Mastering Nginx

Directive Reference

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Directive Explanation Context/Default

ignore_invalid_

headers

Disables ignoring headers with

invalid names. A valid name

is composed of ASCII letters,

numbers, the hyphen, and possibly

the underscore (controlled by the

underscores_in_headers

directive).

Valid contexts: http,

server

Default value: on

image_filter Refer to the Image filter directives

table in the Generating images

section in Chapter 7, NGINX for

the Developer.

Valid context:

location

Default value: -

image_filter_buffer The size of the buffer used to

process images. If more memory

is needed, the server will return a

415 error (Unsupported Media

Type).

Valid contexts: http,

server, location

Default value: 1M

image_filter_jpeg_

quality

The quality of the resulting JPEG

image, after processing. Not

recommended to exceed 95.

Valid contexts: http,

server, location

Default value: 75

image_filter_

sharpen

Increases the sharpness of

a processed image by this

percentage.

Valid contexts: http,

server, location

Default value: 0

image_filter_

transparency

Disables preserving transparency

of transformed GIF and PNG

images. The default on preserves

transparency.

Valid contexts: http,

server, location

Default value: on

imap_auth Sets the supported client

authentication mechanism. It can

be one or more of login, plain,

or cram-md5.

Valid contexts: mail,

server

Default value: plain

imap_capabilities Indicates which IMAP4

capabilities are supported by the

backend server.

Valid contexts: mail,

server

Default value: IMAP4

IMAP4rev1 UIDPLUS

imap_client_buffer Sets the size of the read buffer for

IMAP commands.

Valid contexts: mail,

server

Default value: 4k|8k

(platform dependent)