CODEWITHSUNDEEP
javafileuploadstruts2
Pevi
Pevi

Reputation: 55

Can't struts2 detect the content of a file? (Renaming extension trouble)

We have an application done with struts2. We limited the uploaded files to microsoft documents and acrobat pdf. All go fine. But when a user change the extension of the file, struts 2 is unable to detect that change and accept the file.

For example logo.png -> logo.pdf

Our configuration in the struts2 file is like this:

<interceptor-ref name="interceptorFileStack">
            <param name="fileUpload.allowedTypes">application/pdf,application/msword,application/vnd.openxmlformats-officedocument.wordprocessingml.document</param>
            <param name="fileUpload.allowedExtensions">.pdf,.docx,.doc</param>
            <param name="fileUpload.maximumSize">4194304</param>
</interceptor-ref>

I thought that allowedExtensions control the extension, and allowedTypes the content of the file...

Anyway to detect that change of the extension only with struts 2? Or i need another library? Any recommendation?

Upvotes: 1

Views: 315

Answers (1)

beendr
beendr

Reputation: 654

Most of the time the MIME-Type sent by the browser is derived by the file extension. Thus a renamed jpg->pdf is a "application/pdf" filetype.

If you can't trust your users and have to confirm the correct data type you have to use something like Apache Tika or JHOVE

A small example for Tika would be:

Path path = Paths.get("myfile.txt");
TikaConfig tika = new TikaConfig();
Metadata metadata = new Metadata();
metadata.set(Metadata.RESOURCE_NAME_KEY, path.toString());
String mimetype = tika.getDetector().detect(TikaInputStream.get(path), metadata).toString();
System.out.println("File " + path + " is " + mimetype);

(from the tutorial)

JHOVE is mainly a gui/commandline tool you can use, but it should also be possible to use this via an API.

Upvotes: 2

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