This presentation is on 'Grape', which is an opinionated micro-framework for creating REST-like APIs in Ruby. For details, visit http://intridea.github.io/grape

1. Building an API using
GRAPE
Presented By-
Md. Main Uddin Rony

2. Outlines
What’s Grape?
Basic API
Add Prefix
Add Namespace
Add Module
Add version
Parameters
Declared
Using Helpers
Routes
Raise Exception
Exception Handling
API Format
Useful Resources

3. What’s Grape?

4. Generalized
Rapid
APIs
Erector

5. An opinionated
micro-framework
for creating RESTful
APIs in Ruby

6. •Powerful API framework
•Designed to run on Rack Application
•To fit into Sinatra and Rails Application

7. Installation
‘ gem install grape’
Or
gem 'grape‘ // using Bundler
Run bundle install.

8. Work with Rails
Place API files into and modify
Modify

9. Basic API

10. Add Prefix

11. Add Namespace

12. Add Namespace (Contd.)
Namespaces allow parameter definitions and apply to every method within the namespace.

13. Add Namespace(Contd.)
We can define a route parameter as namespace using

14. Add Module
If we want to mount on a path inside the mounted API itself:

15. Add Version

16. Add Version(Contd.)
Four Strategies:
❑ Path → →
❑ Header → →
❑ Param → →
→
❑ Accept-Version Header →
→

17. Parameters
Request parameters are available through the ”params” hash object.
Parameters are automatically populated from the request body on POST and PUT for form input, JSON and XML content-types.

18. Declared
Grape allows you to access only the parameters that have been declared by your ’params’ block. It filters out the params that have been passed, but are not
allowed.

19. Use Helpers

20. Routes
We can define requirements for your named route parameters using regular expressions on namespace or endpoint.

21. Raise Exception
We can abort the execution of an API method by raising errors with
We can also return JSON formatted objects by raising error! and passing a hash instead of a message.

22. Exception Handling
Grape can be told to rescue all exceptions and return them in the API format.
You can also rescue specific exceptions.

23. API Formats
If we do not specify any, Grape will support XML, JSON, BINARY, and TXT content-types. The default format is :txt

24. Advantages
1. Designed to run on rack or existing application frameworks such as Rails and Sinatra
2. It has built-in support for common conventions, including multiple formats, subdomain/prefix
restriction.
3. Versioning is very easy.
4. A lightweight framework which is loosely coupled with other application frameworks.

25. Useful Resources
1. https://github.com/intridea/grape
2. https://groups.google.com/forum/?fromgroups#!forum/ruby-grape
3. http://intridea.github.io/grape/docs/index.html
4. https://github.com/intridea/grape/wiki
5. http://confreaks.tv/videos/rubyconf2010-the-grapes-of-rapid

26. Questions??

27. THANK YOU!!!!