1 On [[todo/auto-create_tag_pages_according_to_a_template]], [[chrysn]]
4 > Instead of creating a file that gets checked in into the RCS, the
5 > source files could be left out and the output files be written as
6 > long as there is no physical source file (think of a virtual underlay).
7 > Something similar would be required to implement alias directive,
8 > which couldn't be easily done by writing to the RCS as the page's
9 > contents can change depending on which other pages claim it as an alias.
11 `add_autofile` could be adapted to do this, or a similar API could be
14 This would also be useful for autoindex, as suggested on
15 [[plugins/autoindex/discussion]]. I'd also like to use it for
16 [[plugins/contrib/album]].
18 It could also be used for an [[todo/alias_directive]].
22 --------------------------
24 [[!template id=gitbranch branch=smcv/transient-only author="[[smcv]]"]]
25 [[!template id=gitbranch branch=smcv/transient-recentchanges author="[[smcv]]"]]
28 I think this branch is now enough to be useful. It adds the following:
30 If the `transient` plugin is loaded, `$srcdir/.ikiwiki/transient` is added
31 as an underlay. I'm not sure whether this should be a plugin or core, so
32 I erred on the side of more plugins; I think it's "on the edge of the core",
35 Pages with the default extension in the transient underlay are automatically
36 deleted if a page of the same name is created in the srcdir (or an underlay
37 closer to the srcdir in stacking order).
39 With the additional `transient-tag` branch,
40 `tag` enables `transient`, and if `tag_autocreate_commit` is set to 0
41 (default 1), autocreated tags are written to the transient underlay.
42 There is a regression test.
44 With the additional `transient-autoindex` branch,
45 `autoindex` uses autofiles. It also enables `transient`, and if
46 `autoindex_commit` is set to 0 (default 1), autoindexes are written to
47 the transient underlay. There is a regression test.
49 > I wonder why this needs to be configurable? I suppose that gets back to
50 > whether it makes sense to check these files in or not. The benefits of
53 > * You can edit them from the VCS, don't have to go into the web
54 > interface. Of course, files from the underlays have a similar issue,
55 > but does it make sense to make that wart larger?
56 > * You can know you can build the same site with nothing missing
57 > even if you don't there enable autoindex or whatever. (Edge case.)
59 >> I'm not sure that that's a huge wart; you can always "edit by
60 >> overwriting". If you're running a local clone of the wiki on your laptop
61 >> or whatever, you have the underlays already, and can copy from there.
62 >> Tag and autoindex pages have rather simple source code anyway. --s
64 > The benefit of using transient pages seems to just be avoiding commit
65 > clutter? For files that are never committed, transient pages are a clear
66 > win, but I wonder if adding configuration clutter just to avoid some
67 > commit clutter is really worth it.
69 >> According to the last section of
70 >> [[todo/auto-create_tag_pages_according_to_a_template]], chrysn and
71 >> Eric both feel rather strongly that it should be possible to
72 >> not commit any tags. I made it configurable because, as you point out,
73 >> there are also reasons why it makes sense to check these
74 >> automatically-created files in. I'm neutral on this, personally.
76 >> If this is a point of contention, would you accept a branch that
77 >> just adds `transient` and uses it for [[plugins/recentchanges]],
78 >> which aren't checked in and never have been? I've split the
79 >> branch up in the hope that *some* of it can get merged.
81 >> One potentially relevant point is that configuration clutter only
82 >> affects the site admin whereas commit clutter is part of the whole
83 >> wiki's history. --[[smcv]]
85 > Anyway, the configurability
86 > appears subtly broken; the default is only 1 if a new setup file is
87 > generated. With an existing setup file, the 'default' values in
88 > `getsetup` don't take effect, so it will default to undef, which
89 > is treated the same as 0. --[[Joey]]
91 >> Fixed in the branches, hopefully. (How disruptive would it be to have
92 >> defaults take effect whenever the setup file doesn't set a value, btw?
93 >> It seems pretty astonishing to have them work as they do at the moment.) --s
95 autoindex ignores pages in the transient underlay when deciding whether
98 With the additional `transient-recentchanges` branch, new recent changes
99 go in the transient underlay; I tested this manually.
101 Not done yet (in that branch, at least):
103 * `remove` can't remove transient pages: this turns out to be harder than
104 I'd hoped, because I don't want to introduce a vulnerability in the
105 non-regular-file detection, so I'd rather defer that.
107 > Hmm, I'd at least want that to be dealt with before this was used
108 > by default for autoindex or tag. --[[Joey]]
110 >> I'll try to work out which of the checks are required for security
111 >> and which are just nice-to-have, but I'd appreciate any pointers
112 >> you could give. Note that my branch wasn't meant to enable either
113 >> by default, and now hopefully doesn't. --[[smcv]]
115 * Transient tags that don't match any pages aren't deleted: I'm not sure
116 that that's a good idea anyway, though. Similarly, transient autoindexes
117 of directories that become empty aren't deleted.
119 > Doesn't seem necessary, or really desirable to do that. --[[Joey]]
121 >> Good, that was my inclination too. --s
123 * In my `untested/transient` branch, new aggregated files go in the
124 transient underlay too (they'll naturally migrate over time). I haven't
125 tested this yet, it's just a proof-of-concept.
127 > I can confirm that the behavior of autoindex, at least, is excellent.
