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Groups > comp.lang.java.programmer > #28372

[LONG] java.net.URI encoding weirdness

From Stanimir Stamenkov <s7an10@netscape.net>
Newsgroups comp.lang.java.programmer
Subject [LONG] java.net.URI encoding weirdness
Date 2014-05-05 16:11 +0300
Organization A noiseless patient Spider
Message-ID <lk82m6$hhi$1@dont-email.me> (permalink)

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This is a long time observation but I wanted to summarize it and 
give heads up to ones which might not have encountered it, yet.

It doesn't appear java.net.URI behaves in undocumented way, but just 
in no useful way.  In my experience the java.net.URI is only 
suitable for parsing certain URI parts, and not for constructing URI 
instances, either using the properties of an existing URI or using 
values obtained else way.

My use case is simple:  Have an input URI which I want to modify 
certain components/properties of, and produce a new URI.  For 
example, change the 'host' or 'path' of an HTTP URL.

The first example behaves pretty much as I expect:

import java.net.URI;
import java.net.URLEncoder;

public class URITest {

     public static void main(String[] args) throws Exception {
         System.out.println(URLEncoder
                            .encode("#%&/;=?@", "US-ASCII"));

         URI u = URI.create("http://user%40domain@server1:8080"
                            + "/path?param=value#fragment");
         System.out.println(u.toASCIIString());

         URI v = new URI(u.getScheme(),
                         u.getUserInfo(),
                         "server2",
                         u.getPort(),
                         u.getPath(),
                         u.getQuery(),
                         u.getFragment());
         System.out.println(v.toASCIIString());

         URI w = new URI(u.getScheme(),
                         u.getRawUserInfo(),
                         "server3",
                         u.getPort(),
                         u.getRawPath(),
                         u.getRawQuery(),
                         u.getRawFragment());
         System.out.println(w.toASCIIString());
     }

}

It tests the behavior of the URI(scheme, userInfo, host, port, path, 
query, fragment) constructor, and the output is as:

http://user%40domain@server1:8080/path?param=value#fragment
http://user%40domain@server2:8080/path?param=value#fragment
http://user%2540domain@server3:8080/path?param=value#fragment

As I would expect the 'userInfo' is encoded properly when given as 
decoded value (and double-encoded if given as a raw, already encoded 
value).  The other properties, in this case, don't make a difference 
because their values are the same in raw and decoded form.

----

Now, I expect the URI(scheme, authority, path, query, fragment) 
constructor would need a raw 'authority' value as it gets parsed 
into 'userInfo', 'host' and 'port' components/properties:

public class URITest2 {

     public static void main(String[] args) throws Exception {
         URI u = URI.create("http://user%40domain@server1:8080"
                            + "/path?param=value#fragment");
         System.out.println(u.toASCIIString());

         URI v = new URI(u.getScheme(),
                         u.getAuthority(),
                         "/htap",
                         u.getQuery(),
                         u.getFragment());
         System.out.println(v.toASCIIString());

         URI w = new URI(u.getScheme(),
                         u.getRawAuthority(),
                         "/htap",
                         u.getQuery(),
                         u.getFragment());
         System.out.println(w.toASCIIString());
     }

}

The output:

http://user%40domain@server1:8080/path?param=value#fragment
http://user@domain@server1:8080/htap?param=value#fragment
http://user%2540domain@server1:8080/htap?param=value#fragment

shows there's no way to re-construct a correct URI using it.

----

The constructor URI(str) is not particularly interesting as it 
parses the complete URI string, and I've further tried the simpler 
URI(scheme, ssp, fragment) one:

public class URITest2a {

     public static void main(String[] args) throws Exception {
         URI u = URI.create("http://user%40domain@server1:8080"
                            + "/path?param=value#frag%23ment");
         System.out.println(u.toASCIIString());

         URI v = new URI(u.getScheme(),
                         u.getSchemeSpecificPart(),
                         u.getFragment());
         System.out.println(v.toASCIIString());

         URI w = new URI(u.getScheme(),
                         u.getRawSchemeSpecificPart(),
                         u.getRawFragment());
         System.out.println(w.toASCIIString());

         URI x = new URI(u.getScheme(),
                         u.getRawSchemeSpecificPart(),
                         u.getFragment());
         System.out.println(x.toASCIIString());
     }

}

The output:

http://user%40domain@server1:8080/path?param=value#frag%23ment
http://user@domain@server1:8080/path?param=value#frag%23ment
http://user%2540domain@server1:8080/path?param=value#frag%2523ment
http://user%2540domain@server1:8080/path?param=value#frag%23ment

shows the 'fragment' is properly encoded, but then either using the 
'rawSchemeSpecificPart' or the decoded 'schemeSpecificPart' doesn't 
yield correct new URI.

