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/ready/transient author="[[smcv]]"]]
27 I think this branch is now enough to be useful. It adds the following:
29 If the `transient` plugin is loaded, `$srcdir/.ikiwiki/transient` is added
30 as an underlay. I'm not sure whether this should be a plugin or core, so
31 I erred on the side of more plugins; I think it's "on the edge of the core",
34 Pages with the default extension in the transient underlay are automatically
35 deleted if a page of the same name is created in the srcdir (or an underlay
36 closer to the srcdir in stacking order).
38 `tag` enables `transient`, and if `tag_autocreate_commit` is set to 0
39 (default 1), autocreated tags are written to the transient underlay.
40 There is a regression test.
42 `autoindex` uses autofiles. It also enables `transient`, and if
43 `autoindex_commit` is set to 0 (default 1), autoindexes are written to
44 the transient underlay. There is a regression test.
46 > I wonder why this needs to be configurable? I suppose that gets back to
47 > whether it makes sense to check these files in or not. The benefits of
50 > * You can edit them from the VCS, don't have to go into the web
51 > interface. Of course, files from the underlays have a similar issue,
52 > but does it make sense to make that wart larger?
53 > * You can know you can build the same site with nothing missing
54 > even if you don't there enable autoindex or whatever. (Edge case.)
56 >> I'm not sure that that's a huge wart; you can always "edit by
57 >> overwriting". If you're running a local clone of the wiki on your laptop
58 >> or whatever, you have the underlays already, and can copy from there.
59 >> Tag and autoindex pages have rather simple source code anyway. --s
61 > The benefit of using transient pages seems to just be avoiding commit
62 > clutter? For files that are never committed, transient pages are a clear
63 > win, but I wonder if adding configuration clutter just to avoid some
64 > commit clutter is really worth it.
66 >> According to the last section of
67 >> [[todo/auto-create_tag_pages_according_to_a_template]], chrysn and
68 >> Eric both feel rather strongly that it should be possible to
69 >> not commit any tags. I made it configurable because, as you point out,
70 >> there are also reasons why it makes sense to check these
71 >> automatically-created files in. I'm neutral on this, personally.
73 >> If this is a point of contention, would you accept a branch that
74 >> just adds `transient` and uses it for [[plugins/recentchanges]],
75 >> which aren't checked in and never have been?
77 >> One potentially relevant point is that configuration clutter only
78 >> affects the site admin whereas commit clutter is part of the whole
79 >> wiki's history. --[[smcv]]
81 > Anyway, the configurability
82 > appears subtly broken; the default is only 1 if a new setup file is
83 > generated. With an existing setup file, the 'default' values in
84 > `getsetup` don't take effect, so it will default to undef, which
85 > is treated the same as 0. --[[Joey]]
87 >> Fixed in the branch, hopefully. (How disruptive would it be to have
88 >> defaults take effect whenever the setup file doesn't set a value, btw?
89 >> It seems pretty astonishing to have them work as they do at the moment.) --s
91 autoindex ignores pages in the transient underlay when deciding whether
94 New recent changes go in the transient underlay; I tested this manually.
96 Not done yet (in that branch, at least):
98 * `remove` can't remove transient pages: this turns out to be harder than
99 I'd hoped, because I don't want to introduce a vulnerability in the
100 non-regular-file detection, so I'd rather defer that.
102 > Hmm, I'd at least want that to be dealt with before this was used
103 > by default for autoindex or tag. --[[Joey]]
105 >> I'll try to work out which of the checks are required for security
106 >> and which are just nice-to-have, but I'd appreciate any pointers
107 >> you could give. Note that my branch wasn't meant to enable either
108 >> by default, and now hopefully doesn't. --[[smcv]]
110 * Transient tags that don't match any pages aren't deleted: I'm not sure
111 that that's a good idea anyway, though. Similarly, transient autoindexes
112 of directories that become empty aren't deleted.
114 > Doesn't seem necessary, or really desirable to do that. --[[Joey]]
116 >> Good, that was my inclination too. --s
118 * In my `untested/transient` branch, new aggregated files go in the
119 transient underlay too (they'll naturally migrate over time). I haven't
120 tested this yet, it's just a proof-of-concept.
122 > I can confirm that the behavior of autoindex, at least, is excellent.
