Allow custom public share tokens for form links

docs/API_v3.md

@@ -631,7 +631,12 @@ Update a single or all properties of an option-object
   | Parameter | Type | Description |
   |------------------|----------|-------------|
   | _keyValuePairs_ | Array | Array of key-value pairs to update |
-- Restrictions: Currently only the _permissions_ can be updated.
+- Restrictions:
+  - Allowed keys are _permissions_ and _token_.
+  - _token_ updates are only available when the admin setting _allowCustomPublicShareTokens_ is enabled.
+  - _token_ can only be updated on link shares.
+  - _token_ must be unique among link shares and only contain alphanumeric characters.
+  - _token_ length must be between 8 and 256 characters.
 - Response: **Status-Code OK**, as well as the id of the share object.
 
 ```

lib/Constants.php

@@ -15,17 +15,23 @@ class Constants {
 	 */
 	public const CONFIG_KEY_ALLOWPERMITALL = 'allowPermitAll';
 	public const CONFIG_KEY_ALLOWPUBLICLINK = 'allowPublicLink';
+	public const CONFIG_KEY_ALLOWCUSTOMPUBLICTOKEN = 'allowCustomPublicShareTokens';
 	public const CONFIG_KEY_ALLOWSHOWTOALL = 'allowShowToAll';
 	public const CONFIG_KEY_CREATIONALLOWEDGROUPS = 'creationAllowedGroups';
 	public const CONFIG_KEY_RESTRICTCREATION = 'restrictCreation';
 	public const CONFIG_KEYS = [
 		self::CONFIG_KEY_ALLOWPERMITALL,
 		self::CONFIG_KEY_ALLOWPUBLICLINK,
+		self::CONFIG_KEY_ALLOWCUSTOMPUBLICTOKEN,
 		self::CONFIG_KEY_ALLOWSHOWTOALL,
 		self::CONFIG_KEY_CREATIONALLOWEDGROUPS,
 		self::CONFIG_KEY_RESTRICTCREATION
 	];
 
+	public const PUBLIC_SHARE_TOKEN_MIN_LENGTH = 8;
+	public const PUBLIC_SHARE_TOKEN_MAX_LENGTH = 256;
+	public const PUBLIC_SHARE_HASH_REQUIREMENT = '[a-zA-Z0-9]{' . self::PUBLIC_SHARE_TOKEN_MIN_LENGTH . ',' . self::PUBLIC_SHARE_TOKEN_MAX_LENGTH . '}';
+
 	/**
 	 * Maximum String lengths, the database is set to store.
 	 */

lib/Controller/PageController.php

@@ -145,7 +145,7 @@ public function internalLinkView(string $hash): Response {
 	#[NoAdminRequired()]
 	#[NoCSRFRequired()]
 	#[PublicPage()]
-	#[FrontpageRoute(verb: 'GET', url: '/s/{hash}', requirements: ['hash' => '[a-zA-Z0-9]{24,}'])]
+	#[FrontpageRoute(verb: 'GET', url: '/s/{hash}', requirements: ['hash' => Constants::PUBLIC_SHARE_HASH_REQUIREMENT])]
 	public function publicLinkView(string $hash): Response {
 		try {
 			$share = $this->shareMapper->findPublicShareByHash($hash);

lib/Controller/ShareApiController.php

@@ -207,17 +207,21 @@ public function newShare(int $formId, int $shareType, string $shareWith = '', ar
 	}
 
 	/**
-	 * Update permissions of a share
+	 * Update properties of a share
 	 *
 	 * @param int $formId of the form
 	 * @param int $shareId of the share to update
 	 * @param array<string, mixed> $keyValuePairs Array of key=>value pairs to update.
