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Ring is a dynamic and general-purpose programming language that supports multiple paradigms, including procedural, object-oriented, declarative and functional programming styles. It was designed with the goal of providing a simple scripting language that can help to automate tasks. One of the key features of Ring is its flexibility. It allows programmers to choose their preferred style of coding while also providing the ability to mix different styles in a single program. This makes it suitable for a wide range of applications, from web development to desktop applications and game development. Ring comes with an extensive standard library which includes support for file I/O, networking, databases and GUI development among others. It also provides built-in support for JSON and XML parsing. Additionally, Ring supports direct access to C/C++ libraries without requiring external tools or additional coding efforts. This feature makes it possible to extend the capabilities of Ring by leveraging existing C/C++ codebases or libraries. Another notable feature is its support for Natural Language Programming (NLP). This allows developers to write programs using commands that are similar in structure to natural human languages. Despite being relatively new compared to other popular languages like Python or Java, Ring has been gaining attention due its simplicity and versatility.

Ask the right questions secure the right Ring talent among an increasingly shrinking pool of talent.

First 20 minutes

General Ring app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Ring application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you define Ring in the context of Clojure?

Ring is a Clojure library that abstracts HTTP to make it simple and easy to write web applications. It provides a standard interface between web servers and web applications.

What are the core components of Ring?

The core components of Ring are handlers, middleware, and adapters.

Describe the difference between a Ring handler and middleware.

A handler is a function that takes a request map and returns a response map. Middleware is a higher-order function that takes a handler and returns a new handler with additional functionality.

How would you create a basic Ring handler?

A basic Ring handler can be created as a function that takes a request map and returns a response map. For example: `(defn handler [request] {:status 200 :headers {} :body "Hello World"})`.

What is the role of a Ring adapter?

A Ring adapter is used to connect a Ring application with a web server. It translates the server's native request format into a Ring request map and vice versa.

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What you’re looking for early on

Does the candidate demonstrate a strong understanding of Ring's architecture and its components?

Has the candidate shown experience with Clojure and ClojureScript?

Can the candidate articulate how they have used Ring in previous projects?

Does the candidate have a good understanding of HTTP protocols?

Next 20 minutes

Specific Ring development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

How would you use Ring middleware to add a new header to all responses?

You would create a middleware function that takes a handler and returns a new handler. The new handler would call the original handler, modify the response to add the new header, and return the modified response.

What are some common Ring middleware functions?

Some common Ring middleware functions include `wrap-params`, `wrap-session`, `wrap-cookies`, `wrap-flash`, and `wrap-multipart-params`.

How would you handle exceptions in a Ring application?

You can handle exceptions in a Ring application by using the `wrap-try-catch` middleware function. This function catches any exceptions thrown by the handler and returns a 500 response.

Describe the difference between synchronous and asynchronous handlers in Ring.

Synchronous handlers return a response map directly, while asynchronous handlers take an additional callback argument and return a response through the callback.

How would you create an asynchronous handler in Ring?

An asynchronous handler in Ring is a function that takes a request map and a callback, and returns a response through the callback. For example: `(defn handler [request respond raise] (respond {:status 200 :headers {} :body "Hello World"}))`.

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At this point, a skilled Ring engineer should demonstrate strong problem-solving abilities, proficiency in Ring programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Ring.

What does the following Ring code do?
{:status 200 :headers {"Content-Type" "text/plain"} :body "Hello World"}
This is a basic Ring response map. It returns a status of 200, a content-type of text/plain in the headers, and a body of 'Hello World'. This is typically the response format used in Ring to communicate with the client.
What will be the output of the following Ring code?
(defn handler [request] {:status (if (= (:request-method request) :get) 200 404) :headers {"Content-Type" "text/plain"} :body "Hello World"})
This is a Ring handler function. It checks if the request method is GET and if so, it returns a 200 status. If the request method is not GET, it returns a 404 status. In both cases, it returns a content-type of text/plain and a body of 'Hello World'.
What does the following Ring code do?
(defn handler [request] (let [params (:params request)] (if (empty? params) {:status 400 :body "Bad Request"} {:status 200 :body "Good Request"})))
This Ring handler function checks if the request has any parameters. If the parameters are empty, it returns a 400 status with a 'Bad Request' message. If there are parameters, it returns a 200 status with a 'Good Request' message.
What will be the output of the following Ring code?
(defn handler [request] (future (Thread/sleep 5000) {:status 200 :body "Delayed Response"}))
This Ring handler function uses a future to delay the response by 5 seconds. After the delay, it returns a 200 status with a 'Delayed Response' message.

Wrap-up questions

Final candidate for Ring Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Ring application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

What is the purpose of the Ring request and response maps?

The request and response maps are used to represent HTTP requests and responses in a simple and consistent format. They make it easy to manipulate requests and responses as plain data structures.

How would you parse JSON in a Ring request?

You can parse JSON in a Ring request by using the `wrap-json-body` middleware function. This function parses the JSON body of the request and adds it to the request map under the `:body` key.

What are some ways to improve performance in a Ring application?

Some ways to improve performance in a Ring application include using asynchronous handlers, optimizing middleware usage, and using a fast web server adapter.

Ring application related

Product Perfect's Ring development capabilities

Beyond hiring for your Ring engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Ring projects, and can engage in multiple capacities.

Ring Consultive assessments

Ring Application Conversion Assessment Ring Application Integration Assessment Ring Data & Database Integration Assessment

Custom Ring development projects

Custom Ring App Conversion Ring Custom App Development Process App UI Design for Ring Facelifts

Hiring guide for Ring Engineers

Ring Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the Ring engineer at this point.

Ring Consultive assessments

Custom Ring development projects