67 lines
2.1 KiB
Markdown
67 lines
2.1 KiB
Markdown
[Nginx Server Configs homepage](https://github.com/h5bp/server-configs-nginx)
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| [Documentation table of contents](TOC.md)
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# How Nginx works
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If you're familiar with any other webserver, some aspects of
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[the way Nginx works](http://nginx.org/en/docs/http/request_processing.html)
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can cause confusion. This document aims to highlight differences or features
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which may trip up new users.
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## Nginx will only use one location block
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A [location block (directive)](http://nginx.org/en/docs/http/ngx_http_core_module.html#location)
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defines the behavior for a given request which matches the location url pattern. The block used
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is whichever is the most specific for the given request, the rules for
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precedene can be found in [Nginx's wiki](http://wiki.nginx.org/HttpCoreModule#location).
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It is very important when writing nginx configuration files to understand that
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only one location block will be used by Nginx. When in doubt a useful technique
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to identify which location block is to add a header:
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# Make sure js files are served with a long expire
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location ~ /something {
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add_header "section" "something location";
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...
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}
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location /something-else {
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add_header "section" "something else location";
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...
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}
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In the headers for a response, the header added from the block which matched
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will be included:
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$ curl -I "http://nginx.h5bp.dev/something"
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...
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section: something location
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There are some significant concequences to this behavior such as it _not_ being
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possible to build configuration files from small, overlapping, location blocks.
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## try_files in the server_context does not always apply
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Consider the following server block:
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server {
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listen 80;
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server_name example.com;
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root /var/www/example.com;
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try_files $uri $uri/ /fallback.html;
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location ~ ^/somefolder {
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...
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}
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}
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It might be expected that a request for `http://example.com/somefolder/doesnt-exist`
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would result in the contents of `/fallback.html` - but this is not the case. the
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`try_files` directive in the server context _only applies if no location block
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matches_, it is not a default which location blocks override.
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