day 11

day11/services/CsvService.js

@@ -0,0 +1,84 @@
+const multer = require('multer');
+const converter = require('json-2-csv');
+const fs = require('fs');
+const path = require('path');
+const csv = require('fast-csv');
+const db = require('./../models');
+const upload_folder = path.resolve(__dirname, '../uploads');
+
+module.exports = {
+  /**
+   * Import CSV file
+   * @param {request} req
+   * @param {response} res
+   */
+  csv_preview: function (req, res) {
+    return new Promise((resolve, reject) => {
+      const upload = multer({ dest: path.resolve(upload_folder) }).single('file');
+      upload(req, res, async function (error) {
+        if (error) {
+          reject(error);
+        }
+        let data = [];
+        fs.createReadStream(path.resolve(upload_folder, req.file.path))
+          .pipe(csv.parse())
+          .on('error', (error) => reject(error))
+          .on('data', (row) => {
+            data.push(row);
+          })
+          .on('end', (rowCount) => {
+            fs.unlinkSync(path.resolve(upload_folder, req.file.path));
+            console.log(`Parsed ${rowCount} rows`);
+            resolve(data);
+          });
+      });
+    });
+  },
+  csv_import: async function (req, res) {
+    return new Promise((resolve, reject) => {
+      const table = req.params.model;
+      const upload = multer({ dest: path.resolve(upload_folder) }).single('file');
+      let data = [];
+      upload(req, res, async function (error) {
+        if (error) {
+          throw new Error(error);
+        }
+        fs.createReadStream(path.resolve(upload_folder, req.file.path))
+          .pipe(csv.parse({ headers: true }))
+          .on('error', (error) => reject(error))
+          .on('data', (row) => {
+            data.push(row);
+          })
+          .on('end', async (rowCount) => {
+            fs.unlinkSync(path.resolve(upload_folder, req.file.path));
+            console.log(`Parsed ${rowCount} rows`);
+            await db[table].batchInsert(data).catch((error) => {
+              console.log(error);
+              reject(error);
+            });
+            resolve(data);
+          });
+      });
+    });
+  },
+  /**
+   * Export CSV file
+   * @param {request} req
+   * @param {response} res
+   */
+  csv_export: async function (req, res) {
+    try {
+      let fields = await db[req.table].getAll(req.where);
+      fields = JSON.stringify(fields); // do this needed?
+
+      const csv = await converter.json2csvAsync(fields);
+
+      res.header('Content-Type', 'text/csv');
+      res.attachment(req.table + '.csv');
+
+      return res.send(csv);
+    } catch (error) {
+      console.log(error);
+    }
+  },
+};