1. Install developing packages.

How To Install Vapor On A Virtual Machine

1. Install NGINX
2. Install Swift
3. Install Vapor Toolbox
4. Check RAM
5. Create Vapor Sample Project
6. Set Vapor Proxy Behind NGINX
7. Install SuperVisor

My server was 1GB RAM VPS in Ubuntu 20.04 LTS. And I developed vapor on my iMac 5K. So the first thing I did was to create a Linux client.

I prefer VMWare Fusion. As it was free for open source use. I tried VirtualBox, it ran slow with iMac 5K. Parallels Desktop was also good. But it was too expensive.

After all, now you should have a working Ubuntu 20.04.

Install developing packages.

 $ sudo apt update
 $ sudo apt install \
          binutils \
          git \
          gnupg2 \
          libc6-dev \
          libcurl4 \
          libedit2 \
          libgcc-9-dev \
          libpython2.7 \
          libsqlite3-0 \
          libstdc++-9-dev \
          libxml2 \
          libz3-dev \
          pkg-config \
          tzdata \
          zlib1g-dev

Install NGINX

$ sudo apt install nginx

Open Firefox with "localhost".

Install Swift

Download the latest release Swift Toolchain for Ubuntu 20.04.

$ cd Downloads/
$ wget https://download.swift.org/swift-5.5.1-release/ubuntu2004/swift-5.5.1-RELEASE/swift-5.5.1-RELEASE-ubuntu20.04.tar.gz
$ tar xzf swift-5.5.1-RELEASE-ubuntu20.04.tar.gz
$ vi ~/.bashrc

Append

export PATH=/home/zhaoxin/Downloads/swift-5.5.1-RELEASE-ubuntu20.04/usr/bin:”${PATH}”

Save and Quit。

Quit Terminal and Open it again. Type

$ swift --version
Swift version 5.5.1 (swift-5.5.1-RELEASE)
Target: x86_64-unknown-linux-gnu

Install Vapor Toolbox

$ cd ~/Downloads
$ git clone https://github.com/vapor/toolbox.git
$ cd toolbox/
$ git checkout 18.3.3
$ swift build -c release --disable-sandbox --enable-test-discovery
$ sudo mv .build/release/vapor /usr/local/bin

Check RAM

When compile, Vapor needs at least 2GB RAM. So for some VPS with only 1GB RAM, you will get fatalError when compile. You can check RAM with command

$ free -h
              total        used        free      shared  buff/cache   available
Mem:          3.8Gi       1.2Gi       447Mi        14Mi       2.1Gi       2.3Gi
Swap:         923Mi       1.0Mi       921Mi

Above is my VMWare Fusion client. However, for you VPS, you may get a result as below

$ free -h
              total        used        free      shared  buff/cache   available
Mem:          981Mi       215Mi        95Mi       2.0Mi       670Mi       575Mi
Swap:            0B          0B          0B

If that is your case, you must create a swap or you get your Vapor project compiled.

Create Swap File

How To Add Swap Space on Ubuntu 20.04

Vapor Hello Sample Won’t Compile

$ sudo swapon --show

You may get nothing shown as there was no swap for you VPS. Check you disk free space.

df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            447M     0  447M   0% /dev
tmpfs            99M  944K   98M   1% /run
/dev/vda1        24G   12G   11G  51% /
tmpfs           491M     0  491M   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           491M     0  491M   0% /sys/fs/cgroup
/dev/loop0       43M   43M     0 100% /snap/certbot/1514
/dev/loop1       43M   43M     0 100% /snap/certbot/1582
/dev/loop2      100M  100M     0 100% /snap/core/11798
/dev/loop3      100M  100M     0 100% /snap/core/11993
/dev/loop4       62M   62M     0 100% /snap/core20/1169
/dev/loop5       62M   62M     0 100% /snap/core20/1242
tmpfs            99M     0   99M   0% /run/user/0

Look at "/dev/vda1 24G 12G 11G 51% /", That meant you had 11G free space.

Create swap file.

$ sudo fallocate -l 1G /swapfile
$ ls -lh /swapfile
-rw-r--r-- 1 root root 1.0G Apr 25 11:14 /swapfile

Enable swap file

$ sudo chmod 600 /swapfile
$ ls -lh /swapfile
-rw------- 1 root root 1.0G Apr 25 11:14 /swapfile
$ sudo mkswap /swapfile
Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
no label, UUID=6e965805-2ab9-450f-aed6-577e74089dbf
$ sudo swapon /swapfile
$ sudo swapon --show
NAME      TYPE  SIZE USED PRIO
/swapfile file 1024M   0B   -2
$ free - h
              total        used        free      shared  buff/cache   available
Mem:        1004716      166880      147152        2724      690684      643212
Swap:       1048572        5940     1042632

Save Swap File

$ sudo cp /etc/fstab /etc/fstab.bak
$ echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

Create Vapor Sample Project

$ cd
$ mkdir vapor
$ cd vapor
$ git config --global user.email "you@email.com"
$ git config --global user.name "Your Name"
$ vapor new hello -n
$ cd hello/
$ swift run
...
[1686/1686] Build complete!
[ NOTICE ] Server starting on http://127.0.0.1:8080

Open Firefox and type "localhost:8080".

