chore: Restructure files.

sshfrontend/src/libs/readFromKeyboard.ts

@@ -0,0 +1,109 @@
+import type { ServerChannel } from "ssh2";
+
+const pullRate = process.env.KEYBOARD_PULLING_RATE
+  ? parseInt(process.env.KEYBOARD_PULLING_RATE)
+  : 5;
+
+const leftEscape = "\x1B[D";
+const rightEscape = "\x1B[C";
+
+const ourBackspace = "\u0008";
+const clientBackspace = "\x7F";
+
+export async function readFromKeyboard(
+  stream: ServerChannel,
+  disableEcho: boolean = false,
+): Promise<string> {
+  let promise: (value: string | PromiseLike<string>) => void;
+
+  let line = "";
+  let lineIndex = 0;
+
+  async function eventLoop(): Promise<any> {
+    const readStreamDataBuf = stream.read();
+    if (readStreamDataBuf == null) return setTimeout(eventLoop, pullRate);
+
+    const readStreamData = readStreamDataBuf.toString();
+
+    // Fixes several bugs (incl. potential social eng. exploits, ssh-copy-id being broken, etc)
+    for (const character of readStreamData.split("")) {
+      if (character == "\x03") {
+        stream.write("^C");
+        return promise("");
+      } else if (character == "\r" || character == "\n") {
+        return promise(line.replace("\r", ""));
+      } else if (character == clientBackspace) {
+        if (line.length == 0) return setTimeout(eventLoop, pullRate); // Here because if we do it in the parent if statement, shit breaks
+        line = line.substring(0, lineIndex - 1) + line.substring(lineIndex);
+
+        if (!disableEcho) {
+          const deltaCursor = line.length - lineIndex;
+
+          if (deltaCursor == line.length)
+            return setTimeout(eventLoop, pullRate);
+
+          if (deltaCursor < 0) {
+            // Use old technique if the delta is < 0, as the new one is tailored to the start + 1 to end - 1
+            stream.write(ourBackspace + " " + ourBackspace);
+          } else {
+            // Jump forward to the front, and remove the last character
+            stream.write(rightEscape.repeat(deltaCursor) + " " + ourBackspace);
+
+            // Go backwards & rerender text & go backwards again (wtf?)
+            stream.write(
+              leftEscape.repeat(deltaCursor + 1) +
+                line.substring(lineIndex - 1) +
+                leftEscape.repeat(deltaCursor + 1),
+            );
+          }
+
+          lineIndex -= 1;
+        }
+      } else if (character == "\x1B") {
+        if (character == rightEscape) {
+          if (lineIndex + 1 > line.length)
+            return setTimeout(eventLoop, pullRate);
+          lineIndex += 1;
+        } else if (character == leftEscape) {
+          if (lineIndex - 1 < 0) return setTimeout(eventLoop, pullRate);
+          lineIndex -= 1;
+        } else {
+          return setTimeout(eventLoop, pullRate);
+        }
+
+        if (!disableEcho) stream.write(character);
+      } else {
+        lineIndex += 1;
+
+        // There isn't a splice method for String prototypes. So, ugh:
+        line =
+          line.substring(0, lineIndex - 1) +
+          character +
+          line.substring(lineIndex - 1);
+
+        if (!disableEcho) {
+          let deltaCursor = line.length - lineIndex;
+
+          // wtf?
+          if (deltaCursor < 0) {
+            console.log(
+              "FIXME: somehow, our deltaCursor value is negative! please investigate me",
+            );
+            deltaCursor = 0;
+          }
+
+          stream.write(
+            line.substring(lineIndex - 1) + leftEscape.repeat(deltaCursor),
+          );
+        }
+      }
+    }
+
+    setTimeout(eventLoop, pullRate);
+  }
+
+  return new Promise(resolve => {
+    setTimeout(eventLoop, pullRate);
+    promise = resolve;
+  });
+}