artanis
Artanis
Crystal's metaprogramming macros to build a Sinatra-like DSL for the Crystal language.
Rationale
The DSL doesn't stock blocks to be invoked later on, but rather produces actual methods using macros (match
and the sugar get
, post
, etc.) where special chars like /
, .
, (
and )
are replaced as _SLASH_
, _DOT_
, _LPAREN_
and _RPAREN_
. Also, :param
segments are replaced to _PARAM_
.
Eventually methods look like:
get "/posts" | def match_GET__SLASH_posts
get "/posts.xml" | def match_GET__SLASH_posts_DOT_xml
Please read dsl.cr for more details.
Eventually a call method is generated. It iterates over the class methods, selects the generated match_*
methods and generates a big case
statement, transforming the method names back to regular expressions, and eventually calling the method with matched data (if any).
Please read application.cr for more details.
Usage
require "http/server"
require "artanis"
class App < Artanis::Application
get "/" do
"ROOT"
end
get "/forbidden" do
403
end
get "/posts/:id.:format" do
p params["id"]
p params["format"]
"post"
end
get "/posts/:post_id/comments/:id(.:format)" do |post_id, id, format|
p params["format"]?
200
end
end
server = HTTP::Server.new(9292) do |context|
App.call(context)
end
puts "Listening on http://0.0.0.0:9292"
server.listen
Benchmark
Running wrk against the above example (pointless hello world) gives the following results (TL;DR 12µs per request):
$ wrk -c 1000 -t 2 -d 5 http://localhost:9292/fast
Running 5s test @ http://localhost:9292/fast
2 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 12.26ms 14.48ms 423.28ms 99.05%
Req/Sec 41.17k 2.93k 48.65k 76.00%
409663 requests in 5.01s, 25.79MB read
Requests/sec: 81722.08
Transfer/sec: 5.14MB
A better benchmark is available in test/dsl_bench.cr
which monitors some limits of the generated Crystal code, like going over all routes to find nothing takes an awful lot of time, since it must build/execute a regular expression against EVERY routes to eventually... find nothing.
$ crystal run --release test/dsl_bench.cr
get root: 0.84 µs
get param: 1.51 µs
get params (block args): 2.18 µs
get many params: 3.75 µs
get many params (block args): 2.59 µs
not found (method): 0.73 µs
not found (path): 15.93 µs
Keep in mind these numbers tell nothing about reality. They only measure how fast the generated Application.call(request)
method is in predefined cases.
License
Licensed under the MIT License
artanis
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- June 16, 2015
MIT License
Thu, 21 Nov 2024 18:06:11 GMT