Axios is a popular library for making HTTP requests in JavaScript. It offers many features like interceptors, cancellations, etc. Headers play an important role in interacting with APIs, which requires setting them for sending and receiving data from the server. Axios provides an easy way to set the headers for any request. In this article, we will discuss how to set the variable to header axios with code examples.
Setting Header in Axios:
Axios provides a way to set the headers for any specific request. A request header is an HTTP header that can be used to provide information about the request context, including authentication credentials and user-agent identification. Axios uses the headers property to set the request headers. Here's an example:
axios({
method: "get",
url: "https://api.example.com/data",
headers: { "Authorization": "Bearer my-token" }
})
In this example, we are sending an HTTP GET request to https://api.example.com/data. The second argument is an object that contains the headers property. The headers object contains an Authorization property with a value of Bearer my-token. This sets our authorization header with the token.
Setting Global Header in Axios:
Axios also provides a way to set global headers that will be attached to every request made using Axios. This is useful when dealing with an API that requires an authorization token or any header that is required in every request. We can set the header globally using the defaults object. Here's an example:
axios.defaults.headers.common['Authorization'] = "Bearer my-token";
In this example, we are setting the Authorization header with a value of Bearer my-token. This will be attached to every request made using Axios.
Setting Different Headers for Different Requests:
Sometimes we need to set different headers for different requests. We can do this by creating an Axios instance with the desired headers and using that instance for that request. Here's an example:
const axiosInstance = axios.create({
headers: { "Content-Type": "application/json" }
});
axiosInstance.post("https://api.example.com/data", { "name": "John Doe" })
.then(response => console.log(response))
.catch(error => console.error(error));
In this example, we created a new instance of Axios with Content-Type header set to application/json. We then make a POST request to https://api.example.com/data using that instance. Axios will use the headers provided in the instance to make the request.
Conclusion:
Setting headers using Axios is an easy and effective way to communicate with APIs. You can set the headers globally or set them for specific requests. Headers are an important part of any request that we make and provide important context for the request. Set them correctly and you'll save yourself a lot of headache in the future!
In addition to the basic information on setting headers in Axios, there are some more advanced features that can be used to better control how headers are set.
Interceptors:
Axios allows for interceptors to be used to modify or intercept requests and responses. Interceptors are functions that are called before a request is made or a response is received. We can use interceptors to set headers before the request is made. For example:
axios.interceptors.request.use(config => {
config.headers.Authorization = `Bearer ${localStorage.getItem('token')}`;
return config;
});
In this example, the request interceptor modifies the headers by setting the Authorization header with a token saved in the localStorage. This way, we don't have to set the header manually for every request.
Defaults:
Axios provides the ability to set default headers that will be used for all requests. This is useful when working with an API that requires the same headers for each request. We can set these default headers using the defaults object like so:
axios.defaults.headers.common['Authorization'] = `Bearer ${localStorage.getItem('token')}`;
In this example, the Authorization header is set to a token saved in the localStorage. Now, every request made using Axios will include the Authorization header with the token value.
Customizing Instances:
Axios also allows for custom instances to be created, which can have their own custom headers. This is useful when multiple headers are required for a group of requests. For example:
const instance = axios.create({
headers: {
'X-Requested-With': 'XMLHttpRequest',
'Content-Type': 'application/json',
'Accept': 'application/json',
'Authorization': `Bearer ${localStorage.getItem('token')}`
}
})
In this example, we create a custom Axios instance with multiple headers set. Every request made using this instance will include these headers.
In conclusion, setting headers is an important part of working with APIs. Axios provides many options for setting headers, such as interceptors, defaults, and custom instances. By using these features, we can ensure that our requests include the headers necessary for the API to function correctly.
Popular questions
Q1. What is the purpose of setting headers in Axios?
A1. Headers provide important context for requests made by Axios, including authentication credentials and user-agent identification. Setting headers correctly ensures that requests are made with the correct context and that the API responds as expected.
Q2. How can we set the headers for a specific request in Axios?
A2. We can set headers for a specific request by passing an object as a parameter to the Axios request method with the headers property set to an object with the desired headers. Here's an example:
axios({
method: "get",
url: "https://api.example.com/data",
headers: { "Authorization": "Bearer my-token" }
})
Q3. Can we set global headers in Axios?
A3. Yes, Axios allows for global headers to be set using the defaults object. For example:
axios.defaults.headers.common['Authorization'] = "Bearer my-token";
Q4. How can we set different headers for different requests in Axios?
A4. We can create a new instance of Axios with the desired headers and use that instance for the specific request. Here's an example:
const axiosInstance = axios.create({
headers: { "Content-Type": "application/json" }
});
axiosInstance.post("https://api.example.com/data", { "name": "John Doe" })
.then(response => console.log(response))
.catch(error => console.error(error));
Q5. How can we use interceptors to modify or intercept requests and responses in Axios?
A5. We can use interceptors to modify or intercept requests and responses by creating a function that returns a modified config object or error response, and then attach the function to the Axios instance using axios.interceptors. For example:
axios.interceptors.request.use(config => {
config.headers.Authorization = `Bearer ${localStorage.getItem('token')}`;
return config;
});
Tag
AxiosHeader
