--- title: "Use Case" language: "en" documentation_version: "2.x" channel: "maintenance" release_context: {"latest_release_tag":"v2.7.2","unreleased_versions":["v2.7.3"],"latest_release_revision":"d5ae755471c48c6617cb23495e7b65d7c5241b45"} source_revision: "967b61cc6a232aa1ad27dd452c8b5835f94c2a01" working_tree_clean: true source_path: "docs/use_case/README.md" source_sha256: "ccd3e25abfa1e6b5f4b7c4c5e55da25771813e1ef040df40e1f9b49ad9afd225" source_at_revision: true source_url: "https://github.com/matsumotory/ngx_mruby/blob/967b61cc6a232aa1ad27dd452c8b5835f94c2a01/docs/use_case/README.md" html_url: "https://ngx.mruby.org/v2/guides/use-cases/" markdown_url: "https://ngx.mruby.org/v2/markdown/guides/use-cases.md" last_updated: "2026-10-19" --- # Use Case - [Hello World](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#hello-world) - [Reverse Proxy](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#reverse-proxy) - [Change to maintenance mode with Redis](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#change-to-maintenance-mode-with-redis) - [Markdown Web Page](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#markdown-web-page) - [Output Filter Converting Markdown to HTML](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#output-filter-convering-markdown-to-html) - [File Based Access List](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#file-based-access-list) - [File Server like Dropbox Link](https://github.com/matsumotory/ngx_mruby/tree/master/docs/use_case#file-server-like-dropbox-link) - [Dynamic Image Provider (in Japanese)](http://techhey.hatenablog.com/entry/2014/04/19/162323) - [Dynamic reverse proxy using access information (in Japanese)](http://blog.cloudpack.jp/2014/07/08/ngx-mruby-nginx-script/) - [Research ngx_mruby and use output filter (in Russian)](http://habrahabr.ru/post/225313/) - [ACME auto ssl using Let's Encrypt](https://github.com/matsumotory/ngx_mruby/blob/master/test/conf/auto-ssl/nginx.conf.client_example) ## Hello world #### /path/to/hello.rb ```ruby Nginx.echo "Hello World" ``` #### nginx.conf ```nginx server { location /hello { mruby_content_handler /path/to/hello.rb; } } ``` #### Access ```bash $ curl http://127.0.0.1/hello Hello World ``` ## Reverse Proxy #### /path/to/proxy.rb ```ruby backends = [ "127.0.0.1:8001", "127.0.0.1:8002", "127.0.0.1:8003", ] # write algorithm for selecting backend backends[rand(backends.length)] ``` #### nginx.conf ```nginx server { location /proxy { mruby_set $backend /path/to/proxy.rb; proxy_pass http://$backend; } } ``` ## Change to maintenance mode with Redis refs: http://takeswim.hateblo.jp/entry/2013/10/03/182748 This example needs the `Redis` class of mruby-redis, and a running Redis server. The default `build_config.rb` builds mruby-redis again since 2.7.2; 2.7.1 left it out. #### nginx.conf ```nginx worker_processes 1; daemon off; master_process off; events { worker_connections 1024; } http { # Create redis connection object at startup, # and set it into user-data object mruby_init_code ' userdata = Userdata.new "redis_data_key" userdata.redis = Redis.new "127.0.0.1", 6379 '; server { listen 7777; location / { echo "port 7777 contents"; } } server { listen 57777; location /mruby { mruby_set_code $maint ' userdata = Userdata.new "redis_data_key" redis = userdata.redis redis.get "ngx_maint" '; if ($maint = "TRUE") { mruby_set_code $res_maint ' JSON::stringify({"result"=>"ERR", "time"=>Time.now.to_i}) '; echo $res_maint; } if ($maint != "TRUE") { proxy_pass http://127.0.0.1:7777; } } } } ``` ## Markdown Web Page ##### Activate mruby-discount when build ngx_mruby ```ruby # use markdown on mod_mruby conf.gem :git => 