Refactored the `FileService.parseFromUrl` method to return the filepath instead of a stream, and updated the `routes/index.js` file to handle the new return value

src/models/file.js

@@ -18,15 +18,6 @@ const { basedir } = require('../config/constants');
 const dest = path.join(basedir, 'public/csv');
 
 
-// Create a generateFilePath function witch returns a path with a filename and datetime
-function generateFilePath(filename) {
-  return {
-    filepath: path.join(dest, `${filename}-${Date.now()}.csv`),
-    generatedpath: path.join(dest, `${filename}-generated-${Date.now()}.csv`),
-  };
-}
-
-
 // Create a class File that extends EventEmitter
 class File {
 
@@ -38,7 +29,14 @@ class File {
     this.url = url;
   }
   
-
+  // Create a generateFilePath function witch returns a path with a filename and datetime
+  generateFilePath(filename) {
+    const date = new Date();
+    return {
+      filepath: path.join(dest, `${filename}-${date.toISOString().split('T')[0]}.csv`),
+      generatedpath: path.join(dest, `${filename}-generated-${date.toISOString().split('T')[0]}.csv`),
+    };
+  }
 
   /**
    * Download a file from a url
@@ -47,7 +45,7 @@ class File {
   async download() {
     const url = URL.parse(this.url);
     this.filename = slugify(url.hostname, { lower: true });
-    const { filepath, generatedpath } = generateFilePath(this.filename);
+    const { filepath, generatedpath } = this.generateFilePath(this.filename);
     this.filepath = filepath;
     this.generatedpath = generatedpath;
 
@@ -121,74 +119,73 @@ class File {
 
   // create a parse method which read the file and return a stream
   parse(columns) {
-    const stream = new PassThrough();
-    const fileStream = fs.createWriteStream(this.generatedpath);
-
-    // check if columns is valid
-    if (!columns || !columns.length) {
-      // return Promise.reject(new Error('Invalid columns'));
-      emitter.emit('parse.error', { url: this.url, filepath: this.filepath, error: 'Invalid columns' });
-      return false;
-    }
+    return new Promise((resolve, reject) => {
+      const fileStream = fs.createWriteStream(this.generatedpath);
+
+      // check if columns is valid
+      if (!columns || !columns.length) {
+        // return Promise.reject(new Error('Invalid columns'));
+        emitter.emit('parse.error', { url: this.url, filepath: this.filepath, error: 'Invalid columns' });
+        reject(new Error('Invalid columns'));
+        return false;
+      }
 
-    // Create a variable to hold csv columns indexes
-    const columnsIndex = {};
-    for (let column of columns) {
-      columnsIndex[column] = {
-        exist: false,
-        main: (String(column)).split('.')[0],
-        value: column,
-        rest: (String(column)).split('.').slice(1).join('.'),
-        last: (String(column)).split('.').pop(),
-      };
-    }
+      // Create a variable to hold csv columns indexes
+      const columnsIndex = {};
+      for (let column of columns) {
+        columnsIndex[column] = {
+          exist: false,
+          main: (String(column)).split('.')[0],
+          value: column,
+          rest: (String(column)).split('.').slice(1).join('.'),
+          last: (String(column)).split('.').pop(),
+        };
+      }
 
-    const columnsFiltered = [];
+      const columnsFiltered = [];
 
-    let count = 1;
-    fs.createReadStream(this.filepath)
-    .pipe(csvParser({ separator: ';' }))
-    .on('headers', (headers) => {
-      headers = headers.map(header => typeof header === 'string' ? header.trim() : header);
+      let count = 1;
+      fs.createReadStream(this.filepath)
+      .pipe(csvParser({ separator: ';' }))
+      .on('headers', (headers) => {
+        headers = headers.map(header => typeof header === 'string' ? header.trim() : header);
         
-      const result = [];
-      for (let key in columnsIndex) {
-        columnsIndex[key].exist = headers.includes(columnsIndex[key].main);
-        if ( columnsIndex[key].exist ) {
-          columnsFiltered.push(columnsIndex[key].value);
-          result.push(columnsIndex[key].last);
+        const result = [];
+        for (let key in columnsIndex) {
+          columnsIndex[key].exist = headers.includes(columnsIndex[key].main);
+          if ( columnsIndex[key].exist ) {
+            columnsFiltered.push(columnsIndex[key].value);
+            result.push(columnsIndex[key].last);
+          }
         }
-      }
         
