1 files changed, 112 insertions, 0 deletions

diff --git a/src/stores/lib/Request.js b/src/stores/lib/Request.js
new file mode 100644
index 000000000..4a6925cc5
--- /dev/null
+++ b/src/stores/lib/Request.js
@@ -0,0 +1,112 @@
+import { observable, action, computed } from 'mobx';
+import { isEqual } from 'lodash/fp';
+
+export default class Request {
+  static _hooks = [];
+
+  static registerHook(hook) {
+    Request._hooks.push(hook);
+  }
+
+  @observable result = null;
+  @observable error = null;
+  @observable isExecuting = false;
+  @observable isError = false;
+  @observable wasExecuted = false;
+
+  _promise = Promise;
+  _api = {};
+  _method = '';
+  _isWaitingForResponse = false;
+  _currentApiCall = null;
+
+  constructor(api, method) {
+    this._api = api;
+    this._method = method;
+  }
+
+  execute(...callArgs) {
+    // Do not continue if this request is already loading
+    if (this._isWaitingForResponse) return this;
+
+    if (!this._api[this._method]) {
+      throw new Error(`Missing method <${this._method}> on api object:`, this._api);
+    }
+
+    // This timeout is necessary to avoid warnings from mobx
+    // regarding triggering actions as side-effect of getters
+    setTimeout(action(() => {
+      this.isExecuting = true;
+    }), 0);
+
+    // Issue api call & save it as promise that is handled to update the results of the operation
+    this._promise = new Promise((resolve, reject) => {
+      this._api[this._method](...callArgs)
+        .then((result) => {
+          setTimeout(action(() => {
+            this.result = result;
+            if (this._currentApiCall) this._currentApiCall.result = result;
+            this.isExecuting = false;
+            this.isError = false;
+            this.wasExecuted = true;
+            this._isWaitingForResponse = false;
+            this._triggerHooks();
+            resolve(result);
+          }), 1);
+          return result;
+        })
+        .catch(action((error) => {
+          setTimeout(action(() => {
+            this.error = error;
+            this.isExecuting = false;
+            this.isError = true;
+            this.wasExecuted = true;
+            this._isWaitingForResponse = false;
+            this._triggerHooks();
+            reject(error);
+          }), 1);
+        }));
+    });
+
+    this._isWaitingForResponse = true;
+    this._currentApiCall = { args: callArgs, result: null };
+    return this;
+  }
+
+  reload() {
+    return this.execute(...this._currentApiCall.args);
+  }
+
+  isExecutingWithArgs(...args) {
+    return this.isExecuting && this._currentApiCall && isEqual(this._currentApiCall.args, args);
+  }
+
+  @computed get isExecutingFirstTime() {
+    return !this.wasExecuted && this.isExecuting;
+  }
+
+  then(...args) {
+    if (!this._promise) throw new Error('You have to call Request::execute before you can access it as promise');
+    return this._promise.then(...args);
+  }
+
+  catch(...args) {
+    if (!this._promise) throw new Error('You have to call Request::execute before you can access it as promise');
+    return this._promise.catch(...args);
+  }
+
+  _triggerHooks() {
+    Request._hooks.forEach(hook => hook(this));
+  }
+
+  reset() {
+    this.result = null;
+    this.isExecuting = false;
+    this.isError = false;
+    this.wasExecuted = false;
+    this._isWaitingForResponse = false;
+    this._promise = Promise;
+
+    return this;
+  }
+}