1 files changed, 185 insertions, 0 deletions
diff --git a/js/dav/lib/transport.js b/js/dav/lib/transport.js
new file mode 100644
index 00000000..03104de3
--- /dev/null
+++ b/js/dav/lib/transport.js
@@ -0,0 +1,185 @@
+import co from 'co';
+import querystring from 'querystring';
+
+import XMLHttpRequest from './xmlhttprequest';
+
+export class Transport {
+  /**
+   * @param {dav.Credentials} credentials user authorization.
+   */
+  constructor(credentials) {
+    this.credentials = credentials || null;
+  }
+
+  /**
+   * @param {dav.Request} request object with request info.
+   * @return {Promise} a promise that will be resolved with an xhr request after
+   *     its readyState is 4 or the result of applying an optional request
+   *     `transformResponse` function to the xhr object after its readyState is 4.
+   *
+   * Options:
+   *
+   *   (Object) sandbox - optional request sandbox.
+   */
+  send() {}
+}
+
+export class Basic extends Transport {
+  /**
+   * @param {dav.Credentials} credentials user authorization.
+   */
+  constructor(credentials) {
+    super(credentials);
+  }
+
+  send(request, url, options) {
+    return co(function *() {
+      let sandbox = options && options.sandbox;
+      let transformRequest = request.transformRequest;
+      let transformResponse = request.transformResponse;
+      let onerror = request.onerror;
+
+      let xhr = new XMLHttpRequest();
+      if (sandbox) sandbox.add(xhr);
+      xhr.open(
+        request.method,
+        url,
+        true /* async */,
+        this.credentials.username,
+        this.credentials.password
+      );
+
+      if (transformRequest) transformRequest(xhr);
+
+      let result;
+      try {
+        yield xhr.send(request.requestData);
+        result = transformResponse ? transformResponse(xhr) : xhr;
+      } catch (error) {
+        if (onerror) onerror(error);
+        throw error;
+      }
+
+      return result;
+    }.bind(this));
+  }
+}
+
+/**
+ * @param {dav.Credentials} credentials user authorization.
+ */
+export class OAuth2 extends Transport {
+  constructor(credentials) {
+    super(credentials);
+  }
+
+  send(request, url, options={}) {
+    return co(function *() {
+      let sandbox = options.sandbox;
+      let transformRequest = request.transformRequest;
+      let transformResponse = request.transformResponse;
+      let onerror = request.onerror;
+
+      if (!('retry' in options)) options.retry = true;
+
+      let result, xhr;
+      try {
+        let token = yield access(this.credentials, options);
+        xhr = new XMLHttpRequest();
+        if (sandbox) sandbox.add(xhr);
+        xhr.open(request.method, url, true /* async */);
+        xhr.setRequestHeader('Authorization', `Bearer ${token}`);
+        if (transformRequest) transformRequest(xhr);
+        yield xhr.send(request.requestData);
+        result = transformResponse ? transformResponse(xhr) : xhr;
+      } catch (error) {
+        if (options.retry && xhr.status === 401) {
+          // Force expiration.
+          this.credentials.expiration = 0;
+          // Retry once at most.
+          options.retry = false;
+          return this.send(request, url, options);
+        }
+
+        if (onerror) onerror(error);
+        throw error;
+      }
+
+      return result;
+    }.bind(this));
+  }
+}
+
+/**
+ * @return {Promise} promise that will resolve with access token.
+ */
+function access(credentials, options) {
+  if (!credentials.accessToken) {
+    return getAccessToken(credentials, options);
+  }
+
+  if (credentials.refreshToken && isExpired(credentials)) {
+    return refreshAccessToken(credentials, options);
+  }
+
+  return Promise.resolve(credentials.accessToken);
+}
+
+function isExpired(credentials) {
+  return typeof credentials.expiration === 'number' &&
+         Date.now() > credentials.expiration;
+}
+
+let getAccessToken = co.wrap(function *(credentials, options) {
+  let sandbox = options.sandbox;
+  let xhr = new XMLHttpRequest();
+  if (sandbox) sandbox.add(xhr);
+  xhr.open('POST', credentials.tokenUrl, true /* async */);
+  xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
+
+  let data = querystring.stringify({
+    code: credentials.authorizationCode,
+    redirect_uri: credentials.redirectUrl,
+    client_id: credentials.clientId,
+    client_secret: credentials.clientSecret,
+    grant_type: 'authorization_code'
+  });
+
+  let now = Date.now();
+  yield xhr.send(data);
+  let response = JSON.parse(xhr.responseText);
+  credentials.accessToken = response.access_token;
+  credentials.refreshToken = 'refresh_token' in response ?
+    response.refresh_token :
+    null;
+  credentials.expiration = 'expires_in' in response ?
+    now + response.expires_in :
+    null;
+
+  return response.access_token;
+});
+
+let refreshAccessToken = co.wrap(function *(credentials, options) {
+  let sandbox = options.sandbox;
+  let xhr = new XMLHttpRequest();
+  if (sandbox) sandbox.add(xhr);
+  xhr.open('POST', credentials.tokenUrl, true /* async */);
+  xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
+
+  let data = querystring.stringify({
+    client_id: credentials.clientId,
+    client_secret: credentials.clientSecret,
+    refresh_token: credentials.refreshToken,
+    grant_type: 'refresh_token'
+  });
+
+  let now = Date.now();
+  yield xhr.send(data);
+  let response = JSON.parse(xhr.responseText);
+  credentials.accessToken = response.access_token;
+  credentials.expiration = 'expires_in' in response ?
+    now + response.expires_in :
+    null;
+
+  return response.access_token;
+});