Making HTTP requests with content-disposition

Question

I need to write a Java app that can access a web server that returns most content as files (ie. using content-disposition).
Previously I have used something like this to make HTTP GET requests to return files on a web server.
��String strUrl = "http://www.yahoo.com/index.html";
��URL url = new URL( strUrl );
��URLConnection conn = url.openConnection();
��InputStream in = url.openConnection.getInputStream();
��byte[] buf = new byte[conn.getContentLength()];
��in.read( buf, 0, getContentLength() );
This doesn't seem to work when the HTTP header has "content-disposition". Here is the header returned by the web server.
��Server=Microsoft-IIS/4.0
��Date=Thu, 04 Jul 2002 13:18:53 GMT
��Content-Disposition=filename=file.xyz
��Content-Type=text/html
��Cache-control=private
��Transfer-Encoding=chunked
��content-length=30306
The number of bytes actually read (as returned by in.read()) is less than the number of bytes as indicated in the content-length.
How can I handle this?
Mike

Answer 1

I have managed to discover that an incorrect content-type header is causing the problems that I have been encountering with file downloads from a web server.
As I mentioned in a previous post the content-length header was not a good indicator of file download success.
My program downloads pictures from the internet, almost always in .jpeg format. I have found that files are successfully downloaded only when the content-type header contains the words: image/jpeg. In some instances although I am trying to download a picture file the http content-type header is stated as being: text/html.
In those instances where text/html is given as the content-type file download fails in so far as the files are not acutally viewable on the native system (Windows varieties in my case).
To determine the error I used the following code:
URLConnection urlConnect = myURL.openConnection();
System.out.println("Http Header, Content-Type: "+urlConnect.getContentType());
System.out.println("Http Header, Content-Length: "+urlConnect.getContentLength());Even though content-length mostly corresponded with the downloaded files length, if the Conten-Type header was wrong then the file was all but useless.
Regards
Davo