You can make use of every proxy app available on Android playstore. Basically youre iOS device will make use of the hostpot from android phone.
Remember youre android phone must be connected to L2TP VPN.
Every proxy will put all the connection of VPN shared to iOS device.

iOS device in settings we need to add ip and port. You will now be connected to VPN on iOS.

I&#39;m trying to understand how to structure enterprise applciation with Node/Express/Mongo (actually using MEAN stack). 

After reading 2 books and some googling (including similar StackOverflow questions), I couldn&#39;t find any good example of structuring large applications using Express. All sources I&#39;ve read suggest to split application by following entities: 

- routes
- controllers
- models


But the main problem I see with this structure is that controllers are like god objects, they knows about `req`, `res` objects, responsible for validation and *have business logic* included in. 

At other side, routes seems to me like over-engineering because all they doing is  mapping endpoints(paths) to controller methods.

I have Scala/Java background, so I have habit to separate all logic in 3 tiers - controller/service/dao. 

For me following statements are ideal: 

- Controllers are responsible only for interacting with WEB part, i.e. marshalling/unmarshalling, some simple validation (required, min, max, email regex etc); 

- Service layer (which actually I missed in NodeJS/Express apps) is responsible only for business logic, some business validation. Service layer doesn&#39;t know anything about WEB part (i.e. they can be called from other place of application, not only from web context);

- Regarding to DAO layer is all clear for me. Mongoose models are actually DAO, so it most clear thing to me here.

I think examples I&#39;ve seen are very simple, and they shows only concepts of Node/Express, but I want to look at some real world example, with much of the business logic/validation involved in. 

EDIT: 

Another thing isn&#39;t clear to me is absent of DTO objects. Consider this example: 


    const mongoose = require(&#39;mongoose&#39;);
    const Article = mongoose.model(&#39;Article&#39;);
    exports.create = function(req, res) {
        // Create a new article object
        const article = new Article(req.body);
        // saving article and other code
    }

There JSON object from `req.body` is passed as parameter for creating Mongo document. It smells bad for me. I would like to work with concrete classes, not with raw JSON

Thanks.


Building enterprise app with Node/Express

As we use `#` for inserting comments in Python, then how does Python treat:

    # -*- coding: utf-8 -*-

differently?

Is &#39;# -*- coding: utf-8 -*-&#39; also a comment in Python?

In iOS settings, there are options to create a VPN configuration using IPSec, IKEv2, and L2TP. Using the NetworkExtension framework from Apple there&#39;s an option to create VPN using IPSec and IKEv2 protocols only. They do work but problem is that I need to create a connection via L2TP since that&#39;s only supported by the company&#39;s firewall.

There&#39;s a question https://stackoverflow.com/questions/26257872/ios-app-with-custom-vpn-connect from 2014 and it&#39;s [answered](https://stackoverflow.com/a/26775461/4949050) with:

&gt; If you want to connect programmatically in ios 8 you can use only IPSec or IKEv2 protocols. L2TP and PPTP protocols are private for apple. It is not possible to use L2TP and PPTP APIs in your applications. Only Apple is currently using these APIs.

Is there any way to create a L2TP VPN connection from an iOS application (Swift)?

Implementing VPN with L2TP protocol in iOS app

In iOS settings, there are options to create a VPN configuration using IPSec, IKEv2, and L2TP. Using the NetworkExtension framework from Apple there's an option to create VPN using IPSec and IKEv2 protocols only. They do work but problem is that I need to create a connection via L2TP since that's only supported by the company's firewall.
There's a question <a href="https://stackoverflow.com/questions/26257872/ios-app-with-custom-vpn-connect" target="_blank" rel="noopener noreferrer">https://stackoverflow.com/questions/26257872/ios-app-with-custom-vpn-connect</a> from 2014 and it's <a href="https://stackoverflow.com/a/26775461/4949050" target="_blank" rel="noopener noreferrer">answered</a> with:
> If you want to connect programmatically in ios 8 you can use only IPSec or IKEv2 protocols. L2TP and PPTP protocols are private for apple. It is not possible to use L2TP and PPTP APIs in your applications. Only Apple is currently using these APIs.
Is there any way to create a L2TP VPN connection from an iOS application (Swift)?

