Node.js based smart shopping cart app

Information

In this page, there is English description followed by Japanese one.
本ページは英語の説明の後に日本語の説明が続きます。

Getting Started

Installing Node.js and npm

You need to have Node.js and npm installed.

To check if you have them installed, open a terminal or command prompt and run the following commands:

node --version
npm --version

If you see an number output similar to x.x.x for each command, then they are both installed and you can continue to the next section.

To install on Windows or mac, you can download the installer from https://nodejs.org/en/download.

To install on Linux, you can use a package manager. Instructions for installing Node.js on your distribution can be found in the following link:
https://nodejs.org/en/download/package-manager

Prerequisite

This example assumes that you've already run the following program that can communicate the decoded result of barcode data with mbed Device Connector:

Import programGR-PEACH_mbed-os-client-ZXingSample

Fork of https://developer.mbed.org/teams/Renesas/code/GR-PEACH_mbed-os-client-ZXingSample/

Configuring the Applition

In order to run this app, you need to set up the options shown below via .env file stored in the folder GR-PEACH_mbed-os-QRCode-ShoppingCart-node which should be automatically created when cloning this program.

  • ACCESS_KEY
    Set this variable to your Access Key that you can create on mbed Device Connector. if you don't have an Access Key yet, please create it in accordance with the following procedure.
    1. Access https://connector.mbed.com/#accesskeys.
    2. Click CREATE NEW ACCESS KEY.
    /media/uploads/HinoNaka/screenshot7.png
    3. When prompted, enter a name for the access key (e.g. "demo") and click ADD.
    /media/uploads/HinoNaka/screenshot8.png

    After an access key is successfully created, please copy the access key you just created and use it in .env file as follows:

.env

ACCESS_KEY=...
  • PORT
    Set this variable as follows to override the default port for this example if needed. The default port is 8080.

.env

PORT=...

Also, user need to prepare for the comma-delimited list which includes "Item Name" and "Price" which is added to shopping cart, and save it by the name klist.txt as follows:
/media/uploads/HinoNaka/mbed_shoppingcart_fig8.png
The list should be stored in GR-Peach_mbed-os_QRCode_ShoppingCart_node\public\list.

Application Execution

This application consists of 2 tabs. One is Shopping Cart and the other is QR Code Login. In this section, it is described that how those work.

As mentioned above, GR-PEACH_mbed-os-client-ZXingSample should be executed beforehand. For details on how to set up and execute GR-PEACH_mbed-os-client-ZXingSample, please refer to https://developer.mbed.org/teams/Renesas/code/GR-PEACH_mbed-os-client-ZXingSample/. If the program works properly, you can see the following message in your terminal: /media/uploads/HinoNaka/mbed_shoppingcart_fig4.png

After it is confirmed that the program works properly, please follow the procedure below in order to execute this Web Application.

  • How to invoke this Web Application
    You can now run the application by invoking the following: /media/uploads/HinoNaka/shoppingcart_fig1.png
    Then, you should see the following message if the configuration is successfully done, :
    /media/uploads/HinoNaka/shoppingcart_fig2.png
    Please note that 8080 might be changed. It should depends on your PORT setting mentioned above. If you access the above URL using Web browser, you can see the following Smart Shopping Cart tab by default: /media/uploads/HinoNaka/mbed_shoppingcart_fig3.png

  • How Shopping Cart tab works
    When you decode QR code stored in GR-Peach_mbed-os_QRCode_ShoppingCart_node\qrcode by GR-PEACH successfully, the item should be added to shopping cart as follows:
    /media/uploads/HinoNaka/mbed_shoppingcart_fig5.png

  • How QR Code Login tab works
    When you choose QR Code Login tab, you can see the following screen indicating it's Locked status.
    /media/uploads/HinoNaka/mbed_shoppingcart_fig6.png
    Then, if you decode the Unlock qrcode described in GR-Peach_mbed-os_QRCode_ShoppingCart_node\qrcode\qr.pdf, screen should transit to the following one indicating it's Unlocked status.
    /media/uploads/HinoNaka/mbed_shoppingcart_fig7.png
    After that if you you decode the Lock qrcode described in the above qr.pdf, screen should re-transit to Locked status. In this way, the screen transits to Locked and Unlocked status in accordance with the decoded result of QR code.

