[WW-1911] File Upload: content-type validation fails when no file is uploaded

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.6, 2.0.7, 2.0.8, 2.0.9, 2.1.0
• Fix Version/s: 2.0.10
• Component/s: Core Interceptors, Dispatch Filter

Environment

FireFox 2.0; Tomcat 5.0; commons-fileupload 1.2

• Flags: Patch
• Assignee: James Holmes
• Reporter: Lukasz Racon
• Created: 06/May/07 05:36
• Updated: 28/Oct/12 22:07
• Resolved: 25/Jul/07 03:46

Description

If you set allowed types on the file upload interceptor:
<param name="fileUpload.allowedTypes">image/png,image/gif,image/jpeg</param>

it will validate content type even though there is no file uploaded.
This shows up in two cases:
1) If field is required you will get 2 messages:
Content-Type not allowed: image "upload_1120a017_1125f7d74fc__8000_00000013.tmp" application/octet-stream
Image is required.

2) If field is not required you will get invalid content type validation error anyway (which prohibits from executing the action):
Content-Type not allowed: image "upload_1120a017_1125f7d74fc__8000_00000013.tmp" application/octet-stream

Basically it violates the idea of single purpose validator (since it also acts as required field validator).

There are at least 3 ways to fix it:
1) fix org.apache.struts2.interceptor.FileUploadInterceptor.acceptFile method so it does not check content type (allowedTypesSet) if file is empty.
2) fix the ServletFileUpload.parseRequest so it does not show empty downloads (i.e. when file name is null).
3) (one that is in patch) fix org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest.parse so it ignores files that have blank file name.

Attached patch fixes JakartaMultiPartRequest if file name is blank it means no file has been uploaded.

Issue Links

• is related to: WW-1976 FileUpload does not ignore 0 byte files when using Jakarta FileUpload impl