Attach the right extension at the end of the wrong one
On Jul 24, 2011 6:33 PM, "Jakub Liska" <[email protected]> wrote:
> Hey, I have this decision I can't make, what should one do when user
> uploads a document with file extension A but the file's detected mime
> type corresponds to extension B ? In most cases it could yield
> problems right ? I can't decide on the way of dealing with this.
>
> Warn user ? No...
> Change file name ext to Mime type extension ? Probably yes
> Do not use any extension ? Can't, documents will be accessible to
> different users right away
>
> What is the proper steps to verify integrity of these documents anyway
> html,doc,docx,odt,txt,rtf,srt,sub,pdf,odf,odp,xls,ppt ? Or at least
> for some types
>
> I guess that inputStream is always 99,99% read properly from MultiPart
> request otherwise exception would be thrown and action taken.
> But user can upload already corrupted file, MS docs, PDF or open
> document - do I use third party libraries for checking that ? Didn't
> see anything like that in odftoolkit, itextpdf or pdfbox
>
> I just get Media Type
>
> protected MediaType getContentType(InputStream is, String
> httpReqContentType) throws SystemException {
> MediaType httpReqMediaType = MediaType.parse(httpReqContentType);
> MediaType mediaType;
> try {
> mediaType = MediaType.parse(tika.detect(is));
> } catch (IOException ioe) {
> throw new SystemException(ioe.getMessage(), ioe);
> }
> if (mediaType.equals(MediaType.OCTET_STREAM) && httpReqMediaType !=
> null && !httpReqMediaType.equals(MediaType.OCTET_STREAM))
> return httpReqMediaType;
> else
> return mediaType;
> }
>
> Then I check whether it matches one of my supported mime types and
> then the file is meant to be deliver to a third party customer - which
> is practically mission critical here.
>
> What do you guys do in addition to what I just said for everything to
> be rock solid ? Can it produce a lot of emails from customers about
> not getting what they expected ?