How to Deploy this app on HEROKU

HEROKU ( https://id.heroku.com ) is PaaS (Platform as a Service) on which Node.js application can deploy free-of charge. By utilizing it, you can access mbed Shopping Cart and QR Code Login from mobile terminal.

Here is the procedure to deploy this application on HEROKU:

  1. Create your HEROKU account at https://signup.heroku.com/login if you haven't created it yet.
  2. Install Heroku Toolbelt
    32-bit: https://cli-assets.heroku.com/heroku-cli/channels/stable/heroku-cli-x86.exe
    64-bit: https://cli-assets.heroku.com/heroku-cli/channels/stable/heroku-cli-x64.exe )
  3. Launch command prompt (e.g. Windows PowerShell) and move to the project root directory. Then, invoke the command heroku login. At the first time, Email and Password is thought to be required. At that time, please type Email address and password registered at the step 1.
  4. Invoke the command git init
  5. Invoke the command git add . to prepare all the files staged for the next commit
  6. Invoke the command git commit -m "[commit message]" to commit the files staged at the step 5
  7. Invoke the command heroku create. If the command is successfully terminated, the remote repository heroku should be created and associated with the local repository
  8. Invoke the command git push heroku master If the command is successfully terminated, this application should be deployed to HEROKU and its URL should be shown as follows:

remote: -----> Launching...
remote:        Released v3
remote:        https://hogeoge.herokuapp.com/ deployed to Heroku

After all the steps are completed without error, please access the URL http:hogehoge.herokuapp.com/ (i.e URL where https in the URL shown in the step 7 is replaced with http) with Web browser. You should be able to show mbed Shopping Cart on Web browser.

-------------------------------------------------------------------------------------------------------------------------------------------------

Node.jsとnpmのインストール

本アプリケーションを実行するにあたっては、Node.jsとnpmのインストールが必要です。
お使いの開発環境(PC)にNode.js、npmがインストールされているかどうかは、下記コマンドで確認する事ができます。

node --version
npm --version

上記コマンド実行後、x.x.x というバージョン・リビジョン番号が表示されれば、Node.js、npmは既にインストールされていますので、次節以降の手順にしたがってアプリケーションのセットアップを行ってください。未インストールの場合は以降の手順にしたがってNode.js、npmをインストールしてください。

開発環境のホストOSがWindowsまたはmacの場合はhttps://nodejs.org/en/download から入手可能なインストーラを使用してインストールします。

開発環境のホストOSがLinuxの場合は、お使いのディストリビーションに応じたパッケージ管理システムを用いたインストールが可能です。詳細はhttps://nodejs.org/en/download/package-manager を参照ください。

前提条件

本アプリケーションを実行するにあたっては、GR-PEACH上のバーコードデータのデコード結果にmbed Device Connectorからアクセスする下記プログラムを事前にセットアップしておく必要があります。

Import programGR-PEACH_mbed-os-client-ZXingSample

Fork of https://developer.mbed.org/teams/Renesas/code/GR-PEACH_mbed-os-client-ZXingSample/

アプリケーションの設定

本アプリケーションの実行するためには、.envファイルを介して以下に示すオプションを設定する必要があります。なお、.envファイルはGR-PEACH_mbed-os-QRCode-ShoppingCart-nodeフォルダに格納されています。

  • ACCESS_KEY 本変数にはmbed Device Connector上で生成可能なAccess Keyを設定します。Access Keyが未生成の場合は下記に従って作成してください。
    1. https://connector.mbed.com/#accesskeys にアクセスします。
    2. CREATE NEW ACCESS KEYをクリックします。
    /media/uploads/HinoNaka/screenshot7.png
    3. access keyの名称を入力するように促されたら、任意の名称(例えばdemo等)を入力し、ADDをクリックします。
    /media/uploads/HinoNaka/screenshot8.png

    access keyが正常に生成できたら、コピーして下記のように.envファイルでACCESS_KEYに設定します。

.env

ACCESS_KEY=...
  • PORT 本変数にはWebアプリへのアクセスに使用するポート番号を下記のように設定します。デフォルトのポート番号は 8080 です。8080から変更の必要がなければ、設定は省略可能です。

.env

PORT=...