I am using Firebase to observe event and then setting an image inside completion handler

    FirebaseRef.observeSingleEvent(of: .value, with: { (snapshot) in
            if let _ = snapshot.value as? NSNull {
                self.img = UIImage(named:&quot;Some-image&quot;)!
            } else {
                self.img = UIImage(named: &quot;some-other-image&quot;)!
            }
    })

However I am getting this error
&gt; Closure cannot implicitly capture a mutating self parameter

I am not sure what this error is about and searching for solutions hasn&#39;t helped

Closure cannot implicitly capture a mutating self parameter

When I start my app with Xcode, I have a crash, but without an error.

The app is just stopping on this thread:

[![Enter image description here][1]][1]

What can I do to have more information about the issue?

  [1]: https://i.stack.imgur.com/7gCPD.png




dyld`__abort_with_payload: Without an error message

I don&#39;t think this can be done but I&#39;ll ask anyway. I have a protocol:

    protocol X {}

And a class:
  
    class Y:X {}

In the rest of my code I refer to everything using the protocol X. In that code I would like to be able to do something like:

    let a:X = ...
    let b:X = ...
    if a == b {...}

The problem is that if I try to implement `Equatable`:

    protocol X: Equatable {}
    func ==(lhs:X, rhs:X) -&gt; Bool {
        if let l = lhs as? Y, let r = hrs as? Y {
            return l.something == r.something
        }
        return false
    } 

The idea to try and allow the use of `==` whilst hiding the implementations behind the protocol.

Swift doesn&#39;t like this though because `Equatable` has `Self` references and it will no longer allow me to use it as a type. Only as a generic argument.
   

So has anyone found a way to apply an operator to a protocol without the protocol becoming unusable as a type?

Swift Equatable on a protocol

I am using Google Sign-In SDK 4.0.1. When I press googleSignInButton then app will be crash. And gave below error, how to fix this:

    Terminating app due to uncaught exception &#39;NSInvalidArgumentException&#39;, reason: &#39;Your app is missing support for the following URL schemes: com.googleusercontent.apps.107731993306-6s44u18onibp6gi0ddj94si1aifshhg6&#39;
    *** First throw call stack:
    (
    	0   CoreFoundation                      0x0000000101ac0d4b __exceptionPreprocess + 171
    	1   libobjc.A.dylib                     0x000000010110121e objc_exception_throw + 48
    	2   CoreFoundation                      0x0000000101b2a2b5 +[NSException raise:format:] + 197
    	3   xxxxx                           0x000000010084b3cb -[GIDSignIn signInWithOptions:] + 246
    	4   xxxxx                           0x000000010084efc2 -[GIDSignInButton pressed] + 242
    	5   UIKit                               0x00000001028f78bc -[UIApplication sendAction:to:from:forEvent:] + 83
    	6   UIKit                               0x0000000102a7dc38 -[UIControl sendAction:to:forEvent:] + 67
    	7   UIKit                               0x0000000102a7df51 -[UIControl _sendActionsForEvents:withEvent:] + 444
    	8   UIKit                               0x0000000102a7ce4d -[UIControl touchesEnded:withEvent:] + 668
    	9   UIKit                               0x0000000102965545 -[UIWindow _sendTouchesForEvent:] + 2747
    	10  UIKit                               0x0000000102966c33 -[UIWindow sendEvent:] + 4011
    	11  UIKit                               0x00000001029139ab -[UIApplication sendEvent:] + 371
    	12  UIKit                               0x000000010310072d __dispatchPreprocessedEventFromEventQueue + 3248
    	13  UIKit                               0x00000001030f9463 __handleEventQueue + 4879
    	14  CoreFoundation                      0x0000000101a65761 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    	15  CoreFoundation                      0x0000000101a4a98c __CFRunLoopDoSources0 + 556
    	16  CoreFoundation                      0x0000000101a49e76 __CFRunLoopRun + 918
    	17  CoreFoundation                      0x0000000101a49884 CFRunLoopRunSpecific + 420
    	18  GraphicsServices                    0x00000001074cfa6f GSEventRunModal + 161
    	19  UIKit                               0x00000001028f5c68 UIApplicationMain + 159
    	20  xxxxxxxx                           0x00000001007c449f main + 111
    	21  libdyld.dylib                       0x0000000104d5368d start + 1
    	22  ???                                 0x0000000000000001 0x0 + 1
    )
    libc++abi.dylib: terminating with uncaught exception of type NSException`

