fix(files): validate input when creating file/directory

apps/files/src/components/FileEntry/FileEntryName.vue

@@ -211,23 +211,22 @@ export default defineComponent({
 
 		isFileNameValid(name: string) {
 			const trimmedName = name.trim()
+			const char = trimmedName.indexOf('/') !== -1
+				? '/'
+				: forbiddenCharacters.find((char) => trimmedName.includes(char))
+
 			if (trimmedName === '.' || trimmedName === '..') {
 				throw new Error(t('files', '"{name}" is an invalid file name.', { name }))
 			} else if (trimmedName.length === 0) {
 				throw new Error(t('files', 'File name cannot be empty.'))
-			} else if (trimmedName.indexOf('/') !== -1) {
-				throw new Error(t('files', '"/" is not allowed inside a file name.'))
+			} else if (char) {
+				throw new Error(t('files', '"{char}" is not allowed inside a file name.', { char }))
 			} else if (trimmedName.match(window.OC.config.blacklist_files_regex)) {
 				throw new Error(t('files', '"{name}" is not an allowed filetype.', { name }))
 			} else if (this.checkIfNodeExists(name)) {
 				throw new Error(t('files', '{newName} already exists.', { newName: name }))
 			}
 
-			const char = forbiddenCharacters.find((char) => trimmedName.includes(char))
-			if (char) {
-				throw new Error(t('files', '"{char}" is not allowed inside a file name.', { char }))
-			}
-
 			return true
 		},
 

apps/files/src/components/NewNodeDialog.vue

@@ -20,10 +20,12 @@
 		<form @submit.prevent="onCreate">
 			<NcTextField ref="input"
 				data-cy-files-new-node-dialog-input
+				class="dialog__input"
 				:error="!isUniqueName"
 				:helper-text="errorMessage"
 				:label="label"
-				:value.sync="localDefaultName" />
+				:value.sync="localDefaultName"
+				@keyup="checkInputValidity" />
 		</form>
 	</NcDialog>
 </template>
@@ -34,15 +36,19 @@ import type { PropType } from 'vue'
 import { defineComponent } from 'vue'
 import { translate as t } from '@nextcloud/l10n'
 import { getUniqueName } from '@nextcloud/files'
+import { loadState } from '@nextcloud/initial-state'
 
 import NcButton from '@nextcloud/vue/dist/Components/NcButton.js'
 import NcDialog from '@nextcloud/vue/dist/Components/NcDialog.js'
 import NcTextField from '@nextcloud/vue/dist/Components/NcTextField.js'
+import logger from '../logger.js'
 
 interface ICanFocus {
 	focus: () => void
 }
 
+const forbiddenCharacters = loadState<string[]>('files', 'forbiddenCharacters', [])
+
 export default defineComponent({
 	name: 'NewNodeDialog',
 	components: {
@@ -147,6 +153,60 @@ export default defineComponent({
 				this.$emit('close', null)
 			}
 		},
+
+		/**
+		 * Check if the file name is valid and update the
+		 * input validity using browser's native validation.
+		 * @param event the keyup event
+		 */
+		checkInputValidity(event: KeyboardEvent) {
+			const input = event.target as HTMLInputElement
+			const newName = this.localDefaultName.trim?.() || ''
+			logger.debug('Checking input validity', { newName })
+			try {
+				this.isFileNameValid(newName)
+				input.setCustomValidity('')
+				input.title = ''
+			} catch (e) {
+				if (e instanceof Error) {
+					input.setCustomValidity(e.message)
+					input.title = e.message
+				} else {
+					input.setCustomValidity(t('files', 'Invalid file name'))
+				}
+			} finally {
+				input.reportValidity()
+			}
+		},
+
+		isFileNameValid(name: string) {
+			const trimmedName = name.trim()
+			const char = trimmedName.indexOf('/') !== -1
+				? '/'
+				: forbiddenCharacters.find((char) => trimmedName.includes(char))
+
+			if (trimmedName === '.' || trimmedName === '..') {
+				throw new Error(t('files', '"{name}" is an invalid file name.', { name }))
+			} else if (trimmedName.length === 0) {
+				throw new Error(t('files', 'File name cannot be empty.'))
+			} else if (char) {
+				throw new Error(t('files', '"{char}" is not allowed inside a file name.', { char }))
+			} else if (trimmedName.match(window.OC.config.blacklist_files_regex)) {
+				throw new Error(t('files', '"{name}" is not an allowed filetype.', { name }))
+			}
+
+			return true
+		},
 	},
 })
 </script>
+
+<style lang="scss" scoped>
+.dialog__input {
+	:deep(input:invalid) {
+		// Show red border on invalid input
+		border-color: var(--color-error);
+		color: red;
+	}
+}
+</style>