Merge branch 'winh-frontend-user-cache' into 'master'

Introduce UsersCache for storing user entities in frontend

See merge request !11404

3 files changed, 51 insertions, 14 deletions

diff --git a/app/assets/javascripts/lib/utils/ajax_cache.js b/app/assets/javascripts/lib/utils/ajax_cache.js
index cf030d613df..f1fe95e12e8 100644
--- a/app/assets/javascripts/lib/utils/ajax_cache.js
+++ b/app/assets/javascripts/lib/utils/ajax_cache.js
@@ -1,21 +1,11 @@
-class AjaxCache {
+import Cache from './cache';
+
+class AjaxCache extends Cache {
   constructor() {
-    this.internalStorage = { };
+    super();
     this.pendingRequests = { };
   }
 
-  get(endpoint) {
-    return this.internalStorage[endpoint];
-  }
-
-  hasData(endpoint) {
-    return Object.prototype.hasOwnProperty.call(this.internalStorage, endpoint);
-  }
-
-  remove(endpoint) {
-    delete this.internalStorage[endpoint];
-  }
-
   retrieve(endpoint) {
     if (this.hasData(endpoint)) {
       return Promise.resolve(this.get(endpoint));
diff --git a/app/assets/javascripts/lib/utils/cache.js b/app/assets/javascripts/lib/utils/cache.js
new file mode 100644
index 00000000000..3141f1eeafc
--- /dev/null
+++ b/app/assets/javascripts/lib/utils/cache.js
@@ -0,0 +1,19 @@
+class Cache {
+  constructor() {
+    this.internalStorage = { };
+  }
+
+  get(key) {
+    return this.internalStorage[key];
+  }
+
+  hasData(key) {
+    return Object.prototype.hasOwnProperty.call(this.internalStorage, key);
+  }
+
+  remove(key) {
+    delete this.internalStorage[key];
+  }
+}
+
+export default Cache;
diff --git a/app/assets/javascripts/lib/utils/users_cache.js b/app/assets/javascripts/lib/utils/users_cache.js
new file mode 100644
index 00000000000..88f8a622c00
--- /dev/null
+++ b/app/assets/javascripts/lib/utils/users_cache.js
@@ -0,0 +1,28 @@
+import Api from '../../api';
+import Cache from './cache';
+
+class UsersCache extends Cache {
+  retrieve(username) {
+    if (this.hasData(username)) {
+      return Promise.resolve(this.get(username));
+    }
+
+    return Api.users('', { username })
+      .then((users) => {
+        if (!users.length) {
+          throw new Error(`User "${username}" could not be found!`);
+        }
+
+        if (users.length > 1) {
+          throw new Error(`Expected username "${username}" to be unique!`);
+        }
+
+        const user = users[0];
+        this.internalStorage[username] = user;
+        return user;
+      });
+      // missing catch is intentional, error handling depends on use case
+  }
+}
+
+export default new UsersCache();