Application Programming Interface (API) Design discusses best practises for creating libraries intended for general purpose or public use.

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248
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13answers
44k views

Should you write your back-end as an API?

I had a heated discussion today about our MVC application. We have a website written in MVC (ASP.NET), and it usually follows the pattern of do something in the view -> hit the controller -> ...
85
votes
4answers
18k views

What is an Anti-Corruption layer, and how is it used?

I'm trying to figure out what the Anti-Corruption layer really means. I know that it's a way to transition/work around legacy code or bad APIs. What I don't understand is how it works and what makes ...
44
votes
5answers
13k views

How do searches fit into a RESTful interface?

When designing a RESTful interface, the semantics of the request types are deemed vital to the design. GET - List collection or retrieve element PUT - Replace collection or element POST - Create ...
42
votes
6answers
5k views

How necessary is it to follow defensive programming practices for code that will never be made publicly available?

I'm writing a Java implementation of a card game, so I created a special type of Collection I'm calling a Zone. All modification methods of Java's Collection are unsupported, but there's a method in ...
39
votes
3answers
7k views

What's so bad about the DOM?

I keep hearing people (Crockford in particular) saying the DOM is a terrible API, but not really justifying this statement. Apart from cross-browser inconsistencies, what are some reasons why the DOM ...
37
votes
14answers
22k views

RESTful API design. What should I return if there are no rows?

I'm currently coding an API for a social network with the Slim Framework. My question is: What are the best practices when there are no rows to return in the json structure? Lets say that this call /...
34
votes
7answers
13k views

How do I convince my boss to use REST over SOAP? [duplicate]

We need to create an API to our system. How do I convince my boss that REST is a better option than SOAP (or XML-RPC)? I say REST is... easier to implement and maintain not much new to learn -- ...
31
votes
7answers
78k views

Why does java.util.ArrayList allow to add null?

I wonder why java.util.ArrayList allows to add null. Is there any case where I would want to add null to an ArrayList? I am asking this question because in a project we had a bug where some code was ...
29
votes
10answers
7k views

Why is Math.Sqrt() a static function?

In a discussion about static and instance methods, I always think, that Sqrt() should be a instance method of number types instead of a static method. Why is that? It obviously works on a value. // ...
24
votes
3answers
2k views

RESTful API: HTTP verbs with shared or specific URLs?

While creating a RESTful API, should I use HTTP Verbs on the same URL (when it's possible) or should I create an specific URL per action? For example: GET /items # Read all items GET /...
24
votes
7answers
2k views

Why use an opaque “handle” that requires casting in a public API rather than a typesafe struct pointer?

I'm evaluating a library whose public API currently looks like this: libengine.h /* Handle, used for all APIs */ typedef size_t enh; /* Create new engine instance; result returned in handle */ ...
23
votes
10answers
3k views

API design: concrete vs. abstract approach - best practices?

When discussing APIs between systems (on the business level) there are often two different point of views in our team: some people prefer a more - lets say - generic abstract approach, other a ...
22
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4answers
2k views

When creating an api should I stick with small functions and many calls, or a few calls and large functions?

I have a rails platform that I maintain. It has a lot of different web applications built on top of it. However now a client is asking for an API so that they can keep users on their site, but take ...
20
votes
2answers
2k views

Should one always know what an API is doing just by looking at the code?

Recently I have been developing my own API and with that invested interest in API design I have been keenly interested how I can improve my API design. One aspect that has come up a couple times is (...
19
votes
8answers
2k views

“Public APIs are forever: Only one chance to get it right”?

In an OS book I just read that, "Public APIs are forever: Only one chance to get it right". Is it true? Is it applicable only in APIs of Operating Systems or other APIs too? For example, will this be ...
17
votes
4answers
505 views

Database abstraction — is it being overdone?

