Task 3: File Selector

task_3_react/src/client/App.tsx

@@ -1,13 +1,14 @@
 import "./css/App.css";
 import '@fortawesome/fontawesome-free/css/all.css';
-import { readCSV } from './csv';
+import { CSV_Data, fileInfo, responseObject } from './types';
-import { CSV_Data, fileInfo } from './types';
+import { readCSV, convertCSVtoJSON } from './csv';
 
-import React, { useState, useRef } from "react";
+import React, { useState, useRef, useEffect } from "react";
-import Layout from "./Layout";
+import Layout from "./components/Layout";
 import CSVCard from "./components/CSVCard";
 import InfoCard from "./components/InfoCard";
 import DataTable from "./components/DataTable";
+import FileCard from "./components/FileCard";
 
 function App() {
   const [data, setData] = useState([] as CSV_Data);
@@ -18,10 +19,19 @@ function App() {
     rowcount: 0
   });
 
+  const [fileList, setFileList] = useState(null as responseObject | null);
+  // Effect has to be in top level of the component
+  useEffect(() => {
+    fetch("/status", { method: "GET" })
+      .then((response) => response.json())
+      .then((response) => setFileList(response))
+      .catch((error) => console.log(error));
+  });
+
   const formRef = useRef(null);
 
   // This is triggered in CSVCard
-  const handleFileChange = async (e: React.ChangeEvent<HTMLInputElement>): Promise<void> => {
+  const handleFileUpload = async (e: React.ChangeEvent<HTMLInputElement>): Promise<void> => {
     const file = e.target.files?.[0];
     if (!file) throw new Error("No file received");
 
@@ -29,7 +39,7 @@ function App() {
 
     const newFileInfo: fileInfo = {
       filename: file.name,
-      filetype: file.type,
+      filetype: ".csv", // file.type delivers weird name
       filesize: String(file.size) + "B",
       rowcount: data.length
     }
@@ -39,18 +49,31 @@ function App() {
     if (formRef.current) {
       // Upload to server
       const formData = new FormData(formRef.current);
-      const res = await fetch("/upload", {
+      await fetch("/upload", {
         method: "POST",
         body: formData
       });
-      const result = await res.json();
-      console.log(result);
     }
   }
 
+  const handleFileChange = async (fileName: string) => {
+    const response = await fetch(`/download/${fileName}`);
+    const blob = await response.blob();
+    const text = await blob.text();
+
+    if (!response) throw new Error("No file received");
+
+    const data = await convertCSVtoJSON(text);
+    
+    // Updating fileInfo requires more effort since blob doesn't have the metadata
+
+    setData(data);
+  }
+
   return (
       <Layout>
-        <CSVCard handleChange={handleFileChange} formRef={formRef}></CSVCard>
+        <CSVCard handleChange={handleFileUpload} formRef={formRef}></CSVCard>
+        <FileCard fileList={fileList as responseObject} fileChangeHandle={handleFileChange}></FileCard>
         <InfoCard info={info}></InfoCard>
         <DataTable data={data}></DataTable>
       </Layout>

task_3_react/src/client/components/CSVCard.tsx

@@ -8,7 +8,7 @@ const CSVCard = (props: {
   return (
     <article>
         <header>
-            <h2>Select CSV data</h2>
+            <h2>Upload CSV data</h2>
         </header>
         <form ref={props.formRef} action="/upload" method="post" encType="multipart/form-data" >
             <label htmlFor="file-input" className="custom-file-upload">

task_3_react/src/client/components/DataTable.tsx

@@ -56,7 +56,7 @@ const DataTable = (props: {data: CSV_Data}) => {
                                 <tr key={i}>
                                     {
                                         header.map( (col) => (
-                                            <Row col={col} content={row[col] as String}></Row>
+                                            <Row key={i} col={col} content={row[col] as String}></Row>
                                         ))
                                     }
                                 </tr>
@@ -84,7 +84,7 @@ const ColHeader = (props: {col: String, sortingHandle: (s: String) => void, isSe
     );
 }
 
-const Row = (props: {col: String, content: String}) => {
+const Row = (props: {col: String, content: String, key: Key}) => {
     return <td key={props.col as Key}>{props.content}</td>;
 }
 

task_3_react/src/client/components/FileCard.tsx

@@ -0,0 +1,71 @@
+import { responseObject } from "../types";
+
+const FileCard = (props: {
+    fileList: responseObject,
+    fileChangeHandle: (fileName: string) => Promise<void>
+}) => {
+
+    const convert = (res: responseObject) => {
+        let list = [];
+        for (let i = 0; i < res.names.length; i++) {
+            const elem = {
+                filename: res.names[i],
+                uploadTime: res.uploadTimes[i]
+            }
+            list.push(elem);
+        }
+        return list;
+    }
+
+    const list = props.fileList != null ? convert(props.fileList) : null;
+
+    return (
+        <article className="wide">
+            <header>
+                <h2>Select a File</h2>
+            </header>
+                <table id="table-content">
+                    <thead>
+                        <tr>
+                            <th>Filename</th>
+                            <th>Upload Time</th>
+                            <th>Action</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {
+                            list ? list.map( (file, i) => (
+                                <FileRow key={i} filename={file.filename!} uploadTime={file.uploadTime!} fileChangeHandle={props.fileChangeHandle}></FileRow>
+                            )) : <tr></tr>
+                        }
+                    </tbody>
+                </table>
+        </article>
+    );
+}
+
+const FileRow = (props: {
+    filename: string,
+    uploadTime: string,
+    fileChangeHandle: (fileName: string) => Promise<void>
+}) => {
+
+    const remFile = async () => {
+        await fetch(`/delete/${props.filename}`, { method: "DELETE" });
+    }
+
+    return (
+        <tr>
+            <td>{props.filename}</td>
+            <td>{props.uploadTime}</td>
+            <td>
+                <div className="action-icons">
+                    <i onClick={() => { remFile()} }  className="fa-solid fa-trash-can"></i>
+                    <i onClick={() => {props.fileChangeHandle(props.filename)}} className="fa-solid fa-file-arrow-down"></i>
+                </div>
+            </td>
+        </tr>
+    )
+}
+
+export default FileCard;

