Adding a custom middleware to Rails 4
Solution 1
- Move
config/initializers/request_timer.rb
tolib/request_timer.rb
folder. - Add
require_relative '../lib/request_timer'
line toapplication.rb
file. - Change
config.middleware.use "RequestTimer"
toconfig.middleware.use RequestTimer
. Don't use quotes.
I remember that we can't use classes which are at initializers folder without require them at application.rb
.
Regards.
Solution 2
And much easier way to solve this is to put your request_timer.rb
into
app/middleware/request_timer.rb
and then added the middleware as a string in your config/application.rb
Solution 3
You should place your middleware class inside the app/middleware folder. The added middleware should be injected in the list of middlewares which are by default added by rails.
Note: You can insert your middleware from anywhere in the code, but its preferred to insert a middleware in any of the initializers which you are adding for your app.
For example, to insert your middleware after rails inbuilt middleware params parser:
Rails.application.middleware.insert_after ActionDispatch::ParamsParser, "RequestTimer"
Additionally, you can also pass required parameters to your middleware something like:
options = { :foo => 'bar' }
Rails.application.middleware.insert_after ActionDispatch::ParamsParser, "SecuredClient", options
Then you can access these parameters in your middleware as follows:
class RequestTimer
def initialize(app, params)
@app = app
@params = params
end
end
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sameera207
Rails developer, But will code anything for FOOD :D
Updated on September 16, 2022Comments
-
sameera207 over 1 year
I have a Rails 4 sample project (Blog) and I have created a simple middleware called 'request_timer' in
config/initializers/request_timer.rb
#config/initializers/request_timer.rb class RequestTimer def initialize(app) @app = app end def call(env) start_time = Time.now status, headers, response = @app.call(env) stop_time = Time.now [status, headers, response.body] end end
and I have added my middleware in
config/application.rb
in two ways1 ) Adding as a constant
#config/application.rb module Blog class Application < Rails::Application config.middleware.use RequestTimer end end
this way when I try to run my rails app I'm getting the error
/Users/sameera/workspace/ruby-rack/blog/config/application.rb:9:in `require': cannot load such file -- request_timer (LoadError) from /Users/sameera/workspace/ruby-rack/blog/config/application.rb:9:in `<top (required)>' from /Users/sameera/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:74:in `require' from /Users/sameera/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:74:in `block in <top (required)>' from /Users/sameera/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:71:in `tap' from /Users/sameera/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:71:in `<top (required)>' from bin/rails:4:in `require' from bin/rails:4:in `<main>'
2 ) Then I added my middleware as a string
#config/application.rb module Blog class Application < Rails::Application config.middleware.use "RequestTimer" end end
This ways, it allows me to run the rails server, but when I access
localhost:3000
, it errors sayingNoMethodError (undefined method `each' for #<String:0x007fdf649b0028>): rack (1.5.2) lib/rack/etag.rb:58:in `digest_body' rack (1.5.2) lib/rack/etag.rb:26:in `call' rack (1.5.2) lib/rack/conditionalget.rb:25:in `call' rack (1.5.2) lib/rack/head.rb:11:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/params_parser.rb:27:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/flash.rb:241:in `call' rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context' rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/cookies.rb:486:in `call' activerecord (4.0.2) lib/active_record/query_cache.rb:36:in `call' activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call' activerecord (4.0.2) lib/active_record/migration.rb:369:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' activesupport (4.0.2) lib/active_support/callbacks.rb:373:in `_run__2755475928771109453__call__callbacks' activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks' actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/reloader.rb:64:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' railties (4.0.2) lib/rails/rack/logger.rb:38:in `call_app' railties (4.0.2) lib/rails/rack/logger.rb:20:in `block in call' activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `block in tagged' activesupport (4.0.2) lib/active_support/tagged_logging.rb:25:in `tagged' activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `tagged' railties (4.0.2) lib/rails/rack/logger.rb:20:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/request_id.rb:21:in `call' rack (1.5.2) lib/rack/methodoverride.rb:21:in `call' rack (1.5.2) lib/rack/runtime.rb:17:in `call' activesupport (4.0.2) lib/active_support/cache/strategy/local_cache.rb:83:in `call' rack (1.5.2) lib/rack/lock.rb:17:in `call' actionpack (4.0.2) lib/action_dispatch/middleware/static.rb:64:in `call' rack (1.5.2) lib/rack/sendfile.rb:112:in `call' railties (4.0.2) lib/rails/engine.rb:511:in `call' railties (4.0.2) lib/rails/application.rb:97:in `call' rack (1.5.2) lib/rack/lock.rb:17:in `call' rack (1.5.2) lib/rack/content_length.rb:14:in `call' rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service' /Users/sameera/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service' /Users/sameera/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run' /Users/sameera/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'
What would be the reason? I'm using Rails
4.0.2
andrack-1.5.2
andruby 2.0.0p247
. -
concept47 over 9 yearsThanks @onurozgurozkhan!
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rkj over 8 yearsDepends on Rails version I think. For Rails 3.x I used def call(env) @app.call env end
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Gordon Yuan Gao over 7 years@memoht why are you downvoting my answer? it is deprecated, but in rails 5. The question is about rails 4!
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memoht over 7 yearsYou are correct. I removed my comment and will remove the down vote if SO lets me.
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Sunny almost 5 yearsAdding to the answer the fact that this is deprecated in Rails 5 would be useful.
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Joshua Pinter over 3 yearsNote, in Rails 5+ you can no longer use the String for the name of the middleware. You need to use the proper class name. Additionally, according to @rafaelfranca (Rails core), "middleware can't be in app because they can't be reloaded. They should be in lib and if you put them in lib, require_relative will work." github.com/rails/rails/issues/25525#issuecomment-479941866
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Joshua Pinter over 3 yearsNote, in Rails 5+ you can no longer use the String for the name of the middleware. You need to use the proper class name. Additionally, according to @rafaelfranca (Rails core), "middleware can't be in app because they can't be reloaded. They should be in lib and if you put them in lib, require_relative will work." github.com/rails/rails/issues/25525#issuecomment-479941866
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Joshua Pinter over 3 yearsThis is the absolute correct answer for Rails 5+. Here's the relevant discussion with Rails core: github.com/rails/rails/issues/25525#issuecomment-479941866