Popcorn

Table Of Contents

Jump straight in

• .NET Core - We have a .net core middleware that you can drop in to enable Popcorn on Web Apis. Feel free to grab it on nuget.
• Other implementations - See our Roadmap or issues on GitHub for coming work

What is Popcorn?

Popcorn is a communication protocol on top of a RESTful API that allows requesting clients to identify individual fields of resources to include when retrieving the resource or resource collection.

It allows for a recursive selection of fields, allowing multiple calls to be condensed into one.

Features

• Selective inclusion from a RESTful API
  • Configurable response defaults
  • Sorting of responses
  • Selective authorization and permissioning of response values
  • Configurable response inspectors
  • Factory and advanced projection support
  • Set relevant contexts for your API
  • Blind expansion of response objects

Ok, so…. what is it in action?

Okay, maybe some examples will help!

Lets say you have a REST API with an endpoint like so:

https://myserver.com/api/1/contacts

Which returns a list of contacts in the form:

[
 {
   "Id":1,
   "Name":"Liz Lemon"
 },
 {
   "Id":2,
   "Name":"Pete Hornberger"
 },
 {
   "Id":3,
   "Name":"Jack Donaghy"
 },
 ...
}

Now, if you want to get a list of phone numbers for each of those, you now need to make a series of calls to further endpoints, one for each contact you want to look up the information for:

https://myserver.com/api/1/contacts/1/phonenumbers

[
  {"Type":"cell","Number":"867-5309"}
]

https://myserver.com/api/1/contacts/2/phonenumbers

[
  {"Type":"landline","Number":"555-5555"}
]

https://myserver.com/api/1/contacts/3/phonenumbers

[
  {"Type":"cell","Number":"123-4567"}
]

That’s quite a lot of overhead and work! Popcorn aims to simplify this at the client’s request. Let’s say that while we want the numbers for each contact, we don’t really need the type of the number (cell or landline) and would prefer to save the bandwidth by not transfering it. Now, instead of making many calls, all the above can be reduced down to:

https://myserver.com/api/1/contacts?include=[Id,Name,PhoneNumbers[Number]]

Which provides:

[
 {
    
   "Id":1,
   "Name":"Liz Lemon",
   "PhoneNumbers":
   [
    {
     "Number":"867-5309"
    }
   ]
 },
 {
   "Id":2,
   "Name":"Pete Hornberger",
   "PhoneNumbers":
   [
    {
     "Number":"555-5555"
    }
   ]
 },
 {
   "Id":3,
   "Name": "Jack Donaghy",
   "PhoneNumbers":
   [
    {
     "Number":"123-4567"
    }
   ]
 },
 ...
}

Presto! All the information we wanted at our fingertips, and none of the data we didn’t!

Why would I use it?

By implementing the Popcorn protocol, you get a consistent, well defined API abstraction that your API consumers will be able to easily utilize. You will be able to take advantage of the various libraries and tools Popcorn offers; right now this includes a C# automatic implementation for Asp.Net Core and EntityFramework Core, but many more platforms are on the roadmap.

Pros

• Faster calls
• Saves data
• Potential for server-side optimization
• Less boilerplate code to write

Cons

• You don’t get to write as much code
• Your consumers don’t get to write as much code

How can I use it in my project?

First you need to figure out if you’re working with a platform that has a provider implemented in the popcorn project. (Probably check out Documentation).

If there’s a provider already in the project, great! The platform-specific documentation will walk you though incorporating the provider into your project.

If there isn’t a provider yet, you’ll have to roll your own. You’ll still get the benefit of working with a standard, so your consumers will have a well documented spec to work with. Feel free to contribute any platform-specific providers you come up with!

Further Reading

• Quick Start
• Documentation
• Roadmap
• Releases and Release Notes
• Contributing
• License
• Meet the Maintainers