I have a Heroku app with a PostgreSQL DB. Now I want to have a seperate process, possibly on a different machine, to access the DB. The suggestion on the Herkou site is actually what I wanted to do myself:
No, connecting to your database from machines outside of Heroku is not supported.
We recommend that you encapsulate data access in an API to manipulate it.
But I'm not sure how that's done best. I'd like to be able to send some JSON to the API and get back JSON as a result of that request. Like "give me all posts that are expired for a bunch of given userIds" or "update all users to be suspended if their posts contain any of the given words" in an example micropost app.
What's the best way to achieve that? Can I write an extra ruby program that is accessible via TCP and accepts JSON input? Is that even possible with Heroku? Or do I have to integrate the API into my rails app somehow? How?
Thankful for any ideas,
Tom
You will have to integrate the API to your rails app, there are many solutions for this, one of them is using a tool specialized for API building like Grape and mount it with your Rails app. This way you could have your Rails app running and also the API, both sharing the same codebase.
Related
I have an existing web application that's developed with Ruby on Rails and PostgreSQL. I need to create a mobile application (and possibly a separate web application) using the data from that web application, so I'm looking to create an API server. Is it possible to do this without altering the source code from the original Rails/Postgres web application?
Any ideas on the best way to do this? Or can someone point me in the right direction on what to research?
To connect a new application hosted on Heroku to a PostgreSQL database hosted on Heroku just push your new application to Heroku as normal.
Then, under Settings on your new application dashboard, go into Config Variables and add a new config for DATABASE_URL. Put the value of the url for your existing database.
Your new application will need to be under the same account as your existing application. Heroku doesn't allow you to connect across accounts.
You probably want to take a look at this question for additional details.
Sounds like essentially you want to have two applications connecting to the same database offering the same methods, but respond in different formats (html vs, for example, json). One way of doing that relatively easily might be pushing another api only Rails app to heroku that connects to the same Postgres database (which was mentioned in the comments), but you would have to figure out how to handle authentication differently for your API end points. This depends on whether you are exposing these end points to the public or to something like a mobile front-end. You may want to switch to token-based authentication if you were formerly using sessions on the web-app. Once you implement secure authenticatoin for your api routes, all you have to do is make sure your methods, instead of rendering erb or haml templates, are returning raw data consumable by your intended client.
I feel like my question is partially answered through a number of other questions, but I just can't piece everything together for my case.
Basically, I'd like to build a fairly simple web app, but also be able to fairly easily build a mobile app for it down the line. From my research, the best practice would be to build a RESTful JSON API, and then use that API both for my web app and for my mobile app.
I've already gone ahead and developed authentication for my JSON API (using : http://lucatironi.net/tutorial/2015/08/23/rails_api_authentication_warden/) and I've got it up on Heroku. Now for my web app, I'm using HTTParty to consume that API, and I'm getting the JSON back all fine and dandy. However, I'm not quite so sure what to do with the database. My first thought was that maybe I need to access the API's database via it's own API calls, but that seems incredibly complex (just the thought of having to make functions for User.find_by_<every attribute> makes me scared). The other thought would be to have my web app use the API app's database. However, I can't find any info on how to do that if the app is on Heroku.
So basically, I'm wondering what the best way to go about this would be. Surely there is a standard out there that every big or small web app with an API uses. I'm really surprised that something so prevalent these days is hard to find good answers for. Or am I going about this all wrong? Any pointers would be greatly appreciated.
Databases are add-ons in Heroku parlance.
Use heroku addons to get a list of the add-ons for your apps.
$ heroku addons -a appname
Add-on Plan Price
──────────────────────────────────────── ───────── ─────
heroku-postgresql (relaxing-purely-8366) hobby-dev free
└─ as DATABASE
First you may want to remove the database attached to your front-end app:
heroku addons:destroy fat-samurai-1234
Then find the name of the database add-on attached to your API app and attach the add-on to your frontend app.
heroku addons:attach shining-sushi-1234 -a sushi.
https://devcenter.heroku.com/articles/managing-add-ons#creating-an-add-on
As to which approach is legitimate that's a matter of discussion. Many apps today use a single page architecture where the entire app is created on the front end - in javascript. So your app just consumes your REST api. Popular frameworks for this are Ember.js, Bootstrap and Angular.