また、ショッピングカートに追加する品目と値段をカンマ区切りで下記のように記載したリストを準備し、klist.txtという名称でGR-Peach_mbed-os_QRCode_ShoppingCart_node\public\listフォルダに格納してください。

/media/uploads/HinoNaka/mbed_shoppingcart_fig8.png

アプリケーションの実行

本アプリケーションでは、Shopping CartQR Code Loginという2つのタブが実装されています。以下、それぞれの動作方法について記載します。
なお上述の通り、本アプリケーションの実行に際しては、事前にGR-PEACH_mbed-os-client-ZXingSampleを実行しておく必要があります。GR-PEACH_mbed-os-client-ZXingSampleのセットアップ方法、および実行方法に関しては、https://developer.mbed.org/teams/Renesas/code/GR-PEACH_mbed-os-client-ZXingSample/ を参照ください。プログラムが正常に動作している場合、下記のメッセージがターミナルに表示されます。
/media/uploads/HinoNaka/mbed_shoppingcart_fig4.png

プログラムの正常動作が確認できたら、以降の手順に従ってWebアプリケーションを実行します。

  • Webアプリケーションの起動
    下記コマンドでWebアプリケーションを起動可能です。
    /media/uploads/HinoNaka/shoppingcart_fig1.png
    上述のアプリケーション設定が正常に行われていれば、下記メッセージが表示されます。
    /media/uploads/HinoNaka/shoppingcart_fig2.png
    なお、8080PORT設定に応じた値となります。
    続いて、上述のURLにWebブラウザでアクセスすると、下記のSmart Shopping Cartの画面が表示されます。
    /media/uploads/HinoNaka/mbed_shoppingcart_fig3.png

  • Shopping Cartタブ
    GR-Peach_mbed-os_QRCode_ShoppingCart_node\qrcode\qrcode.pdf に記載されている Birthday CakeParty CupsBeer KegsPound of beefBuflle-proof vest のQRコードをデコードすると、下記のようにデコードしたアイテムが都度ショッピングカートに追加されます。
    /media/uploads/HinoNaka/mbed_shoppingcart_fig5.png

  • QR Code Loginタブ
    このタブを選択すると、下記のLock状態を示す画面が表示されます。 /media/uploads/HinoNaka/mbed_shoppingcart_fig6.png
    ここで、GR-Peach_mbed-os_QRCode_ShoppingCart_node\qrcode\qrcode.pdf に記載のUnlock QRコードをデコードすると、Unlock状態を示す下記の画面に遷移します。 /media/uploads/HinoNaka/mbed_shoppingcart_fig7.png

    この後、Lock QRコードをデコードすると画面はLock状態に再度遷移します。

    このようにQR Code Loginタブでは、LockUnlockのQRコードをデコードする都度、対応する画面に遷移するアプリケーションです。

HEROKUへのデプロイ

HEROKU ( https://id.heroku.com) はNode.jsアプリが無償でデプロイ可能なPaaS (Platform as a Service)と呼ばれるサービスです。HEROKUを活用する事で、mbed Shopping CartQR Code Loginにモバイル端末等からアクセスする事が可能となります。

