Merge branch 'kmohrf/flow-control' into 'master'

Allow API store consumers to use traditional flow-control

See merge request !10

src/store/api-helper.js

+import { has } from '@/utilities'
+
+function isErrorObject (obj) {
+    return has(obj, 'message') && has(obj, 'code')
+}
+
+/**
+ * Parses the variety of error formats that are emitted by
+ * Django REST framework and yields error objects.
+ */
+function * extractResponseErrors(responseData) {
+    if (isErrorObject(responseData)) {
+        yield responseData
+    } else if (has(responseData, 'detail') && isErrorObject(responseData.detail)) {
+        yield responseData.detail
+    } else if (Array.isArray(responseData)) {
+        for (const item of responseData) {
+            if (isErrorObject(item)) {
+                yield item
+            }
+        }
+    }
+}
+
+export class APIError extends Error {
+    constructor(message, response) {
+        super(message ?? response?.statusText)
+        this.response = response
+        this.errors = Array.from(extractResponseErrors(response?.data))
+    }
+
+    /**
+     * Handle API response errors by either calling the provided callbacks
+     * or throwing exceptions that can be processed in promise handlers.
+     */
+    static handle(error, message, context, vm) {
+        if (typeof context?.callback === 'function' || typeof context?.callbackCancel === 'function') {
+            // This API request was made by a callback-style caller,
+            // so we do error handling like we used to do it.
+            handleApiError(vm, error, message)
+            context?.callbackCancel?.()
+        } else {
+            // This API request was made by a caller that did not define any callback handlers.
+            // We take this as an indication, that the caller wants to use
+            // traditional flow-control with try-catch statements.
+            throw new APIError(message, error.response)
+        }
+    }
+}
+
+export function handleApiError(vm, err, message) {
+    if (err.response) {
+        vm.$log.error(err.response.status + ' ' + err.response.statusText)
+        vm.$log.error(err.response)
+        let msg = 'Error: '
+        if (message) {
+            msg += message
+        }
+        msg += '\n\n'
+        msg += 'Status code: ' + err.response.status + ' ' + err.response.statusText
+        alert(msg)
+    } else {
+        vm.$log.error(err)
+        if (message) {
+            alert('Error: ' + message + '\nInspect the console for more details.')
+        } else {
+            alert('Unspecified error. Inspect the console for details.')
+        }
+    }
+}
+
+
+/**
+ * Like APIError.handle this is a helper to allow us to migrate from the
+ * callback-oriented to promise-based response handling.
+ *
+ * When a callback is provided it mimics the old callback behaviour and
+ * calls the callback with the response and returns undefined.
+ * If no callback is provided we assume the caller wants to handle
+ * the response promise.
+ */
+export function callOrReturn (response, callback) {
+    if (typeof callback === 'function') {
+        callback(response)
+        return undefined
+    } else {
+        return response
+    }
+}

src/store/handleApiError.js

-export default function handleApiError(vm, err, message) {
-    if (err.response) {
-        vm.$log.error(err.response.status + ' ' + err.response.statusText)
-        vm.$log.error(err.response)
-        let msg = 'Error: '
-        if (message) {
-            msg += message
-        }
-        msg += '\n\n'
-        msg += 'Status code: ' + err.response.status + ' ' + err.response.statusText
-        alert(msg)
-    } else {
-        vm.$log.error(err)
-        if (message) {
-            alert('Error: ' + message + '\nInspect the console for more details.')
-        } else {
-            alert('Unspecified error. Inspect the console for details.')
-        }
-    }
-}

src/store/modules/auth.js

 import axios from 'axios'
 import oidc from 'oidc-client'
-import handleApiError from '../handleApiError'
+import { handleApiError } from '../api-helper'
 
 const oidcmgr = new oidc.UserManager({
     userStore: new oidc.WebStorageStateStore(),

src/store/modules/files.js

 import axios from 'axios'
-import handleApiError from '../handleApiError'
+import { handleApiError } from '../api-helper'
 
 const state = {
     files: [],

src/store/modules/playlists.js

 import axios from 'axios'
-import handleApiError from '../handleApiError'
+import { handleApiError } from '../api-helper'
 
 const state = {
     playlists: [],

src/store/modules/shows.js

 import axios from 'axios'
-import handleApiError from '../handleApiError'
+import { handleApiError } from '../api-helper'
 
 const cloneMinimalShowObject = function (show) {
     /* returns a new minimal object from the current show object with all

src/utilities.js

@@ -5,3 +5,11 @@ export function uppercaseFirst(string = "") {
 export function lowercaseFirst(string = "") {
     return string.charAt(0).toLowerCase() + string.slice(1)
 }
+
+export function has(obj, prop) {
+    try {
+        return Object.prototype.hasOwnProperty.call(obj, prop)
+    } catch (e) {
+        return false
+    }
+}