Strange I/O exception with URL passed

[Martin Asenov]

Hi, guys,

I have a servlet endpoint, where I've passed the following:

http://localhost/mytestapp/dispatch?image1_url=http%3A//4.bp.blogspot.com/_V7lJdZi_T9A/TAxBjmRjECI/AAAAAAAASco/gFOEujSDGzk/s1600/rihanna+red+hair+4.jpg

As you can see, the url, passed as a parameter is UTF-8 encoded. In the 'dispatch' servlet, I do the following:

URL url1 = new URL(getRequest().getParameter("image1_url"));

or

URL url1 = new URL(URLDecoder.decode(getRequest().getParameter("image1_url"), "UTF-8"));

which both result in the following URL:

http://4.bp.blogspot.com/_V7lJdZi_T9A/TAxBjmRjECI/AAAAAAAASco/gFOEujSDGzk/s1600/rihanna red hair 4.jpg - with pluses removed and spaces instead.

When I pass it to ImageIO.read(URL), I get 'Can't get input stream for the URL; Server returned response code 400', which is strange, since ImageIO uses the very same java.net package.

Would you please assist me on how to work this around and have valid URLs when building a URL?

Thanks a lot in advance!

Martin

[Ramon Anger]

Hi Martin,

I think the problem is not connected to utf-8. Depending on the operating system you use plus signs are not valid inside a file name. The pluses are replaced by spaces but there is not file with spaces in the name so the input stream gets no data.

Is there a way to replace the plus signs with for instance underscores?

Best,
Ramon

[Martin Asenov]

Here is a small snippet, which reproduces the error:

    String urlEncoded = "http%3A//4.bp.blogspot.com/_V7lJdZi_T9A/TAxBjmRjECI/AAAAAAAASco/gFOEujSDGzk/s1600/rihanna+red+hair+4.jpg";
    
    BufferedImage test = ImageIO.read(new URL(URLDecoder.decode(urlEncoded, "UTF-8")));

And the exception is:

Exception in thread "main" javax.imageio.IIOException: Can't get input stream from URL!
	at javax.imageio.ImageIO.read(Unknown Source)
	at core.HandleImages.main(HandleImages.java:176)
Caused by: java.io.IOException: Server returned HTTP response code: 400 for URL: http://4.bp.blogspot.com/_V7lJdZi_T9A/TAxBjmRjECI/AAAAAAAASco/gFOEujSDGzk/s1600/rihanna red hair 4.jpg
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
	at java.net.URL.openStream(Unknown Source)
	... 2 more

Of course, I can always do the following:

URL url1 = new URL(URLDecoder.decode(getRequest().getParameter("image1_url"), "UTF-8").replaceAll(" ", "+"))

but I don't consider this the proper way to fix this. Also there might be other symbols that cause the same, of which I'm not aware right now...

Thanks

[Martin Asenov]

Ramon Anger wrote:Hi Martin,

I think the problem is not connected to utf-8. Depending on the operating system you use plus signs are not valid inside a file name. The pluses are replaced by spaces but there is not file with spaces in the name so the input stream gets no data.

Is there a way to replace the plus signs with for instance underscores?

Best,
Ramon

Hi, Ramon,

Well I can't change URLs, since I've not created them Any random image URL could be passed to my app.

Best,
Martin

[Martin Asenov]

Here it is again - I regularly test my app with random images, but I can't even bring this image for reading. These spaces just freak me out. Here is the link:

http://www.sas.usace.army.mil/lakes/thurmond/images/camping%20at%20clark%202.jpg

This code always fails, no matter what I try:

    String urlEncoded2 = "http%3A//www.sas.usace.army.mil/lakes/thurmond/images/camping+at+clark+2.jpg";
    
    BufferedImage test = ImageIO.read(new URL(URLDecoder.decode(urlEncoded2, "UTF-8")));

Please assist me, any help will be greatly appreciated! What I need is to be able to read any image URL passed...

Best regards,
Martin