----

It becomes even funnier when dealing with 'path' and 'query' 
components which contain special URI characters (back to using the 
"most specific" constructor from the first example):

public class URITest3 {

     public static void main(String[] args) throws Exception {
         URI u = URI.create("http://server1/path"
                 + "?param%3D1=value%261&param%3F2=value%232"
                 + "#fragment");
         System.out.println(u.toASCIIString());

         URI v = new URI(u.getScheme(),
                         u.getUserInfo(),
                         "server2",
                         u.getPort(),
                         u.getPath(),
                         u.getQuery(),
                         u.getFragment());
         System.out.println(v.toASCIIString());

         URI w = new URI(u.getScheme(),
                         u.getRawUserInfo(),
                         "server3",
                         u.getPort(),
                         u.getRawPath(),
                         u.getRawQuery(),
                         u.getRawFragment());
         System.out.println(w.toASCIIString());
     }

}

Output:

http://server1/path?param%3D1=value%261&param%3F2=value%232#fragment
http://server2/path?param=1=value&1&param?2=value%232#fragment
http://server3/path?param%253D1=value%25261&param%253F2=value%25232#fragment

The query part gets damaged either way.

----

The only way to construct a proper URI, changing just certain 
components of a source URI, seems to construct it manually:

public class URITest4 {

     public static void main(String[] args) throws Exception {
         URI u = URI.create("http://server1/path"
                 + "?param%3D1=value%261&param%3F2=value%232"
                 + "#fragment");
         System.out.println(u.toASCIIString());

         StringBuilder v = new StringBuilder();
         v.append(u.getScheme()).append("://");
         if (u.getRawUserInfo() != null) {
             v.append(u.getRawUserInfo()).append('@');
         }
         v.append(u.getHost());
         if (u.getPort() != -1) {
             v.append(':').append(u.getPort());
         }

         v.append("/pat2"); // Replace path

         if (u.getRawQuery() != null) {
             v.append('?').append(u.getRawQuery());
         }

         if (u.getRawFragment() != null) {
             v.append('#').append(u.getRawFragment());
         }

         System.out.println(v);
     }

}

I think all this mess is caused by the URI constructors blindly 
encoding special URI characters in given 'path', 'query' etc. 
without considering the context, and you probably shouldn't be using 
the java.net.URI constructors for any serious work.

Do you think Oracle should reconsider the java.net.URI 
implementation so it becomes more useful?  What alternatives to 
java.net.URI you're aware of (may something like 
javax.ws.rs.core.UriBuilder), regarding such 
manipulation/construction use case?

-- 
Stanimir

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Thread

[LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-05 16:11 +0300
  Re: [LONG] java.net.URI encoding weirdness Mike Amling <mamling@chaff.us> - 2014-05-05 11:37 -0500
    Re: [LONG] java.net.URI encoding weirdness Mike Amling <mamling@chaff.us> - 2014-05-05 11:43 -0500
    Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-05 19:50 +0300
  Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-05 11:58 -0700
    Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-05 23:59 +0300
      Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-05 16:51 -0700
        Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 10:26 +0300
          Re: [LONG] java.net.URI encoding weirdness Steven Simpson <ss@domain.invalid> - 2014-05-06 08:47 +0100
            Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 11:02 +0300
          Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-06 10:24 -0700
            Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 22:24 +0300
            Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-06 12:24 -0700
              Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 22:34 +0300
                Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-06 13:04 -0700
                Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 23:07 +0300
              Re: [LONG] java.net.URI encoding weirdness Stanimir Stamenkov <s7an10@netscape.net> - 2014-05-06 23:04 +0300
            Re: [LONG] java.net.URI encoding weirdness Steven Simpson <ss@domain.invalid> - 2014-05-06 20:29 +0100
              Re: [LONG] java.net.URI encoding weirdness markspace <markspace@nospam.nospam> - 2014-05-06 13:01 -0700

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