128 > Haven't tried tag. Joey, can you merge transient and autoindex? --JoeRayhawk
130 >> Here are some other things I'd like to think about first: --[[Joey]]
132 >> * There's a FIXME in autoindex.
134 >>> Right, the extra logic for preventing autoindex pages from being
135 >>> re-created. This is taking a while, so I'm going to leave out the
136 >>>> autoindex part for the moment. The FIXME is only relevant
137 >>>> because I tried to solve
138 >>>> [[todo/autoindex should use add__95__autofile]] first, but
139 >>>> strictly speaking, that's an orthogonal change. --s
141 >> * Suggest making recentchanges unlink the transient page
142 >> first, and only unlink from the old location if it wasn't
143 >> in the transient location. Ok, it only saves 1 syscall :)
145 >>> Is an unlink() really that expensive? But, OK, fixed in the
146 >>> `transient-recentchanges` branch. --s
148 >> * Similarly it's a bit worrying for performance that it
149 >> needs to pull in and use `Cwd` on every ikiwiki startup now.
150 >> I really don't see the need; `wikistatedir` should
151 >> mostly be absolute, and ikiwiki should not chdir in ways
152 >> that break it anyway.
154 >>> The reason to make it absolute is that relative underlays
155 >>> are interpreted as relative to the base underlay directory,
158 >>> The updated `transient-only` branch only loads `Cwd` if
159 >>> the path is relative; an extra commit on branch
160 >>> `smcv/transient-relative` goes behind `add_underlay`'s
161 >>> back to allow use of a cwd-relative underlay. Which direction
162 >>> would you prefer?
164 >>> I note in passing that [[plugins/autoindex]] and `IkiWiki::Render`
165 >>> both need to use `Cwd` and `File::Find` on every refresh, so
166 >>> there's only any point in avoiding `Cwd` for runs that don't
167 >>> actually refresh, like simple uses of the CGI. --s
169 >> * Unsure about the use of `default_pageext` in the `change`
170 >> hook. Is everything in the transientdir really going
171 >> to use that pageext? Would it be better to look up the
172 >> complete source filename?
174 >>> At the moment everything in the transientdir will either
175 >>> have the `default_pageext` or be internal, although I
176 >>> did wonder whether to make [[plugins/contrib/album]]
177 >>> viewer pages optionally be `html`, for better performance
178 >>> when there's a very large number of photos.
180 >>> A more thorough garbage-collection mechanism would be to
181 >>> use File::Find on the transient directory; I'll get there
184 --------------------------
186 ## An earlier version
188 I had a look at implementing this. It turns out to be harder than I thought
189 to have purely in-memory pages (several plugins want to be able to access the
190 source file as a file), but I did get this proof-of-concept branch
191 to write tag and autoindex pages into an underlay.
193 This loses the ability to delete the auto-created pages (although they don't
194 clutter up git this way, at least), and a lot of the code in autoindex is
195 probably now redundant, so this is probably not quite ready for merge, but
196 I'd welcome opinions.
198 Usage: set `tag_underlay` and/or `autoindex_underlay` to an absolute path,
199 which you must create beforehand. I suggest *srcdir* + `/.ikiwiki/transient`.
201 Refinements that could be made if this approach seems reasonable:
203 * make these options boolean, and have the path always be `.ikiwiki/transient`
204 * improve the `remove` plugin so it also deletes from this special underlay
206 >> Perhaps it should be something more generic, so that other plugins could use it (such as "album" mentioned above).
207 >> The `.ikiwiki/transient` would suit this, but instead of saying "tag_underlay" or "autoindex_underlay" have "use_transient_underlay" or something like that?
208 >> Or to make it more flexible, have just one option "transient_underlay" which is set to an absolute path, and if it is set, then one is using a transient-underlay.
209 >> --[[KathrynAndersen]]
211 >>> What I had in mind was more like `tag_autocreate_transient => 1` or
212 >>> `autoindex_transient => 1`; you might conceivably want tags to be
213 >>> checked in but autoindices to be transient, and it's fine for each
214 >>> plugin to make its own decision. Going from that to one boolean
215 >>> (or just always-transient if people don't think that's too
216 >>> astonishing) would be trivial, though.
218 >>> I don't think relocating the transient underlay really makes sense,
219 >>> except for prototyping: you only want one, and `.ikiwiki` is as good
220 >>> a place as any (ikiwiki already needs to be able to write there).
222 >>> For [[plugins/contrib/album]] I think I'd just make the photo viewer
223 >>> pages always-transient - you can always make a transient page
224 >>> permanent by editing it, after all.
226 >>> Do you think this approach has enough potential that I should
227 >>> continue to hack on it? Any thoughts on the implementation? --[[smcv]]
229 >>>> Ah, now I understand what you're getting at. Yes, it makes sense to put transient pages under `.ikiwiki`.
230 >>>> I haven't looked at the code, but I'd be interested in seeing whether it's generic enough to be used by other plugins (such as `album`) without too much fuss.
231 >>>> The idea of a transient underlay gives us a desirable feature for free: that if someone edits the transient page, it is made permanent and added to the repository.
233 >>>> I think the tricky thing with removing these transient underlay pages is the question of how to prevent whatever auto-generated the pages in the first place from generating them again - or, conversely, how to force whatever auto-generated those pages to regenerate them if you've changed your mind.
234 >>>> I think you'd need something similar to `will_render` so that transient pages would be automatically removed if whatever auto-generated them is no longer around.
235 >>>> -- [[KathrynAndersen]]