added browserify, refactored code to separate UI and network logic

frontend/src/download.js

@@ -0,0 +1,132 @@
+const UIWrapper = require('./file').UIWrapper;
+
+let download = () => {
+
+  let xhr = new XMLHttpRequest();
+  xhr.open("get", "/assets" + location.pathname.slice(0, -1), true);
+  xhr.responseType = "blob";
+  
+  let listelem = setupUI();
+  xhr.addEventListener("progress", updateProgress.bind(null, listelem));
+  
+  xhr.onload = function(e) {
+
+    // maybe send a separate request before this one to get the filename?
+
+    // maybe render the html itself with the filename, since it's generated server side
+    // after a get request with the unique id
+    listelem.emit('name', xhr.getResponseHeader("Content-Disposition").match(/filename="(.+)"/)[1]);
+
+    if (this.status == 200) {
+      let self = this;
+      let blob = new Blob([this.response]);
+      let arrayBuffer;
+      let fileReader = new FileReader();
+      fileReader.onload = function() {
+        arrayBuffer = this.result;
+        let array = new Uint8Array(arrayBuffer);
+        salt = strToIv(location.pathname.slice(10, -1));
+
+        window.crypto.subtle.importKey(
+          "jwk",
+          {
+              kty: "oct",
+              k: location.hash.slice(1),
+              alg: "A128CBC",
+              ext: true,
+          },
+          {
+              name: "AES-CBC",
+          },
+          true,
+          ["encrypt", "decrypt"])
+        .then((key) => {  
+          return window.crypto.subtle.decrypt(
+              {
+                name: "AES-CBC",
+                iv: salt,
+              },
+              key,
+              array)
+        })
+        .then((decrypted) => {
+          let dataView = new DataView(decrypted);
+          let blob = new Blob([dataView]);
+          let downloadUrl = URL.createObjectURL(blob);
+          let a = document.createElement("a");
+          a.href = downloadUrl;
+          a.download = xhr.getResponseHeader("Content-Disposition").match(/filename="(.+)"/)[1];
+          document.body.appendChild(a);
+          a.click();
+        })
+        .catch((err) => {
+          alert("This link is either invalid or has expired, or the uploader has deleted the file.");
+          console.error(err);
+        });
+      };
+
+      fileReader.readAsArrayBuffer(blob);
+    } else {
+      alert("This link is either invalid or has expired, or the uploader has deleted the file.")
+    }
+  };
+  xhr.send();
+}
+
+window.download = download;
+
+let setupUI = () => {
+  let li = document.createElement("li");
+  let name = document.createElement("p");
+  li.appendChild(name);
+
+  let progress = document.createElement("p");
+  li.appendChild(progress);
+
+  document.getElementById("downloaded_files").appendChild(li);
+
+  return new UIWrapper(li, name, null, progress);
+}
+
+let ivToStr = (iv) => {
+  let hexStr = "";
+  for (let i in iv) {
+    if (iv[i] < 16) {
+      hexStr += "0" + iv[i].toString(16);
+    } else {
+      hexStr += iv[i].toString(16);
+    }
+  }
+  window.hexStr = hexStr;
+  return hexStr;
+}
+
+let strToIv = (str) => {
+  let iv = new Uint8Array(16);
+  for (let i = 0; i < str.length; i += 2) {
+    iv[i/2] = parseInt((str.charAt(i) + str.charAt(i + 1)), 16);
+  }
+
+  return iv;
+}
+
+let updateProgress = (UIelem, e) => {
+  if (e.lengthComputable) { 
+    let percentComplete = Math.floor((e.loaded / e.total) * 100);
+    UIelem.emit('progress', "Progress: " + percentComplete + "%");
+
+    if (percentComplete === 100) {
+      let finished = document.createElement("p");
+      finished.innerText = "Your download has finished.";
+      UIelem.li.appendChild(finished);
+
+      let close = document.createElement("button");
+      close.innerText = "Ok";
+      close.addEventListener("click", () => {
+        document.getElementById("downloaded_files").removeChild(UIelem.li);
+      });
+
+      UIelem.li.appendChild(close);
+    }
+  } 
+}

frontend/src/file.js

@@ -0,0 +1,27 @@
+const EventEmitter = require('events');
+
+class UIWrapper extends EventEmitter {
+  constructor(li, name, link, progress) {
+    super();
+    this.li = li;
+    this.name = name;
+    this.link = link;
+    this.progress = progress;
+
+    this.on("name", (filename) => {
+      this.name.innerText = filename;
+    });
+
+    this.on("link", (link) => {
+      this.link.innerText = link;
+      this.link.setAttribute('href', link);
+    });
+
+    this.on("progress", (progress) => {
+      this.progress.innerText = progress;
+      
+    });
+  }
+}
+
+exports.UIWrapper = UIWrapper;

