iOS H5 调用支付宝/微信支付不返回 app 的解决方法记录

一. 支付宝 aliPay

alipay://alipayclient/?{"requestType":"SafePay","fromAppUrlScheme":"alipays","dataString":"h5_route_token=\"RZ24aot4PEXC1dhcY8lXk7yXsF2Y63mobilecashierRZ24\"&is_h5_route=\"true\""} 

支付宝支付很简单，拦截链接替换 fromAppUrlScheme 对应的值即可, 常规思路是先解码然后把链接转为数组，字典然后替换其中的值，再对相应的部分编码然后拼接，发现太麻烦了。 重新思考需求，核心是”替换”，把未解码的链接当字符串处理行不行？试了一下，success！这应该是最最最简单的方案了。

官方文档:
用户在支付宝APP或H5收银台完成支付后，会根据商户在手机网站支付API中传入的前台回跳地址return_url自动跳转回商户页面，同时在URL请求中以Query String的形式附带上支付结果参数，详细回跳参数见“手机网站支付接口alipay.trade.wap.pay”前台回跳参数。 注意：在ios系统中，唤起支付宝App支付完成后，不会自动回到浏览器或商户APP。用户可手工切回到浏览器或商户APP；支付宝H5收银台会自动跳转回商户return_url指定的页面。

    let URLScheme =  "*.*.com"

    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        guard let url = navigationAction.request.url as URL?,
            let absoluteString = url.absoluteString as String?
            else { return }

        DDLog(absoluteString)
        if absoluteString.contains("alipay://alipayclient") {
            let tmp = absoluteString.replacingOccurrences(of: "alipays", with: URLScheme)
            UIApplication.openURLString(tmp)
            decisionHandler(.allow)
            return
        }
    }

二. 微信 wxPay

@objcMembers class PHHCouponOrderWebController: UIViewController {
    ///查询结果
    var redirect_url: String = ""

    // MARK: -lifecycle
    deinit {
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: "payReturn"), object: nil)
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
        setupExtendedLayout()
        title = "*支付"
        
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "返回", style: .plain, target: self, action: #selector(handleAction(_:)))
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "查看记录", style: .plain, target: self, action: #selector(handleAction(_:)))
        view.backgroundColor = UIColor.background
        view.addSubview(webView)
        
        NotificationCenter.default.addObserver(self, selector: #selector(refreshOrderResult), name: NSNotification.Name(rawValue: "payReturn"), object: nil)
    }

    // MARK: -funtins
    func refreshOrderResult() {
        guard let urlStr = redirect_url.removingPercentEncoding as String? else { return }
        webView.urlString = urlStr
    }
}

extension PHHCouponOrderWebController: WKUIDelegate{

    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        guard let url = navigationAction.request.url as URL?,
            let absoluteString = url.absoluteString as String?
            else { return }

        if absoluteString.contains("weixin://wap/pay") {
            isLoading = false
            UIApplication.openURL(url)
            decisionHandler(.cancel)
        } else if absoluteString.contains("https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb?") && !isLoading {
            let referer = URLScheme + "://"

            let request = NSMutableURLRequest(url: url, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 20)
            request.allHTTPHeaderFields = navigationAction.request.allHTTPHeaderFields;
            request.setValue(referer , forHTTPHeaderField: "Referer")
                        
            let tmp = URLScheme.addingPercentEncoding(withAllowedCharacters: .urlHostAllowed) ?? ""
            if absoluteString.contains("redirect_url") {
                let range: NSRange = (absoluteString as NSString).range(of: "redirect_url=")
                var reqUrl: String = (absoluteString as NSString).substring(to: range.location + range.length)
                reqUrl = reqUrl + referer
                request.url = URL(string: reqUrl)
                
                redirect_url = (absoluteString as NSString).substring(from: range.location + range.length)
                DDLog(reqUrl, redirect_url)

            } else {
                let reqUrl = "\(absoluteString)&redirect_url=\(tmp)"
                request.url = URL(string: reqUrl)
                DDLog(reqUrl)
            }
            
            webView.load(request as URLRequest)

            isLoading = true
            decisionHandler(.cancel)
        }
        else if (absoluteString.contains("https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb?")) {
            isLoading = false;
            decisionHandler(.allow);
        }
        else {
            decisionHandler(.allow);
        }
    }
}

@implementation AppDelegate

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary *)options{
//URLScheme
    if ([url.absoluteString hasSuffix:@".*.com://"]) {
        [NSNotificationCenter.defaultCenter postNotificationName:@"payReturn" object:nil];
        
    } 
    return YES;
}

注：每次做支付需求，微信支付都比支付宝麻烦，建议大家先弄支付宝。