What does "dispatches" files in rails src folder mean? - ruby-on-rails

I just look up at rails sources and find folder named "dispatches". There is four file in it. I want to know purpose of this files. I know I use this files on my production server, but I never used to think of their purpose. I know there is something about attaching Rails app to Apache server. On my production server rails appname command add this files to public folder automatically. Can I set up this behavior on my development machine?

The rails dispatcher is the entry point for a rails application and is used to bootstrap the environment.
They have a long history and in a lot of ways they are almost obsolete. In days gone by rails apps used to be powered using cgi or fastcgi, which was a way for the webserver to communicate with a rails process. The boot process would be initiated by dispatch.fcgi or dispatch.cgi. Nowadays people are more likely to use apache/nginx+passenger or apache/nginx+mongrel/thin. (Does anyone still use lighttpd?)
I'm a little fuzzy on how dispatch.rb is used, but I think it's used by upstream rails servers such as mongrel/thin to bootstrap the rails process. However, now that rails is rack compatible I'm not entirely sure if that has changed.
You don't need to pay the dispatch.* files any attention.
I hope this helps.

Related

What file runs everything on the ruby server?

I am new to rails and ruby and I wanted to make a small web app using a rails backend (not a good idea considering I am new to both). I am trying to conceptualize the folder structure of rails, and I am confused whether there is a file that runs everything in the folder.. or how does it work? I've used node.js and django (python) and usually I'll have a server file that imports my database and such, but with this rails setup--I am a bit overwhelmed. Any help would be great!
In your rails app, there is no one file that requires and runs all other files. There are a couple of files that do something like this, but they don't load everything.
Instead, rails knows where to look for information when it boots your app. Your database configuration goes to config/database.yml. Boot-time setup goes to config/initializers/. And so on. As a rails dev, you're expected to know this. Convention over configuration, they call it.
A good rails book can help with learning these conventions (what goes where).

Deploy ruby on rails on FTP

Is it possible to deploy Ruby on Rails app on FTP?
If possible then how run migration on it?
My app also have a cronjob. How to set it?
How I deploy my webiste on FTP?
If any tutorial etc availble?
Technically it is possible to deploy by FTP, but the question is, why would you want to? It's a nightmare when compared to a modern, automated deployment system. There's also serious security concerns since FTP is not in any way encrypted and is extremely easy to crack into. Using public Wi-Fi exposes you to the risk of your credentials being captured.
The traditional way to deploy a Rails application is with Capistrano which handles packaging up your application through your version control system and rolling it on to your production system.
If you're not using a version control system that's the first thing you need to fix. Hacking away on files randomly and throwing them to a server over FTP produces quick results but over time it makes it very difficult to get a consistent, tested, reliable build over to your target server.
Remember that Rails is not something that runs automatically like .php files can be, you'll need to use something like Passenger to handle launching your application.
If all this seems a bit convoluted, it's worth trying Heroku to get started. They have a very streamlined approach.
If I understand right what you are asking (is it possible to run Ruby program using only FTP as a protocol), the answer is no, it is not possible. Ruby files is not Web static content (HTML, JS, CSS) that is executed in a browser and hence you can just upload it somewhere (as an option using FTP) and then access via Web. In case of Ruby, apart from uploading content you need to execute commands there (start interpreter, rake etc.) and this is not possible to do using plain FTP.
Normally you may want to use SSH channel to the deployment server to run the program after it has been uploaded. In that case upload is possible via FTP, but as well secure version of it, SFTP (or SCP to just copy files between local and remote machines).
Hope it helps.

Preferable way to distribute a Rails app

Although Rails and PHP have different deployment methods, what is the preferable way to distribute a FOSS Rails app? Suppose one of the major PHP apps - Magento, Drupal, Wordpress had been build upon RoR, what would have been the preferable way for them to have distributed their application?
Packaging up the code as a gem seems to be the wrong approach for a complete out-of-the-box application, but I could be wrong.
Coming from the world of PHP with its upload-and-go approach, and being a newcomer to Rails, it's rather opaque at the moment to see how code could be easily and effectively distributed.
Packaging a completed Rails app as a gem is probably the wrong approach. I think the best solution is to provide access to a git repository or a tarball of your git repo.
If you want to offer your users something more than rake db:schema:load to setup your app it's pretty easy to create custom setup commands.
Many applications are packaged with the source code just like typical PHP applications. While deploying Rails applications may seem difficult its expected that the user will know how to set up the server properly according to their environment and needs. The only issue you need to worry about is distributing the code, setting up the server is not a domain that you are going to want to help with.
For information on deployment in Rails you should see the deployment page here.
Well, usually Rails apps run in environment running Apache + Passenger (aka mod_rails).
Deployment is easily done with Capistrano gem.
When you're running Rails app in shared host environment, they usually use fcgi/cgi dispatchers to run Ruby.