frontend/src/main.js

@@ -0,0 +1,3 @@
+require('./upload');
+require('./download');
+require('./file');

frontend/src/upload.js

@@ -0,0 +1,142 @@
+const EventEmitter = require('events');
+const UIWrapper = require('./file').UIWrapper;
+
+let onChange = (event) => {
+  let file = event.target.files[0];
+  let reader = new FileReader();
+  reader.readAsArrayBuffer(file);
+
+  let random_iv = window.crypto.getRandomValues(new Uint8Array(16));
+  let hex = ivToStr(random_iv);
+
+  reader.onload = function(event) {
+    let self = this;
+    window.crypto.subtle.generateKey({
+      name: "AES-CBC",
+      length: 128 
+    },
+    true,
+    ["encrypt", "decrypt"])
+    .then((key) => {
+      let arrayBuffer = self.result;
+      let array = new Uint8Array(arrayBuffer);
+
+      window.crypto.subtle.encrypt({
+        name: "AES-CBC",
+        iv: random_iv },
+        key,
+        array)
+      .then(uploadFile.bind(null, file, hex, key))
+      .catch((err) => console.error(err));
+
+    }).catch((err) => console.error(err));   
+  };
+}
+
+window.onChange = onChange;
+
+let uploadFile = (file, hex, key, encrypted) => {
+  let dataView = new DataView(encrypted);
+  let blob = new Blob([dataView], { type: file.type });
+  
+  let fd = new FormData();
+  fd.append("fname", file.name);
+  fd.append("data", blob, file.name);
+
+  let xhr = new XMLHttpRequest();
+  xhr.open("post", "/upload/" + hex, true);
+
+  let listelem = setupUI();
+  listelem.emit('name', file.name);
+  xhr.upload.addEventListener("progress", updateProgress.bind(null, listelem));
+
+  xhr.onreadystatechange = () => { 
+    if (xhr.readyState == XMLHttpRequest.DONE) {
+      window.crypto.subtle.exportKey("jwk", key).then((keydata) => {
+        localStorage.setItem(hex, xhr.responseText);
+
+        listelem.emit('link', "http://localhost:3000/download/" + hex + "/#" + keydata.k)
+
+        console.log("Share this link with a friend: http://localhost:3000/download/" + hex + "/#" + keydata.k);
+      })
+    }
+  };
+
+  xhr.send(fd);
+}
+
+let updateProgress = (UIelem, e) => {
+  if (e.lengthComputable) {
+    let percentComplete = Math.floor((e.loaded / e.total) * 100);
+    UIelem.emit('progress', "Progress: " + percentComplete + "%")
+
+    if (percentComplete === 100) {
+      let btn = document.createElement("button");
+      btn.innerText = "Delete from server";
+      btn.addEventListener("click", () => {
+        let segments = UIelem.link.innerText.split("/");
+        let key = segments[segments.length - 2];
+
+        let xhr = new XMLHttpRequest();
+        xhr.open("post", "/delete/" + key, true);
+        xhr.setRequestHeader("Content-Type", "application/json");
+        if (!localStorage.getItem(key)) return;
+
+        xhr.send(JSON.stringify({delete_token: localStorage.getItem(key)}));
+
+        xhr.onreadystatechange = () => {
+          if (xhr.readyState === XMLHttpRequest.DONE) {
+            document.getElementById("uploaded_files").removeChild(UIelem.li);
+            localStorage.removeItem(key);
+          }
+
+          if (xhr.status === 200) {
+            console.log("The file was successfully deleted.");
+          } else {
+            console.log("The file has expired, or has already been deleted.");
+          }
+        }
+        
+      });
+      UIelem.li.appendChild(btn);
+    }
+  }
+}
+
+let setupUI = () => {
+  let li = document.createElement("li");
+  let name = document.createElement("p");
+  li.appendChild(name);
+  
+  let link = document.createElement("a");
+  li.appendChild(link);
+
+  let progress = document.createElement("p");
+  li.appendChild(progress);
+
+  document.getElementById("uploaded_files").appendChild(li);
+
+  return new UIWrapper(li, name, link, progress);
+}
+
+let ivToStr = (iv) => {
+  let hexStr = "";
+  for (let i in iv) {
+    if (iv[i] < 16) {
+      hexStr += "0" + iv[i].toString(16);
+    } else {
+      hexStr += iv[i].toString(16);
+    }
+  }
+  window.hexStr = hexStr;
+  return hexStr;
+}
+
+let strToIv = (str) => {
+  let iv = new Uint8Array(16);
+  for (let i = 0; i < str.length; i += 2) {
+    iv[i/2] = parseInt((str.charAt(i) + str.charAt(i + 1)), 16);
+  }
+
+  return iv;
+}