Nginx：初學者指南

本指南對 nginx 進行了基本介紹，並描述了一些可以用它完成的簡單任務。假設讀者的機器上已經安裝了 nginx。如果不是，請參閱安裝 Nginx 頁面。本指南介紹如何啟動和停止 nginx、重新載入其配置、解釋設定檔的結構並介紹如何設定 nginx 來提供靜態內容、如何將 nginx 設定為代理伺服器以及如何 將其與 FastCGI 應用程式連接。

nginx 有一個主進程和多個工作進程。主進程的主要目的是讀取和評估配置，以及維護工作進程。工作進程實際處理請求。 nginx 採用基於事件的模型並且依賴作業系統 在工作進程之間有效分配請求的機制。工作進程的數量在設定檔中定義，對於給定的配置可以是固定的，也可以自動調整為可用 CPU 核心的數量（請參閱worker_processes）。

nginx 及其模組的工作方式是在設定檔中決定的。預設情況下，設定檔名稱為nginx.conf，並放置在/usr/local/nginx/conf、/etc/nginx或/usr/local/etc/nginx目錄中。

啟動、停止和重新載入設定

要啟動 nginx，請執行執行檔。 nginx 啟動後，可以使用 -s 參數呼叫可執行檔來控制它。使用以下語法：

nginx -s <em>signal</em>

其中signal 可能是以下之一：

• stop —快速關閉
• quittstop
 —快速關閉
• quit
• reopen  －重新開啟日誌檔案

例如，要停止nginx 程序並等待工作流程完成目前要求的服務，可以執行下列指令：

nginx -s quit

此指令應在相同目錄下執行啟動nginx 的使用者。

設定檔中所做的變更將不會套用，直到重新載入設定的指令傳送到 nginx 或重新啟動。若要重新載入配置，請執行：

nginx -s reload

一旦主進程收到重新載入配置的訊號，它就會檢查新設定檔的語法有效性並嘗試套用其中提供的配置。如果成功，主進程將啟動新的工作進程並發送 向舊工作進程發送訊息，請求它們關閉。否則，主進程將回滾更改並繼續使用舊配置。舊的工作進程，收到關閉命令，停止接受新連線並 繼續服務當前請求，直到所有此類請求都得到服務。之後，舊的工作進程退出。

借助 Unix 工具（例如

kill 實用程式），也可以向 nginx 進程發送訊號。在這種情況下，訊號將直接傳送到具有給定進程 ID 的進程。 nginx主進程的進程ID預設寫入 目錄/usr/local/nginx/logs或/var/run中的nginx.pid。例如，如果主進程ID 為1628，要發送QUIT 訊號導致nginx 正常關閉，請執行：

kill -s QUIT 1628

要獲取所有正在運行的nginx 進程的列表，可以使用

ps 實用程序，例如，透過以下方式：

ps -ax | grep nginx

有關向nginx 發送訊號的更多信息，請參閱控制nginx。

設定檔的結構

nginx 由由設定檔中指定的指令控制的模組組成。指令分為簡單指令和區塊指令。一個簡單的指令由名稱和參數組成，以空格分隔，並以 分號 (

;)。區塊指令與簡單指令有相同的結構，但它不是以分號結尾，而是以一組用大括號括起來的附加指令（{ 和}）結尾。如果區塊指令可以有其他指令 大括號內的指令稱為上下文（例如：事件、http、伺服器、 和位置）。

Directives placed in the configuration file outside of any contexts are considered to be in the main context. Theevents and http directives reside in the main context, server in http, and location in server.

The rest of a line after the # sign is considered a comment.

Serving Static Content

An important web server task is serving out files (such as images or static HTML pages). You will implement an example where, depending on the request, files will be served from different local directories: /data/www(which may contain HTML files) and /data/images (containing images). This will require editing of the configuration file and setting up of a server block inside the http block with two location blocks.

First, create the /data/www directory and put an index.html file with any text content into it and create the/data/images directory and place some images in it.

Next, open the configuration file. The default configuration file already includes several examples of the serverblock, mostly commented out. For now comment out all such blocks and start a new server block:

http {
    server {
    }
}

Generally, the configuration file may include several server blocks distinguished by ports on which they listento and by server names. Once nginx decides which server processes a request, it tests the URI specified in the request’s header against the parameters of the location directives defined inside the server block.

Add the following location block to the server block:

location / {
    root /data/www;
}

This location block specifies the “/” prefix compared with the URI from the request. For matching requests, the URI will be added to the path specified in the root directive, that is, to /data/www, to form the path to the requested file on the local file system. If there are several matching location blocks nginx selects the one with the longest prefix. The location block above provides the shortest prefix, of length one, and so only if all otherlocation blocks fail to provide a match, this block will be used.

