Consuming REST APIs in a React Application can be done in various
ways, but in this tutorial, we will be discussing how we can consume
REST APIs using two of the most popular methods known as Axios (a promise-based HTTP client) and Fetch API
(a browser in-built web API). I will discuss and implement each of
these methods in detail and shed light on some of the cool features each
of them have to offer.
APIs are what we can use to supercharge our React applications with data. There are certain operations that can’t be done on the client-side, so these operations are implemented on the server-side. We can then use the APIs to consume the data on the client-side.
APIs consist of a set of data, that is often in JSON format with specified endpoints. When we access data from an API, we want to access specific endpoints within that API framework. We can also say that an API is a contractual agreement between two services over the shape of request and response. The code is just a byproduct. It also contains the terms of this data exchange.
In React, there are various ways we can consume REST APIs in our applications, these ways include using the JavaScript inbuilt
Note: A good knowledge of ReactJS, React Hooks, JavaScript and CSS will come in handy as you work your way throughout this tutorial.
Let’s get started with learning more about the REST API.
The sample response below is from the Github Open API. We’ll be using this API to build a React app later on in this tutorial.
{
"login": "bktivist123",
"id": 26572907,
"node_id": "MDQ6VXNlcjI2NTcyOTA3",
"avatar_url": "https://avatars3.githubusercontent.com/u/26572907?v=4",
"gravatar_id": "",
"url": "https://api.github.com/users/hacktivist123",
"html_url": "https://github.com/hacktivist123",
"followers_url": "https://api.github.com/users/bktivist123/followers",
"following_url": "https://api.github.com/users/bktivist123/following{/other_user}",
"gists_url": "https://api.github.com/users/bktivist123/gists{/gist_id}",
"starred_url": "https://api.github.com/users/bktivist123/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/bktivist123/subscriptions",
"organizations_url": "https://api.github.com/users/bktivist123/orgs",
"repos_url": "https://api.github.com/users/bktivist123/repos",
"events_url": "https://api.github.com/users/bktivist123/events{/privacy}",
"received_events_url": "https://api.github.com/users/bktivist123/received_events",
"type": "User",
"site_admin": false,
"name": "Shesh",
"company": null,
"blog": "https://shessh.xyz",
"location": "Lagos, NN",
"email": null,
"hireable": true,
"bio": "☕ Software Engineer | | Developer Advocateš„|| ❤ Everything JavaScript",
"public_repos": 68,
"public_gists": 1,
"followers": 130,
"following": 246,
"created_at": "2017-03-21T12:55:48Z",
"updated_at": "2020-05-11T13:02:57Z"
}
The response above is from the Github REST API when I make a
It defines concepts such as CORS and the HTTP Origin header semantics, supplanting their separate definitions elsewhere.
The
Once a response has been fetched, there are several inbuilt methods available to define what the body content is and how it should be handled.
In the code above, we are fetching data from a URL that returns data as JSON and then printing it to the console. The simplest form of using fetch() often takes just one argument which is the path to the resource you want to fetch and then return a promise containing the response from the fetch request. This response is an object.
The response is just a regular HTTP response and not the actual JSON. In other to get the JSON body content from the response, we’d have to change the response to actual JSON using the json() method on the response.
This request can either be made inside a Lifecycle Method if your component is a Class Component or inside a
For example, In the code below, we will make a fetch request inside a class component, which means we’ll have to do it inside a lifecycle method. In this particular case, our fetch request will be made inside a
In
the code above, we are creating a very simple class component that
makes a fetch request that logs the final data from the fetch request we
have made to the API URL into the browser console after the React
component has finished mounting.
The
The simple application will display all the repositories and their description that belongs to a particular user. For this tutorial, I’ll be using my GitHub username, you can also use yours if you wish.
The first thing we need to do is to generate our React app by using
The command above will bootstrap a new React app for us. As soon as our new app has been created, all that’s left to do is to run the following command and begin coding:
If our React is created properly we should see this in our browser window when we navigate to
In your
The List.js file will handle the display of our Repositories in the form of a list, and the withListLoading.js file will hold a higher-order component that will be displayed when the Fetch request we will be making is still ongoing.