After being exposed to numerous database abstraction layers, I'm starting to wonder what the point is of every library inventing their own different paradigm to access data. Picking up a new DAL feels ...
16
votes
3answers
1k views

Detecting IEnumerable “State Machines”

I just read an interesting article called Getting too cute with c# yield return It made me wonder what the best way is to detect whether an IEnumerable is an actual enumerable collection, or if it's ...
16
votes
3answers
10k views

Is there a list of common usernames to reserve in a new system?

I need to reserve usernames in my new website. These generally fall into three categories 1) usernames no-one should have (eg: admin, user, service, help, root, etc) 2) names of super famous people ...
15
votes
4answers
3k views

Why doesn't Java String have static string manipulation methods?

Why didn't Java designers create static versions of string manipulation methods in the java.lang.String class? The following methods are what I refer to, but the question can be extended to other non-...
15
votes
4answers
6k views

Why does the Java collections APIs not have a last method? [closed]

This is for ordered collections e.g. java.util.List. Why did the language designers not include a last method? The only reasons I can think of are: ambiguity when the collection is empty (return ...
15
votes
6answers
1k views

What do great APIs have in common? [closed]

What is it about great APIs that makes them great? I think that adhering to the "do one thing and do it well" mantra is a good sign and being is a good mapping to the problem domain is important, but ...
15
votes
2answers
5k views

Should I make up my own HTTP status codes? (a la Twitter 420: Enhance Your Calm)

I'm currently implementing an HTTP API, my first ever. I've been spending a lot of time looking at the Wikipedia page for HTTP status codes, because I'm determined to implement the right codes for ...
15
votes
1answer
2k views

Why PATCH method is not idempotent?

I was wondering about this. Suppose I have a user resource with id and name fields. If I want to update a field I could just do a PATCH request to the resource like this PATCH /users/42 {"name": "...
14
votes
6answers
5k views

Many small requests vs. few large requests (API Design)

I'm currently working on a project with an organization as follows: Client - Gets data from the main server via REST api. Server - Requests data from various other servers via third-party APIs Third-...
13
votes
5answers
12k views

How best do you represent a bi-directional sync in a REST api?

Assuming a system where there's a Web Application with a resource, and a reference to a remote application with another similar resource, how do you represent a bi-directional sync action which ...
13
votes
5answers
1k views

In API design, when to use/avoid ad hoc polymorphism?

Sue is designing a JavaScript library, Magician.js. Its linchpin is a function which pulls a Rabbit out of the argument passed. She knows its users may want to pull a rabbit out of a String, a Number,...
13
votes
1answer
9k views

When to use nested resources in a RESTful API

I have two resources: users and links. Users can have several links associated with them. I have designed my RESTful API so that you can reach the links associated with a user at the following URI: /...
12
votes
6answers
6k views

Should an Http API always return a body?

Is there some sort of standard regarding http api responses? After reading this discourse thread I started to wonder. We are developing our public http json api at my work, and we do not return ...
12
votes
1answer
230 views

Maintain API vs. using idioms in a port

I'm working on a port from Python to Rust and ran into some code that can't be expressed as naturally in Rust as they can in Python. One case of this is using default parameters: class Foo: def ...
12
votes
1answer
5k views

What is the proper way of nesting resources in REST model?

I'm designing a REST API of service and got stuck on proper way to nest resources. Resources: partners, tickets, settings Connections between resources: partner has many tickets, partner has set ...
10
votes
3answers
11k views

Is it OK to return HTML from a JSON API?

On my current project I am responsible for the implementation of a service which involves the consumption of newly created RESTful APIs, documented as solely supporting JSON. The client consistently ...
10
votes
2answers
10k views

Implementing the command pattern in a RESTful API

I'm in the process of designing an HTTP API, hopefully making it as RESTful as possible. There are some actions which functionality spreads over a few resources, and sometime needs to be undone. I ...
10
votes
2answers
351 views

Is the 'Law of Demeter' applicable to public/API method signatures?

Given that changes to the API/public method signature should be minimal to prevent breaking those client codes that use these methods, I was wondering if the Law of Demeter is less applicable to these....
9
votes
3answers
410 views

CRUD API: How do you specify which fields to update?