Set Vapor Proxy Behind NGINX

403 forbidden behind nginx

$ cd /etc/nginx/sites-available/
$ sudo cp default default.bak
$ sudo rm default
$ sudo vi default

Copy and paste below to default and save.

server {
        listen 80 default_server;
        listen [::]:80 default_server;

root /var/www/html;

index index.html index.htm index.nginx-debian.html;

server_name _;
        try_files $uri @proxy;
        location @proxy {
                proxy_pass http://127.0.0.1:8080;
                proxy_pass_header Server;
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_pass_header Server;
                proxy_connect_timeout 3s;
                proxy_read_timeout 10s;
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                #try_files $uri $uri/ =404;
        }
}

Restart NGINX.

sudo systemctl restart nginx

How To Install Vapor On A Virtual Machine

Install SuperVisor

$ sudo apt install supervisor
$ cd /etc/supervisor/conf.d/
$ sudo vi hello.conf

Copy and paste below code and save.

[program:hello]
command=/home/zhaoxin/vapor/hello/.build/debug/Run serve --env production
directory=/home/zhaoxin/vapor/hello
user=zhaoxin
stdout_logfile=/var/log/supervisor/%(program_name)-stdout.log
stderr_logfile=/var/log/supervisor/%(program_name)-stderr.log

$ sudo supervisorctl reread
$ sudo supervisorctl add hello
$ sudo supervisorctl start hello

Supervisor

PasscodeLock is the sample project of AppLocker. I took some hours and found how it worked.

Let The App Run

The original project used Carthage to manage the framework. It depended Valet. However, the latest Valet is 4.x but PasscodeLock depends 3.x. So we need to specify the version.

pod 'Valet' , '< 4.0'

I switched Carthage to CocoaPods. So I also had to remove the Carthage part in building phase.

Core

// AppALConstants.swift
// MARK: - Keyboard
@IBAction func keyboardPressed(_ sender: UIButton) {
    switch sender.tag {
    case ALConstants.button.delete.rawValue:
        drawing(isNeedClear: true)
    case ALConstants.button.cancel.rawValue:
        clearView()
        dismiss(animated: true) {
            self.onSuccessfulDismiss?(nil)
        }
    default:
        drawing(isNeedClear: false, tag: sender.tag)
    }
}

private func drawing(isNeedClear: Bool, tag: Int? = nil) { // Fill or cancel fill for indicators
    let results = pinIndicators.filter { $0.isNeedClear == isNeedClear }
    let pinView = isNeedClear ? results.last : results.first
    pinView?.isNeedClear = !isNeedClear
    
    UIView.animate(withDuration: ALConstants.duration, animations: {
        pinView?.backgroundColor = isNeedClear ? .clear : .white
    }) { _ in
        isNeedClear ? self.pin = String(self.pin.dropLast()) : self.pincodeChecker(tag ?? 0)
    }
}

private func pincodeChecker(_ pinNumber: Int) {
    if pin.count < ALConstants.maxPinLength {
        pin.append("\(pinNumber)")
        if pin.count == ALConstants.maxPinLength {
            switch mode {
            case .create:
                createModeAction()
            case .change:
                changeModeAction()
            case .deactive:
                deactiveModeAction()
            case .validate:
                validateModeAction()
            }
        }
    }
}

When a user presses a key, private func drawing(isNeedClear: Bool, tag: Int? = nil) is called.

1. pinView is the current indicator. It is set to turn white.
2. then func pincodeChecker(_ pinNumber: Int) is called, the result is pin.
3. when pin.count is 4, the indicators are cleared.

I have a review and find this article is the fourth time that I am talking about UISplitViewController. That is because UISplitViewController is hard and UISplitViewController changes.

Finally, this time we will only talk the modern part of UISplitViewController, which means those talks are base on iOS 14 and later.

UISplitViewController In General

Above picture is from Apple's document site.

UISplitViewController

The typical app of UISplitViewController is the Mail app in app.

You should be aware that the order of the ViewControllers. There are primary, supplementary and secondary.
While, in Xcode, the orders are different.

Whenever you find an unknown bug, first make sure you have one and only one UINavigationViewController that is in the primary ViewController.

Goal

Our goal is to have an app all in blue. So first I added some data to it.

First, I choose all background to system blue in storyboard. Then added data.

