3
Last modified at [$Date: 2005-03-13 23:24:22 -0600 (Sun, 13 Mar 2005) $]
9
* Source code should follow style guidelines.
10
OK, we all agree pretty code is good. Probably best to clean this
11
up by hand immediately upon branching a 2.1 tree.
12
Status: Justin volunteers to hand-edit the entire source tree ;)
15
Recall when the release plan for 2.0 was written:
16
Absolute Enforcement of an "Apache Style" for code.
17
Watch this slip into 3.0.
20
The style guide needs to be reviewed before this can be done.
21
http://httpd.apache.org/dev/styleguide.html
22
The current file is dated April 20th 1998!
25
It's survived since '98 because it's welldone :-) Suggest we
26
simply follow whatever is documented in styleguide.html as we
27
branch the next tree. Really sort of straightforward, if you
28
dislike a bit within that doc, bring it up on the dev@httpd
29
list prior to the next branch.
31
So Bill sums up ... let's get the code cleaned up in CVS head.
32
Remember, it just takes cvs diff -b (that is, --ignore-space-change)
33
to see the code changes and ignore that cruft. Get editing Justin :)
35
* Replace stat [deferred open] with open/fstat in directory_walk.
36
Justin, Ian, OtherBill all interested in this. Implies setting up
37
the apr_file_t member in request_rec, and having all modules use
38
that file, and allow the cleanup to close it [if it isn't a shared,
41
* The Async Apache Server implemented in terms of APR.
42
[Bill Stoddard's pet project.]
43
Message-ID: <008301c17d42$9b446970$01000100@sashimi> (dev@apr)
45
OtherBill notes that this can proceed in two parts...
47
Async accept, setup, and tear-down of the request
48
e.g. dealing with the incoming request headers, prior to
49
dispatching the request to a thread for processing.
50
This doesn't need to wait for a 2.x/3.0 bump.
52
Async delegation of the entire request processing chain
53
Too many handlers use stack storage and presume it is
54
available for the life of the request, so a complete
55
async implementation would need to happen 3.0 release.
57
Brian notes that async writes will provide a bigger
58
scalability win than async reads for most servers.
59
We may want to try a hybrid sync-read/async-write MPM
60
as a next step. This should be relatively easy to
61
build: start with the current worker or leader/followers
62
model, but hand off each response brigade to a "completion
63
thread" that multiplexes writes on many connections, so
64
that the worker thread doesn't have to wait around for
65
the sendfile to complete.
68
MAKING APACHE REPOSITORY-AGNOSTIC
69
(or: remove knowledge of the filesystem)
71
[ 2002/10/01: discussion in progress on items below; this isn't
74
* dav_resource concept for an HTTP resource ("ap_resource")
76
* r->filename, r->canonical_filename, r->finfo need to
77
disappear. All users need to use new APIs on the ap_resource
80
(backwards compat: today, when this occurs with mod_dav and a
81
custom backend, the above items refer to the topmost directory
82
mapped by a location; e.g. docroot)
84
Need to preserve a 'filename'-like string for mime-by-name
85
sorts of operations. But this only needs to be the name itself
88
Justin: Can we leverage the path info, or do we not trust the
91
gstein: well, it isn't the "path info", but the actual URI of
92
the resource. And of course we trust the user... that is
93
the resource they requested.
95
dav_resource->uri is the field you want. path_info might
96
still exist, but that portion might be related to the
97
CGI concept of "path translated" or some other further
100
To continue, I would suggest that "path translated" and
101
having *any* path info is Badness. It means that you did
102
not fully resolve a resource for the given URI. The
103
"abs_path" in a URI identifies a resource, and that
104
should get fully resolved. None of this "resolve to
105
<here> and then we have a magical second resolution
106
(inside the CGI script)" or somesuch.
108
Justin: Well, let's consider mod_mbox for a second. It is sort of
109
a virtual filesystem in its own right - as it introduces
110
it's own notion of a URI space, but it is intrinsically
111
tied to the filesystem to do the lookups. But, for the
112
portion that isn't resolved on the file system, it has
113
its own addressing scheme. Do we need the ability to
116
* The translate_name hook goes away
118
Wrowe altogether disagrees. translate_name today even operates
119
on URIs ... this mechansim needs to be preserved.