In the List.js file we created inside the
The
code above is a basic React list component that would display the data,
in this case, the repositories name and their descriptions in a list.
Now, Let me explain the code bit by bit.
We are initializing a prop for the component called repos.
Here, all we are doing is making a conditional statement that will render a message when the length of the repos we get from the request we make is equal to zero.
Here,
we are mapping through each of the repositories that will be provided
by the API request we make and extracting each of the repositories names
and their descriptions then we are displaying each of them in a list.
Here we are exporting our
In the withListLoading.js file we created inside the components folder, let’s paste in the following code:
The
code above is a higher-order React component that takes in another
component and then returns some logic. In our case, our higher component
will wait to check if the current
In your *App.js file inside the src folder, let’s paste in the following code:
Our
App.js is a functional component that makes use of React Hooks for
handling state and also side effects. If you’re not familiar with React
Hooks, read my Getting Started with React Hooks Guide.
Let me explain the code above bit by bit.
Here, we are importing all the external files we need and also the components we created in our components folder. We are also importing the React Hooks we need from React.
Here, we are creating a new component called
Here, we are initializing a
We are then making a basic
Here we are basically just rendering the Component we assigned our higher-order component to and also filling the
Now, we should see this in our browser, when the fetch request is still being made, courtesy of our
Now, let’s style our project a little bit, in your App.css file, copy and paste this code.
So
in the code above, we are styling our app to look more pleasing to the
eyes, we have assigned various class names to each element in our App.js file and thus we are using these class names to style our app.
Now our app looks much better. š
So that’s how we can use the Fetch API to consume a REST API. In the next section, we’ll be discussing Axios and how we can use it to consume the same API in the same App.
The code above shows the basic ways we can make a GET and POST HTTP request with Axios.
Axios also provides a set of shorthand method for performing different HTTP requests. The Methods are as follows:
In the code above, we are making the same request as what we did above but this time with the shorthand method. Axios provides flexibility and makes your HTTP requests even more readable.
For example, we can make multiple requests to the GitHub api using the
The code above makes simultaneous requests to an array of arguments in parallel and returns the response data, in our case, it will log to the console the
Now let’s install Axios in our React app by running either of the following:
With NPM:
With Yarn:
After installation is complete, we have to import axios into our App.js. In our App.js we’ll add the following line to the top of our App.js file:
After adding the line of code our App.js all we have to do inside our
You may have noticed that we have now replaced the fetch API with the Axios shorthand method
In this block of code, we are making a GET request then we are returning a promise that contains the repos data and assigning the data to a constant variable called
If we did everything correctly, we should see our app still render the same way without any change.
So this is how we can use Axios client to consume a REST API.
APIs are what we can use to supercharge our React applications with data. There are certain operations that can’t be done on the client-side, so these operations are implemented on the server-side. We can then use the APIs to consume the data on the client-side.
APIs consist of a set of data, that is often in JSON format with specified endpoints. When we access data from an API, we want to access specific endpoints within that API framework. We can also say that an API is a contractual agreement between two services over the shape of request and response. The code is just a byproduct. It also contains the terms of this data exchange.
In React, there are various ways we can consume REST APIs in our applications, these ways include using the JavaScript inbuilt
fetch()
method and Axios which is a promise-based HTTP client for the browser and Node.js.Note: A good knowledge of ReactJS, React Hooks, JavaScript and CSS will come in handy as you work your way throughout this tutorial.
Let’s get started with learning more about the REST API.
What Is A REST API
A REST API is an API that follows what is structured in accordance with the REST Structure for APIs. REST stands for “Representational State Transfer”. It consists of various rules that developers follow when creating APIs.The Benefits Of REST APIs
- Very easy to learn and understand;
- It provides developers with the ability to organize complicated applications into simple resources;
- It easy for external clients to build on your REST API without any complications;
- It is very easy to scale;
- A REST API is not language or platform-specific, but can be consumed with any language or run on any platform.
An Example Of A REST API Response
The way a REST API is structured depends on the product it’s been made for — but the rules of REST must be followed.The sample response below is from the Github Open API. We’ll be using this API to build a React app later on in this tutorial.
