HTTP response status code 423 Locked is a client error that is returned by the server to indicate that the target file or folder is locked.
The 423 Locked error message is part of WebDAV, used as a file system over HTTP. Clients have the option to LOCK or UNLOCK files and if a client attempts to modify a locked resource, this is the error that is returned by the server.
When a lock is first granted by a server, the
Lock-Token response header is sent to the client, which can be used to later unlock the resource or refresh the lock.
As part of the response, the server will include an appropriate precondition or post-condition code to help guide the client. This might include
Search engines like Google will not index a URL with 423 Locked response status, and consequently, URLs that have been indexed in the past but are now returning this HTTP status code will be removed from the search results.
In the example, the client attempts to upload a file to the target folder. However, it is currently locked. The operation is not allowed and the 423 Locked error message is returned. In the subsequent request, the client asks that the resource be unlocked by including the
Lock-Token as part of the If request header.
In the example, the request is successful because there was only one lock on the folder at the time. However, it is relevant to consider that a successful UNLOCK only means that the lock referred to by the specified
Lock-Token has been removed. Other locks can still be in use, and once again return the 423 Locked status.
PUT /documents/ HTTP/1.1 Host: www.example.ai Content-Type: applications/pdf Content-Length: 10000 <PDF file transferred>
HTTP/1.1 423 Locked Content-Type: application/xml Content-Length: 163 <?xml version="1.0" encoding="utf-8" ?> <d:error xmlns:d="DAV:"> <d:lock-token-submitted> <d:href>/documents/</d:href> </d:lock-token-submitted> </d:error>
Second request, incorporating unlock request
PUT /documents/ HTTP/1.1 Host: www.example.ai Content-Type: applications/pdf Content-Length: 10000 If: (<urn:uuid:123…789>) <PDF file transferred>
HTTP/1.1 204 No Content
Apache HttpComponents Core
The 423 Locked status code is a client error generated by the server when conflicting access is required to a locked resource. The client can try again when the resource is unlocked. The client may be capable of unlocking it, or the lock timer may expire, if applicable.