Reactive Extensions for UIWebView

RxUIWebViewDelegateProxy.swift

//
//  RxUIWebViewDelegateProxy.swift
//
//  Created by Casey Liss on 24/3/16.
//  Copyright © 2016 Casey Liss. All rights reserved.
//

import Foundation
import RxSwift
import RxCocoa

class RxUIWebViewDelegateProxy: DelegateProxy, UIWebViewDelegate, DelegateProxyType {
    
    class func currentDelegateFor(object: AnyObject) -> AnyObject? {
        let webView: UIWebView = (object as? UIWebView)!
        return webView.delegate
    }
    
    class func setCurrentDelegate(delegate: AnyObject?, toObject object: AnyObject) {
        let webView: UIWebView = (object as? UIWebView)!
        webView.delegate = delegate as? UIWebViewDelegate
    }
}

UIWebView+Rx.swift

//
//  UIWebView+Rx.swift
//
//  Created by Casey Liss on 24/3/16.
//  Copyright © 2016 Casey Liss. All rights reserved.
//

import Foundation
import RxSwift
import RxCocoa

// This file is largely inspired by:
// https://github.com/RxSwiftCommunity/RxMKMapView/blob/master/Pod/Classes/MKMapView%2BRx.swift

// Taken from RxCococa until marked as public
func castOrThrow<T>(resultType: T.Type, _ object: AnyObject) throws -> T {
    guard let returnValue = object as? T else {
        throw RxCocoaError.CastingError(object: object, targetType: resultType)
    }
    return returnValue
}


extension UIWebView {
    
    /**
     Reactive wrapper for `delegate`.
     
     For more information, take a look at `DelegateProxyType` protocol documentation.
    */
    public var rx_delegate: DelegateProxy {
        return proxyForObject(RxUIWebViewDelegateProxy.self, self)
    }
    
    /**
     Signaled after a web view starts loading a frame.
    */
    public var rx_didStartLoad: ControlEvent<Void> {
        let source = rx_delegate.observe(#selector(UIWebViewDelegate.webViewDidStartLoad(_:))).map { _ in return() }
        return ControlEvent(events: source)
    }
    
    /**
     Signaled after a web view finishes loading a frame.
    */
    public var rx_didFinishLoad: ControlEvent<Void> {
        let source = rx_delegate.observe(#selector(UIWebViewDelegate.webViewDidFinishLoad(_:))).map { _ in return() }
        return ControlEvent(events: source)
    }
    
    /**
     Signaled when a web view failed to load a frame.
    */
    public var rx_didFailLoad: ControlEvent<NSError> {
        let source = rx_delegate.observe(#selector(UIWebViewDelegate.webView(_:didFailLoadWithError:))).map { error in
            return try castOrThrow(NSError.self, error[1])
        }
        return ControlEvent(events: source)
    }
}