Let's say you have some kind of data structure, which is persisted in some kind of database. For simplicity, let's call this data structure Person. You are now tasked to design a CRUD API, which ...
9
votes
4answers
499 views

Dependency Inversion expands the API, results in unnecessary tests

This question has bothered me for a few days, and it feels like several practices contradict each other. Example Iteration 1 public class FooDao : IFooDao { private IFooConnection fooConnection;...
9
votes
1answer
4k views

When should I use AtomPub?

I have been conducting some research into RESTful web service design and I've reached what I think is a key decision point so I thought I'd offer it up to the community to get some advice. In keeping ...
9
votes
3answers
228 views

Breaking API changes: how can I make the transition easy for library users?

In the past, I used the standard way of adding @Deprecated annotations to API methods which will be removed in a later version. Now I am preparing a major version for a library, with many API parts ...
9
votes
1answer
157 views

Idiomatic wrapping of C++ template type API in C

I'm working on wrapping a C++ API which provides access to a data store (Hazelcast) in C functions, so that the data store can also be accessed from C-only code. The Hazelcast C++ API for the Map ...
8
votes
3answers
170 views

In REST parlance what is the difference between a resource and a representation?

My understanding of REST that is enables modelling service operations as representation of state and transition from one state to another making use of HTTP. I have always understood resources as ...
8
votes
2answers
804 views

Is implementing an interface defined in a subpackage an anti-pattern?

Let's say I have the following: package me.my.pkg; public interface Something { /* ... couple of methods go here ... */ } and: package me.my; import me.my.pkg.Something; public class SomeClass ...
8
votes
2answers
233 views

As an API-user, would you tolerate BestPractice Exceptions?

I'm in the process of designing an API, part of which involves writing POCOs to a database. In C#, we have the DateTime structure. The "default" value for this (DateTime.MinValue) is 01/01/0001. ...
8
votes
1answer
660 views

Versioning APIs

Suppose that you have a large project supported by an API base. The project also ships a public API that end(ish) users can use. Sometimes you need to make changes to the API base that supports ...
8
votes
2answers
3k views

What is the best pattern for adding an existing item to a collection in REST API?

I'm designing a pragmatic REST API and I'm a little stuck on how best to add existing entities to a collection. My domain model includes a Project that has a collection of Sites. This is a strict many-...
8
votes
2answers
304 views

How to handle complex calculated fields in an ORM

In our API we've got a few central datatypes which need to be "decorated" (so to speak) after retrieval from the database with calculated values. The database is accessed through an ORM which follows ...
8
votes
1answer
714 views

What API design for storing generic data in a more specific format?

for In the project I am working on we send messages about widgets over message queues, serializing them onto the queues as XML. The XML schema contains tags for properties that are common to all types ...
7
votes
3answers
262 views

Does a mobile app need more access than the public API of a site?

I have a site with a public API, and some mobile app developers have been brought in to produce an iPhone app for the site. They insist they need to see the database schema, but as I understand it, ...
7
votes
4answers
1k views

Best Practice: Should error messages be handled by the API or by the App?

I am designing an application that interacts with a RESTful API. When returning error messages like Unable to sign up user Should the error message be generated by the app? or by the API? I am ...
7
votes
3answers
419 views

Is it safe to assume that one controller will only ever use one primary model?

So, I'm designing an MVC framework. In the name of keeping everything statically typed and non-magical, I've come to quite a problem with "automatically" passing models to a controller. So, ...
7
votes
2answers
6k views

C++ Library API Design

I'm looking for a good resource for learning about good API design for C++ libraries, looking at shared objects/dlls etc. There are many resources on writing nice APIs, nice classes, templates and so ...
7
votes
1answer
2k views

Sending a collection of data to an API. Multiple small calls vs one big call

I am currently creating an API and implemented a few basic REST actions such as get, update, search etc. Another program that collects data needs to synchronize these to this API. My current thought ...