Can we please have a notification scheme enabled for Undertow Jira?
by Darran Lofthouse
Can we please have a notification scheme enabling for the Undertow Jira
project so that we can receive e-mail notifications.
I would suggest just use the same one as is used for Remoting JMX, it
should be sufficient to have the notifications go to the general mailing
list and interested individuals.
Regards,
Darran Lofthouse.
9 years, 8 months
Undertow development mode
by Stuart Douglas
Hi,
In Wildfly upstream I am introducing a 'development mode' flag (it is actually in Alpha3 as well, but I am going to change how it is represented in the model).
Basically the idea with this is that when this flag is set the server behaves in a way that is much more developer friendly, but is not suitable for production use. So far the changes are:
- Set JSP development mode
- Display stack traces in error pages. We do not do this by default for security reasons.
- Disable caching so file changes are picked up straight away
- Optionally persist session information across redeployments (still needs a little bit of work), which should prevent a developer from having to re-log in every time they redeploy.
I was wondering if anyone had any ideas for other features we could add to make development easier?
Stuart
10 years, 8 months
Rewrites and predicates
by Stuart Douglas
Hi everyone,
I recently added support for rewrites and redirects, and I would like some feedback on the syntax / implementation. It is actually quite a general mechanism that can be used for lots of things. There are actually a few parts to it that I will explain below.
Exchange attributes
Exchange attributes provide a general way of referencing some information from the exchange. Some examples:
%U or %{REQUEST_URL} - The request URL
%m or %{METHOD} - The request method
%{o,Content-Type} - The outgoing (response) content type header
%{i,Content-Type} - The incoming (request) header
These are intended to be re-usable in any place that requires dynamic specification of attributes (e.g. in the access log you can use exchange attributes to specify the log format). They are also extensible, you can add additional attributes via a service loader approach.
Predicates
Predicates provide a simple way of making a true/false decision based on an exchange. Many handlers have a requirement that they be applied conditionally, and predicates provide a general way to specify a condition. Predicates can be created programatically (they are just java classes that implement the Predicate interface), however there is also a simple language for specifying a predicate. I will give some examples below:
regex['/resources/*.\.css'] - regular expression match of the relative URL
regex[pattern='text/.*', value='%{i,Content-Type}, full-match=true] - Matches requests with a text/.* content type
equals[{'%{i,Content-Type}', 'text/xml'}] - Matches if the content type header is text/xml
contains[search='MSIE', value='%{i,User-Agent}'] and path-suffix['.js'] - User agent contains MSIE and request URL ends with .js
regex['/resources/(*.)\.css'] and equals[{'$1', 'myCssFile'}] - regex match, with a reference to match group 1 later in the expression
These predicates are also extensible, and they use the exchange attributes mentioned above meaning that they can be used to reference any part of the exchange. These should give users enough flexibility to match requests based on any criteria they can think up.
Handler builders
We also support a way of specifying handlers, using similar language to predicates. Some examples:
rewrite['/myfile.html'] - performs a rewrite
set['%{o,Content-Type}', 'text/xhtml'] - sets a header (this can be used to set any exchange attribute)
redirect[/myfile.html] - performs a redirect
Now that we have all the pieces the actual config goes in a file called undertow-handlers.conf. Its basic syntax is predicate -> handler. An example file could look like below:
regex['(.*).css'] -> rewrite['${1}.xcss']
path-template['/foo/{bar}'] -> set[attribute='%{q,SomeHeader}', value='${bar}']
basically the rules are matched in order, and if it matches the handler on the right is executed. The handler on the right can also use context information from the match, such as regex match groups or path template segments.
I think this should be sufficient in order to enable arbitrarily complex configs. The use of attributes and predicates should also mean that this config is consistent across everything we provide, even in other areas (e.g. the access log handler uses exchange attributes, so the basic syntax is the same).
Does anyone have any thoughts on this config?
Stuart
10 years, 9 months