123 > Haven't tried tag. Joey, can you merge transient and autoindex? --JoeRayhawk
125 >> Here are some other things I'd like to think about first: --[[Joey]]
127 >> * There's a FIXME in autoindex.
129 >>> Right, the extra logic for preventing autoindex pages from being
130 >>> re-created. I've started on regression tests for this, but I'll
131 >>> need to rummage through the commit log for the exact requirements
132 >>> and the reasoning behind them, so it could take a while. --s
134 >> * Suggest making recentchanges unlink the transient page
135 >> first, and only unlink from the old location if it wasn't
136 >> in the transient location. Ok, it only saves 1 syscall :)
138 >>> Is an unlink() really that expensive? But, OK, fixed in the
139 >>> updated branch. --s
141 >> * Similarly it's a bit worrying for performance that it
142 >> needs to pull in and use `Cwd` on every ikiwiki startup now.
143 >> I really don't see the need; `wikistatedir` should
144 >> mostly be absolute, and ikiwiki should not chdir in ways
145 >> that break it anyway.
147 >>> The reason to make it absolute is that relative underlays
148 >>> are interpreted as relative to the base underlay directory,
151 >>> The updated branch only loads `Cwd` if the path is relative;
152 >>> an extra commit on branch `smcv/transient-relative` goes
153 >>> behind `add_underlay`'s back to allow use of a cwd-relative
154 >>> underlay. Which direction would you prefer? --s
156 >> * Unsure about the use of `default_pageext` in the `change`
157 >> hook. Is everything in the transientdir really going
158 >> to use that pageext? Would it be better to look up the
159 >> complete source filename?
161 >>> At the moment everything in the transientdir will either
162 >>> have the `default_pageext` or be internal, although I
163 >>> did wonder whether to make [[plugins/contrib/album]]
164 >>> viewer pages optionally be `html`, for better performance
165 >>> when there's a very large number of photos.
167 >>> A more thorough garbage-collection mechanism would be to
168 >>> use File::Find on the transient directory; I'll get there
171 --------------------------
173 ## An earlier version
175 I had a look at implementing this. It turns out to be harder than I thought
176 to have purely in-memory pages (several plugins want to be able to access the
177 source file as a file), but I did get this proof-of-concept branch
178 to write tag and autoindex pages into an underlay.
180 This loses the ability to delete the auto-created pages (although they don't
181 clutter up git this way, at least), and a lot of the code in autoindex is
182 probably now redundant, so this is probably not quite ready for merge, but
183 I'd welcome opinions.
185 Usage: set `tag_underlay` and/or `autoindex_underlay` to an absolute path,
186 which you must create beforehand. I suggest *srcdir* + `/.ikiwiki/transient`.
188 Refinements that could be made if this approach seems reasonable:
190 * make these options boolean, and have the path always be `.ikiwiki/transient`
191 * improve the `remove` plugin so it also deletes from this special underlay
193 >> Perhaps it should be something more generic, so that other plugins could use it (such as "album" mentioned above).
194 >> The `.ikiwiki/transient` would suit this, but instead of saying "tag_underlay" or "autoindex_underlay" have "use_transient_underlay" or something like that?
195 >> 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.
196 >> --[[KathrynAndersen]]
198 >>> What I had in mind was more like `tag_autocreate_transient => 1` or
199 >>> `autoindex_transient => 1`; you might conceivably want tags to be
200 >>> checked in but autoindices to be transient, and it's fine for each
201 >>> plugin to make its own decision. Going from that to one boolean
202 >>> (or just always-transient if people don't think that's too
203 >>> astonishing) would be trivial, though.
205 >>> I don't think relocating the transient underlay really makes sense,
206 >>> except for prototyping: you only want one, and `.ikiwiki` is as good
207 >>> a place as any (ikiwiki already needs to be able to write there).
209 >>> For [[plugins/contrib/album]] I think I'd just make the photo viewer
210 >>> pages always-transient - you can always make a transient page
211 >>> permanent by editing it, after all.
213 >>> Do you think this approach has enough potential that I should
214 >>> continue to hack on it? Any thoughts on the implementation? --[[smcv]]
216 >>>> Ah, now I understand what you're getting at. Yes, it makes sense to put transient pages under `.ikiwiki`.
217 >>>> 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.
218 >>>> 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.
220 >>>> 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.
221 >>>> 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.
222 >>>> -- [[KathrynAndersen]]