What is curl and what are its uses for rails developers? - ruby-on-rails

Ive seen mentions of curl here and there on rails blogs and ive scanned some posts here on stackoverflow but im still a bit in the dark as to its use especially when it comes to rails development.
Is it useful for testing? Im currently learning the ins and outs of testing and one of the things i need to do is test a before filter that only allows an action to be called if the user came from a certain external site. Is this an occasion where curl would be used?

curl is a command line program which can retrieve urls, it's quite flexible, for example it can use limited regexes to download a range of files.
You might want to use it for testing, by seeing what happens to your application under certain circumstances, if you want to test what happens if your user comes from a certain site then use the -e option on curl.
The man page is online Here

No, I don't think you'd use cURL for TDD. Using cURL would imply communicating with a remote service, which would be an integration test.
Are you talking about this? http://www.viget.com/extend/curl-and-your-rails-2-app/
In that post, cURL isn't being used in the rails app at all. It's being used on the terminal to test/demo the app's REST service, not in a TDD fashion.
cURL is good for this purpose because its many options allow you to simulate different headers from user agents, such as language acceptance, characterset acceptance, cache usage, etc...

Have a look at hurl—which is written in Rails—and then imagine a more powerful command-line version. That's pretty much cURL.

Ruby (Rail?) hackers might also be interested in one of the many Ruby bindings for libcurl, the library that powers the curl tool. Like them mentioned here: http://curl.haxx.se/libcurl/ruby/

Related

How to use rdfdistiller via curl

I am trying to use the rdf distiller by Gregg Kollegg:
which works nicely via the web ui:
http://rdf.greggkellogg.net/distiller?command=serialize&url=http:%2F%2Fceur-ws.org%2FVol-2549%2F
now i'd like to get the result via curl and kind find an example/documentation for it.
I have also filed an issue for this at:
https://github.com/gkellogg/rdf-distiller/issues/35
How would the curl command look like to get one of the offered triple formats?
Thanks for your interest in the Ruby RDF Distiller. It's been a useful tool for many years, and has grown to allow access to more formats and functionality from the various Linked Data Ruby gems.
I provided an answer on the Github Issue. If you're using the web interface, as you selection options from the UI, it will update the URL in the "Alternative access to the Distiller" section. To get "raw" output, that bypasses the HTML text box, use the "raw" option, although this seems to work better using "curl".
Also noted in the issue response, is that the entire Distiller service is powered using the "rdf" CLI, which is installed when you install the "rdf" or "linkeddata" ruby gems. (The "linkeddata" gem depends on all of the various gems in the Ruby RDF ecosystem, so provides the fullest functionality).
PRs against the repo to improve documentation or functionality are welcome.

how to implement same functions in different languages?

I have a REST interface.
Now I want to have a client for ruby, javascript, python and java (and maybe more in the future)
Currently I am maintaining 4 different projects and their tests.
How can I improve this and what tools can I use?
currently I am starting to describe the API in a file (e.g. yaml/json) and then generate sources for each language by some logic specific to language, but that is a lot of work, and I am certain I am not the first to run into this issue.
I searched the web for generate source from yaml and such but couldn't find anything
edit: someone suggested I'd use yeoman. so currently I am investigating that.
I believe Postman as a tool is good for that. You can specify an API endpoint and generate clients for multiple languages.

How to run multiple "Applications" under one compoundJS instance?

I've been using nodeJS + expressJS for several years now developing a custom Application Platform for our organization. Our central framework provides a common set of services (authentication, language, administration, etc...) for any installed Modules/Applications under it.
I would like to switch our framework out with compoundJS. However I'm not familiar with the design constraints imposed by it (and Rails apps in general) and can't seem to figure out how to accomplish what I'm after.
I would like to only have a single server instance running: all
requests first process through our common authentication checking.
Then are passed on to an application's controllers.
I would also like to have each application separated out: preferably
under a separate site/applications/ directory. Each of these
applications could be designed using compoundJS normally. And I would like to install them like:
cd site/applications
npm install site-hr
npm install site-finance
npm install site-payroll
this would then have all the routes from /hr, /finance, /payroll operational.
How do I accomplish this?
Is there a way to get compoundJS to search the nonstandard /applications/* folders for models/controllers/views and load them while keeping the central /site configurations?
Or is there a better way?
Sorry for the late answer, but I needed something similar: I needed to put together tool applications in a portal.
I found a way to include child applications in a parent's Compound application as node modules. I wrote a guide on how to do it and sent a pull request to add it in the advanced folder of CompoundJS' guides. It is also available here. It requires a bit of work, but it works fine with 4 applications for us.
Hope it can help.
It's simple. Just use app.use in config/environment.js to map your sub-apps:
var mod = require('your-compound-module');
app.use('/subroot', mod());
When you visit /subroot/any-path, then it will be handled by /anypath route of your sub-app. Note, that you don't need any additional work on path helpers, as they will start with '/subroot' automatically (handled on compound side).
This is a good point, but we haven't seen any implementation yet. May be years later there would be some.
Using a proxy layer in front of the instances would be a general method, usually with Nginx, Vanish Cache etc. For the bleeding edge techs, I've heard Phusion Passenger has implemented Node.js support, but I haven't successfully tested yet. If you are familiar with Ruby, it would be a good try.
If you really want to construct a big project with many modules, you can try out some industrialized frameworks for instance Architect for Cloud9 IDE project.
For authentication, I think it's necessary to use independent methods in each application, but they can share with one user database.

What tools to use for a website with lots of "realtime" page updates (coming from a Rails background)?

