one. Regular expression matching, where:
* ~ is case-sensitive matching
* ~* is case-insensitive matching
* !~ and !~* are case-sensitive mismatch and case-insensitive mismatch
II. File and directory matching, where:
* -f and !-f are used to determine whether a file exists
* -d and !-d are used to determine whether a directory exists
* -e and !-e are used to determine whether a file or directory exists
* - x and !-x are used to determine whether the file is executable
three. The last parameter of the rewrite instruction is the flag flag. The flag flags are:
1.last is equivalent to the [L] flag in apache, which means rewrite.
2.break After the matching of this rule is completed, the matching is terminated, and the following rules are no longer matched.
3.redirect returns 302 temporary redirection, and the browser address will display the redirected URL address.
4.permanent returns 301 permanent redirection, and the browser address will display the redirected URL address.
Use last and break to implement URI rewriting, and the browser address bar remains unchanged. And there are subtle differences between the two. The alias directive must be marked with last; when the proxy_pass directive is used, the break mark must be used. The Last tag will re-request the server{...} tag where the rewrite rule is located after the execution of this rewrite rule, and the break tag will terminate the matching after the matching of this rule is completed.
For example: if we redirect a URL like /photo/123456 to /path/to/photo/12/1234/123456.png
rewrite "/photo/([0-9]{2})([0-9]{ 2})([0-9]{2})"/path/to/photo/$1/$1$2/$1$2$3.png ;
Four. NginxRewrite rule related instructions
1. Use environment of the break instruction
: server, location, if;
the function of this instruction is to complete the current rule set and no longer process the rewrite instruction.
2. The if command
uses the environment: server, location
This command is used to check whether a condition is met, and if the condition is met, the statement in the curly brackets is executed. The If directive does not support nesting, and does not support multiple conditional && and || processing.
3. Return instruction
syntax: returncode;
usage environment: server, location, if;
this instruction is used to end the execution of the rule and return the status code to the client.
Example: If the accessed URL ends with ".sh" or ".bash", return 403 status code
location ~ .*\.(sh|bash)?$
{
return 403;
}
4. Rewrite command
syntax: rewriteregex replacement flag
Use environment: server, location, if
This command redirects the URI according to the expression, or modifies the string. Instructions are executed according to the order in the configuration file. Note that rewrite expressions are only valid for relative paths. If you want to pair hostnames, you should use an if statement, example:
if( $host ~* www\.(.*) )
{
set $host_without_www $1;
rewrite ^(.*)$ http://$host_without_www$1 permanent;
}
5.Set instruction
syntax: setvariable value; default value: none; use environment: server, location, if;
this instruction is used to define a variable and assign a value to the variable. The value of a variable can be text, variables, and combinations of text variables.
Example: set$varname "hello world";
6.Uninitialized_variable_warn指令
语法：uninitialized_variable_warnon|off
使用环境：http,server,location,if
该指令用于开启和关闭未初始化变量的警告信息，默认值为开启。
五．Nginx的Rewrite规则编写实例
1.当访问的文件和目录不存在时，重定向到某个php文件
if( !-e $request_filename )
{
rewrite ^/(.*)$ index.php last;
}
2.目录对换 /123456/xxxx ====> /xxxx?id=123456
rewrite ^/(\d+)/(.+)/ /$2?id=$1 last;
3.如果客户端使用的是IE浏览器，则重定向到/ie目录下
if( $http_user_agent ~ MSIE)
{
rewrite ^(.*)$ /ie/$1 break;
}
4.禁止访问多个目录
location ~ ^/(cron|templates)/
{
deny all;
break;
}
5.禁止访问以/data开头的文件
location ~ ^/data
{
deny all;
}
6.禁止访问以.sh,.flv,.mp3为文件后缀名的文件
location ~ .*\.(sh|flv|mp3)$
{
return 403;
}
7.设置某些类型文件的浏览器缓存时间
location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
{
expires 30d;
}
location ~ .*\.(js|css)$
{
expires 1h;
}
8.给favicon.ico和robots.txt设置过期时间;
这里为favicon.ico为99天,robots.txt为7天并不记录404错误日志
location ~(favicon.ico) {
log_not_found off;
expires 99d;
break;
}
location ~(robots.txt) {
log_not_found off;
expires 7d;
break;
}
9.设定某个文件的过期时间;这里为600秒，并不记录访问日志
location ^~ /html/scripts/loadhead_1.js {