以下、HEROKUへ本アプリをデプロイする手順を説明します。

  1. HEROKUのアカウントを所有していない場合は https://signup.heroku.com/login でアカウントを作成してください
  2. Heroku Toolbeltをインストールします
    32-bit版: https://cli-assets.heroku.com/heroku-cli/channels/stable/heroku-cli-x86.exe
    64-bit版: https://cli-assets.heroku.com/heroku-cli/channels/stable/heroku-cli-x64.exe )
  3. ターミナルソフトウェア(例えばWindows PowerShell)を立上げます。そして本アプリのルートディレクトリへ移動し、heroku loginコマンドを実行します。Emailアドレスとパスワードの入力を求められた場合は、アカウント生成時に入力したアドレスとパスワードを入力してください。
  4. git initコマンドを実行します
  5. git add .コマンドを実行し、全ファイルをコミット対象に設定します
  6. git commit -m "[commit message]" で、全ファイルをコミットします
  7. heroku createを実行します。本コマンドが正常終了すると、リモートリポジトリ herokuが設定されます
  8. git push heroku master本コマンドが正常終了すると、HEROKUへのデプロイが完了し、下記のように本WebアプリのURLが表示されます

remote: -----> Launching...
remote:        Released v3
remote:        https://hogeoge.herokuapp.com/ deployed to Heroku

上記の全ての手順が完了したら、http:hogehoge.herokuapp.com/ ( 8. で表示されたURL中のhttpshttpに置換えたもの)へブラウザ等でアクセスします。途中でエラーが発生していなければ、mbed Shopping CartがWebブラウザ上に表示されます。