 	 * @return DataResponse<Http::STATUS_OK, int, array{}>
 	 * @throws OCSBadRequestException Share doesn't belong to given Form
 	 * @throws OCSBadRequestException Invalid permission given
+	 * @throws OCSBadRequestException Invalid share token
+	 * @throws OCSBadRequestException Share hash exists, please retry
+	 * @throws OCSForbiddenException Custom public share tokens are not allowed
 	 * @throws OCSForbiddenException This form is not owned by the current user
 	 * @throws OCSForbiddenException Empty keyValuePairs, will not update
-	 * @throws OCSForbiddenException Not allowed to update other properties than permissions
+	 * @throws OCSForbiddenException Not allowed to update token on non-link share
+	 * @throws OCSForbiddenException Not allowed to update unknown properties
 	 * @throws OCSNotFoundException Could not find share
 	 *
 	 * 200: the id of the updated share
@@ -226,7 +230,7 @@ public function newShare(int $formId, int $shareType, string $shareWith = '', ar
 	#[NoAdminRequired()]
 	#[ApiRoute(verb: 'PATCH', url: '/api/v3/forms/{formId}/shares/{shareId}')]
 	public function updateShare(int $formId, int $shareId, array $keyValuePairs): DataResponse {
-		$this->logger->debug('Updating share: {shareId} of form {formId}, permissions: {permissions}', [
+		$this->logger->debug('Updating share: {shareId} of form {formId}, values: {keyValuePairs}', [
 			'formId' => $formId,
 			'shareId' => $shareId,
 			'keyValuePairs' => $keyValuePairs
@@ -256,22 +260,64 @@ public function updateShare(int $formId, int $shareId, array $keyValuePairs): Da
 			throw new OCSForbiddenException('Empty keyValuePairs, will not update');
 		}
 
-		//Don't allow to change other properties than permissions
-		if (count($keyValuePairs) > 1 || !array_key_exists('permissions', $keyValuePairs)) {
-			$this->logger->debug('Not allowed to update other properties than permissions');
-			throw new OCSForbiddenException('Not allowed to update other properties than permissions');
+		$allowedKeys = ['permissions', 'token'];
+		foreach (array_keys($keyValuePairs) as $key) {
+			if (!in_array($key, $allowedKeys, true)) {
+				$this->logger->debug('Not allowed to update other properties than permissions or token');
+				throw new OCSForbiddenException('Not allowed to update other properties than permissions or token');
+			}
 		}
 
-		if (!$this->validatePermissions($keyValuePairs['permissions'], $formShare->getShareType())) {
+		if (array_key_exists('permissions', $keyValuePairs) && !$this->validatePermissions($keyValuePairs['permissions'], $formShare->getShareType())) {
 			throw new OCSBadRequestException('Invalid permission given');
 		}
 
+		if (array_key_exists('token', $keyValuePairs)) {
+			if (!$this->configService->getAllowCustomPublicToken()) {
+				$this->logger->debug('Custom public share tokens are not allowed.');
+				throw new OCSForbiddenException('Custom public share tokens are not allowed.');
+			}
+
+			if ($formShare->getShareType() !== IShare::TYPE_LINK) {
+				$this->logger->debug('Not allowed to update token on non-link share');
+				throw new OCSForbiddenException('Not allowed to update token on non-link share');
+			}
+
+			if (!is_string($keyValuePairs['token'])) {
+				throw new OCSBadRequestException('Invalid share token');
+			}
+
+			$token = $keyValuePairs['token'];
+			if (!array_key_exists('permissions', $keyValuePairs) && $token === $formShare->getShareWith()) {
+				return new DataResponse($formShare->getId());
+			}
+
+			if ($token !== $formShare->getShareWith()) {
+				$this->validatePublicShareToken($token);
+
+				try {
+					$existingShare = $this->shareMapper->findPublicShareByHash($token);
+					if ($existingShare->getId() !== $formShare->getId()) {
+						$this->logger->debug('Share hash already exists.');
+						throw new OCSBadRequestException('Share hash exists, please retry.');
+					}
+				} catch (DoesNotExistException $e) {
+					// Just continue, this is what we expect to happen (share hash not existing yet).
