Building the UPDATE Post by Id Endpoint
We will research how to update an existing post using the "UPDATE POST BY ID" route within the postsRoutes.js
file. This route handles the updating of a post based on its unique ID.
Route Definition
The code below defines the "UPDATE POST BY ID" route using router.put()
:
jsrouter.put("/post/:id", validatePostData, async (req, res, next) => { ... }
This route is configured to handle HTTP PUT requests, specifically for updating posts;
It includes a parameterized
:id
in the route path to identify the post to be updated;The
validatePostData
middleware is added to ensure data validation before proceeding. The logic of thevalidatePostData
middleware remains the same as in the previous step.
Obtaining Data from the Request
Here, we extract the necessary data from the request, including the post ID and the updated post content:
js9123456const postId = req.params.id;const updatedData = {username: req.body.username,postTitle: req.body.postTitle,postContent: req.body.postContent,};
The post ID is extracted from the request parameters, making it available for further processing. The
:id
parameter from the route URL is captured usingreq.params.id
;The
username
,postTitle
, andpostContent
are extracted from the request body.
Update the Post in the Database
Updating an existing post involves several steps, as outlined below:
js991234567891011121314const data = await readData();const postIndex = data.findIndex((post) => post.id === postId);if (postIndex === -1) {return res.status(404).json({ error: "Post not found" });}data[postIndex] = {...data[postIndex],...updatedData,};await fs.writeFile("./database/posts.json", JSON.stringify(data));
We read the existing data from the JSON file using the asynchronous
readData
function, as explained earlier;The
postIndex
variable stores the index of the post to be updated in thedata
array by comparing post IDs;If the post is not found (i.e.,
postIndex === -1
), a 404 (Not Found) response with an error message is returned to the client;To update the post data, we merge the existing post data (
...data[postIndex]
) with the updated data (...updatedData
). This ensures that only the specified fields are updated and existing data is retained;Finally, the updated
data
array is written back to the JSON file to save the changes made to the post.
Sending a Response
Upon successful post update, a JSON response is sent to the client. The response includes a status code of 200 (OK), indicating a successful update and the updated post data.
jsres.status(200).json(data[postIndex]);
Error Handling
We wrap the route code in a try-catch block to handle potential errors during data retrieval or request processing. Any errors that occur are logged to the console for debugging purposes:
js912345try {// ... (code for retrieving and processing data)} catch (error) {console.error(error.message);}
Complete code of the postsRoutes.js file at this step
js999123456789101112131415161718192021222324252627282930313233343536const express = require("express");const fs = require("fs/promises");const validatePostData = require("../middlewares/validateData");const router = express.Router();// Function to read data from the JSON fileasync function readData() {try {// Read the contents of the `posts.json` fileconst data = await fs.readFile("./database/posts.json");// Parse the JSON data into a JavaScript objectreturn JSON.parse(data);} catch (error) {// If an error occurs during reading or parsing, throw the errorthrow error;}}// GET ALL POSTSrouter.get("/", async (req, res, next) => {try {// Call the `readData` function to retrieve the list of postsconst data = await readData();// Send the retrieved data as the responseres.status(200).send(data);} catch (error) {// If an error occurs during data retrieval or sending the responseconsole.error(error.message); // Log the error to the console for debugging}});// GET POST BY IDrouter.get("/post/:id", async (req, res, next) => {try {// Extract the post ID from the request parameters
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