Committer:
Osamu Nakamura
Date:
Fri Jan 12 19:05:14 2018 +0900
Revision:
0:a40b9a259b52
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Osamu Nakamura 0:a40b9a259b52 1 # dotenv
Osamu Nakamura 0:a40b9a259b52 2
Osamu Nakamura 0:a40b9a259b52 3 <img src="https://raw.githubusercontent.com/motdotla/dotenv/master/dotenv.png" alt="dotenv" align="right" />
Osamu Nakamura 0:a40b9a259b52 4
Osamu Nakamura 0:a40b9a259b52 5 Dotenv is a zero-dependency module that loads environment variables from a `.env` file into [`process.env`](https://nodejs.org/docs/latest/api/process.html#process_process_env). Storing configuration in the environment separate from code is based on [The Twelve-Factor App](http://12factor.net/config) methodology.
Osamu Nakamura 0:a40b9a259b52 6
Osamu Nakamura 0:a40b9a259b52 7 [![BuildStatus](https://img.shields.io/travis/motdotla/dotenv/master.svg?style=flat-square)](https://travis-ci.org/motdotla/dotenv)
Osamu Nakamura 0:a40b9a259b52 8 [![NPM version](https://img.shields.io/npm/v/dotenv.svg?style=flat-square)](https://www.npmjs.com/package/dotenv)
Osamu Nakamura 0:a40b9a259b52 9 [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat-square)](https://github.com/feross/standard)
Osamu Nakamura 0:a40b9a259b52 10
Osamu Nakamura 0:a40b9a259b52 11 ## Install
Osamu Nakamura 0:a40b9a259b52 12
Osamu Nakamura 0:a40b9a259b52 13 ```bash
Osamu Nakamura 0:a40b9a259b52 14 npm install dotenv --save
Osamu Nakamura 0:a40b9a259b52 15 ```
Osamu Nakamura 0:a40b9a259b52 16
Osamu Nakamura 0:a40b9a259b52 17 ## Usage
Osamu Nakamura 0:a40b9a259b52 18
Osamu Nakamura 0:a40b9a259b52 19 As early as possible in your application, require and configure dotenv.
Osamu Nakamura 0:a40b9a259b52 20
Osamu Nakamura 0:a40b9a259b52 21 ```javascript
Osamu Nakamura 0:a40b9a259b52 22 require('dotenv').config();
Osamu Nakamura 0:a40b9a259b52 23 ```
Osamu Nakamura 0:a40b9a259b52 24
Osamu Nakamura 0:a40b9a259b52 25 Create a `.env` file in the root directory of your project. Add
Osamu Nakamura 0:a40b9a259b52 26 environment-specific variables on new lines in the form of `NAME=VALUE`.
Osamu Nakamura 0:a40b9a259b52 27 For example:
Osamu Nakamura 0:a40b9a259b52 28
Osamu Nakamura 0:a40b9a259b52 29 ```
Osamu Nakamura 0:a40b9a259b52 30 DB_HOST=localhost
Osamu Nakamura 0:a40b9a259b52 31 DB_USER=root
Osamu Nakamura 0:a40b9a259b52 32 DB_PASS=s1mpl3
Osamu Nakamura 0:a40b9a259b52 33 ```
Osamu Nakamura 0:a40b9a259b52 34
Osamu Nakamura 0:a40b9a259b52 35 That's it.
Osamu Nakamura 0:a40b9a259b52 36
Osamu Nakamura 0:a40b9a259b52 37 `process.env` now has the keys and values you defined in your `.env` file.
Osamu Nakamura 0:a40b9a259b52 38
Osamu Nakamura 0:a40b9a259b52 39 ```javascript
Osamu Nakamura 0:a40b9a259b52 40 db.connect({
Osamu Nakamura 0:a40b9a259b52 41 host: process.env.DB_HOST,
Osamu Nakamura 0:a40b9a259b52 42 username: process.env.DB_USER,
Osamu Nakamura 0:a40b9a259b52 43 password: process.env.DB_PASS
Osamu Nakamura 0:a40b9a259b52 44 });
Osamu Nakamura 0:a40b9a259b52 45 ```
Osamu Nakamura 0:a40b9a259b52 46
Osamu Nakamura 0:a40b9a259b52 47 ### Preload
Osamu Nakamura 0:a40b9a259b52 48
Osamu Nakamura 0:a40b9a259b52 49 If you are using iojs-v1.6.0 or later, you can use the `--require` (`-r`) command line option to preload dotenv. By doing this, you do not need to require and load dotenv in your application code.
Osamu Nakamura 0:a40b9a259b52 50
Osamu Nakamura 0:a40b9a259b52 51
Osamu Nakamura 0:a40b9a259b52 52 ```bash