task_3_react/src/client/components/InfoCard.tsx

@@ -14,6 +14,7 @@ const InfoCard = (props: {
             <h2>Data infos</h2>
         </header>
          <div className="info">
+            {noFileMessage}
             <h4>Filename</h4>
             <p>{props.info.filename}</p>
 
@@ -26,7 +27,6 @@ const InfoCard = (props: {
             <h4>Number of rows</h4>
             <p>{props.info.rowcount}</p>
         </div>
-        {noFileMessage}
     </article>
   );
 }

task_3_react/src/client/components/Layout.tsx

@@ -1,5 +1,5 @@
 import React from "react";
-import "./css/Layout.css";
+import "../css/Layout.css";
 
 const Layout = (props: { children: React.ReactNode }) => {
   return (

task_3_react/src/client/css/App.css

@@ -36,6 +36,19 @@ article {
     width: 400px;
 }
 
+article.wide {
+    width: 800px
+}
+
+.action-icons {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 10px;
+    font-size: 18px;
+    cursor: pointer;
+}
+
 body>main {
     max-height: calc(100vh - 100px);
     overflow-y: auto;

task_3_react/src/client/csv.ts

@@ -1,7 +1,7 @@
 import { CSV_Data } from './types';
 import { csv2json } from 'json-2-csv';
 
-const convertCSVtoJSON = async ( csvText: string ) => {
+export const convertCSVtoJSON = async ( csvText: string ) => {
     // Type cast OK, as the typing of the external library is not perfect -> Actually it is.
     // NOTE: On transpilation to JS, it will be (more or less) disregarded anyway.
     // If you claim it isn't good typing, it's the same as expecting it to guess the typing,

task_3_react/src/client/types.d.ts

@@ -9,3 +9,9 @@ export type fileInfo = {
     filesize: string;
     rowcount: number;
 }
+
+// FileCard receives this via props
+export type responseObject = {
+  names: string[],
+  uploadTimes: string[]
+}

task_3_react/src/server/main.ts

@@ -1,19 +1,24 @@
 import express from "express";
 import ViteExpress from "vite-express";
 import multer from "multer";
+import * as fs from "node:fs/promises";
+import { responseObject } from "./types";
+import path from "path";
 
 const app = express();
 
+// Set up file storage
 const storage = multer.diskStorage({
   destination: "./src/server/uploads",
   filename: (_req, file, cb) => {
     // Suggested in Multer's readme
-    const uniqueSuffix = Date.now() + "-" + Math.round(Math.random() * 1E9);
+    const uniqueSuffix = Date.now() + "-" + Math.round(Math.random() * 1E3);
-    cb(null, file.fieldname + "-" + uniqueSuffix)
+    cb(null, file.fieldname + "-" + uniqueSuffix);
   }
 });
-const upload = multer({ storage: storage });
 
+// CSV file upload endpoint
+const upload = multer({ storage: storage });
 app.post(
   "/upload", 
   upload.single("dataFile"), 
@@ -22,6 +27,48 @@ app.post(
   }
 );
 
+// Endpoint to send back file names/upload times
+app.get("/status", async (_req, res) => {
+  const resObject: responseObject = {
+    names: [],
+    uploadTimes: []
+  };
+
+  const dir = await fs.opendir("./src/server/uploads/");
+  for await (const file of dir) {
+    resObject.names.push(file.name);
+    const stats = await fs.stat(`./src/server/uploads/${file.name}`);
+    resObject.uploadTimes.push(stats.birthtime.toString());
+  }
+
+  res.status(200).json(resObject);
+})
+
+// Endpoint to send back whole files
+app.get("/download/:fileName", (req, res) => {
+  const fileName = req.params.fileName;
+  const filePath = path.join(__dirname, "uploads", fileName); // Filepaths must be absolute
+  res.sendFile(filePath, err => {
+    if (err) {
+      console.error("Error sending file:", err);
+      res.status(500).send("Error downloading file");
+    }
+  });
+}) 
+
+// Endpoint to remove files from server
+app.delete("/delete/:fileName", async (req, res) => {
+  const fileName = req.params.fileName;
+  const filePath = path.join(__dirname, "uploads", fileName);
+  try {
+    await fs.unlink(filePath);    // deletes the file
+    res.status(200).send("File deleted successfully");
+  } catch (error) {
+    console.error("Error deleting file:", error);
+    res.status(500).send("Error deleting file");
+  }
+});
+
 
 // example route which returns a message
 app.get("/hello", async function (_req, res) {

task_3_react/src/server/types.d.ts

@@ -0,0 +1,4 @@
+export type responseObject = {
+  names: string[],
+  uploadTimes: string[]
+}