Docserver: refactor the Handler/ServerInstance relationship into a servlet

Docserver: refactor the Handler/ServerInstance relationship into a servlet
architecture. Currently there are just two servlets: the cron servlet and the
main render servlet. Soon there will be more, e.g. for codereview patches.

BUG=234022
R=cduvall@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=197574

[not at google - send to devlin, 2013-04-26 23:04:06]

Hey Clark,

This is specifically to make https://chromiumcodereview.appspot.com/14125010
easier to implement, but it's a decent cleanup. We'll end up having some more
servlets (e.g. search) so might as well do this now.

The "always online" stuff is making me sad every time I need to account for it.
:( oh well.

[方觉(Fang Jue), 2013-04-29 12:14:15]

https://chromiumcodereview.appspot.com/14273035/diff/2001/chrome/common/exten...
File chrome/common/extensions/docs/server2/render_servlet.py (right):

https://chromiumcodereview.appspot.com/14273035/diff/2001/chrome/common/exten...
chrome/common/extensions/docs/server2/render_servlet.py:90: templates =
server_instance.template_data_source_factory.Create(request,
These code (and below) will also be shared by PatchServlet, right? Maybe they
should be moved into a separate method (and then let PatchServlet inherit from
RenderServlet and override Get?)

[not at google - send to devlin, 2013-04-29 16:09:13]

https://chromiumcodereview.appspot.com/14273035/diff/2001/chrome/common/exten...
File chrome/common/extensions/docs/server2/render_servlet.py (right):

https://chromiumcodereview.appspot.com/14273035/diff/2001/chrome/common/exten...
chrome/common/extensions/docs/server2/render_servlet.py:90: templates =
server_instance.template_data_source_factory.Create(request,
On 2013/04/29 12:14:15, 方觉(Fang Jue) wrote:
> These code (and below) will also be shared by PatchServlet, right? Maybe they
> should be moved into a separate method (and then let PatchServlet inherit from
> RenderServlet and override Get?)

As they say, composition over inheritance - composing these servlets is a little
bit weird but I'm not fussed. It *is* unfortunate to be creating these fake
request objects, I'm going to have a look at doing something more formal than
that. Probably removing the strict appengine format of these things, the
writing-to-out thing is partially what creates the messiness.

However - why will PatchServlet have to use a lot of this code? In the current
state of this patch you can pass a custom ServerInstance into RenderServlet.Get.
The PatchServlet should be able to call that with a ServerInstance that has the
patched subversion file system.

[not at google - send to devlin, 2013-04-29 21:07:46]

ok - lots of changes made here. Trying to adapt the appengine servlet
infrastructure into this wasn't working, so I wrote a new request/response thing
(see servlet.py).

[方觉(Fang Jue), 2013-04-30 01:09:53]

On 2013/04/29 16:09:13, kalman wrote:
> However - why will PatchServlet have to use a lot of this code? In the current
> state of this patch you can pass a custom ServerInstance into
RenderServlet.Get.
> The PatchServlet should be able to call that with a ServerInstance that has
the
> patched subversion file system.

Currently ServerInstance.Get will do everything well. In this patch, it is moved
into RenderServlet but it will also be used by PatchServlet.

[cduvall, 2013-05-01 00:21:21]

lgtm

[not at google - send to devlin, 2013-05-01 06:15:39]

Committed patchset #4 manually as r197574 (presubmit successful).