My AppDelegate.Swift is
 

    class AppDelegate: UIResponder, UIApplicationDelegate, GIDSignInDelegate {
    public func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error!) {
       if (error == nil) {
        
        let userId:NSString = user.userID as NSString;                  // For client-side use only!
        let idToken: NSString = user.authentication.idToken as NSString; // Safe to send to the server
        let fullName:NSString = user.profile.name as NSString;
        let givenName:NSString = user.profile.givenName as NSString;
        let familyName:NSString = user.profile.familyName as NSString;
        let email:NSString = user.profile.email as NSString;
        print(userId)
        print(userId,idToken,fullName,givenName,familyName,email)
        }
        
       else {
        print(&quot;\(error.localizedDescription)&quot;)
        }
    }

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -&gt; Bool {
        
        let kclientID:NSString = &quot;107731993306-xxxxxxxxxxxxxxxxx.apps.googleusercontent.com&quot;
        
       GIDSignIn.sharedInstance().clientID = kclientID as String!
               
        GIDSignIn.sharedInstance().delegate = self
        return true
    }

    
    func application(application: UIApplication,
                     openURL url: NSURL, options: [String: AnyObject], annotation:Any, sourceApplication:String?) -&gt; Bool {
        
        return GIDSignIn.sharedInstance().handle(url as URL!, sourceApplication:sourceApplication, annotation: annotation)
    } 

&gt; Please give me the solution. Why it is crashed?

App getting crash when click on GoogleSignIn button

I can&#39;t find this information. Is it true that Android React Native runs on sdkMin18 and therefore makes it supported by most android versions?

Which version does React Native support (iOS and Android)?

This might be a simple question but because of clear understanding between print() and debug() print in swift I am unable to understand where to use each one. 

print() vs debugPrint() in swift

   Here is an example of what I want to do: 


    func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError)
    {
        let  nm =  NetworkModel()
        nm.sendlog(&quot;file name :AppDelegate , line number : 288&quot;, info: &quot; Failed to register: \(error)&quot;)
    }


current scenario i done that hard coded value `line number` and `file name` . but is it possible to programatically pick `line number` and `file name` . 

How to print out the method name and line number in swift

I often do this,

    let when = DispatchTime.now() + 2.0
    DispatchQueue.main.asyncAfter(deadline: when) {
       beep()
    }

and in one app we often do this

    tickle.fresh(){
    	msg in
    	paint()
    }

but if you do *this*

    let when = DispatchTime.now() + 2.0
    DispatchQueue.main.asyncAfter(deadline: when) {
       tickle.fresh(){
    	  msg in
    	  paint()
       }
    }

of course you have to do *this*

    let when = DispatchTime.now() + 2.0
    DispatchQueue.main.asyncAfter(deadline: when) { [weak self] _ in
       tickle.fresh(){
    	  msg in
    	  self?.paint()
       }
    }

or, maybe *this* 

    let when = DispatchTime.now() + 2.0
    DispatchQueue.main.asyncAfter(deadline: when) {
       tickle.fresh(){
    	  [weak self] msg in
    	  self?.paint()
       }
    }

*or maybe this*

    let when = DispatchTime.now() + 2.0
    DispatchQueue.main.asyncAfter(deadline: when) { [weak self] _ in
       tickle.fresh(){
    	  [weak self] msg in
    	  self?.paint()
       }
    }

#W T H should we do?

All three suggestions *seem* to work perfectly. What&#39;s the full depth of meaning here? And which should one do? Is a strong reference to a weak reference, a weak or strong reference? To be or not to be?  That&#39;s the question!

Where does the weak self go?

When I send request to google api (using either axios or just https), e.g. `https://www.googleapis.com/blogger/v3/blogs/2399953?key=...`

I always hit the &quot;**Client network socket disconnected before secure TLS connection was established**&quot; error.

