Installing Yii
==============

You can install Yii in two ways, using the [Composer](https://getcomposer.org/) package manager or by downloading an archive file.
The former is the preferred way, as it allows you to install new [extensions](structure-extensions.md) or update Yii by simply running a single command.

Standard installations of Yii result in both the framework and a project template being downloaded and installed.
A project template is a working Yii project implementing some basic features, such as login, contact form, etc.
Its code is organized in a recommended way. Therefore, it can serve as a good starting point for your projects.
    
In this and the next few sections, we will describe how to install Yii with the so-called *Basic Project Template* and
how to implement new features on top of this template. Yii also provides another template called
the [Advanced Project Template](https://www.yiiframework.com/extension/yiisoft/yii2-app-advanced/doc/guide) which is better used in a team development environment
to develop applications with multiple tiers.

> Info: The Basic Project Template is suitable for developing 90 percent of Web applications. It differs
  from the Advanced Project Template mainly in how their code is organized. If you are new to Yii, we strongly
  recommend you stick to the Basic Project Template for its simplicity yet sufficient functionalities.


Installing via Composer <span id="installing-via-composer"></span>
-----------------------

### Installing Composer

If you do not already have Composer installed, you may do so by following the instructions at
[getcomposer.org](https://getcomposer.org/download/). On Linux and Mac OS X, you'll run the following commands:

```bash
curl -sS https://getcomposer.org/installer | php
sudo mv composer.phar /usr/local/bin/composer
```

On Windows, you'll download and run [Composer-Setup.exe](https://getcomposer.org/Composer-Setup.exe).

Please refer to the [Troubleshooting section of the Composer Documentation](https://getcomposer.org/doc/articles/troubleshooting.md)
if you encounter any problems.
If you are new to Composer, we also recommend to read at least the [Basic usage section](https://getcomposer.org/doc/01-basic-usage.md)
of the Composer documentation.

In this guide all composer commands assume you have installed composer [globally](https://getcomposer.org/doc/00-intro.md#globally)
so that it is available as the `composer` command. If you are using the `composer.phar` in the local directory instead,
you have to adjust the example commands accordingly.

If you had Composer already installed before, make sure you use an up to date version. You can update Composer
by running `composer self-update`.

> Note: During the installation of Yii, Composer will need to request a lot of information from the Github API.
> The number of requests depends on the number of dependencies your application has and may be bigger than the
> **Github API rate limit**. If you hit this limit, Composer may ask for your Github login credentials to obtain
> a Github API access token. On fast connections you may hit this limit earlier than Composer can handle so we
> recommend to configure the access token before installing Yii.
> Please refer to the [Composer documentation about Github API tokens](https://getcomposer.org/doc/articles/troubleshooting.md#api-rate-limit-and-oauth-tokens)
> for instructions on how to do this.

### Installing Yii <span id="installing-from-composer"></span>

With Composer installed, you can install Yii application template by running the following command
under a Web-accessible folder:

```bash
composer create-project --prefer-dist yiisoft/yii2-app-basic basic
```

This will install the latest stable version of Yii application template in a directory named `basic`.
You can choose a different directory name if you want.

> Info: If the `composer create-project` command fails you may also refer to the 
> [Troubleshooting section of the Composer Documentation](https://getcomposer.org/doc/articles/troubleshooting.md)
> for common errors. When you have fixed the error, you can resume the aborted installation
> by running `composer update` inside of the `basic` directory.

> Tip: If you want to install the latest development version of Yii, you may use the following command instead,
> which adds a [stability option](https://getcomposer.org/doc/04-schema.md#minimum-stability):
>
> ```bash
> composer create-project --prefer-dist --stability=dev yiisoft/yii2-app-basic basic
> ```
>
> Note that the development version of Yii should not be used for production as it may break your running code.


Installing from an Archive File <span id="installing-from-archive-file"></span>
-------------------------------

Installing Yii from an archive file involves three steps:

1. Download the archive file from [yiiframework.com](http://www.yiiframework.com/download/).
2. Unpack the downloaded file to a Web-accessible folder.
3. Modify the `config/web.php` file by entering a secret key for the `cookieValidationKey` configuration item
   (this is done automatically if you are installing Yii using Composer):

   ```php
   // !!! insert a secret key in the following (if it is empty) - this is required by cookie validation
   'cookieValidationKey' => 'enter your secret key here',
   ```


Other Installation Options <span id="other-installation-options"></span>
--------------------------

The above installation instructions show how to install Yii, which also creates a basic Web application that works out of the box.
This approach is a good starting point for most projects, either small or big. It is especially suitable if you just
start learning Yii.

