URLSession` handles cache based on the `URLRequest.CachePolicy` property:

```swift
let getRequest = Request.get("boards". cachePolicy: .useProtocolCachePolicy)
```

`URLRequest.CachePolicy.useProtocolCachePolicy` is the default policy for URL
load requests. `URLSession` will automatically add the `If-None-Match` header
in the request before sending it to the backend. When `URLSession` gets the
`304 Not Modified` response status it will call the `URLSessionDataTask`
completion block with the `200` status code and data loaded from the cached
response.

You can set `cachePolicy` property to `.reloadIgnoringLocalCacheData` if you
want to prevent this automatic cache management. Then `URLSession` will not
add the `If-None-Match` header to the client requests, and the server will
always return a full response.

## Networking

`Networking` class is a core component of **Malibu** that executes actual HTTP
requests on a specified API service.

### Initialization

It's pretty straightforward to create a new `Networking` instance:

```swift
// Simple networking that works with `SharkywatersEndpoint` requests.
let simpleNetworking = Networking<SharkywatersEndpoint>()

// More advanced networking
let networking = Networking<SharkywatersEndpoint>(
  // `OperationQueue` Mode
  mode: .async,
  // Optional mock provider
  mockProvider: customMockProvider,
  // `default`, `ephemeral`, `background` or `custom`
  sessionConfiguration: .default,
  // Custom `URLSessionDelegate` could set if needed
  sessionDelegate: self
)
```

### Mode

**Malibu** uses `OperationQueue` to execute/cancel requests. It makes it
easier to manage request lifetime and concurrency.

When you create a new networking instance there is an optional argument to
specify **mode** which will be used:

- `sync`
- `async`
- `limited(maxConcurrentOperationCount)`

### Mocks

Mocking is great when it comes to writing your tests. But it also could speed
up your development while the backend developers are working really hardly
on API implementation.

In order to start mocking you have to do the following:

**Create a mock provider**

```swift
// Delay is optional, 0.0 by default.
let mockProvider = MockProvider(delay: 1.0) { endpoint in
  switch endpoint {
    case .fetchBoards:
      // With response data from a file:
      return Mock(fileName: "boards.json")
    case .showBoard(let id):
      // With response from JSON dictionary:
      return Mock(json: ["id": 1, "title": "Balsa Fish"])
    case .updateBoard(let id, let title):
      // `Data` mock:
      return Mock(
        // Needed response
        response: mockedResponse,
        // Response data
        data: responseData,
        // Custom error, `nil` by default
        error: customError
      )
    default:
      return nil
  }
}
```

**Create a networking instance with your mock provider**

Both real and fake requests can be used in a mix:
```swift
let networking = Networking<SharkywatersEndpoint>(mockProvider: mockProvider)
```

### Session configuration

`SessionConfiguration` is a wrapper around `URLSessionConfiguration` and could
represent 3 standard session types + 1 custom type:
* `default` - configuration that uses the global singleton credential, cache and
cookie storage objects.
* `ephemeral` - configuration with no persistent disk storage for cookies, cache
or credentials.
* `background` - session configuration that can be used to perform networking
operations on behalf of a suspended application, within certain constraints.
* `custom(URLSessionConfiguration)` - if you're not satisfied with standard
types, your custom `URLSessionConfiguration` goes here.

### Pre-processing

```swift
// Use this closure to modify your `Request` value before `URLRequest`
// is created on base of it
networking.beforeEach = { request in
  return request.adding(
    parameters: ["userId": "12345"],
    headers: ["token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9"]
  )
}

// Use this closure to modify generated `URLRequest` object
// before the request is made
networking.preProcessRequest = { (request: URLRequest) in
  var request = request
  request.addValue("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9", forHTTPHeaderField: "token")
  return request
}
```

### Middleware

**Middleware** is the function which works as the first promise in the chain,
before the actual request. It could be used to prepare networking, do some
kind of pre-processing task, cancel request under particular conditions, etc.

For example, in the combination with https://github.com/hyperoslo/OhMyAuth

```swift
// Set middleware in your configuration
// Remember to `resolve` or `reject` the promise
networking.middleware = { promise in
  AuthContainer.serviceNamed("service")?.accessToken { accessToken, error in
    if let error == error {
      promise.reject(error)
      return
    }

    guard let accessToken = accessToken else {
      promise.reject(CustomError())
      return
    }

    self.networking.authenticate(bearerToken: accessToken)
    promise.resolve()
  }
}

// Send your request like you usually do.
// Valid access token will be set to headers before the each request.
networking.request(request)
  .validate()
  .toJsonDictionary()
```

### Authentication

```swift
// HTTP basic authentication with username and password
networking.authenticate(username: "malibu", password: "surfingparadise")

// OAuth 2.0 authentication with Bearer token
networking.authenticate(bearerToken: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9")

// Custom authorization header
networking.authenticate(authorizationHeader: "Malibu-Header")
```

### Making a request

`Networking` is set up and ready, so it's time to fire some requests.

```swift
let networking = Networking<SharkywatersEndpoint>()

networking.request(.fetchBoards)
  .validate()
  .toJsonDictionary()
  .done({ data in
    print(data)
  })

networking.request(.createBoard(kind: 2, title: "Balsa Fish"))
  .validate()
  .toJsonDictionary()
  .done({ data in
    print(data)
  })

networking.request(.deleteBoard(id: 11))
  .fail({ error in
    print(error)
  })
```

### Response and NetworkPromise

`Response` object consists of `Data`, `URLRequest` and `HTTPURLResponse`
properties.