Osamu Nakamura 0:a40b9a259b52 53 $ node -r dotenv/config your_script.js
Osamu Nakamura 0:a40b9a259b52 54 ```
Osamu Nakamura 0:a40b9a259b52 55
Osamu Nakamura 0:a40b9a259b52 56 The configuration options below are supported as command line arguments in the format `dotenv_config_<option>=value`
Osamu Nakamura 0:a40b9a259b52 57
Osamu Nakamura 0:a40b9a259b52 58 ```bash
Osamu Nakamura 0:a40b9a259b52 59 $ node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/your/env/vars
Osamu Nakamura 0:a40b9a259b52 60 ```
Osamu Nakamura 0:a40b9a259b52 61
Osamu Nakamura 0:a40b9a259b52 62 ## Config
Osamu Nakamura 0:a40b9a259b52 63
Osamu Nakamura 0:a40b9a259b52 64 _Alias: `load`_
Osamu Nakamura 0:a40b9a259b52 65
Osamu Nakamura 0:a40b9a259b52 66 `config` will read your .env file, parse the contents, and assign it to
Osamu Nakamura 0:a40b9a259b52 67 [`process.env`](https://nodejs.org/docs/latest/api/process.html#process_process_env). You can additionally, pass options to
Osamu Nakamura 0:a40b9a259b52 68 `config`.
Osamu Nakamura 0:a40b9a259b52 69
Osamu Nakamura 0:a40b9a259b52 70 ### Options
Osamu Nakamura 0:a40b9a259b52 71
Osamu Nakamura 0:a40b9a259b52 72 #### Silent
Osamu Nakamura 0:a40b9a259b52 73
Osamu Nakamura 0:a40b9a259b52 74 Default: `false`
Osamu Nakamura 0:a40b9a259b52 75
Osamu Nakamura 0:a40b9a259b52 76 Dotenv outputs a warning to your console if missing a `.env` file. Suppress
Osamu Nakamura 0:a40b9a259b52 77 this warning using silent.
Osamu Nakamura 0:a40b9a259b52 78
Osamu Nakamura 0:a40b9a259b52 79 ```js
Osamu Nakamura 0:a40b9a259b52 80 require('dotenv').config({silent: true});
Osamu Nakamura 0:a40b9a259b52 81 ```
Osamu Nakamura 0:a40b9a259b52 82
Osamu Nakamura 0:a40b9a259b52 83 #### Path
Osamu Nakamura 0:a40b9a259b52 84
Osamu Nakamura 0:a40b9a259b52 85 Default: `.env`
Osamu Nakamura 0:a40b9a259b52 86
Osamu Nakamura 0:a40b9a259b52 87 You can specify a custom path if your file containing environment variables is
Osamu Nakamura 0:a40b9a259b52 88 named or located differently.
Osamu Nakamura 0:a40b9a259b52 89
Osamu Nakamura 0:a40b9a259b52 90 ```js
Osamu Nakamura 0:a40b9a259b52 91 require('dotenv').config({path: '/custom/path/to/your/env/vars'});
Osamu Nakamura 0:a40b9a259b52 92 ```
Osamu Nakamura 0:a40b9a259b52 93
Osamu Nakamura 0:a40b9a259b52 94 #### Encoding
Osamu Nakamura 0:a40b9a259b52 95
Osamu Nakamura 0:a40b9a259b52 96 Default: `utf8`
Osamu Nakamura 0:a40b9a259b52 97
Osamu Nakamura 0:a40b9a259b52 98 You may specify the encoding of your file containing environment variables
Osamu Nakamura 0:a40b9a259b52 99 using this option.
Osamu Nakamura 0:a40b9a259b52 100
Osamu Nakamura 0:a40b9a259b52 101 ```js
Osamu Nakamura 0:a40b9a259b52 102 require('dotenv').config({encoding: 'base64'});
Osamu Nakamura 0:a40b9a259b52 103 ```
Osamu Nakamura 0:a40b9a259b52 104
Osamu Nakamura 0:a40b9a259b52 105 ## Parse
Osamu Nakamura 0:a40b9a259b52 106
Osamu Nakamura 0:a40b9a259b52 107 The engine which parses the contents of your file containing environment
Osamu Nakamura 0:a40b9a259b52 108 variables is available to use. It accepts a String or Buffer and will return
Osamu Nakamura 0:a40b9a259b52 109 an Object with the parsed keys and values.
Osamu Nakamura 0:a40b9a259b52 110
Osamu Nakamura 0:a40b9a259b52 111 ```js
Osamu Nakamura 0:a40b9a259b52 112 var dotenv = require('dotenv');
Osamu Nakamura 0:a40b9a259b52 113 var buf = new Buffer('BASIC=basic');
Osamu Nakamura 0:a40b9a259b52 114 var config = dotenv.parse(buf); // will return an object
