Help please! I'm struggling with:
HttpUrlConnection converts request headers to lowercase
HttpUrlConnection.addRequestProperty overrides existing properties
https://issues.apache.org/jira/browse/HARMONY-6452
The JIRA is slightly confusing because it contains two issues.
However, they are rather closely linked and this confusion is trivial
in comparison to the confusion I now face trying to figure out
what behaviour to implement to be compatible with the reference
implementation.
The reference implementation seems rather inconsistent so I am wonder
if it is really worth trying to match its behaviour rather than merely
meeting the spec with a simpler implementation.
For example, my testing suggests that the reference implementation
treats keys provided to the setRequestProperty method case-insensitively
and additionally preserves the case of the first instance of a
particular key string. So if you do:
URLConnection conn =
(URLConnection)(new URL("http://example.org/";).openConnection());
conn.setRequestProperty("KEY", "upper");
conn.setRequestProperty("key", "lower");
System.out.println("KEY=" + conn.getRequestProperty("KEY"));
System.out.println("key=" + conn.getRequestProperty("key"));
System.out.println("properties=" + conn.getRequestProperties());
then the RI outputs:
KEY=lower
key=lower
properties={KEY=[lower]}
and if you do:
URLConnection conn =
(URLConnection)(new URL("http://example.org/";).openConnection());
conn.setRequestProperty("key", "lower");
conn.setRequestProperty("KEY", "upper");
System.out.println("KEY=" + conn.getRequestProperty("KEY"));
System.out.println("key=" + conn.getRequestProperty("key"));
System.out.println("properties=" + conn.getRequestProperties());
then the RI outputs:
KEY=upper
key=upper
properties={key=[upper]}
This appears to be consistent - albeit over-complicated IMHO. But
my testing also shows that the addRequestProperty (which appends the
value to the value list associated with the key) does not treat keys
case-insensitively so if you do:
URLConnection conn =
(URLConnection)(new URL("http://example.org/";).openConnection());
conn.setRequestProperty("KEY", "upper");
conn.addRequestProperty("key", "lower");
System.out.println("KEY=" + conn.getRequestProperty("KEY"));
System.out.println("key=" + conn.getRequestProperty("key"));
System.out.println("properties=" + conn.getRequestProperties());
you get:
KEY=lower
key=lower
properties={KEY=[upper], key=[lower]}
where as I'd have expected:
properties={KEY=[lower,upper]}
(since that is what you get if you do set* and add* with "KEY" in upper
case for both calls).
Personally, I struggle to see any consistency in the RI and suspect that
we'd be better of just treating keys case-sensitively in all cases.
This would at least have the virtue of being self-consistent and more
predictable than the current implementation. I tried writing test cases
to map out the behaviour of the RI but just when I thought I'd figured
it out I'd write another test and find that it didn't behave as I'd have
expected.
What do people think? By my reading, treating keys case-sensitively in
all cases would be consistent with the spec but will this cause problems
for users? Am I missing something and in fact the RI consistent?
I think since the same class is used to implement response headers, we
may have to "be liberal"[0] and treat keys case-insensitively for the
getRequestProperty() method or at least lookup case-sensitively thent
also look them up case-insensitively before returning null.
Regards,
Mark.
[0] "Be liberal in what you accept, and conservative in what you send."
- Jon Postel
