Nginx & detailed example location -> index, return, rewrite, try_files, alias The meaning and precautions of each attribute

1. Preparation

1.1 In this case, the centos7 system is used as a demonstration, and the configuration file is /etc/nginx/conf.d/test.confin , the content is as follows

server {
  listen  8000;
  server_name           127.0.0.1;
  root                  /home/cookcyq/web/;
  error_page  404              /40x.html;
  error_page  500 502 503 504  /50x.html;
  
  location / {
    return 200 'Hello,world';
  }
}

Please be sure to remember these configurations, the following cases are based on the above as a foreshadowing.

1.2 /home/cookcyq/web/The directory is as follows:

home
	cookcyq
		web
			40x.html 内容为：40xxxxxxxx.html
			50x.html 内容为：50xxxxxxxx.html
			index.html 内容为: indexxxxxx.html

1.3 Introduce the above files in /etc/nginx/nginx.confthe configuration file (the following section will be automatically added when downloading, if you don’t see it, you can add it manually)

http{
	...
	include /etc/nginx/conf.d/*.conf;
}

1.4 Restart nginx, visit http://127.0.0.1/:8000/to see the output Hello, world
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and then officially enter this article

2、location -> return

2.1 return status code + string

location /a {
	return 200 'Hi, I am a.';
}

Restart nginx, access http://127.0.0.1:8000/athe output :
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2.2 Redirection

location /a {
  return https://www.baidu.com;
 }

Restart nginx, visit http://127.0.0.1:8000/aRedirect to https://www.baidu.com
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3、location -> index

3.1 Preparations

Create a new directory under the /home/cookcyq/web/directory , and create index.html and test.html, the structure is as follows

home
	cookcyq
		web
			a
				index.html  内容为: Hello, index.html.
				test.html 	  内容为：Hello,test.html.

3.2 use

root                  /home/cookcyq/web/;
....
location /a {
    index index.html;
 }

http://127.0.0.1:8000/aWhen you visit now, you will visit the files/home/cookcyq/web/a/ underindex.html
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The function of index is to access index.html by default when no files are accessed

Now let's specify one, such as http://127.0.0.1:8000/a/test.htmlwill access the file/home/cookcyq/web/a/ under If we specify a file that does not exist, such as , there are two situations:test.html
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http://127.0.0.1:8000/a/ffff.html

If present, location / {} is accessed first

location / { 
	return "Hello,wolrd" 
}

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If there is no location / { … }, visit the previously configured error_page 404 /40x.html; ie /home/cookcyq/web/40.html.

4、location -> try_files

There are quite a lot of details in try_files, if you accidentally fall into the pit, please be careful.

4.1 Preparations

/home/cookcyq/web/Create a new b directory under the directory structure as follows

home
	cookcyq
		web
			b
				foo.html  		内容为: Hello, foo.html.
				bar.html	  	内容为：Hello,bar.html.
				index.html		内容为：Hello,b1, index.html.
				b2
					bird.html 		内容为：Hello,Bird.html
					index.html   	内容为：Hello,b2, index.html

Be sure to keep these structures in mind, the following will use the above structure as an example.

4.2 use

location /b {
	try_files $uri $uri/ /b/index.html;
}

Parameter explanation:

Parameter one $uri indicates access to /b/path/anyfile
The second parameter $uri/ indicates that when accessing /b/path/, access the index.xxx index file in this directory.
Note: If there is no index.xxx index file in this directory, it will return 403, and if it accesses a directory that does not exist, then returns 500.
Parameter three means that if the previous two cannot be found, visit /b/index.html
Note: If /b/index.html does not exist, return 500

Next, I will demonstrate how to trigger these three parameters one by one:
4.2.1 http://127.0.0.1:8000/b/foo.htmlAccess corresponds to $uri
4.2.2 http://127.0.0.1:8000/b/b2/bird.htmlAccess corresponds to $uri
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4.2.3 http://127.0.0.1:8000/b/Access corresponds to $uri/
4.2.4 http://127.0.0.1:8000/b/b2/Access corresponds to $uri/
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4.2.5 Access http://127.0.0.1:8000/b/oooo.htmlSince oooo.html does not exist, it corresponds to the third parameter /b/index.html.
4.2.6 Access http://127.0.0.1:8000/b/b2/oooo.htmlSince oooo.html does not exist, it corresponds to the third parameter /b/index.html.
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4.2.7 Access http://127.0.0.1:8000/b/oooo.htmlor http://127.0.0.1:8000/b/b2/oooo.htmlSince oooo.html does not exist, and the third parameter /b/index.htmldoes not exist (manually delete or rename index.html to achieve the effect), return 500
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4.3 Precautions

The third parameter is recommended to use the form of an absolute path /path/index.html, please do not use it $uri/index.html, because $uri/it is a dynamic directory, it will change with the change of the url, so it is easy to cause the problem that the directory cannot be found and report 500
The third parameter /represents the root root directory, but it does not add location /b {}, for example, the third parameter /index.htmlcorresponds root/index.html to not root/b/index.html, which is why the third parameter above is /b/index.html, and if it is location /b { index /index.html } will accumulate in the form root/b/index.htmlof , which should be noted.

