Switch to GET API; Save the server root respond in a variable

Author: Jaipreet Singh

jupyterlab_git/handlers.py

@@ -445,7 +445,7 @@ def post(self):
 
 class GitServerRootHandler(GitHandler):
 
-    def post(self):
+    def get(self):
         # Similar to https://github.com/jupyter/nbdime/blob/master/nbdime/webapp/nb_server_extension.py#L90-L91
         self.finish(json.dumps({
             "server_root": getattr(self.contents_manager, 'root_dir', None)

src/components/diff/DiffWidget.tsx

@@ -68,6 +68,7 @@ export async function openDiffView(
   }
 }
 
+let serverRootResultCache = null;
 /**
  * Gets the path of the file relative to the Jupyter server root. This resolves the server root path after calling
  * the `/git/server_root` REST API, and uses the Git repo root and the file path relative to the repo root to resolve
@@ -79,10 +80,15 @@ export async function getRelativeFilePath(
   path: string,
   topRepoPath: string
 ): Promise<string> {
-  const response = await httpGitRequest('/git/server_root', 'POST', {});
-  const responseData = await response.json();
-  return PathExt.join(
-    PathExt.relative(responseData['server_root'], topRepoPath),
-    path
-  );
+  if (serverRootResultCache !== null) {
+    return serverRootResultCache;
+  } else {
+    const response = await httpGitRequest('/git/server_root', 'GET', null);
+    const responseData = await response.json();
+    serverRootResultCache = PathExt.join(
+      PathExt.relative(responseData['server_root'], topRepoPath),
+      path
+    );
+    return serverRootResultCache;
+  }
 }

src/git.ts

@@ -132,12 +132,19 @@ export interface IIdentity {
 export function httpGitRequest(
   url: string,
   method: string,
-  request: Object
+  request: Object | null
 ): Promise<Response> {
-  let fullRequest = {
-    method: method,
-    body: JSON.stringify(request)
-  };
+  let fullRequest;
+  if (request === null) {
+    fullRequest = {
+      method: method
+    };
+  } else {
+    fullRequest = {
+      method: method,
+      body: JSON.stringify(request)
+    };
+  }
 
   let setting = ServerConnection.makeSettings();
   let fullUrl = URLExt.join(setting.baseUrl, url);