{
"login": "bktivist123",
"id": 26572907,
"node_id": "MDQ6VXNlcjI2NTcyOTA3",
"avatar_url": "https://avatars3.githubusercontent.com/u/26572907?v=4",
"gravatar_id": "",
"url": "https://api.github.com/users/hacktivist123",
"html_url": "https://github.com/hacktivist123",
"followers_url": "https://api.github.com/users/bktivist123/followers",
"following_url": "https://api.github.com/users/bktivist123/following{/other_user}",
"gists_url": "https://api.github.com/users/bktivist123/gists{/gist_id}",
"starred_url": "https://api.github.com/users/bktivist123/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/bktivist123/subscriptions",
"organizations_url": "https://api.github.com/users/bktivist123/orgs",
"repos_url": "https://api.github.com/users/bktivist123/repos",
"events_url": "https://api.github.com/users/bktivist123/events{/privacy}",
"received_events_url": "https://api.github.com/users/bktivist123/received_events",
"type": "User",
"site_admin": false,
"name": "Shesh",
"company": null,
"blog": "https://shessh.xyz",
"location": "Lagos, NN",
"email": null,
"hireable": true,
"bio": "☕ Software Engineer | | Developer Advocateš„|| ❤ Everything JavaScript",
"public_repos": 68,
"public_gists": 1,
"followers": 130,
"following": 246,
"created_at": "2017-03-21T12:55:48Z",
"updated_at": "2020-05-11T13:02:57Z"
}
The response above is from the Github REST API when I make a
GET
request to the following endpoint https://api.github.com/users/
bktivist123. It returns all the stored data about a user called hacktivist123. With this response, we can decide to render it whichever way we like in our React app.Consuming APIs Using The Fetch API
Thefetch()
API is an inbuilt JavaScript method for getting resources from a server or an API endpoint. It’s similar to XMLHttpRequest
, but the fetch API provides a more powerful and flexible feature set.It defines concepts such as CORS and the HTTP Origin header semantics, supplanting their separate definitions elsewhere.
The
fetch()
API method always takes in a compulsory argument, which is the path or
URL to the resource you want to fetch. It returns a promise that points
to the response from the request, whether the request is successful or
not. You can also optionally pass in an init options object as the
second argument.Once a response has been fetched, there are several inbuilt methods available to define what the body content is and how it should be handled.
The Difference Between The Fetch API And jQuery Ajax
The Fetch API is different from jQuery Ajax in three main ways, which are:- The promise returned from a
fetch()
request will not reject when there’s an HTTP error, no matter the nature of the response status. Instead, it will resolve the request normally, if the response status code is a 400 or 500 type code, it’ll set the ok status. A request will only be rejected either because of network failure or if something is preventing the request from completing fetch()
will not allow the use of cross-site cookies i.e you cannot carry out a cross-site session usingfetch()
fetch()
will also not send cookies by default unless you set thecredentials
in the init option.
Parameters For The Fetch API
resource
This is the path to the resource you want to fetch, this can either be a direct link to the resource path or a request objectinit
This is an object containing any custom setting or credentials you’ll like to provide for yourfetch()
request. The following are a few of the possible options that can be contained in theinit
object:method
This is for specifying the HTTP request method e.g GET, POST, etc.headers
This is for specifying any headers you would like to add to your request, usually contained in an object or an object literal.body
This is for specifying a body that you want to add to your request: this can be aBlob
,BufferSource
,FormData
,URLSearchParams
,USVString
, orReadableStream
objectmode
This is for specifying the mode you want to use for the request, e.g.,cors
,no-cors
, orsame-origin
.credentials
This for specifying the request credentials you want to use for the request, this option must be provided if you consider sending cookies automatically for the current domain.
Basic Syntax for Using the Fetch() API
A basic fetch request is really simple to write, take a look at the following code:In the code above, we are fetching data from a URL that returns data as JSON and then printing it to the console. The simplest form of using fetch() often takes just one argument which is the path to the resource you want to fetch and then return a promise containing the response from the fetch request. This response is an object.
