Initial U-Navigator prototype

server/multipart.js

@@ -0,0 +1,59 @@
+export async function readRequestBody(req, limitBytes) {
+  const chunks = [];
+  let size = 0;
+
+  for await (const chunk of req) {
+    size += chunk.length;
+    if (size > limitBytes) {
+      const error = new Error('Request body is too large');
+      error.status = 413;
+      throw error;
+    }
+    chunks.push(chunk);
+  }
+
+  return Buffer.concat(chunks);
+}
+
+export function parseMultipart(buffer, contentType) {
+  const match = /boundary=(?:"([^"]+)"|([^;]+))/i.exec(contentType || '');
+  if (!match) {
+    const error = new Error('Missing multipart boundary');
+    error.status = 400;
+    throw error;
+  }
+
+  const boundary = `--${match[1] || match[2]}`;
+  const binary = buffer.toString('binary');
+  const parts = [];
+
+  for (const raw of binary.split(boundary)) {
+    if (!raw || raw === '--\r\n' || raw === '--') {
+      continue;
+    }
+
+    const trimmed = raw.replace(/^\r\n/, '').replace(/\r\n--$/, '');
+    const separator = trimmed.indexOf('\r\n\r\n');
+    if (separator === -1) {
+      continue;
+    }
+
+    const headerText = trimmed.slice(0, separator);
+    let bodyText = trimmed.slice(separator + 4);
+    if (bodyText.endsWith('\r\n')) {
+      bodyText = bodyText.slice(0, -2);
+    }
+
+    const disposition = /content-disposition:\s*form-data;\s*([^\r\n]+)/i.exec(headerText)?.[1] || '';
+    const name = /name="([^"]+)"/i.exec(disposition)?.[1] || '';
+    const filename = /filename="([^"]*)"/i.exec(disposition)?.[1] || '';
+
+    parts.push({
+      name,
+      filename,
+      data: Buffer.from(bodyText, 'binary')
+    });
+  }
+
+  return parts;
+}