But if I send request to https://api.github.com, it works just fine. I have googled the error, but I can&#39;t find much useful information.  Here https://github.com/nodejs/node/issues/21088 said if the server uses TLS 1.0, it may happen but apparently it is not my case. 

I also try [googleapis][1] but still hit the same error.

Any idea how to fix the error ?


---- update ----

My question was closed 5 months ago. I opened [an issue][2] against googleapi and it was also closed. I had gave it up but to my surprise it keeps getting traffic. So I updated my question and hope it will be reopened.

First, google api has moved to here https://github.com/googleapis/google-api-nodejs-client

Second, just using vpn to run [the first example][3] there (using vpn because google service is blocked for whatever reason), I will get connect ETIMEDOUT while I can get the result from browser. 

    const {google} = require(&#39;googleapis&#39;);
    const blogger = google.blogger({
      version: &#39;v3&#39;,
      auth: &#39;YOUR API KEY&#39;
    });
    
    blogger.blogs.get({blogId: &#39;3213900&#39;}, (err, res) =&gt; {
      if (err) {
        console.error(err);
        throw err;
      }
      console.log(`The blog url is ${res.data.url}`);
    });
    //But I can get result in browser https://blogger.googleapis.com/v3/blogs/3213900?key=xxx

I think the problem was solvable because nodejs doesn&#39;t send the request through my vpn proxy. So my question is somewhat related to this one, https://stackoverflow.com/questions/33350604/what-could-cause-connect-etimedout-error-when-the-url-is-working-in-browser

But the solution there did not work for me. One answer in this  SO https://stackoverflow.com/questions/3862813/how-can-i-use-an-http-proxy-with-node-js-http-client mentioned using [request][4] and it works!

    var request = require(&quot;request&quot;);
    
    request(
      {
        url:
          &quot;https://blogger.googleapis.com/v3/blogs/3213900?key=xxx&quot;,
        method: &quot;GET&quot;,
        proxy: my-vpn-proxy,
      },
      function (error, response, body) {
        if (!error &amp;&amp; response.statusCode == 200) {
          console.log(body);
        }
      }
    );

Too bad request was deprecated! I can&#39;t make axios works too!

I also tried [tunnel][5] and got `read ECONNRESET error`; I tried [global-tunnel-ng][6] and got the error

    TypeError: Cannot read property &#39;proxy&#39; of undefined
        
But [https-proxy-agent][7] works too,

    var url = require(&#39;url&#39;);
    var https = require(&#39;https&#39;);
    var HttpsProxyAgent = require(&#39;https-proxy-agent&#39;);
     
    // HTTP/HTTPS proxy to connect to
    var proxy = &#39;my-vpn-proxy&#39;;
    
    var endpoint = &#39;https://blogger.googleapis.com/v3/blogs/3213900?key=xxx&#39;;
    var opts = url.parse(endpoint);
     
    var agent = new HttpsProxyAgent(proxy);
    opts.agent = agent;
     
    https.get(opts, function (res) {
      console.log(&#39;&quot;response&quot; event!&#39;, res.headers);
      res.pipe(process.stdout);
    });

So I think this problem may be solvable. 


  [1]: https://www.npmjs.com/package/googleapis
  [2]: https://github.com/googleapis/google-api-nodejs-client/issues/1471
  [3]: https://github.com/googleapis/google-api-nodejs-client#first-example
  [4]: https://github.com/request/request
  [5]: https://www.npmjs.com/package/tunnel
  [6]: https://www.npmjs.com/package/global-tunnel-ng
  [7]: https://www.npmjs.com/package/https-proxy-agent


Content Type	Original Author	Original Content on Stackoverflow
Question	Najdan Tomić	View Question on Stackoverflow
Solution 1 - Ios	Hrushikesh Sawant	View Answer on Stackoverflow

Implementing VPN with L2TP protocol in iOS app

Ios Problem Overview

Ios Solutions

Solution 1 - Ios

Is '# -- coding: utf-8 --' also a comment in Python?

Building enterprise app with Node/Express

Attributions