The response is just a regular HTTP response and not the actual JSON. In other to get the JSON body content from the response, we’d have to change the response to actual JSON using the json() method on the response.
Using Fetch API In React Apps
Using the Fetch API in React Apps is the normal way we’d use the Fetch API in javascript, there is no change in syntax, the only issue is deciding where to make the fetch request in our React app. Most fetch requests or any HTTP request of any sort is usually done in a React Component.This request can either be made inside a Lifecycle Method if your component is a Class Component or inside a
useEffect()
React Hook if your component is a Functional Component.For example, In the code below, we will make a fetch request inside a class component, which means we’ll have to do it inside a lifecycle method. In this particular case, our fetch request will be made inside a
componentDidMount
lifecycle method because we want to make the request just after our React Component has mounted.The
fetch()
method takes in the path to the resource we want to fetch, which is assigned to a variable called apiUrl
.
After the fetch request has been completed it returns a promise that
contains a response object. Then, we are extracting the JSON body
content from the response using the json()
method, finally we log the final data from the promise into the console.Let’s Consume A REST API With Fetch Method
In this section, we will be building a simple react application that consumes an external API, we will be using the Fetch method to consume the API.The simple application will display all the repositories and their description that belongs to a particular user. For this tutorial, I’ll be using my GitHub username, you can also use yours if you wish.
The first thing we need to do is to generate our React app by using
create-react-app
:The command above will bootstrap a new React app for us. As soon as our new app has been created, all that’s left to do is to run the following command and begin coding:
If our React is created properly we should see this in our browser window when we navigate to
localhost:3000
after running the above command.In your
src
folder, create a new folder called component
. This folder will hold all of our React components. In the new folder, create two files titled List.js and withListLoading.js. These two files will hold the components that will be needed in our app.The List.js file will handle the display of our Repositories in the form of a list, and the withListLoading.js file will hold a higher-order component that will be displayed when the Fetch request we will be making is still ongoing.
In the List.js file we created inside the
components
folder, let’s paste in the following code:Now, Let me explain the code bit by bit.
We are initializing a prop for the component called repos.
Here, all we are doing is making a conditional statement that will render a message when the length of the repos we get from the request we make is equal to zero.
Here we are exporting our
List
component so that we can use it somewhere else.In the withListLoading.js file we created inside the components folder, let’s paste in the following code:
isLoading
state of the component it takes is true
or false
. If the current isLoading
state is true, it will display a message Hold on, fetching data may take some time :). Immediately the isLoading
state changes to false
it’ll render the component it took in. In our case, it’ll render the List component.In your *App.js file inside the src folder, let’s paste in the following code:
Let me explain the code above bit by bit.
Here, we are importing all the external files we need and also the components we created in our components folder. We are also importing the React Hooks we need from React.
Here, we are creating a new component called
ListLoading
and assigning our withListLoading
higher-order component wrapped around our list component. We are then creating our state values loading
and repos
using the useState()
React Hook.useEffect()
React Hook. In the useEffect()
hook, we are setting our initial loading state to true, while this is true, our higher-order component will display a message.
We are then creating a constant variable called user
and assigning the API URL we’ll be getting the repositories data from.We are then making a basic
fetch()
request like we discussed above and then after the request is done we
are setting the app loading state to false and populating the repos
state with the data we got from the request.isLoading
prop and repos
prop with their state value.Now, we should see this in our browser, when the fetch request is still being made, courtesy of our
withListLoading
higher-order component:Now, let’s style our project a little bit, in your App.css file, copy and paste this code.
Now our app looks much better. š
So that’s how we can use the Fetch API to consume a REST API. In the next section, we’ll be discussing Axios and how we can use it to consume the same API in the same App.
Consuming APIs With Axios
Axios is an easy to use promise-based HTTP client for the browser and node.js. Since Axios is promise-based, we can take advantage of async and await for more readable and asynchronous code. With Axios, we get the ability to intercept and cancel request, it also has a built-in feature that provides client-side protection against cross-site request forgery.Features Of Axios
- Request and response interception
- Streamlined error handling
- Protection against XSRF
- Support for upload progress
- Response timeout
- The ability to cancel requests
- Support for older browsers
- Automatic JSON data transformation
Making Requests With Axios
Making HTTP Requests with Axios is quite easy. The code below is basically how to make an HTTP request.The code above shows the basic ways we can make a GET and POST HTTP request with Axios.
