colin/nixpkgs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

convert nginx documentation to common mark

Browse Source
This commit is contained in:
Justus K 2020-12-02 20:14:05 +01:00
parent bdbcbddde6
commit 58baa3f39c
No known key found for this signature in database
GPG Key ID: 8C62FE98A62FC462
3 changed files with 12 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
doc/builders/packages/index.xml
View File

@ -14,7 +14,7 @@
<xi:include href="kakoune.section.xml" />
<xi:include href="linux.xml" />
<xi:include href="locales.xml" />
<xi:include href="nginx.xml" />
<xi:include href="nginx.section.xml" />
<xi:include href="opengl.section.xml" />
<xi:include href="shell-helpers.xml" />
<xi:include href="steam.xml" />

11
doc/builders/packages/nginx.section.md Normal file
View File

@ -0,0 +1,11 @@
# Nginx {#sec-nginx}
[Nginx](https://nginx.org) is a reverse proxy and lightweight webserver.
## ETags on static files served from the Nix store {#sec-nginx-etag}
HTTP has a couple different mechanisms for caching to prevent clients from having to download the same content repeatedly if a resource has not changed since the last time it was requested. When nginx is used as a server for static files, it implements the caching mechanism based on the [`Last-Modified`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified) response header automatically; unfortunately, it works by using filesystem timestamps to determine the value of the `Last-Modified` header. This doesn't give the desired behavior when the file is in the Nix store, because all file timestamps are set to 0 (for reasons related to build reproducibility).
Fortunately, HTTP supports an alternative (and more effective) caching mechanism: the [`ETag`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag) response header. The value of the `ETag` header specifies some identifier for the particular content that the server is sending (e.g. a hash). When a client makes a second request for the same resource, it sends that value back in an `If-None-Match` header. If the ETag value is unchanged, then the server does not need to resend the content.
As of NixOS 19.09, the nginx package in Nixpkgs is patched such that when nginx serves a file out of `/nix/store`, the hash in the store path is used as the `ETag` header in the HTTP response, thus providing proper caching functionality. This happens automatically; you do not need to do modify any configuration to get this behavior.

25
doc/builders/packages/nginx.xml
View File

@ -1,25 +0,0 @@
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xml:id="sec-nginx">
<title>Nginx</title>
<para>
<link xlink:href="https://nginx.org/">Nginx</link> is a reverse proxy and lightweight webserver.
</para>
<section xml:id="sec-nginx-etag">
<title>ETags on static files served from the Nix store</title>
<para>
HTTP has a couple different mechanisms for caching to prevent clients from having to download the same content repeatedly if a resource has not changed since the last time it was requested. When nginx is used as a server for static files, it implements the caching mechanism based on the <link xlink:href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified"><literal>Last-Modified</literal></link> response header automatically; unfortunately, it works by using filesystem timestamps to determine the value of the <literal>Last-Modified</literal> header. This doesn't give the desired behavior when the file is in the Nix store, because all file timestamps are set to 0 (for reasons related to build reproducibility).
</para>
<para>
Fortunately, HTTP supports an alternative (and more effective) caching mechanism: the <link xlink:href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag"><literal>ETag</literal></link> response header. The value of the <literal>ETag</literal> header specifies some identifier for the particular content that the server is sending (e.g. a hash). When a client makes a second request for the same resource, it sends that value back in an <literal>If-None-Match</literal> header. If the ETag value is unchanged, then the server does not need to resend the content.
</para>
<para>
As of NixOS 19.09, the nginx package in Nixpkgs is patched such that when nginx serves a file out of <filename>/nix/store</filename>, the hash in the store path is used as the <literal>ETag</literal> header in the HTTP response, thus providing proper caching functionality. This happens automatically; you do not need to do modify any configuration to get this behavior.
</para>
</section>
</section>