'git://github.com/matsumotory/mruby-discount.git' ``` ##### nginx.conf ```nginx location ~ \.rb$ { mruby_add_handler on; } ``` ##### md.rb ```ruby r = Nginx::Request.new r.content_type = "text/html" # setup markdown engine title = "md test" css = "https://gist.github.com/andyferra/2554919/raw/2e66cabdafe1c9a7f354aa2ebf5bc38265e638e5/github.css" md = Discount.new css, title # create markdown data body = < 'git://github.com/matsumotory/mruby-discount.git' ``` #### nginx.conf ```nginx location ~ \.md$ { mruby_output_filter /path/to/filter.rb cache; } ``` #### /path/to/filter.rb ```ruby f = Nginx::Filter.new # setup markdown convert engine css = "https://gist.github.com/andyferra/2554919/raw/2e66cabdafe1c9a7f354aa2ebf5bc38265e638e5/github.css" title = "markdown" md = Discount.new css, title # convert markdown to html, # and add output filter f.body = md.md2html f.body ``` #### test.md ```markdown # Section ## aaa - hoge - foo ## bbb __code__ a = 1 b = a + 1 ``` #### Access markdown file http://example.com/test.md image *** ![response](https://dl.dropboxusercontent.com/s/fkzsuv94tr541zg/md_test.png) *** ## File Based Access List ##### nginx.conf ```nginx location / { mruby_access_handler /path/to/access_check.rb; } ``` ##### /path/to/access_check.rb ```ruby r = Nginx::Request.new filename = File.join r.var.document_root, ".access_list" if File.exists? filename deny_list = Array.new File.open(filename) do |file| while line = file.gets deny_list << line.chomp end end if deny_list.include? r.var.remote_addr Nginx.errlogger Nginx::LOG_ERR, "ACL: FORBIDDEN Client Matched in #{filename}" Nginx.return Nginx::HTTP_FORBIDDEN else Nginx.errlogger Nginx::LOG_ERR, "ACL: OK Client Unmatched in #{filename}" Nginx.return Nginx::HTTP_OK end else Nginx.return Nginx::HTTP_OK end ``` ##### /path/to/.access_list ``` 192.168.12.9 192.168.12.10 ``` ##### Access to nginx(run with 192.168.12.9 listening 0.0.0.0:80) ```bash $ curl http://127.0.0.1/ hello world $ curl http://192.168.12.9/ 403 Forbidden

403 Forbidden

nginx/1.4.4
``` ##### error.log ``` 2014/03/10 17:14:20 [error] 11376#0: *4 ACL: OK Client Unmatched in /usr/local/nginx-1.4.4/html/.access_list, client: 127.0.0.1, server: localhost, request: "GET / HTTP/1.1", host: "127.0.0.1" 2014/03/10 17:15:09 [error] 11376#0: *7 ACL: FORBIDDEN Client Matched in /usr/local/nginx-1.4.4/html/.access_list, client: 192.168.12.9, server: localhost, request: "GET / HTTP/1.1", host: "192.168.12.9" ``` ## File Server like Dropbox Link This example needs the `Redis` class of mruby-redis, and a running Redis server. The default `build_config.rb` builds mruby-redis again since 2.7.2; 2.7.1 left it out. ##### nginx.conf ```nginx location /dropbox { mruby_rewrite_handler /path/to/dropbox.rb; } ``` ##### /path/to/dropbox.rb ```ruby redis = Redis.new "127.0.0.1", 6379 reqst = Nginx::Request.new file = redis.hget reqst.uri, "file" expr = redis.hget reqst.uri, "expire" Nginx.errlogger Nginx::LOG_ERR, "dropbox: uri=#{reqst.uri} file=#{file} expire=#{Time.at expr.to_i}" redis.close if expr.to_i >= Time.now.to_i Nginx.redirect file else Nginx.return Nginx::DECLINED end ``` ##### Input data by redis-cli ```redis HSET /dropbox/aaabbbcccddd file /files/hoge.html HSET /dropbox/aaabbbcccddd expire 1400000000 ``` ##### /files/hoge.html ```html hoge ``` ##### access to http://127.0.0.1/dropbox/aaabbbcccddd ```curl $ curl http://127.0.0.1/dropbox/aaabbbcccddd hoge ``` ##### error.log ``` 2014/03/11 00:02:30 [error] 12245#0: *109 dropbox: uri=/dropbox/aaabbbcccddd file=/files/hoge.html expire=Wed May 14 01:53:20 2014, client: 127.0.0.1, server: localhost, request: "GET /dropbox/aaabbbcccddd HTTP/1.1", host: "127.0.0.1" ```