But there are other installation options available:

* If you only want to install the core framework and would like to build an entire  application from scratch,
  you may follow the instructions as explained in [Building Application from Scratch](tutorial-start-from-scratch.md).
* If you want to start with a more sophisticated application, better suited to team development environments,
  you may consider installing the [Advanced Project Template](https://github.com/yiisoft/yii2-app-advanced/blob/master/docs/guide/README.md).


Installing Assets <span id="installing-assets"></span>
-----------------

Yii relies on [Bower](http://bower.io/) and/or [NPM](https://www.npmjs.org/) packages for the asset (CSS and JavaScript) libraries installation.
It uses Composer to obtain these libraries, allowing PHP and CSS/JavaScript package versions to resolve at the same time.
This can be achieved either by usage of [asset-packagist.org](https://asset-packagist.org) or [composer asset plugin](https://github.com/francoispluchino/composer-asset-plugin/).
Please refer to [Assets documentation](structure-assets.md) for more details.

You may want to either manage your assets via native Bower/NPM client, use CDN or avoid assets installation entirely.
In order to prevent assets installation via Composer, add the following lines to your 'composer.json':

```json
"replace": {
    "bower-asset/jquery": ">=1.11.0",
    "bower-asset/inputmask": ">=3.2.0",
    "bower-asset/punycode": ">=1.3.0",
    "bower-asset/yii2-pjax": ">=2.0.0"
},
```

> Note: in case of bypassing asset installation via Composer, you are responsible for the assets installation and resolving
> version collisions. Be prepared for possible inconsistencies among asset files from different extensions.


Verifying the Installation <span id="verifying-installation"></span>
--------------------------

After installation is done, either configure your web server (see next section) or use the
[built-in PHP web server](https://secure.php.net/manual/en/features.commandline.webserver.php) by running the following
console command while in the project root directory:
 
```bash
php yii serve
```

> Note: By default the HTTP-server will listen to port 8080. However if that port is already in use or you wish to 
serve multiple applications this way, you might want to specify what port to use. Just add the --port argument:

```bash
php yii serve --port=8888
```

You can use your browser to access the installed Yii application with the following URL:

```
http://localhost:8080/
```

![Successful Installation of Yii](images/start-app-installed.png)

You should see the above "Congratulations!" page in your browser. If not, please check if your PHP installation satisfies
Yii's requirements. You can check if the minimum requirements are met using one of the following approaches:

* Copy `/requirements.php` to `/web/requirements.php` and then use a browser to access it via `http://localhost/requirements.php`
* Run the following commands:

  ```bash
  cd basic
  php requirements.php
  ```

You should configure your PHP installation so that it meets the minimum requirements of Yii. Most importantly, you
should have PHP 5.4 or above. Ideally latest PHP 7. You should also install the [PDO PHP Extension](https://secure.php.net/manual/en/pdo.installation.php)
and a corresponding database driver (such as `pdo_mysql` for MySQL databases), if your application needs a database.


Configuring Web Servers <span id="configuring-web-servers"></span>
-----------------------

> Info: You may skip this subsection for now if you are just test driving Yii with no intention
  of deploying it to a production server.

The application installed according to the above instructions should work out of box with either
an [Apache HTTP server](http://httpd.apache.org/) or an [Nginx HTTP server](http://nginx.org/), on
Windows, Mac OS X, or Linux running PHP 5.4 or higher. Yii 2.0 is also compatible with facebook's
[HHVM](http://hhvm.com/). However, there are some edge cases where HHVM behaves different than native
PHP, so you have to take some extra care when using HHVM.

On a production server, you may want to configure your Web server so that the application can be accessed
via the URL `http://www.example.com/index.php` instead of `http://www.example.com/basic/web/index.php`. Such configuration
requires pointing the document root of your Web server to the `basic/web` folder. You may also
want to hide `index.php` from the URL, as described in the [Routing and URL Creation](runtime-routing.md) section.
In this subsection, you'll learn how to configure your Apache or Nginx server to achieve these goals.

> Info: By setting `basic/web` as the document root, you also prevent end users from accessing
your private application code and sensitive data files that are stored in the sibling directories
of `basic/web`. Denying access to those other folders is a security improvement.

> Info: If your application will run in a shared hosting environment where you do not have permission
to modify its Web server configuration, you may still adjust the structure of your application for better security. Please refer to
the [Shared Hosting Environment](tutorial-shared-hosting.md) section for more details.

> Info: If you are running your Yii application behind a reverse proxy, you might need to configure
> [Trusted proxies and headers](runtime-requests.md#trusted-proxies) in the request component.

