Within last week’s tutorial, you’ve learned how to reply rendered HTML for a given request. Obviously, there are situations where replying HTML won’t fit your needs and you want to send JSON data as a response. This guide will show you how to reply JSON for a given request using hapi.
Before diving into the details, have a look at the series outline and find posts that match your interests and needs.
hapi Series Overview
- What You’ll Build
- Prepare Your Project: Stack & Structure
- Environment Variables and Storing Secrets
- Set Up MongoDB and Connect With Mongoose
- Sending Emails in Node.js
- Load the User’s Profile Picture From Gravatar Using Virtuals in Mongoose
- Implement a User Profile Editing Screen
- Generate a Username in Mongoose Middleware
- Displaying Seasons and Episodes for TV Shows with Mongoose Relationship Population
- Implementing Pagination for Movies
- Implement a Watchlist
- Create a Full Text Search with MongoDB
- Create a REST API with JSON Endpoints
- Update Mongoose Models for JSON Responses
- API Pagination for TV Shows
- Customize API Endpoints with Query Parameters
- Always Throw and Handle API Validation Errors
- Advanced API Validation With Custom Errors
- Create an API Documentation with Swagger
- Customize Your Swagger API Documentation URL
- Describe Endpoint Details in Your Swagger API Documentation
- 10 Tips on API Testing With Postman
- JWT Authentication in Swagger API Documentation
- API Versioning with Request Headers
- API Login With Username and Password to Generate a JWT
- JWT Authentication and Private API Endpoints
- Refresh Tokens With JWT Authentication
- Create a JWT Utility
- JWT Refresh Token for Multiple Devices
- Check Refresh Token in Authentication Strategy
- Rate Limit Your Refresh Token API Endpoint
- How to Revoke a JWT
- Invalidate JWTs With Blacklists
- JWT Logout (Part 1/2)
- JWT “Immediate” Logout (Part 2/2)
- A Better Place to Invalidate Tokens
- How to Switch the JWT Signing Algorithm
- Roll Your Own Refresh Token Authentication Scheme
- JWT Claims 101
- Use JWT With Asymmetric Signatures (RS256 & Co.)
- Encrypt the JWT Payload (The Simple Way)
- Increase JWT Security Beyond the Signature
- Unsigned JSON Web Tokens (Unsecured JWS)
- JWK and JWKS Overview
- Provide a JWKS API Endpoint
- Create a JWK from a Shared Secret
- JWT Verification via JWKS API Endpoint
- What is JOSE in JWT
- Encrypt a JWT (the JWE Way)
- Authenticate Encrypted JWTs (JWE)
- Encrypted and Signed JWT (Nested JWT)
- Bringing Back JWT Decoding and Authentication
- Bringing Back JWT Claims in the JWT Payload
- Basic Authentication With Username and Password
- Authentication and Remember Me Using Cookies
- How to Set a Default Authentication Strategy
- Define Multiple Authentication Strategies for a Route
- Restrict User Access With Scopes
- Show „Insufficient Scope“ View for Routes With Restricted Access
- Access Restriction With Dynamic and Advanced Scopes
- hapi - How to Fix „unknown authentication strategy“
- Authenticate with GitHub And Remember the Login
- Authenticate with GitLab And Remember the User
- How to Combine Bell With Another Authentication Strategy
- Custom OAuth Bell Strategy to Connect With any Server
- Redirect to Previous Page After Login
- How to Implement a Complete Sign Up Flow With Email and Password
- How to Implement a Complete Login Flow
- Implement a Password-Reset Flow
- Views in hapi 9 (and above)
- How to Render and Reply Views
- How to Reply and Render Pug Views (Using Pug 2.0)
- How to Create a Dynamic Handlebars Layout Template
- Create and Use Handlebars Partial Views
- Create and Use Custom Handlebars Helpers
- Specify a Different Handlebars Layout for a Specific View
- How to Create Jade-Like Layout Blocks in Handlebars
- Use Vue.js Mustache Tags in Handlebars Templates
- How to Use Multiple Handlebars Layouts
- How to Access and Handle Request Payload
- Access Request Headers
- How to Manage Cookies and HTTP States Across Requests
- Detect and Get the Client IP Address
- How to Upload Files
- Quick Access to Logged In User in Route Handlers
- How to Fix “handler method did not return a value, a promise, or throw an error”
- How to Fix “X must return an error, a takeover response, or a continue signal”
- How to Reply a JSON Response
- How to Set Response Status Code
- How to Handle 404 Responses for Missing Routes
- Query Parameter Validation With Joi
- Path Parameter Validation With Joi
- Request Payload Validation With Joi
- Validate Query and Path Parameters, Payload and Headers All at Once on Your Routes
- Validate Request Headers With Joi
- Reply Custom View for Failed Validations
- Handle Failed Validations and Show Errors Details at Inputs
- How to Fix AssertionError, Cannot validate HEAD or GET requests
Reply JSON as a Response
In a previously published article about routing in hapi, we already introduced the reply interface and the allowed arguments as the response payload. The reply interface accepts multiple types (e.g. string, buffer, stream, JSON serializable object) as payload. And that means, we can use any regular JavaScript object as an argument for reply() and hapi will automatically convert it into valid JSON.
Let’s make things approachable and define an exemplary route that simply responds a given request with a static JS object:
hapi v17
server.route({
method: 'GET',
path: '/',
handler: (request, h) => {
var data = {
key: 'value',
another: false,
number: 10,
func: function() {
return this.number * 10
}
}
return data
}
})
hapi v16
server.route({
method: 'GET',
path: '/',
handler: (request, reply) => {
var data = {
key: 'value',
another: false,
number: 10,
func: function() {
return this.number * 10
}
}
reply(data)
}
})
The data object is very basic. Of course, you can create more complex objects including nested ones and arrays, etc. Hapi will do the work for you and convert the given data properly. As you can see, the data object also contains a function. You’ll recognize what hapi does in those situations in a second.
If you want to check the response, just request your defined route that reply’s with JSON in your browser or use a tool like Postman for debugging purposes. The response payload for the above defined data object looks like this.
{
"key": "value",
"another": false,
"number": 10
}
As you can see, hapi creates valid JSON payload that can be consumed and processed by any client. Any function within the object that should be replied will be omitted. That’s straight forward, isn’t it? Hapi ships with functionality to reply JSON data by default!
Outlook
This guide showed you how to leverage hapi and the integrated functionality to reply JSON data as the response payload. Hapi also converts the given JS object into valid JSON without further developer interference.
We appreciate feedback and love to help you if there’s a question on your mind. Let us know in the comments or on twitter @futurestud_io.
Make it rock & enjoy coding!