Member Avatar for Clawsy

Hi,
I have an urgent ugly problem. I have a php file on a server that reads the name of the files of a directory from the server and POST them to my java application. When I try to read it, i get

Server returned HTTP response code: 400 for URL:

. This does not happens on files that do not contain white spaces. Only at URLs like: " world.gif" but not at "".
I tried to encode the URL... I could not solve it. Please can you help me? I need it fast...
Thanks!

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  • Latest Post Latest Post by PatrickSharp

Dani AI

Generated

Brief summary: the 400 comes from sending an HTTP request line that contains literal spaces. Servers and HTTP clients expect path characters to be percent-encoded (space -> %20); a literal space in the request-line will often be rejected with HTTP 400. saw that only filenames with spaces failed, and tried Java form-encoding which does not solve the path-encoding problem.

Why the common fixes fail

  • java.net.URLEncoder is intended for HTML form encoding (application/x-www-form-urlencoded) and is not the right tool for a URI path. It converts spaces to plus signs and will mangle ":" and "/" if you feed it a whole URL. See the Java docs for details: URLEncoder and the URI rules in RFC 3986.

Reliable Java approach

  • Build a java.net.URI from components so Java will quote illegal characters in the path for you, then convert to a URL/connection. This avoids hand-mangling the whole URL string and handles other reserved characters correctly. Use the multi-argument URI constructor rather than URLEncoder for path segments. See java.net.URI for the constructor behavior.

Quick troubleshooting tips

  • If you only have raw URL strings, parse out scheme/host/path and percent-encode the path only (not the whole URL).
  • Test the final request with curl or a packet capture to see the actual request-line sent to the server.
  • For long-term stability, avoid spaces in filenames on web servers (use hyphens/underscores) and prefer building requests from components rather than editing full URL strings.

Recommended Answers

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Member Avatar for PatrickSharp

Ah, if only a nickle I had for each urgent problem needing to be solved fast...

/** imports
*/
import java.net.URLDecoder;
import java.net.URLEncoder;

// ...

String addr = " with spaces.gif";
		
String junk = URLEncoder.encode(addr,"UTF-8"); 
System.out.println(junk);
junk = URLDecoder.decode(addr,"UTF-8");
System.out.println(junk);

Your output is:

http%3A%2F%2Fwww.blah.blah%2Fimage+with+spaces.gif
[url] with spaces.gif
Member Avatar for Clawsy

Of course, that's quite simple, thanks, but it useless as long as it cannot be parsed and throws malformed URL exception. I had a midi file loaded from URL. I vizited Sun forums and found out some topics and they could not solve this... white spaces in URL are forbidden. The encoding doesn't help as I said and as they posted there, too.
If you encode the URL it becomes unparsable. Sad but true. (same problem on that forum).
However, thanks.

Edited by Clawsy because: n/a
Member Avatar for PatrickSharp

How about trying just replacing the spaces with :

URLString.replaceAll(" ","%20");

I'm personally OK with spaces in filenames, except if they live on a webserver for this very same reason :)

IF you are requesting the filename with a Get or FTP request, then replace the spaces with %20 .

Edited by PatrickSharp because: n/a
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