-      // Emit a parse.start event with the url and filepath
-      emitter.emit('parse.start', { url: this.url, filepath: this.filepath, headers, result: result });
-
-      stream.write(result.join(';') + "\n");
-      fileStream.write(result.join(';') + "\n");
-    })
-    .on('data', (row) => {
-      // Emit a parse.data event with the url, filepath and data
-      let result = this.processRow(row, columnsIndex, columnsFiltered);
-      emitter.emit('parse.data', { url: this.url, filepath: this.filepath, data: row, result, index: count });
-      stream.write(result.join(';') + "\n");
-      fileStream.write(result.join(';') + "\n");
-      count++;
-    })
-    .on('error', (err) => {
-      // Emit a parse.error event with the error
-      emitter.emit('parse.error', { url: this.url, filepath: this.filepath, error: err.message });
-
-      fileStream.close();
-      fs.unlink(this.generatedpath, () => {});
-    })
-    .on('end', () => {
-      // Emit a parse.end event with the url and filepath
-      stream.end();
-      fileStream.close();
-      emitter.emit('parse.end', { url: this.url, filepath: this.filepath, count: count - 1, generated: path.basename(this.generatedpath) });
-    });
+        // Emit a parse.start event with the url and filepath
+        emitter.emit('parse.start', { url: this.url, filepath: this.filepath, headers, result: result });
+
+        fileStream.write(result.join(';') + "\n");
+      })
+      .on('data', (row) => {
+        // Emit a parse.data event with the url, filepath and data
+        let result = this.processRow(row, columnsIndex, columnsFiltered);
+        emitter.emit('parse.data', { url: this.url, filepath: this.filepath, data: row, result, index: count });
+        fileStream.write(result.join(';') + "\n");
+        count++;
+      })
+      .on('error', (err) => {
+        // Emit a parse.error event with the error
+        emitter.emit('parse.error', { url: this.url, filepath: this.filepath, error: err.message });
 
-    return stream;
+        fileStream.close();
+        reject(err);
+        fs.unlink(this.generatedpath, () => {});
+      })
+      .on('end', () => {
+        // Emit a parse.end event with the url and filepath
+        fileStream.close();
+        resolve(this.generatedpath);
+        emitter.emit('parse.end', { url: this.url, filepath: this.filepath, count: count - 1, generated: path.basename(this.generatedpath) });
+      });
+    });
   }
 
   /**

src/routes/index.js

@@ -105,7 +105,7 @@ router.get('/', async function(req, res, next) {
   return res;
 });
 
-router.post('/', async function(req, res, next) {  
+router.post('/', function(req, res, next) {  
   // const url = 'https://bodacc-datadila.opendatasoft.com/api/explore/v2.1/catalog/datasets/annonces-commerciales/exports/csv?lang=fr&refine=publicationavis%3A%22A%22&refine=publicationavis_facette%3A%22Bodacc%20A%22&refine=familleavis_lib%3A%22Ventes%20et%20cessions%22&timezone=Asia%2FBaghdad&use_labels=true&delimiter=%3B';
 
   // get url from form
@@ -120,22 +120,16 @@ router.post('/', async function(req, res, next) {
     return res.status(500).send('Invalid columns');
   }
 
-  let stream = null;
-  try {
-    stream = await fileService.parseFromUrl(url, columns);
-  } catch (err) {
+  fileService.parseFromUrl(url, columns)
+  .then((filepath) => {
+    res.send({
+      success: true
+    })
+  })
+  .catch(err => {
     console.error('routes [/] error', err.message);
-  }
-
-  if ( !stream ) {
     return res.status(500).send('Invalid stream');
-  }
-
-  res.setHeader('Content-Disposition', 'attachment; filename="mon_fichier.csv"');
-  res.setHeader('Content-Type', 'text/csv; charset=utf-8');
-  stream.pipe(res);
-
-  // res.render('index', { title: 'Express' });
+  });
 });
 
 module.exports = router;

src/services/file.js

@@ -29,14 +29,15 @@ class FileService {
     const file = new File(url);
     const filepath = await file.download();
 
-    const stream = file.parse(columns);
-    if ( !stream ) {
-      emitter.emit('parseFromUrl.error', { url, columns, error: 'Invalid stream' });
-      return Promise.reject(new Error('Invalid stream'));
-    }
-
-    emitter.emit('parseFromUrl.end', { url, columns, filepath });
-    return Promise.resolve(stream);
+    return file.parse(columns)
+    .then((filepath) => {
+      emitter.emit('parseFromUrl.end', { url, columns, filepath });
+      return filepath;
+    })
+    .catch((err) => {
+      emitter.emit('parseFromUrl.error', { url, columns, error: err.message });
+      return err;
+    });
   }
 
   /**