The other approach would be to to create a classic server side app - while it's possible to create an app that would consume the REST api there is a significant overhead involved so it will be more performant to connect directly to the database.
How can I access the Appery.io (or any future db) that is exposed to the REST API using RoR?
So I have an app i built using Appery.io and I also created a test app using RoR that I would like to use to pull information from the Appery.io db and display it on my RoR app.
I am somewhat familiar with REST and get the idea of what it is doing but I am not to certain on how to connect or make a connection from my RoR app to my Appery.io app. Appery.io has the following documentation for their db api, Appery.io DB API .
I have been looking around and also have seen people mention the following gems for HTTP request:
Weary
HTTParty
RestClient
Would I use one of those? I also read about using Active Resource as a possible solution?
Any help with getting started or a tutorial or article to point me in the right direction would be very helpful.
Thanks!
You won't be establishing an ongoing connection, each request/response will be a single query to your Appery DB. You authenticate those calls using a custom header with API key as defined in the documentation. There's an example using cURL that might be a good place to start playing with the API before you pull it into your RoR app. That example shows you how to get your key, too.
It looks like you can use the predefined APIs, or you can define a custom REST API associated with your Appery app? Instructions for building an API appear to be here.
Once you get the calls working from cURL (or other web request client of your choice), adding the calls to the RoR app should be more straightforward. Any of those gems could probably ease that process: I've only used RestClient personally, but found it very straightforward.
Any of those call methods (cURL, other clients, the gems, etc) will allow you specify your URI, method (e.g. GET or POST), headers, request body (where appropriate), and will allow you to examine your response. Take a look at the gem documentation to see how those map exactly - it will vary slightly from tool to tool.
If you don't have prior experience with calling external APIs, and would like a conceptual explanation, I like this article as a (very short!) beginner's guide.
I am currently have a running site. However, I need to do some task to sync some data to my friend's site.
So that, I need another app for fetching data from my running app's DB and submit data to another site using a gem call mechanize.
My problem will be:
Do I need a whole Rails app to do the job? If not, what would be the best practice in my case?
Is there any easy way for accessing my running app's DB? For now, the only thing I know is AR.
Thanks
API
What you're looking for is an API -- a way to connect to a source of data & use that data in some other application:
In computer programming, an application programming interface (API)
specifies how some software components should interact with each other
APIs are actually very simple -- you have a series of endpoints which an application can connect to, pulling data, typically as JSON objects. As noted by Rajarshi Das, these endpoints will likely be based on the RESTful resource structure
Rails
Rails, by design, is very good at providing API's:
This Railscast shows how to use the rails-api gem to create a RESTful API that your other app can connect to
We have a Rails App and a Sinatra API with separate codebases. They need to work together with the same database.
We can create a record using the API, and then display a page for that record using the Rails app. When creating the record using the API, there are many other records that need to be created at the same time. This all happens fine on the Rails app.
Here's the problem: What is the best way to test that when the API creates the record, all the other records are created and the page renders properly on the Rails app?
I am writing a test in the Rails app for this. Since the API is separate from the Rails app, I can create a mock. But the mock needs to do everything the API would do, so it is not really a mock.
Is it possible (or practical) to include in the Rails app the API file that contains the call to create the record?
Or is there a better way to test for this?
Well, you have two web applications. That is, two applications that expose a (more or less) public interface on the Net and that respond to HTTP calls.
Why do not use a HTTP client to invoke all of the two servers and perform a complete test (a "workflow test", if you like)?
You can probably use any existing web testing tool for this, or write a test script with any language.
No, it is not possible to include in the Rails app a file from the API.
They are hosted on different servers. Even if I got it working on my local machine, it would not work in production.
EDIT: Actually, this is not true. If the file only needs to be shared for testing, then it will only run on the local machine (unless there is some kind of CI system). So the production environment doesn't matter. Only the testing (CI) environments matter.