And here is a proposal for some actionable items to contribute to this effort:
1) review and document the current usage (by application) of filters (classes and their order) 2) review the logic in the filters and compare it to the one of ContextFilter (what is different, what is added, what is duplicated etc...) 3) identify the filters that "extends" the ContextFilter class and figure out how to refactor their code to work in a filter chain where the first filter is ContextFilter Jacopo On Fri, Sep 9, 2016 at 10:07 AM, Jacopo Cappellato < [email protected]> wrote: > A web application, in order to leverage the OFBiz framework, requires that > a series of objects are in its contexts (servlet context, session and > request) such as "delegator", "delegatorName", "dispatcher", "security" > etc. etc... > This setup is performed by the logic contained in the servlet filter > implemented by the following class: > > org.apache.ofbiz.webapp.control.ContextFilter > > The execution of this logic is required for the application to run > properly. > However, this filter is deployed in most but not all the web application > in the OFBiz codebase: there are few exceptions due to the fact that a few > web applications require the execution of other filters (e.g. > CatalogUrlFilter, etc...). > > Unfortunately the way these filters have been implemented have issues > including: > * some of them extend the ContextFilter and override its behavior by > copying some logic and adding new one; in these cases the ContextFilter is > also deployed but after the execution of the extended filter > * some of them have been copied from ContextFilter and then adapted, > introducing a lot of redundant code difficult to maintain; in these cases > the ContextFilter is not deployed > > There is now a chance for the community to help cleaning up these classes > and I am proposing the following guidelines: > > 1) servlet filters should be chained (rather than extended or replaced) > 2) ContextFilter should always be used and should always be the first > (OFBiz) filter in the chain > 3) if some of the behavior/logic of ContextFilter conflicts with the ones > of other filters, then ContextFilter should be enhanced to prevent that > (e.g. we can improve the code, move some of its logic in a separate filter > that can be executed after etc...) > 4) the other filters should work well after the ContextFilter and add > behavior rather than overriding behavior or duplicating behavior > > As a beneficial side effect of this effort, we will get a cleaner picture > (documented by the logic of ContextFilter) of all the context objects > required by OFBiz web applications. > > I hope it helps > > Jacopo >
