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本文主要针对nginx的几个主要cache指令做一个简单的整理，另外部分指令做了实际测试，本文具体包括如下指令：
proxy_headers_hash_bucket_size、proxy_headers_hash_max_size 、proxy_hide_header 、proxy_http_version 、proxy_ignore_client_abort 、proxy_hide_header 、proxy_ignore_headers、proxy_intercept_errors
9. proxy_headers_hash_bucket_size
syntax:
| proxy_headers_hash_bucket_size size;
|
default:
| proxy_headers_hash_bucket_size 64;
|
context:
| http, server, location
|
为 proxy_hide_header和proxy_set_header指令设置hash tables的bucket size尺寸大小。另外，提供了一个单独的文件详细介绍建立哈希表建立方法。
Sets the bucket size for hash tables used by the proxy_hide_header and proxy_set_header directives. Details of setting up hash tables are provided in a separate document.
10. proxy_headers_hash_max_size
syntax:
| proxy_headers_hash_max_size size;
|
default:
| proxy_headers_hash_max_size 512;
|
context:
| http, server, location
|
设置用于proxy_hide_header和proxy_set_header指令的hash table的最大大小。另外，提供了一个单独的文件详细介绍建立哈希表建立方法。
Sets the maximum size of hash tables used by the proxy_hide_header and proxy_set_header directives. Details of setting up hash tables are provided in a separate document.
11. proxy_hide_header
syntax:
| proxy_hide_header field;
|
default:
| —
|
context:
| http, server, location
|
在默认情况下，nginx不把重方向代理服务器获取来的一些header头（包括：Date， Server, X-Pad以及X-Accel-....等指令）传递给客户端。这个proxy_hide_header指令可以指定其他不传递的header到客户端。相反若是需要传递某些头到客户端可以通过proxy_pass_header指令进行
By default, nginx does not pass the header fields “Date”, “Server”, “X-Pad”, and “X-Accel-...” from the response of a proxied server to a client. The proxy_hide_header directive sets additional fields that will not be passed. If, on the contrary, the passing of fields needs to be permitted, the proxy_pass_header directive can be used.
12. proxy_http_version
syntax:
| proxy_http_version 1.0 | 1.1;
|
default:
| proxy_http_version 1.0;
|
context:
| http, server, location
|
该指令出现在版本1.1.4。
设置nginx服务器的http版本，默认情况下是1.0版本。为了利用keepalive连接功能，推荐设置1.1版本
注：在http1.0版本中，规定每次http请求都需要重新开启一个tcp连接来进行数据的传输，但是由于tcp连接是个昂贵的网络连接，每次都需要重建立连接是非常不划算的功能。
在http1.1中以及可以通过keepalive指令指示后续http请求可以复用前面已经建立的tcp连接来传递http的各种数据等，因此可以较好的提高效率。
This directive appeared in version 1.1.4.
Sets the HTTP protocol version for proxying. By default, version 1.0 is used. Version 1.1 is recommended for use with keepalive connections.
13. proxy_ignore_client_abort
syntax:
| proxy_ignore_client_abort on | off;
|
default:
| proxy_ignore_client_abort off;
|
context:
| http, server, location
|
如果一个客户端不在等待响应而关闭了请求的连接，这个指令将决定是否关闭同一个被代理服务器的连接。
Determines should the connection with a proxied server be closed if a client closes a connection without waiting for a response.
14. proxy_hide_header
syntax:
| proxy_hide_header field;
|
default:
| —
|
context:
| http, server, location
|
默认情况下，nginx不将被代理服务器的如下响应头（http head）传递给客户端，包括“Date”, “Server”, “X-Pad”, and “X-Accel-...”。proxy_hide_header 这里可以设置额外的不传递给客户端的http head信息。相反可以使用proxy_pass_header 指令指定将哪些信息传递给客户端。
By default, nginx does not pass the header fields “Date”, “Server”, “X-Pad”, and “X-Accel-...” from the response of a proxied server to a client. The proxy_hide_header directive sets additional fields that will not be passed. If, on the contrary, the passing of fields needs to be permitted, the proxy_pass_header directive can be used.
15. proxy_ignore_headers
syntax:
| proxy_ignore_headers field...;
|
default:
| —
|
context:
| http, server, location
|
对从被代理服务器返回的响应数据中的一些header信息设置禁止处理。下面信息域能被忽略：“X-Accel-Redirect”, “X-Accel-Expires”, “X-Accel-Limit-Rate” (1.1.6), “X-Accel-Buffering” (1.1.6), “X-Accel-Charset” (1.1.6), “Expires”, “Cache-Control”, and “Set-Cookie” (0.8.44).
如果没有被禁用，处理这些header具有以下作用：
“X-Accel-Expires”, “Expires”, “Cache-Control”, and “Set-Cookie”设置响应缓存的参数。
“X-Accel-Redirect”执行内部重定向到指定的URI;
“X-Accel-Limit-Rate”设置传输到客户端的响应速率限制;
“X-Accel-Buffering” 启用或禁用缓存的响应;
“X-Accel-Charset” 设置响应所需的字符集。
Disables processing of certain response header fields from the proxied server. The following fields can be ignored: “X-Accel-Redirect”, “X-Accel-Expires”, “X-Accel-Limit-Rate” (1.1.6), “X-Accel-Buffering” (1.1.6), “X-Accel-Charset” (1.1.6), “Expires”, “Cache-Control”, and “Set-Cookie” (0.8.44).
If not disabled, processing of these header fields has the following effect:
“X-Accel-Expires”, “Expires”, “Cache-Control”, and “Set-Cookie” set parameters of response caching;
“X-Accel-Redirect” performs an internal redirect to the specified URI;
“X-Accel-Limit-Rate” sets a rate limit for transmission of a response to a client;
“X-Accel-Buffering” enables or disables buffering of a response;
“X-Accel-Charset” sets the desired charset of a response.
16. proxy_intercept_errors
syntax:
| proxy_intercept_errors on | off;
|
default:
| proxy_intercept_errors off;
|
context:
| http, server, location
|
确定当被代理服务器的响应返回码大于或者等400时，是否需要将请求传递给客户端或者重定向到nginx进行处理，通过error_page指令。
Determines whether proxied responses with codes greater than or equal to 400 should be passed to a client or be redirected to nginx for processing using the error_page directive.