Next, add the second location block:

location /images/ {
    root /data;
}

It will be a match for requests starting with /images/ (location / also matches such requests, but has shorter prefix).

The resulting configuration of the server block should look like this:

server {
    location / {
        root /data/www;
    }

    location /images/ {
        root /data;
    }
}

This is already a working configuration of a server that listens on the standard port 80 and is accessible on the local machine at http://localhost/. In response to requests with URIs starting with /images/, the server will send files from the /data/images directory. For example, in response to the http://localhost/images/example.pngrequest nginx will send the /data/images/example.png file. If such file does not exist, nginx will send a response indicating the 404 error. Requests with URIs not starting with /images/ will be mapped onto the /data/wwwdirectory. For example, in response to the http://localhost/some/example.html request nginx will send the/data/www/some/example.html file.

To apply the new configuration, start nginx if it is not yet started or send the reload signal to the nginx’s master process, by executing:

nginx -s reload

In case something does not work as expected, you may try to find out the reason in access.log anderror.log files in the directory /usr/local/nginx/logs or /var/log/nginx.

Setting Up a Simple Proxy Server

One of the frequent uses of nginx is setting it up as a proxy server, which means a server that receives requests, passes them to the proxied servers, retrieves responses from them, and sends them to the clients.

We will configure a basic proxy server, which serves requests of images with files from the local directory and sends all other requests to a proxied server. In this example, both servers will be defined on a single nginx instance.

First, define the proxied server by adding one more server block to the nginx’s configuration file with the following contents:

server {
    listen 8080;
    root /data/up1;

    location / {
    }
}

This will be a simple server that listens on the port 8080 (previously, the listen directive has not been specified since the standard port 80 was used) and maps all requests to the /data/up1 directory on the local file system. Create this directory and put the index.html file into it. Note that the root directive is placed in theserver context. Such root directive is used when the location block selected for serving a request does not include own root directive.

Next, use the server configuration from the previous section and modify it to make it a proxy server configuration. In the first location block, put the proxy_pass directive with the protocol, name and port of the proxied server specified in the parameter (in our case, it is http://localhost:8080):

server {
    location / {
        proxy_pass http://localhost:8080;
    }

    location /images/ {
        root /data;
    }
}

We will modify the second location block, which currently maps requests with the /images/ prefix to the files under the /data/images directory, to make it match the requests of images with typical file extensions. The modified location block looks like this:

location ~ \.(gif|jpg|png)$ {
    root /data/images;
}

The parameter is a regular expression matching all URIs ending with .gif, .jpg, or .png. A regular expression should be preceded with ~. The corresponding requests will be mapped to the /data/images directory.

When nginx selects a location block to serve a request it first checks location directives that specify prefixes, remembering location with the longest prefix, and then checks regular expressions. If there is a match with a regular expression, nginx picks this location or, otherwise, it picks the one remembered earlier.

The resulting configuration of a proxy server will look like this:

server {
    location / {
        proxy_pass http://localhost:8080/;
    }

    location ~ \.(gif|jpg|png)$ {
        root /data/images;
    }
}

This server will filter requests ending with .gif, .jpg, or .png and map them to the /data/images directory (by adding URI to the root directive’s parameter) and pass all other requests to the proxied server configured above.

To apply new configuration, send the reload signal to nginx as described in the previous sections.

There are many more directives that may be used to further configure a proxy connection.

Setting Up FastCGI Proxying

nginx can be used to route requests to FastCGI servers which run applications built with various frameworks and programming languages such as PHP.

The most basic nginx configuration to work with a FastCGI server includes using the fastcgi_pass directive instead of the proxy_pass directive, and fastcgi_param directives to set parameters passed to a FastCGI server. Suppose the FastCGI server is accessible on localhost:9000. Taking the proxy configuration from the previous section as a basis, replace the proxy_pass directive with the fastcgi_pass directive and change the parameter to localhost:9000. In PHP, the SCRIPT_FILENAME parameter is used for determining the script name, and the QUERY_STRING parameter is used to pass request parameters. The resulting configuration would be:

server {
    location / {
        fastcgi_pass  localhost:9000;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param QUERY_STRING    $query_string;
    }

    location ~ \.(gif|jpg|png)$ {
        root /data/images;
    }
}

This will set up a server that will route all requests except for requests for static images to the proxied server operating on localhost:9000 through the FastCGI protocol.

以上就介绍了Nginx: Beginner’s Guide，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。