Added ability to delete existing files through storage adapters

refs https://github.com/TryGhost/Toolbox/issues/120

- When editing an uploaded media thumbnail  file there'a need to remove existing thumbnail to keep media files:thumbnails 1:1. - Because the API client only has a public URL under which the resource is served it can only provide that as an API input, the `urlToPath` was also added to the base class of LocalStorageAdapter (it might be moved up to the BaseAdapter in the future if we see a need)

core/server/adapters/storage/LocalFilesStorage.js

@@ -1,4 +1,4 @@
-// # Local File System Video Storage module
+// # Local File System Storage module
 // The (default) module for storing media, using the local file system
 const config = require('../../../shared/config');
 const constants = require('@tryghost/constants');
@@ -8,6 +8,7 @@ class LocalFilesStorage extends LocalStorageBase {
     constructor() {
         super({
             storagePath: config.getContentPath('files'),
+            siteUrl: config.getSiteUrl(),
             staticFileURLPrefix: constants.STATIC_FILES_URL_PREFIX
         });
     }

core/server/adapters/storage/LocalImagesStorage.js

@@ -19,6 +19,7 @@ class LocalImagesStorage extends LocalStorageBase {
         super({
             storagePath: config.getContentPath('images'),
             staticFileURLPrefix: urlUtils.STATIC_IMAGE_URL_PREFIX,
+            siteUrl: config.getSiteUrl(),
             errorMessages: messages
         });
     }

core/server/adapters/storage/LocalMediaStorage.js

@@ -1,4 +1,4 @@
-// # Local File System Video Storage module
+// # Local File System Media Storage module
 // The (default) module for storing media, using the local file system
 const config = require('../../../shared/config');
 const constants = require('@tryghost/constants');
@@ -15,6 +15,7 @@ class LocalMediaStore extends LocalStorageBase {
         super({
             storagePath: config.getContentPath('media'),
             staticFileURLPrefix: constants.STATIC_MEDIA_URL_PREFIX,
+            siteUrl: config.getSiteUrl(),
             errorMessages: messages
         });
     }

core/server/adapters/storage/LocalStorageBase.js

@@ -16,7 +16,8 @@ const StorageBase = require('ghost-storage-base');
 const messages = {
     notFound: 'File not found',
     notFoundWithRef: 'File not found: {file}',
-    cannotRead: 'Could not read file: {file}'
+    cannotRead: 'Could not read file: {file}',
+    invalidUrlParameter: `The URL "{url}" is not a valid URL for this site.`
 };
 
 class LocalStorageBase extends StorageBase {
@@ -24,17 +25,20 @@ class LocalStorageBase extends StorageBase {
      *
      * @param {Object} options
      * @param {String} options.storagePath
+     * @param {String} options.siteUrl
      * @param {String} [options.staticFileURLPrefix]
      * @param {Object} [options.errorMessages]
      * @param {String} [options.errorMessages.notFound]
      * @param {String} [options.errorMessages.notFoundWithRef]
      * @param {String} [options.errorMessages.cannotRead]
      */
-    constructor({storagePath, staticFileURLPrefix, errorMessages}) {
+    constructor({storagePath, staticFileURLPrefix, siteUrl, errorMessages}) {
         super();
 
         this.storagePath = storagePath;
         this.staticFileURLPrefix = staticFileURLPrefix;
+        this.siteUrl = siteUrl;
+        this.staticFileUrl = `${siteUrl}${staticFileURLPrefix}`;
         this.errorMessages = errorMessages || messages;
     }
 
@@ -71,6 +75,26 @@ class LocalStorageBase extends StorageBase {
         return fullUrl;
     }
 
+    /**
+     *
+     * @param {String} url full url under which the stored content is served, result of save method
+     * @returns {String} path under which the content is stored
+     */
+    urlToPath(url) {
+        let filePath;
+
+        if (url.match(this.staticFileUrl)) {
+            filePath = url.replace(this.staticFileUrl, '');
+            filePath = path.join(this.storagePath, filePath);
+        } else {
+            throw new errors.IncorrectUsageError({
+                message: tpl(messages.invalidUrlParameter, {url})
+            });
+        }
+
+        return filePath;
+    }
+
     exists(fileName, targetDir) {
         const filePath = path.join(targetDir || this.storagePath, fileName);
 
@@ -132,11 +156,12 @@ class LocalStorageBase extends StorageBase {
     }
 
     /**
-     * Not implemented.
+     * @param {String} filePath
      * @returns {Promise.<*>}
      */
-    delete() {
-        return Promise.reject('not implemented');
+    async delete(fileName, targetDir) {
+        const filePath = path.join(targetDir, fileName);
+        return await fs.remove(filePath);
     }
 
     /**

test/unit/server/adapters/storage/LocalBaseStorage.test.js

@@ -0,0 +1,32 @@
+const should = require('should');
+const LocalStorageBase = require('../../../../../core/server/adapters/storage/LocalStorageBase');
+
+describe('Local Storage Base', function () {
+    describe('urlToPath', function () {
+        it('returns path from url', function () {
+            let localStorageBase = new LocalStorageBase({
+                storagePath: '/media-storage/path/',
+                staticFileURLPrefix: 'content/media',
+                siteUrl: 'http://example.com/blog/'
+            });
+
+            localStorageBase.urlToPath('http://example.com/blog/content/media/2021/11/media.mp4')
+                .should.eql('/media-storage/path/2021/11/media.mp4');
+        });
+
+        it('throws if the url does not match current site', function () {
+            let localStorageBase = new LocalStorageBase({
+                storagePath: '/media-storage/path/',
+                staticFileURLPrefix: 'content/media',
+                url: 'http://example.com/blog/'
+            });
+
+            try {
+                localStorageBase.urlToPath('http://anothersite.com/blog/content/media/2021/11/media.mp4');
+                should.fail('urlToPath when urls do not match');
+            } catch (error) {
+                error.message.should.eql('The URL "http://anothersite.com/blog/content/media/2021/11/media.mp4" is not a valid URL for this site.');
+            }
+        });
+    });
+});