App 内安装其他应用（WKWebView）

实现WKNavigationDelegate代理方法

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    WKNavigationActionPolicy policy =WKNavigationActionPolicyAllow;
    
    NSString *strRequest = [navigationAction.request.URL.absoluteString stringByRemovingPercentEncoding];
    
    strRequest = [strRequest stringByReplacingOccurrencesOfString:@"///" withString:@"//"];
    
    // 在App Store中下载
    if([[navigationAction.request.URL host] isEqualToString:@"itunes.apple.com"] && [[UIApplication sharedApplication] openURL:navigationAction.request.URL] ){
        policy = WKNavigationActionPolicyCancel;
    }
    
    // 企业证书App通用前缀
    NSString *hasPrefix = @"itms-services://?action=download-manifest&url=";
    
    // 下载其他产品app
    if ([strRequest containsString:hasPrefix]) {
        /**
         url 后面的链接地址https://download.fir.im/apps/xxx/install?download_token=xxxxxx,
         需要 URLEncode 成 https%3A%2F%2Fdownload.fir.im%2Fapps%2F%3Aid%2Finstall%3Fdownload_token%3Dxxxxxx
         */
        NSRange range = [strRequest rangeOfString:hasPrefix];
        NSString *str = [strRequest substringFromIndex:range.length];
        // 转码后的地址
        [self openDownLoadUrl:[NSString stringWithFormat:@"%@%@", hasPrefix, [str encodeString]]];
    }
    
    // 若是安装描述文件证书，退出当前控制器
    if ([strRequest hasSuffix:@".mobileprovision"]) {
        [self.navigationController popViewControllerAnimated:YES];
    }
    
    decisionHandler(policy);
}