Is there a way for a ruby on rails app to support web-based upgrades like Wordpress does?

I've been using Wordpress for awhile, it's installed on my own server, and one of the features I most love about it is how every time there is a new version it alerts you within the app's web-based admin and with one click I can upgrade the app. I don't have to get anywhere near a console.
Personally I wouldn't mind updating manually, but I can see how this could significantly affect the adoption of a piece of software. I'm working on creating a full-featured ruby on rails forum software and I would love to figure out how to include this feature. Any ideas if this could be done with rails?
Could a rails app modify it's own files? If it did, would the server need to be restarted?
To complicate things further, what if the app was deployed from a repo. Could the rails app check in a commit of itself after updating?
Maybe packaging the core of the app as a gem would be simpler? Then maybe the upgrade would not actually modify the rails MVC stack (the rails app would just be super-basic), instead if the forum was all contained within a gem then all it has to do is trigger a 'gem update [name]'. If this occurred, I don't think the Gemfile would even need to be updated. Would a server restart even be required to load the updated gem?
Ideas or feedback on any of this?
Rails files can be modified and even deleted on production - in my case aplication is still working unchanged as all classes are cached in memory. It means Rails instances must be restarted to take new change.
I suppose WordPress is Perl via CGI and you just drop application into web directory to have it working immediately - same with updates - just overwrite files and Apache picks them up immediately.
In case of Rails is that you don't know target deployment architecture thus restarting application may not be trivial. E.g. with passenger I can just do touch tmp\restart.txt and then all instances are killed and started again. Some deployments may need init.d script restart invocation.
Maybe you could recommend or prepare a ready to use deployment model which supports autoupdate. In other cases users could do updates manually.

How to deploy a Rails app to Dreamhost?

I'm kind of lost, I try to deploy my application on a shared dreamhost server.
Now everything works fine locally. It's my first try at Rails, and I'm not really a programmer or sysadmin, just hacking something together.
On Dreamhost, if I start webrick, it works fine on port 3000, but webricks gets killed pretty quickly, I guess that makes sense.
So what do I have to do to make it run?
I enabled fastcgi support and mod_rails.
Now, how do I get the app constantly running?
I keep reading about having to do things to .htaccess and to dispatch.fcgi.
But I can't find any dispatch file in my rails app (2.3.2).
Do I have to create that one manually? Doesn't really feeld very rails-like to me. I didn't really manage to find out what this dispatch file does, and why it's needed.
Any help would be greatly appreciated.
I looked at the DH Wiki, but couldn't figure it out (http://wiki.dreamhost.com/Rails)
Additions:
I enabled mod_rails and pointed to the public directory (I had already done that).
I keep getting an error: screencast.com/t/KamqVawk
Hm, server logs look like there is actually no request, so this might be a problem on dreamhosts end. It's strange I see that the access.log show a new change date, when I try to access the page, but there is no request noted, error.log is empty too.
Dreamhost Support Answer:
The server was up to date, so that wasn't the problem.
They proposed freezing the Gems, which I did (see: http://wiki.dreamhost.com/Freezing_Gems)
But it didn't help.
I guess I'm giving up, and looking into hosting which is specialized for rails.
Thx for all your help!
Changed to hostingrails.com
I got the app working on hostingrails.com, passenger on hostingrails.com showed me errors, which weren't shown by dreamhost or mongrel. By correcting these errors, I got the app working.
Dreamhost won't let you use webrick if you're using shared hosting. You can either use FastCGI or Passenger to host Rails on shared DH (mongrel is an option if you upgrade to DreamhostPS, but that's obviously more expensive).
For FastCGI, you will need a dispatch.fcgi file (older versions of Rails would generate one when you created a new Rails app, but that stopped around 2.2 if I remember correctly) as well as code in your .htaccess to send requests to the dispatcher. See the Dreamhost Ruby on Rails wiki page for details about setting up FastCGI.
The more preferable option is to set up your application to run on Phusion Passenger (aka mod_rails). It should be pretty simple through your Dreamhost panel, you just need to enable the domain to use mod_rails, and then set the directory for the domain to the public directory of your application. See the Passenger wiki page for more details.

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