Osamu Nakamura 0:a40b9a259b52 115 console.log(typeof config, config) // object { BASIC : 'basic' }
Osamu Nakamura 0:a40b9a259b52 116 ```
Osamu Nakamura 0:a40b9a259b52 117
Osamu Nakamura 0:a40b9a259b52 118 ### Rules
Osamu Nakamura 0:a40b9a259b52 119
Osamu Nakamura 0:a40b9a259b52 120 The parsing engine currently supports the following rules:
Osamu Nakamura 0:a40b9a259b52 121
Osamu Nakamura 0:a40b9a259b52 122 - `BASIC=basic` becomes `{BASIC: 'basic'}`
Osamu Nakamura 0:a40b9a259b52 123 - empty lines are skipped
Osamu Nakamura 0:a40b9a259b52 124 - lines beginning with `#` are treated as comments
Osamu Nakamura 0:a40b9a259b52 125 - empty values become empty strings (`EMPTY=` becomes `{EMPTY: ''}`)
Osamu Nakamura 0:a40b9a259b52 126 - single and double quoted values are escaped (`SINGLE_QUOTE='quoted'` becomes `{SINGLE_QUOTE: "quoted"}`)
Osamu Nakamura 0:a40b9a259b52 127 - new lines are expanded if in double quotes (`MULTILINE="new\nline"` becomes
Osamu Nakamura 0:a40b9a259b52 128
Osamu Nakamura 0:a40b9a259b52 129 ```
Osamu Nakamura 0:a40b9a259b52 130 {MULTILINE: 'new
Osamu Nakamura 0:a40b9a259b52 131 line'}
Osamu Nakamura 0:a40b9a259b52 132 ```
Osamu Nakamura 0:a40b9a259b52 133 - inner quotes are maintained (think JSON) (`JSON={"foo": "bar"}` becomes `{JSON:"{\"foo\": \"bar\"}"`)
Osamu Nakamura 0:a40b9a259b52 134
Osamu Nakamura 0:a40b9a259b52 135 ## FAQ
Osamu Nakamura 0:a40b9a259b52 136
Osamu Nakamura 0:a40b9a259b52 137 ### Should I commit my `.env` file?
Osamu Nakamura 0:a40b9a259b52 138
Osamu Nakamura 0:a40b9a259b52 139 No. We **strongly** recommend against committing your `.env` file to version
Osamu Nakamura 0:a40b9a259b52 140 control. It should only include environment-specific values such as database
Osamu Nakamura 0:a40b9a259b52 141 passwords or API keys. Your production database should have a different
Osamu Nakamura 0:a40b9a259b52 142 password than your development database.
Osamu Nakamura 0:a40b9a259b52 143
Osamu Nakamura 0:a40b9a259b52 144 ### Should I have multiple `.env` files?
Osamu Nakamura 0:a40b9a259b52 145
Osamu Nakamura 0:a40b9a259b52 146 No. We **strongly** recommend against having a "main" `.env` file and an "environment" `.env` file like `.env.test`. Your config should vary between deploys, and you should not be sharing values between environments.
Osamu Nakamura 0:a40b9a259b52 147
Osamu Nakamura 0:a40b9a259b52 148 > In a twelve-factor app, env vars are granular controls, each fully orthogonal to other env vars. They are never grouped together as “environments”, but instead are independently managed for each deploy. This is a model that scales up smoothly as the app naturally expands into more deploys over its lifetime.
Osamu Nakamura 0:a40b9a259b52 149 >
Osamu Nakamura 0:a40b9a259b52 150 > – [The Twelve-Factor App](http://12factor.net/config)
Osamu Nakamura 0:a40b9a259b52 151
Osamu Nakamura 0:a40b9a259b52 152 ### What happens to environment variables that were already set?
Osamu Nakamura 0:a40b9a259b52 153
Osamu Nakamura 0:a40b9a259b52 154 We will never modify any environment variables that have already been set. In particular, if there is a variable in your `.env` file which collides with one that already exists in your environment, then that variable will be skipped. This behavior allows you to override all `.env` configurations with a machine-specific environment, although it is not recommended.
Osamu Nakamura 0:a40b9a259b52 155
Osamu Nakamura 0:a40b9a259b52 156 ### Can I customize/write plugins for dotenv?
