Context

There are many services for crypto network nodes which provide public endpoints: API, RPC and sometimes gPRC. While browsing swagger documentation I found that the pages are loaded pretty slow. Let’s take a look at swagger for Galactica API served by IT-Rocket, it took 13s to load the page: itrocket01 As one can see, most of the time is spent on fetching openapi.yml. Looks like the issue is with my Internet provider, since from remote servers I got the same content within 500ms. But I read the docs from my local machine, so I tried to understand what I could do. Another noticeable point is it’s size: 2.4MB. Usually text files can be compressed pretty well, upto 10 times, which can improve situation dramatically. Compression is controlled by client header 'Accept-Encoding: gzip', let’s check it:

% curl 'https://galactica-testnet-api.itrocket.net/static/openapi.yml' \
  -H 'accept: application/json,*/*' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 2331k  100 2331k    0     0  86756      0  0:00:27  0:00:27 --:--:-- 66983

% curl 'https://galactica-testnet-api.itrocket.net/static/openapi.yml' \
  -H 'Accept-Encoding: gzip' \
  -H 'accept: application/json,*/*' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 2331k  100 2331k    0     0    99k      0  0:00:23  0:00:23 --:--:--  181k

Unfortunately, server doesn’t react on the header. Let’s compare with another public endpoint:

% curl 'https://api.galactica.crptmax.com/static/openapi.yml' \
  -H 'accept: application/json,*/*' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 2331k  100 2331k    0     0   577k      0  0:00:04  0:00:04 --:--:--  609k

% curl 'https://api.galactica.crptmax.com/static/openapi.yml' \
  -H 'Accept-Encoding: gzip' \                 
  -H 'accept: application/json,*/*' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  278k    0  278k    0     0   116k      0 --:--:--  0:00:02 --:--:--  116k

The difference is clear: 278K/2s vs 2.3M/4s.

Configuration

crptmax.com uses Nginx to proxy all HTTP traffic, let’s check how to set it up.

Compression is enabled by default in Nginx:

$ cat /etc/nginx/nginx.conf
...
http {
	...
	##
	# Gzip Settings
	##

	gzip on;

	# gzip_vary on;
	# gzip_proxied any;
	# gzip_comp_level 6;
	# gzip_buffers 16 8k;
	# gzip_http_version 1.1;
	gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
	...
}

However, it is required to add application/x-yaml mime type to enable compression for openapi.yml:

gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

After any configuration change, check it is correct and reload:

$ sudo nginx -t && sudo nginx -s reload

That’s it, compression for *.yml is enabled.

PS.

Compression on IT-Rockets works for RPC, let’s check Zero-gravity public endpoints:

$ time curl 'https://og-testnet-rpc.itrocket.net/dump_consensus_state' \
  -H 'accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7' \
  > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  649k    0  649k    0     0  1652k      0 --:--:-- --:--:-- --:--:-- 1656k

real	0m0.406s
user	0m0.090s
sys	0m0.008s

$ time curl 'https://og-testnet-rpc.itrocket.net/dump_consensus_state' \
  -H 'Accept-Encoding: gzip' \
  -H 'accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7' \
  > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  127k    0  127k    0     0   369k      0 --:--:-- --:--:-- --:--:--  369k

real	0m0.360s
user	0m0.083s
sys	0m0.016s

127K vs 649K with almost the same time.