access_log off;
root /opt/lampp/htdocs/web;
expires 600;
break;
}
10.文件反盗链并设置过期时间
这里的return412 为自定义的http状态码，默认为403，方便找出正确的盗链的请求
“rewrite ^/ http://img.linuxidc.net/leech.gif;”显示一张防盗链图片
“access_log off;”不记录访问日志，减轻压力
“expires 3d”所有文件3天的浏览器缓存
location ~*^.+\.(jpg|jpeg|gif|png|swf|rar|zip|css|js)$ {
valid_referers none blocked *.linuxidc.com*.linuxidc.net localhost 208.97.167.194;
if ($invalid_referer) {
rewrite ^/ http://img.linuxidc.net/leech.gif;
return 412;
break;
}
access_log off;
root /opt/lampp/htdocs/web;
expires 3d;
break;
}
11.只允许固定ip访问网站，并加上密码
root /opt/htdocs/www;
allow 208.97.167.194;
allow 222.33.1.2;
allow 231.152.49.4;
deny all;
auth_basic “C1G_ADMIN”;
auth_basic_user_file htpasswd;
12将多级目录下的文件转成一个文件，增强seo效果
/job-123-456-789.html 指向/job/123/456/789.html
rewrite^/job-([0-9]+)-([0-9]+)-([0-9]+)\.html$ /job/$1/$2/jobshow_$3.html last;
13.文件和目录不存在的时候重定向：
if (!-e $request_filename) {
proxy_pass http://127.0.0.1;
}
14.将根目录下某个文件夹指向2级目录
如/shanghaijob/ 指向 /area/shanghai/
如果你将last改成permanent，那么浏览器地址栏显是/location/shanghai/
rewrite ^/([0-9a-z]+)job/(.*)$ /area/$1/$2last;
上面例子有个问题是访问/shanghai时将不会匹配
rewrite ^/([0-9a-z]+)job$ /area/$1/ last;
rewrite ^/([0-9a-z]+)job/(.*)$ /area/$1/$2last;
这样/shanghai 也可以访问了，但页面中的相对链接无法使用，
如./list_1.html真实地址是/area/shanghia/list_1.html会变成/list_1.html,导至无法访问。
那我加上自动跳转也是不行咯
(-d $request_filename)它有个条件是必需为真实目录，而我的rewrite不是的，所以没有效果
if (-d $request_filename){
rewrite ^/(.*)([^/])$ http://$host/$1$2/permanent;
}
知道原因后就好办了，让我手动跳转吧
rewrite ^/([0-9a-z]+)job$ /$1job/permanent;
rewrite ^/([0-9a-z]+)job/(.*)$ /area/$1/$2last;
15.域名跳转
server
{
listen 80;
server_name jump.linuxidc.com;
index index.html index.htm index.php;
root /opt/lampp/htdocs/www;
rewrite ^/ http://www.linuxidc.com/;
access_log off;
}
16.多域名转向
server_name www.linuxidc.comwww.linuxidc.net;
index index.html index.htm index.php;
root /opt/lampp/htdocs;
if ($host ~ "linuxidc\.net") {
rewrite ^(.*) http://www.linuxidc.com$1permanent;
}
六．nginx全局变量
arg_PARAMETER #这个变量包含GET请求中，如果有变量PARAMETER时的值。
args #这个变量等于请求行中(GET请求)的参数，如：foo=123&bar=blahblah;
binary_remote_addr #二进制的客户地址。
body_bytes_sent #响应时送出的body字节数数量。即使连接中断，这个数据也是精确的。
content_length #请求头中的Content-length字段。
content_type #请求头中的Content-Type字段。
cookie_COOKIE #cookie COOKIE变量的值
document_root #当前请求在root指令中指定的值。
document_uri #与uri相同。
host #请求主机头字段，否则为服务器名称。
hostname #Set to themachine’s hostname as returned by gethostname
http_HEADER
is_args #如果有args参数，这个变量等于”?”，否则等于”"，空值。
http_user_agent #客户端agent信息
http_cookie #客户端cookie信息
limit_rate #这个变量可以限制连接速率。
query_string #与args相同。
request_body_file #客户端请求主体信息的临时文件名。
request_method #客户端请求的动作，通常为GET或POST。
remote_addr #客户端的IP地址。
remote_port #客户端的端口。
remote_user #已经经过Auth Basic Module验证的用户名。
request_completion #如果请求结束，设置为OK. 当请求未结束或如果该请求不是请求链串的最后一个时，为空(Empty)。
request_method #GET或POST
request_filename #当前请求的文件路径，由root或alias指令与URI请求生成。
request_uri #包含请求参数的原始URI，不包含主机名，如：”/foo/bar.php?arg=baz”。不能修改。
scheme #HTTP方法（如http，https）。
server_protocol #请求使用的协议，通常是HTTP/1.0或HTTP/1.1。
server_addr #服务器地址，在完成一次系统调用后可以确定这个值。
server_name #服务器名称。
server_port #请求到达服务器的端口号。
七．Apache和Nginx规则的对应关系
Apache的RewriteCond对应Nginx的if
Apache的RewriteRule对应Nginx的rewrite
Apache的[R]对应Nginx的redirect
Apache的[P]对应Nginx的last
Apache的[R,L]对应Nginx的redirect
Apache的[P,L]对应Nginx的last
Apache的[PT,L]对应Nginx的last
例如：允许指定的域名访问本站，其他的域名一律转向www.linuxidc.net
Apache:
RewriteCond %{HTTP_HOST} !^(.*?)\.aaa\.com$[NC]
RewriteCond %{HTTP_HOST} !^localhost$
RewriteCond %{HTTP_HOST}!^192\.168\.0\.(.*?)$
RewriteRule ^/(.*)$ http://www.linuxidc.net[R,L]
Nginx:
if( $host ~* ^(.*)\.aaa\.com$ )
{
set $allowHost ‘1’;
}
if( $host ~* ^localhost )
{
set $allowHost ‘1’;
}
if( $host ~* ^192\.168\.1\.(.*?)$ )
{
set $allowHost ‘1’;
}
if( $allowHost !~ ‘1’ )
{
rewrite ^/(.*)$ http://www.linuxidc.netredirect ;
}
推荐阅读：
Nginx实现反向代理和负载均衡的配置及优化 http://www.linuxidc.com/Linux/2013-11/92909.htm
Nginx做负载均衡报:nginx: [emerg] could not build the types_hash http://www.linuxidc.com/Linux/2013-10/92063.htm
Nginx 负载均衡模块 ngx_http_upstream_module 详述 http://www.linuxidc.com/Linux/2013-10/91907.htm
Nginx+Firebug 让浏览器告诉你负载均衡将请求分到了哪台服务器 http://www.linuxidc.com/Linux/2013-10/91824.htm
Ubuntu安装Nginx php5-fpm MySQL(LNMP环境搭建) http://www.linuxidc.com/Linux/2012-10/72458.htm
http://www.linuxidc.com/Linux/2014-01/95493.htm