Error Reference

Every error condition the static asset controller and storage helpers can raise, with cause and fix.

Error conditions

Message	Cause	HTTP Status
"Invalid bucket name"	bucketName fails isValidName()	400
"Invalid object name or path"	objectName fails isValidPath()	400
"Invalid folder path"	Upload's folderPath query param is empty after trimming leading/trailing slashes	400
"Folder path exceeds max depth of {n}"	Upload's folderPath has more segments than maxFolderDepth (default 2)	400
"Invalid folder path segment: {segment}"	One folderPath segment fails isValidName()	400
"Empty file content | name: {originalName}"	The uploaded file's buffer is empty after multipart parsing (or after re-reading a disk-spooled file)	400
"Invalid maxKeys | Expected a positive integer | value: {value}"	listObjects's maxKeys query param does not parse to a positive integer	400
[upload] Bucket does not exist | name: {bucket}	helper.upload() found no matching bucket via isBucketExists()	400 (default)
[upload] Invalid original file name	A file's originalName fails isValidName(), checked inside helper.upload()	400 (default)
[upload] Invalid folder path	helper.upload()'s own folderPath depth/isValidPath() check failed	400 (default)
[upload] Invalid file size | size: {size}	A file's size is undefined, null, or negative	400 (default)
[upload] Invalid normalized object name | name: {name}	The name returned by normalizeNameFn fails isValidPath()	400 (default)
[createBucket] Invalid name to create bucket!	MinioHelper.createBucket() called with a name failing isValidName() - only reachable calling the helper directly, the controller validates first	400 (default)
[parseMultipartBody] storage: {storage} | Invalid storage type | Valids: ['memory', 'disk']	extra.parseMultipartBody.storage set to something other than 'memory'/'disk' - a configuration error, not user input	400 (default)

NOTE

Entries marked "default" pass no explicit statusCode to getError(); ApplicationError defaults statusCode to 400 in that case.

Name validation rules

Bucket names are validated with isValidName() (single segment, no path separators). Object names, which may include folder segments (e.g. 2026/uploads/report.pdf), are validated with isValidPath() - every segment still runs through isValidName().

Pattern	Example	Reason
Path traversal	../etc/passwd	Contains .., /, or \
Hidden files	.hidden	Starts with .
Shell metacharacters	file;rm -rf /	Contains ;, |, &, $, `, <, >, {, }, [, ], !, or #
Control characters	file\ninjected	Contains \n, \r, or \0
Long names	256+ characters	Exceeds the 255-character limit
Empty names	"", " "	Empty or whitespace-only
Double slashes (path only)	a//b.png	isValidPath() rejects empty segments
Excess folder depth (path only)	a/b/c/d.png with maxFolderDepth: 2	folderDepth = segments.length - 1 exceeds the limit
Long paths (path only)	1025+ characters	Exceeds the 1024-character normalized-path limit

Troubleshooting

"Invalid bucket name" / "Invalid object name or path"

• Cause: the name fails the rules above.
• Fix: strip path separators, leading dots, shell metacharacters, and control characters; keep names under 255 characters (1024 for a full object path); never send an empty or whitespace-only value.

// Wrong - contains a path separator, rejected by isValidName()
await fetch('/assets/buckets/user/uploads', { method: 'POST' });

// Right - one segment
await fetch('/assets/buckets/user-uploads', { method: 'POST' });

"Folder path exceeds max depth" / "Invalid folder path segment"

• Cause: the upload's folderPath query parameter has more segments than maxFolderDepth allows (default 2), or one segment fails isValidName().
• Fix: flatten the folder structure, or raise the limit via extra.maxFolderDepth when registering the backend.

{
  storage: StaticAssetStorageTypes.DISK,
  helper: new DiskHelper({ basePath: './uploads' }),
  extra: { maxFolderDepth: 4 },
}

"Empty file content"

• Cause: the uploaded file's buffer is empty - either the client sent a zero-byte file field, or parseMultipartBody produced no readable content.
• Fix: verify the FormData field actually carries file bytes before submitting; a zero-byte file is rejected, this is not a size-limit issue.

"Invalid maxKeys"

• Cause: listObjects's maxKeys query string does not parse to a positive integer via Number(maxKeys) + Number.isInteger() - e.g. maxKeys=abc or maxKeys=-1.
• Fix: only send positive integer strings, or omit the parameter entirely.

url.searchParams.set('maxKeys', '50'); // OK
// url.searchParams.set('maxKeys', 'all'); // 400

"[upload] Bucket does not exist"

• Cause: helper.upload() checked isBucketExists() and found no match - the bucket was never created, or was deleted between requests.
• Fix: create the bucket first with POST /buckets/:bucketName, or check GET /buckets/:bucketName before uploading.

Controller not registering / no routes appear

• Cause: STATIC_ASSET_COMPONENT_OPTIONS was never bound, or was bound to {} - the component's default. binding() iterates the options object and produces zero controllers for an empty map, without throwing.
• Fix: bind a non-empty options object before this.component(StaticAssetComponent):

this.bind<TStaticAssetsComponentOptions>({
  key: StaticAssetComponentBindingKeys.STATIC_ASSET_COMPONENT_OPTIONS,
}).toValue({
  [uniqueKey]: {
    controller: { name: 'AssetController', basePath: '/assets' },
    storage: StaticAssetStorageTypes.DISK,
    helper: new DiskHelper({ basePath: './uploads' }),
  },
});
this.component(StaticAssetComponent);

Files not uploading (DiskHelper)

• Cause: the process lacks filesystem permissions on basePath, or the disk is out of space. DiskHelper's constructor already creates basePath if it does not exist, so a missing directory is rarely the issue.
• Fix: verify the process has read/write permissions to the target path and enough free space.

Files not uploading (MinioHelper)

• Cause: MinIO server connectivity or authentication failure.
• Fix:
  • Confirm the MinIO server is reachable at endPoint/port.
  • Verify accessKey/secretKey.
  • Check useSSL matches the server's actual TLS configuration.

Large file uploads failing or timing out

• Cause: parseMultipartBody: { storage: 'memory' } (the default) buffers the entire file in process memory before writing it to the backend.
• Fix: switch to disk-based spooling:

extra: {
  parseMultipartBody: { storage: 'disk', uploadDir: './tmp/uploads' },
}

BunS3Helper fails to construct or import

• Cause: running on Node.js. BunS3Helper imports S3Client from the bun builtin module, which only resolves under the Bun runtime.
• Fix: use MinioHelper (also S3-compatible) on Node.js, or run the app under Bun.

See also

• Overview - quick start, imports, and common configuration tasks
• Usage & Examples - task-oriented walkthroughs for every endpoint and MetaLink setup
• Full Reference - controller factory, IStorageHelper interface, MetaLink schema, internals