For a long time, inspired by the article
Article came to the rescue
So, what do we need
The examples will be based on Debian.
Installing nginx and nginx-extras
apt-get update
apt-get install nginx-extras
Installing LuaJIT
apt-get -y install lua5.1 luajit-5.1 libluajit-5.1-dev
Installing imagemagick
apt-get -y install imagemagick
and libraries magickwand to it, in my case for version 6
apt-cache search libmagickwand
apt-get -y install libmagickwand-6.q16-3 libmagickwand-6.q16-dev
Building lua-imagick
Clone the repository (well, or take the zip and unpack it)
cd ~
git clone https://github.com/isage/lua-imagick.git
cd lua-imagick
mkdir build
cd build
cmake ..
make
make install
If everything went well, you can configure Nginx.
I will give an example of the backend host config, which, in fact, is engaged in resizing. It is proxied by the front server in the same way as with Nginx, on which caching takes place for a certain time (day), etc. things.
nginx backend config
# Backend image server
server {
listen 8082;
listen [::]:8082;
set $files_root /var/www/example.lh/frontend/web;
root $files_root;
access_log off;
expires 1d;
location /files {
# Π΄Π΅ΡΠΎΠ»ΡΠ½ΡΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΡ ΡΠ΅ΡΠ°ΠΉΠ·Π°
set $w 700;
set $h 700;
set $q 89;
#1-89 allowed
if ($arg_q ~ "^([1-9]|[1-8][0-9])$") {
set $q $arg_q;
}
if ($arg_resize ~ "([d-]+)x([d+!^]+)") {
set $w $1;
set $h $2;
rewrite ^(.*)$ /resize/$w/$h/$q$uri last;
}
rewrite ^(.*)$ /resize/$w/$h/$q$uri last;
}
location ~* ^/resize/([d]+)/([d+!^]+)/([d]+)/files/(.+)$ {
default_type 'text/plain';
set $w $1;
set $h $2;
set $q $3;
set $fname $4;
# ΠΡΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ Π²ΡΠ½Π΅ΡΡΠΈ Π²Π΅ΡΡ Lua ΠΊΠΎΠ΄ Π² ΠΎΡΠ΄Π΅Π»ΡΠ½ΡΠΉ ΡΠ°ΠΉΠ»
# content_by_lua_file /var/www/some.lua;
# lua_code_cache off; #dev
content_by_lua '
local magick = require "imagick"
local img = magick.open(ngx.var.files_root .. "/files/" .. ngx.var.fname)
if not img then ngx.exit(ngx.HTTP_NOT_FOUND) end
img:set_gravity(magick.gravity["CenterGravity"])
if string.match(ngx.var.h, "%d+%+") then
local h = string.gsub(ngx.var.h, "(%+)", "")
resize = ngx.var.w .. "x" .. h
-- Π΄Π»Ρ png Ρ Π°Π»ΡΡΠ° ΠΊΠ°Π½Π°Π»ΠΎΠΌ
img:set_bg_color(img:has_alphachannel() and "none" or img:get_bg_color())
img:smart_resize(resize)
img:extent(ngx.var.w, h)
else
img:smart_resize(ngx.var.w .. "x" .. ngx.var.h)
end
if ngx.var.arg_q then img:set_quality(ngx.var.q) end
ngx.say(img:blob())
';
}
}
# Upstream
upstream imageserver {
server localhost:8082;
}
server {
listen 80;
server_name examaple.lh;
# ΠΎΡΠΏΡΠ°Π²Π»ΡΠ΅ΠΌ Π²ΡΠ΅ jpg ΠΈ png ΠΊΠ°ΡΡΠΈΠ½ΠΊΠΈ Π½Π° imageserver
location ~* ^/files/.+.(jpg|png) {
proxy_buffers 8 2m;
proxy_buffer_size 10m;
proxy_busy_buffers_size 10m;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://imageserver; # Backend image server
}
}
What was required (expanding the image at the edges) is done with img:extent()
and is determined using the parameter resize
with sign +
at the end.
The following options are available:
- WxH (Keep aspect-ratio, use higher dimension)
- WxH^ (Keep aspect-ratio, use lower dimension (crop))
- WxH! (Ignore aspect-ratio)
- WxH+ (Keep aspect-ratio, add side borders)
Pivot table with resize results
Request uri parameter
Output image size
?resize=400Γ200
200 Γ 200
?resize=400Γ200^
400 Γ 400
?resize=400Γ200!
400Γ200 (Not proportional)
?resize=400Γ200+
400Γ200 (Proportional)
Π‘onclusion
Given the power and simplicity of this approach, you can implement things with rather complex logic, for example, add watermarks or implement authorization with limited access. In order to learn about the capabilities of the API for working with images, you can refer to the library documentation.
Source: habr.com