Nginx uses image_filter to dynamically generate thumbnails

"I need to generate thumbnails for some images now. Now I have added image_filter, but I don't know how to access the source image I uploaded"

At the beginning, I felt that it was not easy to use the program area for processing. In fact, I could use a little brains to analyze it, or I could not modify the program to dynamically generate thumbnails and access the source image.

The premise is that you need to set the image access rules.

Let's take a look at what is the nginx image filter module.

Httpimagefiltermodule is used to crop an excessively large image to a specified size. It is a built-in module of nginx and is not enabled by default.
To enable httpimagefiltermodule, You need to include the parameter -- with-http_image_filter_module at compilation

This module has two commands:
Syntax: image_filter (test | size | resize width height | crop width height)
Default Value: None
Context: Location

This command specifies the image conversion format:

Test-test whether the response is in JPEG, GIF, or PNG format (other formats such as BMP are not supported). If an error occurs, 415 is returned.
Size-return the JSON data of the image, for example: ("IMG": ("width": 100, "height": 100, "type": "GIF "))
Resize-reduce the image proportionally according to the settings, for example, the image size of 100*100 is set to 50*25, and the image size after reduction is 25*25. If you only want to set a dimension, you can use "-" instead. If an error occurs, 415 is returned.
Crop-scale down the image according to the settings, and then crop it to an image of the same size as the settings. For example, if the image is 100*100 and the image is set to 50*25, the reduced image is 50*50, and nginx selects 25 pixels in the middle to form a 50*25 image, therefore, images are missing. If you only want to set a dimension, you can use "-" instead. If an error occurs, 415 is returned.

Syntax: image_filter_buffer size
Default Value: image_filter_buffer 1 m
Available locations: HTTP, server, and location

This command sets the maximum cache size for a single image. If the size of the filtered image exceeds the cache size, an Error 415 is returned.

Focus at the beginning:

With the above knowledge, coupled with locaiont, if, and image_filter, nginx can dynamically generate thumbnails.

Assume that your image is in the/IMG directory.

Access to thumbnails

Http://www.xxx.cn/img/9GUMJR7200AJ0003_90x90.jpg

Source image access method

Http://www.xxx.cn/img/9GUMJR7200AJ0003_90x0.jpg

Http://www.xxx.cn/img/9GUMJR7200AJ0003_0x50.jpg

Http://www.xxx.cn/img/9GUMJR7200AJ0003_0x0.jpg

Http://www.xxx.cn/img/9GUMJR7200AJ0003.jpg

Add the following configuration to the server context:

Location ~ */Img /(. +) _ (\ D +) x (\ D + )\. (JPG | GIF | PNG) $ {set $ h $2; set $ W $3; if ($ H = "0") {rewrite/img /(. +) _ (\ D +) x (\ D + )\. (JPG | GIF | PNG) $/img/$1. $4 last;} if ($ W = "0") {rewrite/img /(. +) _ (\ D +) x (\ D + )\. (JPG | GIF | PNG) $/img/$1. $4 last ;}# generate the thumbnail image_filter resize $ h $ W based on the given length and width; # the maximum size of the source image is 2 MB. If the image to be cropped exceeds 2 MB, a 415 error is returned, you need to adjust the image_filter_buffer 2 m; # error_page 415/img/notfound.jpg; try_files/img/$1. $4/I Mg/notfound.jpg;} location ~ */IMG {}

Http://wiki.nginx.org/HttpImageFilterModule

Nginx uses image_filter to dynamically generate thumbnails