`NetworkPromise` is just a `typealias` to `Promise<Response>`, which is returned
by every request method. You may use `NetworkPromise` object to add different
callbacks and build chains of tasks. It has a range of useful helpers, such as
validations and serialization.

```swift
let networkPromise = networking.request(.fetchBoards)

// Cancel the task
networkPromise.cancel()

// Create chains and add callbacks on promise object
networkPromise
  .validate()
  .toString()
  .then({ string in
    // ...
  })
  .done({ _ in
    // ...
  })
```

### Offline storage

Want to **store request** when there is no network connection?

```swift
let request = Request.delete(
  "boards/1",
  storePolicy: .offline // Set store policy
)
```

Want to **replay** cached requests?

```swift
networking.replay().done({ result
  print(result)
})
```

Request storage is networking-specific, and while it replays cached requests
it will be set to `Sync` mode. Cached request will go through normal request
lifecycle, with applied middleware and pre-process operations. Request will be
automatically removed from the storage when it's completed.

### Backfoot surfer

**Malibu** has a shared networking object with default configurations for the
case when you need just something simple to catch the wave. It's not necessary
to create a custom `RequestConvertible` type, just call the same `request` method right
on `Malibu`:

```swift
Malibu.request(Request.get("http://sharkywaters.com/api/boards")
```

## Response

### Serialization

**Malibu** gives you a bunch of methods to serialize response data:

```swift
let networkPromise = networking.request(.fetchBoards)

networkPromise.toData() // -> Promise<Data>
networkPromise.toString() // -> Promise<String>
networkPromise.toJsonArray() // -> Promise<[[String: Any]]>
networkPromise.toJsonDictionary() // -> Promise<[String: Any]>
```

### Validation

**Malibu** comes with 4 validation methods:

```swift
// Validates a status code to be within 200..<300
// Validates a response content type based on a request's "Accept" header
networking.request(.fetchBoards).validate()

// Validates a response content type
networking.request(.fetchBoards).validate(
  contentTypes: ["application/json; charset=utf-8"]
)

// Validates a status code
networking.request(.fetchBoards).validate(statusCodes: [200])

// Validates with custom validator conforming to `Validating` protocol
networking.request(.fetchBoards).validate(using: CustomValidator())
```

## Logging

If you want to see some request, response and error info in the console, you
get this for free. Just choose one of the available log levels:

* `none` - logging is disabled, so your console is not littered with networking
stuff.
* `error` - prints only errors that occur during the request execution.
* `info` - prints incoming request method + url, response status code and errors.
* `verbose` - prints incoming request headers and parameters in addition to
everything printed in the `info` level.

Optionally you can set your own loggers and adjust the logging to your needs:

```swift
// Custom logger that conforms to `ErrorLogging` protocol
Malibu.logger.errorLogger = CustomErrorLogger.self

// Custom logger that conforms to `RequestLogging` protocol
Malibu.logger.requestLogger = RequestLogger.self

// Custom logger that conforms to `ResponseLogging` protocol
Malibu.logger.responseLogger = ResponseLogger.self
```

## Author

Hyper Interaktiv AS, ios@hyper.no

## Installation

**Malibu** is available through [CocoaPods](http://cocoapods.org). To install
it, simply add the following line to your Podfile:

```ruby
pod 'Malibu'
```

**Malibu** is also available through [Carthage](https://github.com/Carthage/Carthage).
To install just write into your Cartfile:

```ruby
github "vadymmarkov/Malibu"
```

**Malibu** can also be installed manually.
Just *Download* and *drop* ```/Sources``` folder in your project.  

## Author

Vadym Markov, markov.vadym@gmail.com

## Credits

This library was originally done at [Hyper](http://hyper.no), a digital
communications agency with a passion for [good code](https://github.com/hyperoslo)
and delightful user experiences.

Credits go to [Alamofire](https://github.com/Alamofire/Alamofire) for
inspiration and to [When](https://github.com/vadymmarkov/When) for ***promises***.

## Contributing

Check the [CONTRIBUTING](https://github.com/vadymmarkov/Malibu/blob/master/CONTRIBUTING.md) file for more info.

## License

**Malibu** is available under the MIT license. See the [LICENSE](https://github.com/vadymmarkov/Malibu/blob/master/LICENSE.md) file for more info.