Web Request in Next.js
What is web request?
- You need to update your web page with data from an external source
- You need to post data to an external source
- Basically anything that happens on the Internet
Different ways of client-server communication
- Protocol: a set of rules that governs how data is transferred between two parties
- HTTP: HyperText Transfer Protocol
- HTTPS: HTTP + Secure
- WebSockets: a protocol that allows for two-way communication between client and server
Restful API
Built on top of HTTP/s protocol.
- REST: Representational State Transfer
- Stateless: Server does not keep track of client’s state
When a client request is made via a RESTful API, information is delivered in one of several formats via HTTP: JSON (Javascript Object Notation), HTML, XLT, or plain text. JSON is the most generally popular file format to use because, despite its name, it’s language-agnostic, as well as readable by both humans and machines.
Try it out
const response = await fetch("https://www.boredapi.com/api/activity");But what is await?
Asynchronous programming
- Promises
- A promise is an object that may produce some value some time in the future (e.g. a web request, reading files, some expensive computation, etc.)
- Two ways to handle a promise:
More about requests
- URL: Uniform Resource Locator
- method:
GET,POST,PUT,DELETE - headers: metadata about the request (cookies, authentication, etc.)
- body: data to be sent to the server
More about responses
- Status code: 200, 404, 500, etc.
- Response body: data sent back from the server (JSON, HTML, etc.)
Do you know JSON?
{
"firstName": "Duke",
"lastName": "Java",
"age": 18,
"streetAddress": "100 Internet Dr",
"city": "JavaTown",
"state": "JA",
"postalCode": "12345",
"phoneNumbers": [{ "Mobile": "111-111-1111" }, { "Home": "222-222-2222" }]
}Building a RESTful API in Next.js
- Next.js API Routes
- handling requests using
reqobject - sending responses using
resobject
export default function handler(req, res) {
if (req.method === "POST") {
req.body.name === "" && res.status(401).json({ error: "Missing name!" });
res.status(200).json({ msg: `Hello, ${req.body.name}` });
} else {
res.status(200).json({ msg: "Hello" });
}
}Cool JavaScript fact
&& is a short-circuit operator. It evaluates the second operand only if the first operand evaluates to true.
Sending data using fetch
const response = await fetch("/api/hello", {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({ name: text }),
});JSON.stringify converts a JavaScript object to a JSON string.
Check if the response is successful:
if (!response.ok) {
return {
code: response.status,
error: await data.error,
};
}
return {
code: response.status,
msg: data.msg,
};