Osamu Nakamura 0:a40b9a259b52 157
Osamu Nakamura 0:a40b9a259b52 158 For `dotenv@2.x.x`: Yes. `dotenv.config()` now returns an object representing
Osamu Nakamura 0:a40b9a259b52 159 the parsed `.env` file. This gives you everything you need to continue
Osamu Nakamura 0:a40b9a259b52 160 setting values on `process.env`. For example:
Osamu Nakamura 0:a40b9a259b52 161
Osamu Nakamura 0:a40b9a259b52 162 ```js
Osamu Nakamura 0:a40b9a259b52 163 var dotenv = require('dotenv')
Osamu Nakamura 0:a40b9a259b52 164 var variableExpansion = require('dotenv-expand')
Osamu Nakamura 0:a40b9a259b52 165 const myEnv = dotenv.config()
Osamu Nakamura 0:a40b9a259b52 166 variableExpansion(myEnv)
Osamu Nakamura 0:a40b9a259b52 167 ```
Osamu Nakamura 0:a40b9a259b52 168
Osamu Nakamura 0:a40b9a259b52 169 ### What about variable expansion?
Osamu Nakamura 0:a40b9a259b52 170
Osamu Nakamura 0:a40b9a259b52 171 For `dotenv@2.x.x`: Use [dotenv-expand](https://github.com/motdotla/dotenv-expand).
Osamu Nakamura 0:a40b9a259b52 172
Osamu Nakamura 0:a40b9a259b52 173 For `dotenv@1.x.x`: We haven't been presented with a compelling use case for expanding variables and believe it leads to env vars that are not "fully orthogonal" as [The Twelve-Factor App](http://12factor.net/config) outlines.<sup>[[1](https://github.com/motdotla/dotenv/issues/39)][[2](https://github.com/motdotla/dotenv/pull/97)]</sup> Please open an issue if you have a compelling use case.
Osamu Nakamura 0:a40b9a259b52 174
Osamu Nakamura 0:a40b9a259b52 175
Osamu Nakamura 0:a40b9a259b52 176 ## Contributing Guide
Osamu Nakamura 0:a40b9a259b52 177
Osamu Nakamura 0:a40b9a259b52 178 See [CONTRIBUTING.md](CONTRIBUTING.md)
Osamu Nakamura 0:a40b9a259b52 179
Osamu Nakamura 0:a40b9a259b52 180 ## Change Log
Osamu Nakamura 0:a40b9a259b52 181
Osamu Nakamura 0:a40b9a259b52 182 See [CHANGELOG.md](CHANGELOG.md)
Osamu Nakamura 0:a40b9a259b52 183
Osamu Nakamura 0:a40b9a259b52 184 ## License
Osamu Nakamura 0:a40b9a259b52 185
Osamu Nakamura 0:a40b9a259b52 186 See [LICENSE](LICENSE)
Osamu Nakamura 0:a40b9a259b52 187
Osamu Nakamura 0:a40b9a259b52 188 ## Who's using dotenv
Osamu Nakamura 0:a40b9a259b52 189
Osamu Nakamura 0:a40b9a259b52 190 Here's just a few of many repositories using dotenv:
Osamu Nakamura 0:a40b9a259b52 191
Osamu Nakamura 0:a40b9a259b52 192 * [npm](https://github.com/npm/newww)
Osamu Nakamura 0:a40b9a259b52 193 * [jaws](https://github.com/jaws-framework/jaws-core-js)
Osamu Nakamura 0:a40b9a259b52 194 * [node-lambda](https://github.com/motdotla/node-lambda)
Osamu Nakamura 0:a40b9a259b52 195 * [resume-cli](https://www.npmjs.com/package/resume-cli)
Osamu Nakamura 0:a40b9a259b52 196 * [phant](https://www.npmjs.com/package/phant)
Osamu Nakamura 0:a40b9a259b52 197 * [adafruit-io-node](https://github.com/adafruit/adafruit-io-node)
Osamu Nakamura 0:a40b9a259b52 198 * [mockbin](https://www.npmjs.com/package/mockbin)
Osamu Nakamura 0:a40b9a259b52 199 * [and many more...](https://www.npmjs.com/browse/depended/dotenv)
Osamu Nakamura 0:a40b9a259b52 200
Osamu Nakamura 0:a40b9a259b52 201 ## Go well with dotenv
Osamu Nakamura 0:a40b9a259b52 202
Osamu Nakamura 0:a40b9a259b52 203 Here's some projects that expand on dotenv. Check them out.
Osamu Nakamura 0:a40b9a259b52 204
Osamu Nakamura 0:a40b9a259b52 205 * [require-environment-variables](https://github.com/bjoshuanoah/require-environment-variables)
Osamu Nakamura 0:a40b9a259b52 206 * [dotenv-safe](https://github.com/rolodato/dotenv-safe)