diff --git a/src/webdav.ts b/src/webdav.ts
new file mode 100644
index 0000000..c307551
--- /dev/null
+++ b/src/webdav.ts
@@ -0,0 +1,230 @@
+import { Buffer } from "buffer";
+import { FileStats, Vault } from "obsidian";
+import { AuthType, BufferLike, createClient } from "webdav/web";
+import type { WebDAVClient, ResponseDataDetailed, FileStat } from "webdav/web";
+
+import {
+  arrayBufferToBuffer,
+  bufferToArrayBuffer,
+  mkdirpInVault,
+} from "./misc";
+import { decryptArrayBuffer, encryptArrayBuffer } from "./encrypt";
+import { fileURLToPath } from "url";
+
+export interface WebdavConfig {
+  address: string;
+  username: string;
+  password: string;
+  authType: "digest" | "basic";
+}
+
+export const DEFAULT_WEBDAV_CONFIG = {
+  address: "",
+  username: "",
+  password: "",
+  authType: "basic",
+} as WebdavConfig;
+
+export const getWebdavClient = (webdavConfig: WebdavConfig) => {
+  if (webdavConfig.username !== "" && webdavConfig.password !== "") {
+    return createClient(webdavConfig.address, {
+      username: webdavConfig.username,
+      password: webdavConfig.password,
+      authType:
+        webdavConfig.authType === "digest"
+          ? AuthType.Digest
+          : AuthType.Password,
+    });
+  } else {
+    console.log("no password");
+    return createClient(webdavConfig.address);
+  }
+};
+
+const getWebdavPath = (fileOrFolderPath: string) => {
+  if (!fileOrFolderPath.startsWith("/")) {
+    return `/${fileOrFolderPath}`;
+  }
+  return fileOrFolderPath;
+};
+
+const getNormPath = (fileOrFolderPath: string) => {
+  if (fileOrFolderPath.startsWith("/")) {
+    return fileOrFolderPath.slice(1);
+  }
+  return fileOrFolderPath;
+};
+
+export const getRemoteMeta = async (
+  client: WebDAVClient,
+  fileOrFolderPath: string
+) => {
+  const res = (await client.stat(getWebdavPath(fileOrFolderPath), {
+    details: true,
+  })) as ResponseDataDetailed<FileStat>;
+  res.data.filename = getNormPath(res.data.filename);
+  return res;
+};
+
+export const uploadToRemote = async (
+  client: WebDAVClient,
+  fileOrFolderPath: string,
+  vault: Vault,
+  isRecursively: boolean = false,
+  password: string = "",
+  remoteEncryptedKey: string = ""
+) => {
+  let uploadFile = fileOrFolderPath;
+  if (password !== "") {
+    uploadFile = remoteEncryptedKey;
+  }
+  uploadFile = getWebdavPath(uploadFile);
+
+  const isFolder = fileOrFolderPath.endsWith("/");
+
+  if (isFolder && isRecursively) {
+    throw Error("upload function doesn't implement recursive function yet!");
+  } else if (isFolder && !isRecursively) {
+    // folder
+    if (password === "") {
+      // if not encrypted, mkdir a remote folder
+      client.createDirectory(uploadFile, {
+        recursive: true,
+      });
+      return await getRemoteMeta(client, uploadFile);
+    } else {
+      // if encrypted, upload a fake file with the encrypted file name
+      await client.putFileContents(uploadFile, "", {
+        overwrite: true,
+        onUploadProgress: (progress) => {
+          console.log(`Uploaded ${progress.loaded} bytes of ${progress.total}`);
+        },
+      });
+
+      return await getRemoteMeta(client, uploadFile);
+    }
+  } else {
+    // file
+    // we ignore isRecursively parameter here
+    const localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    let remoteContent = localContent;
+    if (password !== "") {
+      remoteContent = await encryptArrayBuffer(localContent, password);
+    }
+    await client.putFileContents(uploadFile, remoteContent, {
+      overwrite: true,
+      onUploadProgress: (progress) => {
+        console.log(`Uploaded ${progress.loaded} bytes of ${progress.total}`);
+      },
+    });
+
+    return await getRemoteMeta(client, uploadFile);
+  }
+};
+
+export const listFromRemote = async (client: WebDAVClient, prefix?: string) => {
+  if (prefix !== undefined) {
+    throw Error("prefix not supported");
+  }
+  const contents = (await client.getDirectoryContents("/", {
+    deep: true,
+    details: false /* no need for verbose details here */,
+    glob: "/**" /* avoid dot files by using glob */,
+  })) as FileStat[];
+  for (const singleItem of contents) {
+    singleItem.filename = getNormPath(singleItem.filename);
+  }
+  return {
+    Contents: contents,
+  };
+};
+
+export const downloadFromRemoteRaw = async (
+  client: WebDAVClient,
+  fileOrFolderPath: string
+) => {
+  const buff = (await client.getFileContents(
+    getWebdavPath(fileOrFolderPath)
+  )) as BufferLike;
+  if (buff instanceof ArrayBuffer) {
+    return buff;
+  } else if (buff instanceof Buffer) {
+    return bufferToArrayBuffer(buff);
+  }
+  throw Error(`unexpected file content result with type ${typeof buff}`);
+};
+
+export const downloadFromRemote = async (
+  client: WebDAVClient,
+  fileOrFolderPath: string,
+  vault: Vault,
+  mtime: number,
+  password: string = "",
+  remoteEncryptedKey: string = ""
+) => {
+  const isFolder = fileOrFolderPath.endsWith("/");
+
+  await mkdirpInVault(fileOrFolderPath, vault);
+
+  // the file is always local file
+  // we need to encrypt it
+
+  if (isFolder) {
+    // mkdirp locally is enough
+    // do nothing here
+  } else {
+    let downloadFile = fileOrFolderPath;
+    if (password !== "") {
+      downloadFile = remoteEncryptedKey;
+    }
+    downloadFile = getWebdavPath(downloadFile);
+    const remoteContent = await downloadFromRemoteRaw(client, downloadFile);
+    let localContent = remoteContent;
+    if (password !== "") {
+      localContent = await decryptArrayBuffer(remoteContent, password);
+    }
+    await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
+      mtime: mtime,
+    });
+  }
+};
+
+export const deleteFromRemote = async (
+  client: WebDAVClient,
+  fileOrFolderPath: string,
+  password: string = "",
+  remoteEncryptedKey: string = ""
+) => {
+  if (fileOrFolderPath === "/") {
+    return;
+  }
+  let remoteFileName = fileOrFolderPath;
+  if (password !== "") {
+    remoteFileName = remoteEncryptedKey;
+  }
+  remoteFileName = getWebdavPath(remoteFileName);
+  try {
+    await client.deleteFile(remoteFileName);
+    console.log(`delete ${remoteFileName} succeeded`);
+  } catch (err) {
+    console.error("some error while deleting");
+    console.log(err);
+  }
+};
+
+export const checkWebdavConnectivity = async (client: WebDAVClient) => {
+  try {
+    const results = await getRemoteMeta(client, "/");
+    if (
+      results === undefined ||
+      results.data === undefined ||
+      results.data.type === undefined ||
+      results.data.type !== "directory"
+    ) {
+      return false;
+    }
+    return true;
+  } catch (err) {
+    return false;
+  }
+};