PrimaryTableViewController.swift

//
//  PrimaryTableViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class PrimaryTableViewController: UITableViewController {
    private var items:[Int] = (1...3).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    // MARK: - Table view data source
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "mainCell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
    
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if let splitViewController = self.splitViewController {
            splitViewController.show(.supplementary)
        }
    }
}

SupplementaryViewController.swift

//
//  SupplementaryViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SupplementaryViewController: UIViewController {
    private var items:[Int] = (1...5).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

extension SupplementaryViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "supportCell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

extension SupplementaryViewController:UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if let splitViewController = self.splitViewController {
            splitViewController.show(.secondary)
        }
    }
}

SecondViewController.swift

//
//  SecondViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SecondViewController: UIViewController {
    private var items:[Int] = (1...10).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

extension SecondViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

The app run like this.

As you can see, the color of the title bar is not blue.

We need to add an image to background of the navigationBar.

UIColor+Image.swift

//
//  UIColor+Image.swift
//  Any Counter 2
//
//  Created by zhaoxin on 2021/10/20.
//  Copyright © 2021 ParusSoft.com. All rights reserved.
//

import Foundation
import UIKit

extension UIImage {
    static func from(color: UIColor) -> UIImage {
        let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()
        context!.setFillColor(color.cgColor)
        context!.fill(rect)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img!
    }
}

SecondViewController.swift

//
//  SecondViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SecondViewController: UIViewController {
    private var items:[Int] = (1...10).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        navigationController?.navigationBar.setBackgroundImage(UIImage.from(color: .systemBlue), for: .default)
    }
}

extension SecondViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

The title bar turned to blue when the device was landscape. But in portrait, the color didn't change. Also, there was extra space in portrait.

View Hierarchy

We captured the portrait view controller in Xcode and looked into the view's hierarchy. We found that there were two instead of one UINavigationController used.

UISplitViewController is complex and hard to predict. Because it is combined states of two UINavigationViewControllers.
So each time we encounter a problem, we must consider the current state of the two UINavigationViewControllers.

Solution

First, we wanted all UINavigationController turn blue. So we do it in the UISplitViewController.

SplitViewController.swift

//
//  SplitViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SplitViewController: UISplitViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        children.forEach {
            if let nav = $0 as? UINavigationController {
                nav.navigationBar.setBackgroundImage(UIImage.from(color: .systemBlue), for: .default)
            }
        }
    }
}

And remove the previous changes in SecondViewController.swift.

Now the portrait view controller was blue, however, the gap was still there.

When you set both UINavigationViewControllers, the space doubles in portrait mode.
You must to hide a second UINavigationViewController to remove the space.
However, isHidden of navigationBar didn't work here.
You have to set background image to nil to hide the UINavigationViewController.

SecondViewController.swift

//
//  SecondViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SecondViewController: UIViewController {
    private var items:[Int] = (1...10).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let frame = view.frame
        if frame.height > frame.width {
            self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
        }
    }
}

extension SecondViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

Now the gap was gone. However, when rotating, the title went blank again.

set background image when screen rotate

SecondViewController.swift

//
//  SecondViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SecondViewController: UIViewController {
    private var items:[Int] = (1...10).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let frame = view.frame
        if frame.height > frame.width {
            self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
        }
    }

    // MARK: - rotate
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        if size.height > size.width {
            self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
        } else {
            self.navigationController?.navigationBar.setBackgroundImage(UIImage.from(color: .systemBlue), for: .default)
        }
    }
}

extension SecondViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

SupplementaryViewController.swift

//
//  SupplementaryViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SupplementaryViewController: UIViewController {
    private var items:[Int] = (1...5).map { $0 }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let frame = view.frame
        if frame.height > frame.width {
            self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
        }
    }
    

    // MARK: - rotate
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        if size.height > size.width {
            self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
        } else {
            self.navigationController?.navigationBar.setBackgroundImage(UIImage.from(color: .systemBlue), for: .default)
        }
    }

}

extension SupplementaryViewController:UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "supportCell", for: indexPath)
        let item = items[indexPath.row]
        cell.textLabel?.text = String(item)
        
        return cell
    }
}

extension SupplementaryViewController:UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if let splitViewController = self.splitViewController {
            splitViewController.show(.secondary)
        }
    }
}

TintColor Lost When Landscape

There was a bug on landscape. TintColor set in storyboard was lost.

SplitViewController.swift

//
//  SplitViewController.swift
//  UISplitView Sample
//
//  Created by zhaoxin on 2021/10/21.
//

import UIKit

class SplitViewController: UISplitViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        children.forEach {
            if let nav = $0 as? UINavigationController {
                nav.navigationBar.setBackgroundImage(UIImage.from(color: .systemBlue), for: .default)
                nav.navigationBar.tintColor = .systemYellow
            }
        }
    }
}

Sample Project

*UISplitView Sample