121
* The doc for map_to_storage is totally opaque to me. It has
122
something to do with filesystems, but it also talks about
123
security and per_dir_config and other stuff. I presume something
124
needs to happen there -- at least better doc.
126
Wrowe agrees and will write it up.
128
* The directory_walk concept disappears. All configuration is
129
tagged to Locations. The "mod_filesystem" module might have some
130
internal concept of the same config appearing in multiple
131
places, but that is handled internally rather than by Apache
134
Wrowe suggests this is wrong, instead it's private to filesystem
135
requests, and is already invoked from map_to_storage, not the core
136
handler. <Directory > and <Files > blocks are preserved as-is,
137
but <Directory > sections become specific to the filesystem handler
138
alone. Because alternate filesystem schemes could be loaded, this
139
should be exposed, from the core, for other file-based stores to
140
share. Consider an archive store where the layers become
141
<Directory path> -> <Archive store> -> <File name>
143
Justin: How do we map Directory entries to Locations?
145
* The "Location tree" is an in-memory representation of the URL
146
namespace. Nodes of the tree have configuration specific to that
147
location in the namespace.
152
const char *name; /* name of this node relative to parent */
154
struct ap_conf_vector_t *locn_config;
156
apr_hash_t *children; /* NULL if no child configs */
159
The following config:
161
<Location /server-status>
162
SetHandler server-status
168
Creates a node with name=="server_status", and the node is a
169
child of the "/" node. (hmm. node->name is redundant with the
170
hash key; maybe drop node->name)
172
In the config vector, mod_access has stored its Order, Deny, and
173
Allow configs. mod_core has stored the SetHandler.
175
During the Location walk, we merge the config vectors normally.
177
Note that an Alias simply associates a filesystem path (in
178
mod_filesystem) with that Location in the tree. Merging
179
continues with child locations, but a merge is never done
180
through filesystem locations. Config on a specific subdir needs
181
to be mapped back into the corresponding point in the Location
182
tree for proper merging.
184
* Config is parsed into a tree, as we did for the 2.0 timeframe,
185
but that tree is just a representation of the config (for
186
multiple runs and for in-memory manipulation and usage). It is
187
unrelated to the "Location tree".
189
* Calls to apr_file_io functions generally need to be replaced
190
with operations against the ap_resource. For example, rather
191
than calling apr_dir_open/read/close(), a caller uses
192
resource->repos->get_children() or somesuch.
194
Note that things like mod_dir, mod_autoindex, and mod_negotation
195
need to be converted to use these mechanisms so that their
196
functions will work on logical repositories rather than just
199
* How do we handle CGI scripts? Especially when the resource may
200
not be backed by a file? Ideally, we should be able to come up
201
with some mechanism to allow CGIs to work in a
202
repository-independent manner.
204
- Writing the virtual data as a file and then executing it?
205
- Can a shell be executed in a streamy manner? (Portably?)
206
- Have an 'execute_resource' hook/func that allows the
207
repository to choose its manner - be it exec() or whatever.
208
- Won't this approach lead to duplication of code? Helper fns?
210
gstein: PHP, Perl, and Python scripts are nominally executed by
211
a filter inserted by mod_php/perl/python. I'd suggest
212
that shell/batch scripts are similar.
214
But to ask further: what if it is an executable
215
*program* rather than just a script? Do we yank that out
216
of the repository, drop it onto the filesystem, and run
219
I'll vote -0.9 for CGIs as a filter. Keep 'em handlers.
221
Justin: So, do we give up executing CGIs from virtual repositories?
222
That seems like a sad tradeoff to make. I'd like to have
223
my CGI scripts under DAV (SVN) control.
225
* How do we handle overlaying of Location and Directory entries?
226
Right now, we have a problem when /cgi-bin/ is ScriptAlias'd and
227
mod_dav has control over /. Some people believe that /cgi-bin/
228
shouldn't be under DAV control, while others do believe it
229
should be. What's the right strategy?