### Recommended Apache Configuration <span id="recommended-apache-configuration"></span>

Use the following configuration in Apache's `httpd.conf` file or within a virtual host configuration. Note that you
should replace `path/to/basic/web` with the actual path for `basic/web`.

```apache
# Set document root to be "basic/web"
DocumentRoot "path/to/basic/web"

<Directory "path/to/basic/web">
    # use mod_rewrite for pretty URL support
    RewriteEngine on
    
    # if $showScriptName is false in UrlManager, do not allow accessing URLs with script name
    RewriteRule ^index.php/ - [L,R=404]
    
    # If a directory or a file exists, use the request directly
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    
    # Otherwise forward the request to index.php
    RewriteRule . index.php

    # ...other settings...
</Directory>
```


### Recommended Nginx Configuration <span id="recommended-nginx-configuration"></span>

To use [Nginx](http://wiki.nginx.org/), you should install PHP as an [FPM SAPI](https://secure.php.net/install.fpm).
You may use the following Nginx configuration, replacing `path/to/basic/web` with the actual path for 
`basic/web` and `mysite.test` with the actual hostname to serve.

```nginx
server {
    charset utf-8;
    client_max_body_size 128M;

    listen 80; ## listen for ipv4
    #listen [::]:80 default_server ipv6only=on; ## listen for ipv6

    server_name mysite.test;
    root        /path/to/basic/web;
    index       index.php;

    access_log  /path/to/basic/log/access.log;
    error_log   /path/to/basic/log/error.log;

    location / {
        # Redirect everything that isn't a real file to index.php
        try_files $uri $uri/ /index.php$is_args$args;
    }

    # uncomment to avoid processing of calls to non-existing static files by Yii
    #location ~ \.(js|css|png|jpg|gif|swf|ico|pdf|mov|fla|zip|rar)$ {
    #    try_files $uri =404;
    #}
    #error_page 404 /404.html;

    # deny accessing php files for the /assets directory
    location ~ ^/assets/.*\.php$ {
        deny all;
    }

    location ~ \.php$ {
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_pass 127.0.0.1:9000;
        #fastcgi_pass unix:/var/run/php5-fpm.sock;
        try_files $uri =404;
    }

    location ~* /\. {
        deny all;
    }
}
```

When using this configuration, you should also set `cgi.fix_pathinfo=0` in the `php.ini` file
in order to avoid many unnecessary system `stat()` calls.

Also note that when running an HTTPS server, you need to add `fastcgi_param HTTPS on;` so that Yii
can properly detect if a connection is secure.

### Recommended NGINX Unit Configuration <span id="recommended-nginx-unit-configuration"></span>

You can run Yii-based apps using [NGINX Unit](https://unit.nginx.org/) with a PHP language module.
Here is a sample configuration.

```json
{
    "listeners": {
        "*:80": {
            "pass": "routes/yii"
        }
    },

    "routes": {
        "yii": [
            {
                "match": {
                    "uri": [
                        "!/assets/*",
                        "*.php",
                        "*.php/*"
                    ]
                },

                "action": {
                    "pass": "applications/yii/direct"
                }
            },
            {
                "action": {
                    "share": "/path/to/app/web/",
                    "fallback": {
                        "pass": "applications/yii/index"
                    }
                }
            }
        ]
    },

    "applications": {
        "yii": {
            "type": "php",
            "user": "www-data",
            "targets": {
                "direct": {
                    "root": "/path/to/app/web/"
                },

                "index": {
                    "root": "/path/to/app/web/",
                    "script": "index.php"
                }
            }
        }
    }
}
```

You can also [set up](https://unit.nginx.org/configuration/#php) your PHP environment or supply a custom `php.ini` in the same configuration.

### IIS Configuration <span id="iis-configuration"></span>

It's recommended to host the application in a virtual host (Web site) where document root points to `path/to/app/web` folder and that Web site is configured to run PHP. In that `web` folder you have to place a file named `web.config` i.e. `path/to/app/web/web.config`. Content of the file should be the following:

```xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<directoryBrowse enabled="false" />
  <rewrite>
    <rules>
      <rule name="Hide Yii Index" stopProcessing="true">
        <match url="." ignoreCase="false" />
        <conditions>
        <add input="{REQUEST_FILENAME}" matchType="IsFile" 
              ignoreCase="false" negate="true" />
        <add input="{REQUEST_FILENAME}" matchType="IsDirectory" 
              ignoreCase="false" negate="true" />
        </conditions>
        <action type="Rewrite" url="index.php" appendQueryString="true" />
      </rule> 
    </rules>
  </rewrite>
</system.webServer>
</configuration>
```
Also the following list of Microsoft's official resources could be useful in order to configure PHP on IIS:
 1. [How to set up your first IIS Web site](https://support.microsoft.com/en-us/help/323972/how-to-set-up-your-first-iis-web-site)
 2. [Configure a PHP Website on IIS](https://docs.microsoft.com/en-us/iis/application-frameworks/scenario-build-a-php-website-on-iis/configure-a-php-website-on-iis)