Axios also provides a set of shorthand method for performing different HTTP requests. The Methods are as follows:
axios.request(config)
axios.get(url[, config])
axios.delete(url[, config])
axios.head(url[, config])
axios.options(url[, config])
axios.post(url[, data[, config]])
axios.put(url[, data[, config]])
axios.patch(url[, data[, config]])
In the code above, we are making the same request as what we did above but this time with the shorthand method. Axios provides flexibility and makes your HTTP requests even more readable.
Making Multiple Requests With Axios
Axios provides developers the ability to make and handle simultaneous HTTP requests using theaxios.all()
method. This method takes in an array of arguments and it returns a
single promise object that resolves only when all arguments passed in
the array have resolved.For example, we can make multiple requests to the GitHub api using the
axios.all()
method like so:The code above makes simultaneous requests to an array of arguments in parallel and returns the response data, in our case, it will log to the console the
created_at
object from each of the API responses.Let’s Consume A REST API With Axios Client
In this section, all we’ll be doing is replacingfetch()
method with Axios in our existing React Application. All we need to do
is to install Axios and then use it in our App.js file for making the
HTTP request to the GitHub API.Now let’s install Axios in our React app by running either of the following:
With NPM:
With Yarn:
After installation is complete, we have to import axios into our App.js. In our App.js we’ll add the following line to the top of our App.js file:
After adding the line of code our App.js all we have to do inside our
useEffect()
is to write the following code:axios.get
to make a get
request to the API.In this block of code, we are making a GET request then we are returning a promise that contains the repos data and assigning the data to a constant variable called
allRepos
. We are then setting the current loading state to false and also passing the data from the request to the repos state variable.If we did everything correctly, we should see our app still render the same way without any change.
So this is how we can use Axios client to consume a REST API.
Fetch vs Axios
In this section, I will be listing our certain features and then I’ll talk about how well Fetch and Axios support these features.- Basic Syntax
Both Fetch and Axios have very simple syntaxes for making requests. But Axios has an upper hand because Axios automatically converts a response to JSON, so when using Axios we skip the step of converting the response to JSON, unlike Fetch() where we’d still have to convert the response to JSON. Lastly, Axios shorthand methods allow us to make specific HTTP Requests easier. - Browser Compatibility
One of the many reasons why developers would prefer Axios over Fetch is because Axios is supported across major browsers and versions unlike Fetch that is only supported in Chrome 42+, Firefox 39+, Edge 14+, and Safari 10.1+. - Handling Response Timeout
Setting a timeout for responses is very easy to do in Axios by making use of thetimeout
option inside the request object. But in Fetch, it is not that easy to do this. Fetch provides a similar feature by using theAbortController()
interface but it takes more time to implement and can get confusing. - Intercepting HTTP Requests
Axios allows developers to intercept HTTP requests. HTTP interceptors are needed when we need to change HTTP requests from our application to the server. Interceptors give us the ability to do that without having to write extra code. - Making Multiple Requests Simultaneously
Axios allows us to make multiple HTTP requests with the use of theaxios.all()
method ( I talked about this above).fetch()
provides the same feature with the use of thepromise.all()
method, we can make multiplefetch()
requests inside it.
Conclusion
Axios andfetch()
are all great ways of consuming APIs but I advise you to use fetch()
when building relatively small applications and make use of Axios when
building large applications for scalability reasons.
I hope you enjoyed working through this tutorial, you could always read
more on Consuming REST APIs with either Fetch or Axios from the
references below. If you have any questions, you can leave it in the
comments section below and I’ll be happy to answer every single one.Related Resources
- “REST API Structure,”
- “CORS,”
- “HTTP Headers,”
- “Fetch API,” Mozilla Developer Network
- “Using Axios And React,” Paul Halliday
- “How To Make HTTP Requests Like A Pro With Axios,” Faraz Kelhini