5、location -> rewrite

The details of rewrite are quite a lot, but it is easy to understand.

5.1 Preparations

/home/cookcyq/web/Create a new c directory under the directory structure as follows

home
	cookcyq
		web
			c
				c.html  	内容为：Hello, c.html.
			r
				1.html  	内容为：Hello, 1.html.
				2.html	  	内容为：Hello, 2.html.
				3.html		内容为：Hello, 3.html.

Be sure to keep these structures in mind, the following will use the above structure as an example.

5.2 use

Syntax: rewrite [matching pattern] [redirect target] [command (optional)]

5.2.1 Easy to use

location /c {
	rewrite ^(.*)$ /r/1.html;
}

When you visit,
http://127.0.0.1:8000/c
http://127.0.0.1:8000/c/c.html
http://127.0.0.1:8000/c/xxx/xxx/xxx
you will be redirected to visit root/r/1.html
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Remember to remove the previous location / { return 200 'Hello, world' } statement, because the return command will skip the following location

5.2.2 With last directive

location /c {
    rewrite ^(.*)$ /r/1.html last;
    # 不会触发这个，因为 last 会跳过下面的执行语句
    rewrite ^(.*)$ /r/2.html last; 
}

When you visit,
http://127.0.0.1:8000/c
http://127.0.0.1:8000/c/c.html
http://127.0.0.1:8000/c/xxx/xxx/xxx
you will be redirected to visit root/r/1.html
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5.2.3 With last directive

location /c {
    rewrite ^(.*)$ /r/1.html last;
    # 不会触发这个，因为 last 会跳过下面的执行语句，但它会继续走进下一个 location 块
    rewrite ^(.*)$ /r/2.html last; 
}
# 这里监听 /r/1.html 再做一次重定向
location = /r/1.html {
	rewrite ^(.*)$ /r/3.html last;
}

When accessing
http://127.0.0.1:8000/c
http://127.0.0.1:8000/c/c.html
http://127.0.0.1:8000/c/xxx/xxx/xxx
will be redirected to visit root/r/3.html
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5.2.4 with break instruction

location /c {
  rewrite ^(.*)$ /r/1.html break;
  # 不会触发这个，因为 break 会跳过下面的执行语句
  rewrite ^(.*)$ /r/2.html last; 
}

http://127.0.0.1:8000/c
http://127.0.0.1:8000/c/c.html
http://127.0.0.1:8000/c/xxx/xxx/xxx
Will redirect access to root/r/1.html
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5.2.5 with break instruction

location /c {
    rewrite ^(.*)$ /r/1.html break;
    # 不会触发这个，因为 break 会跳过下面的执行语句，同时也会跳过下面的 location 块
    rewrite ^(.*)$ /r/2.html last; 
  }
  # 由于 break 这里不会触发到
  location = /r/1.html {
    rewrite ^(.*)$ /r/3.html last;
  }

http://127.0.0.1:8000/c
http://127.0.0.1:8000/c/c.html
http://127.0.0.1:8000/c/xxx/xxx/xxx
Will redirect access to root/r/1.html
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5.2.6 Error-prone redirection cases

location /c {
  rewrite ^(.*)$ /r/1.html last;
}
location = /r/1.html {
  index /r/2.html;
}

Think about it, where does it end up being redirected to?

In fact, if you know the function of index, the answer is much simpler. Here, only root/r/1.html will be redirected and root/r/2.html will not be accessed, because index is only used as the default access when no files are accessed. Directive for indexing files.
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5.3 Precautions

If the rewrite redirect target does not exist, it will go to error_page 404 /40x.html
If the root is /home/cookcyq/web and it is not added /, then the redirection target must be added /, /otherwise the redirection target can be added or not/

6、location -> root 与 alias

If we don't want each location to inherit root, but have its own root, then the root and alias commands in location are a good choice.

6.1 Preparations

Directory Structure

home
	cookcyq
		web
			d
				1.html 			内容为 Hello, 1.html
				index.html 		内容为 Hello, web index.html
		my
			d
				foo.html 		内容为 Hello, foo.html.
				index.html 		内容为 Hello, my index.html.

6.2 root

root /home/cookcyq/web/;
location /d {
	root /home/cookcyq/my/;
	try_files $uri $uri/ /d/index.html;
}

when we visit http://127.0.0.1:8000/d/foo.htmlwe will visit/home/cookcyq/my/d/foo.html
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6.3 alias

root /home/cookcyq/web/;
location /d {
	alias /home/cookcyq/my/d/;
	try_files $uri $uri/ /d/index.html;
}

when we visit http://127.0.0.1:8000/d/foo.htmlwe will visit/home/cookcyq/my/d/foo.html
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6.4 The difference between root and alias

The final path formed by the root command is: root+location xxx/*
The final path formed by the alias command is:alias/*