+				}
+
+				$formShare->setShareWith($token);
+			}
+		}
+
 		$this->formsService->obtainFormLock($form);
 
-		$formShare->setPermissions($keyValuePairs['permissions']);
+		if (array_key_exists('permissions', $keyValuePairs)) {
+			$formShare->setPermissions($keyValuePairs['permissions']);
+		}
 		$formShare = $this->shareMapper->update($formShare);
 
-		if (in_array($formShare->getShareType(), [IShare::TYPE_USER, IShare::TYPE_GROUP, IShare::TYPE_USERGROUP, IShare::TYPE_CIRCLE], true)) {
+		if (array_key_exists('permissions', $keyValuePairs)
+			&& in_array($formShare->getShareType(), [IShare::TYPE_USER, IShare::TYPE_GROUP, IShare::TYPE_USERGROUP, IShare::TYPE_CIRCLE], true)) {
 			if (in_array(Constants::PERMISSION_RESULTS, $keyValuePairs['permissions'], true)) {
 				$userFolder = $this->rootFolder->getUserFolder($form->getOwnerId());
 				$uploadedFilesFolderPath = $this->formsService->getFormUploadedFilesFolderPath($form);
@@ -421,4 +467,22 @@ private function validatePermissions(array $permissions, int $shareType): bool {
 		}
 		return true;
 	}
+
+	/**
+	 * @throws OCSBadRequestException If token does not satisfy basic safety checks
+	 */
+	private function validatePublicShareToken(string $token): void {
+		if ($token !== trim($token)) {
+			throw new OCSBadRequestException('Invalid share token');
+		}
+
+		$tokenLength = strlen($token);
+		if ($tokenLength < Constants::PUBLIC_SHARE_TOKEN_MIN_LENGTH || $tokenLength > Constants::PUBLIC_SHARE_TOKEN_MAX_LENGTH) {
+			throw new OCSBadRequestException('Invalid share token');
+		}
+
+		if (preg_match('/^[a-zA-Z0-9]+$/', $token) !== 1) {
+			throw new OCSBadRequestException('Invalid share token');
+		}
+	}
 }

lib/Service/ConfigService.php

@@ -37,7 +37,10 @@ public function getAllowPermitAll(): bool {
 	public function getAllowPublicLink(): bool {
 		return json_decode($this->config->getAppValue($this->appName, Constants::CONFIG_KEY_ALLOWPUBLICLINK, 'true'));
 	}
-	public function getAllowShowToAll() : bool {
+	public function getAllowCustomPublicToken(): bool {
+		return json_decode($this->config->getAppValue($this->appName, Constants::CONFIG_KEY_ALLOWCUSTOMPUBLICTOKEN, 'false'));
+	}
+	public function getAllowShowToAll(): bool {
 		return json_decode($this->config->getAppValue($this->appName, Constants::CONFIG_KEY_ALLOWSHOWTOALL, 'true'));
 	}
 	private function getUnformattedCreationAllowedGroups(): array {
@@ -57,6 +60,7 @@ public function getAppConfig(): array {
 		return [
 			Constants::CONFIG_KEY_ALLOWPERMITALL => $this->getAllowPermitAll(),
 			Constants::CONFIG_KEY_ALLOWPUBLICLINK => $this->getAllowPublicLink(),
+			Constants::CONFIG_KEY_ALLOWCUSTOMPUBLICTOKEN => $this->getAllowCustomPublicToken(),
 			Constants::CONFIG_KEY_ALLOWSHOWTOALL => $this->getAllowShowToAll(),
 			Constants::CONFIG_KEY_CREATIONALLOWEDGROUPS => $this->getCreationAllowedGroups(),
 			Constants::CONFIG_KEY_RESTRICTCREATION => $this->getRestrictCreation(),

openapi.json

@@ -5157,7 +5157,7 @@
         "/ocs/v2.php/apps/forms/api/v3/forms/{formId}/shares/{shareId}": {
             "patch": {
                 "operationId": "share_api-update-share",
-                "summary": "Update permissions of a share",
+                "summary": "Update properties of a share",
                 "description": "This endpoint allows CORS requests",
                 "tags": [
                     "share_api"
@@ -5254,7 +5254,7 @@
                         }
                     },
                     "400": {
-                        "description": "Invalid permission given",
+                        "description": "Share hash exists, please retry",
                         "content": {
                             "application/json": {
                                 "schema": {
@@ -5282,7 +5282,7 @@
                         }
                     },
                     "403": {
-                        "description": "Not allowed to update other properties than permissions",
+                        "description": "Not allowed to update unknown properties",
                         "content": {
                             "application/json": {
                                 "schema": {

src/FormsSettings.vue

@@ -32,6 +32,13 @@
 				@update:modelValue="onAllowPublicLinkChange">
 				{{ t('forms', 'Allow sharing by link') }}
 			</NcCheckboxRadioSwitch>
+			<NcCheckboxRadioSwitch
+				ref="switchAllowCustomPublicShareTokens"
+				v-model="appConfig.allowCustomPublicShareTokens"
+				type="switch"
+				@update:modelValue="onAllowCustomPublicShareTokensChange">
+				{{ t('forms', 'Allow custom public share tokens') }}
+			</NcCheckboxRadioSwitch>
 			<NcCheckboxRadioSwitch
 				ref="switchAllowPermitAll"
 				v-model="appConfig.allowPermitAll"
@@ -115,6 +122,13 @@ export default {
 			el.loading = false
 		},
 
+		async onAllowCustomPublicShareTokensChange(newVal) {
+			const el = this.$refs.switchAllowCustomPublicShareTokens
+			el.loading = true
+			await this.saveAppConfig('allowCustomPublicShareTokens', newVal)
+			el.loading = false
+		},
+
 		async onAllowPermitAllChange(newVal) {
 			const el = this.$refs.switchAllowPermitAll
 			el.loading = true