Refactor File class to include download progress and error handling

src/models/File.js

@@ -7,7 +7,6 @@ const https = require('https');
 const exec = util.promisify(require('child_process').exec);
 
 const EventEmitter = require('events');
-const csv = require('csv-parser');
 const slugify = require('slugify');
 
 const dest = path.join(appRoot, 'public/csv');
@@ -22,7 +21,10 @@ function generateFilePath(filename) {
 // Create a class File that extends EventEmitter
 class File extends EventEmitter {
 
-  // Create a constructor that takes a url as a parameter
+  /**
+   * Create a new File instance
+   * @param {string} url 
+   */
   constructor(url) {
     super();
     this.url = url;
@@ -30,7 +32,10 @@ class File extends EventEmitter {
   
 
 
-  // Create a download method that downloads the file from the url
+  /**
+   * Download a file from a url
+   * @returns {Promise<string>} filepath
+   */
   async download() {
     const url = URL.parse(this.url);
     this.filename = slugify(url.hostname, { lower: true });
@@ -46,13 +51,41 @@ class File extends EventEmitter {
     file.on('error', (err) => {
       fs.unlink(filepath, () => {
         // Emit a download.error event with the error
-        this.emit('download.error', { url: this.url, filepath: this.filepath, error: err, type: 'file' });
+        this.emit('download.error', { url: this.url, filepath: this.filepath, error: err.message, type: 'file' });
       });
     });
 
     return new Promise((resolve, reject) => {
       request
       .get(url.href, (response) => {
+        // Check if response is valid
+        if (response.statusCode !== 200) {
+          // Emit a download.error event with the error
+          this.emit('download.error', { url: this.url, filepath: this.filepath, error: response.statusMessage, type: 'response' });
+          return reject(response.statusMessage);
+        }
+
+        // Get the content length and parse it to an integer
+        const contentLength = parseInt(response.headers['content-length'], 10);
+
+        const step = Math.floor(contentLength / 100);
+        let stepLimit = step;
+        // Create a variable to hold the downloaded size
+        let downloaded = 0;
+
+        // Handle response data
+        response.on('data', (chunk) => {
+          // Add the size of the chunk to the downloaded variable
+          downloaded += chunk.length;
+
+          // Check if the downloaded size is bigger than the step limit
+          if (downloaded > stepLimit) {
+            // Emit a download.progress event with the url, filepath and downloaded size
+            this.emit('download.progress', { url: this.url, filepath: this.filepath, percentage: Math.floor((downloaded / contentLength) * 100) });
+            stepLimit += step;
+          }
+        });
+
         response.pipe(file);
 
         file.on('finish', () => {
@@ -66,10 +99,12 @@ class File extends EventEmitter {
       .on('error', (err) => {
         fs.unlink(filepath, () => {
           // Emit a download.error event with the error
-          this.emit('download.error', { url: this.url, filepath: this.filepath, error: err, type: 'request' });
+          this.emit('download.error', { url: this.url, filepath: this.filepath, error: err.message, type: 'request' });
           reject(err.message);
         });
       });
     });
   }
-}
+}
+
+module.exports = File;