title: Rails ActionCable error during websocket handshake
body: <p>I'm trying to build a messaging app with Rails 5 ActionCable, but I'm getting the above error in the JS console.</p>
  
  <p><code>ws://localhost:3002/cable' failed: Error during WebSocket handshake: Unexpected response code: 404</code></p>
  
  <p>I'm using the Redis and Puma gems.</p>
  
  <p>I have a Redis server running <code>7937:M 24 Jul 18:20:53.379 * The server is now ready to accept connections on port 6379</code></p>
  
  <p>I start the Rails server with Puma: <code>rails s Puma -p 3002</code> (is this even required?)</p>
  
  <p><code>config/cable.yml</code> looks like this...</p>
  
  <pre><code>development:
    adapter: redis
    url: redis://localhost:6379
  
  test:
    adapter: async
  
  production:
    adapter: redis
    url: redis://localhost:6379/1
  </code></pre>
  
  <p>When I enter <code>rails c</code> and I execute the broadcast:</p>
  
  <pre><code>2.2.4 :003 &gt; ActionCable.server.broadcast("messages:1", text: "test")
  [ActionCable] Broadcasting to messages:1: {:text=&gt;"test"}
   =&gt; 0
  </code></pre>
  
  <p>...you can see it returns 0, so it fails. And the console error message looks like...</p>
  
  <p><code>WebSocket connection to 'ws://localhost:3002/cable' failed: WebSocket is closed before the connection is established.</code></p>
  
  <p>I'm a complete beginner when it comes to NGINX. Is this an NGINX issue? If so, how do I resolve it? Do I reconfigure my <code>nginx.conf</code> file in <code>/usr/local/etc/nginx/</code>? Currently it looks like this...</p>
  
  <pre><code>#user  nobody;
  worker_processes  1;
  
  #error_log  logs/error.log;
  #error_log  logs/error.log  notice;
  #error_log  logs/error.log  info;
  
  #pid        logs/nginx.pid;
  
  
  events {
      worker_connections  1024;
  }
  
  
  http {
      include       mime.types;
      default_type  application/octet-stream;
  
      #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
      #                  '$status $body_bytes_sent "$http_referer" '
      #                  '"$http_user_agent" "$http_x_forwarded_for"';
  
      #access_log  logs/access.log  main;
  
      sendfile        on;
      #tcp_nopush     on;
  
      #keepalive_timeout  0;
      keepalive_timeout  65;
  
      #gzip  on;
  
      server {
          listen       8080;
          server_name  localhost;
  
          #charset koi8-r;
  
          #access_log  logs/host.access.log  main;
  
          location / {
              root   html;
              index  index.html index.htm;
          }
  
          #error_page  404              /404.html;
  
          # redirect server error pages to the static page /50x.html
          #
          error_page   500 502 503 504  /50x.html;
          location = /50x.html {
              root   html;
          }
  
          # proxy the PHP scripts to Apache listening on 127.0.0.1:80
          #
          #location ~ \.php$ {
          #    proxy_pass   http://127.0.0.1;
          #}
  
          # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
          #
          #location ~ \.php$ {
          #    root           html;
          #    fastcgi_pass   127.0.0.1:9000;
          #    fastcgi_index  index.php;
          #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
          #    include        fastcgi_params;
          #}
  
          # deny access to .htaccess files, if Apache's document root
          # concurs with nginx's one
          #
          #location ~ /\.ht {
          #    deny  all;
          #}
      }
  
  
      # another virtual host using mix of IP-, name-, and port-based configuration
      #
      #server {
      #    listen       8000;
      #    listen       somename:8080;
      #    server_name  somename  alias  another.alias;
  
      #    location / {
      #        root   html;
      #        index  index.html index.htm;
      #    }
      #}
  
  
      # HTTPS server
      #
      #server {
      #    listen       443 ssl;
      #    server_name  localhost;
  
      #    ssl_certificate      cert.pem;
      #    ssl_certificate_key  cert.key;
  
      #    ssl_session_cache    shared:SSL:1m;
      #    ssl_session_timeout  5m;
  
      #    ssl_ciphers  HIGH:!aNULL:!MD5;
      #    ssl_prefer_server_ciphers  on;
  
      #    location / {
      #        root   html;
      #        index  index.html index.htm;
      #    }
      #}
      include servers/*;
  }
  </code></pre>