We are planning to make a "large" website for I'd say 5000 up to many more users. We think of putting in lots of real time functionality, where data changes instantly propagate to all connected clients. New frameworks like Meteor and DerbyJS look really promising for this kind of stuff.
Now, I wonder if it is possible to do typical backend stuff like sending (bulk) emails, cleaning up the database, generating pdfs, etc. with those new frameworks. And in a way that is productive and doesn't suck. I also wonder how difficult it is to create complex forms with them. I got used to the convenient Rails view helpers and Ruby gems to handle those kind of things.
Meteor and DerbyJS are both quite new, so I do expect lots of functionality will be added in the near future. However, I also wonder if it might be a good idea to combine those frameworks with a "traditional" Rails app, that serves up certain complex pages which do not need realtime updates. And/or with a Rails or Sinatra app that provides an API to do the heavy backend processing. Those Rails apps could then access the same databases then the Meteor/DerbyJS app. Anyone thinks this is a good idea? Or rather not? Why?
It would be nice if anyone with sufficient experience with those new "single page app realtime" frameworks could comment on this. Where are they heading towards? Will they be able to handle "complete" web apps with authentication and backend processing? Will it be as productive/convenient to program with them as with Rails? Well, I guess no one can know that for sure yet ;-) Well, any thoughts, guesses and ideas are welcome!
For things like sending bulk emails and generating PDFs, Derby let's you simply use normal Node.js modules. npm now has over 10,000 packages, so there are packages for most things you might want to do on the server. Derby doesn't control your server, and it works on top of any normal Express server. You should probably stick with Node.js code as much as possible and not use Rails along with Derby. That is not to say that you can't send messages to a separate Rails app, but since you already have to have a Node.js app running to host Derby, you might as well use it for stuff like this.
To communicate with such server-side code, you can use Derby's model events. We are still exploring how this kind of code works and we don't have a lot of examples, but it is something that we will have a clear story around. We are building an app ourselves that communicates with an email server, so we should have some real experience with this pretty soon.
You can also just use a normal AJAX request or send a message over Socket.IO manually if you don't want to use the Derby model to do this kind of communication. You are free to make your own server-side only routes with Express along with your Derby app routes. We think it is nice to have this kind of flexibility in case there are any use cases that we didn't properly anticipate with the framework.
As far as creating forms goes, Derby has a very powerful templating system, and I am working on making it a lot better still. We are working on a new UI components feature that will make it possible to build libraries of self-contained UI widgets that can simply be dropped into a Derby app while still playing nicely with automatic view-model bindings and data syncing. Once this feature is completed, I think form component libraries will be written rather quickly.
We do expect to include all of the features needed for a normal app, much like Rails does. It won't look like Rails or work like Rails, but it will be similarly feature complete eventually.
For backend tasks (such as sending emails, cleaning up the database, generating pdfs) it's better to use resque or sidekiq
Now, I wonder if it is possible to do typical backend stuff like
sending (bulk) emails, cleaning up the database, generating pdfs, etc.
with those new frameworks. And in a way that is productive and doesn't
suck. I also wonder how difficult it is to create complex forms with
them. I got used to the convenient Rails view helpers and Ruby gems to
handle those kind of things.
Also, my question is not only about background jobs, but also about stuff one can might do during a request, like generating a pdf, or simply rendering complex views with rails helpers or code from gems. –
You're mixing metaphors here - a single page app is just a site where the content is loaded without doing a full page reload, be that a front end in pure js or you could use normal html and pjax.
The kind of things you are describing would be done in a background task regardless of the fornt-end framework you used. But +1 for sidekiq if you're using ruby.
As for notifying all the other users of things that have changed, you can look into using http://pusher.com or http://pubnub.com if you don't want to maintain a websocket server.

What's the best way to integrate a Django and Rails app sharing the same MySQL datastore?

I'm going to be collaborating with a Python developer on a web
application. I'm going to be building a part of it in Ruby and he is
going to build another part of it using Django. I don't know much about
Django.
My plan for integrating the two parts is to simply map a certain URL
path prefix (say, any request that begins with /services) to the Python
code, while leaving Rails to process other requests.
The Python and Ruby parts of the app will share and make updates to the
same MySQL datastore.
My questions:
What do people think generally of this sort of integration strategy?
Is there a better alternative (short of writing it all in one language)?
What's the best way to share sensitive session data (i.e. a logged in
user's id) across the two parts of the app?
As I see it you can't use Django's auth, you can't use Django's ORM, you can't use Django's admin, you can't use Django's sessions - all you are left with is URL mapping to views and the template system. I'd not use Django, but a simpler Python framework. Time your Python programmer expanded his world...
One possible way that should be pretty clean is to decide which one of the apps is the "main" one and have the other one communicate with it over a well-defined API, rather than directly interacting with the underlying database.
If you're doing it right, you're already building your Rails application with a RESTful API. The Django app could act as a REST client to it.
I'm sure it could work the other way around too (with the rest-client gem, for instance).
That way, things like validations and other core business logic are enforced in one place, rather than two.
A project, product, whatever you call it, needs a leader.
This is the first proof that you don't have one. Someone should decide either you're doing ruby or python. I prefer ruby myself, but I understand those who prefer python.
I think starting a product asking yourself those kind of questions is a BAD start.
If your colleague only knows prototype, and you only know JQuery, are you going to mix the technologies too? Same for DB? And for testing frameworks?
This is a never ending arguing subject. One should decide, IMHO, if you want so;ething good to happen. I work with a lot of teams, as a consultant, Agile teams, very mature teams for some of them, and that's the kind of stuff they avoid at all cost.
Except if one of you is going to work on some specific part of the project, which REALLY needs one or other of the technologies, but still think the other one is best for the rest of the application.
I think, for example, at a batch computing. You have ALL your web app in ror or django, and you have a script, called by CRON or whatever, computing huge amounts of data outside the web app, filling a DB or whatever.
My2Cts.

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