[[!tag plugins/meta patch]]
+[[!template id=gitbranch branch=jon/defaultmeta author="[[Jon]]"]]
I'd like to define [[plugins/meta]] values to apply across all pages
site-wide unless the pages define their own: default values for meta
definitions essentially.
-Here's a patch to achieve this (also in the "defaultmeta" branch of
-my github ikiwiki fork):
+ <snip old patch, see below for latest>
+
+-- [[Jon]]
+
+> This doesn't support multiple-argument meta directives like
+> `link=x rel=y`, or meta directives with special side-effects like
+> `updated`.
+>
+> The first could be solved (if you care) by a syntax like this:
+>
+> meta_defaults => [
+> { copyright => "© me" },
+> { link => "about:blank", rel => "silly", },
+> ]
+>
+> The second could perhaps be solved by invoking `meta::preprocess` from within
+> `scan` (which might be a simplification anyway), although this is complicated
+> by the fact that some (but not all!) meta headers are idempotent.
+>
+> --[[smcv]]
+
+>> Thanks for your comment. I've revised the patch to use the config syntax
+>> you suggest. I need to perform some more testing to make sure I've
+>> addressed the issues you highlight.
+>>
+>> I had to patch part of IkiWiki core, the merge routine in Setup, because
+>> the use of `possibly_foolish_untaint` was causing the hashrefs at the deep
+>> end of the data structure to be converted into strings. The specific change
+>> I've made may not be acceptable, though -- I'd appreciate someone providing
+>> some feedback on that hunk!
+
+>>> Well, re that hunk, taint checking is currently disabled, but
+>>> if the perl bug that disallows it is fixed and it is turned back on,
+>>> the hash values will remain tainted, which will probably lead to
+>>> problems.
+>>>
+>>> I'm also leery of using such a complex data structure in config.
+>>> The websetup plugin would be hard pressed to provide a UI for such a
+>>> data structure. (It lacks even UI for a single hash ref yet, let alone
+>>> a list.)
+>>>
+>>> Also, it seems sorta wrong to have two so very different syntaxes to
+>>> represent the same meta data. A user without a lot of experience will
+>>> be hard pressed to map from a directive to this in the setup file.
+>>>
+>>> All of which leads me to think the setup file could just contain
+>>> a text that could hold meta directives. Which generalizes really to
+>>> a text that contains any directives, and is, perhaps appended to the
+>>> top of every page. Which nearly generalizes to the sidebar plugin,
+>>> or perhaps something more general than that...
+>>>
+>>> However, excessive generalization is the root of all evil, so
+>>> I'm not necessarily saying that's a good idea. Indeed, my memory
+>>> concerns below invalidate this idea pretty well. --[[Joey]]
+
+ diff --git a/IkiWiki/Plugin/meta.pm b/IkiWiki/Plugin/meta.pm
+ index 6fe9cda..2f8c098 100644
+ --- a/IkiWiki/Plugin/meta.pm
+ +++ b/IkiWiki/Plugin/meta.pm
+ @@ -13,6 +13,8 @@ sub import {
+ hook(type => "needsbuild", id => "meta", call => \&needsbuild);
+ hook(type => "preprocess", id => "meta", call => \&preprocess, scan => 1);
+ hook(type => "pagetemplate", id => "meta", call => \&pagetemplate);
+ + hook(type => "scan", id => "meta", call => \&scan)
+ + if $config{"meta_defaults"};
+ }
+
+ sub getsetup () {
+ @@ -305,6 +307,15 @@ sub match {
+ }
+ }
+
+ +sub scan() {
+ + my %params = @_;
+ + my $page = $params{page};
+ + foreach my $default (@{$config{"meta_defaults"}}) {
+ + preprocess(%$default, page => $page,
+ + destpage => $page, preview => 0);
+ + }
+ +}
+ +
+ package IkiWiki::PageSpec;
+
+ sub match_title ($$;@) {
+ diff --git a/IkiWiki/Setup.pm b/IkiWiki/Setup.pm
+ index 8a25ecc..e4d50c9 100644
+ --- a/IkiWiki/Setup.pm
+ +++ b/IkiWiki/Setup.pm
+ @@ -51,7 +51,13 @@ sub merge ($) {
+ $config{$c}=$setup{$c};
+ }
+ else {
+ - $config{$c}=[map { IkiWiki::possibly_foolish_untaint($_) } @{$setup{$c}}]
+ + $config{$c}=[map {
+ + if(ref $_ eq 'HASH') {
+ + $_
+ + } else {
+ + IkiWiki::possibly_foolish_untaint($_)
+ + }
+ + } @{$setup{$c}}];
+ }
+ }
+ elsif (ref $setup{$c} eq 'HASH') {
+ diff --git a/doc/ikiwiki/directive/meta.mdwn b/doc/ikiwiki/directive/meta.mdwn
+ index 000f461..8d34ee4 100644
+ --- a/doc/ikiwiki/directive/meta.mdwn
+ +++ b/doc/ikiwiki/directive/meta.mdwn
+ @@ -12,6 +12,16 @@ also specifies some additional sub-parameters.
+ The field values are treated as HTML entity-escaped text, so you can include
+ a quote in the text by writing `"` and so on.
+
+ +You can also define site-wide defaults for meta values by including them
+ +in your setup file. The key used is `meta_defaults` and the value is a list
+ +of hashes, one per meta directive. e.g.:
+ +
+ + meta_defaults = [
+ + { copyright => "Copyright 2007 by Joey Hess" },
+ + { license => "GPL v2+" },
+ + { link => "somepage", rel => "site entrypoint", },
+ + ],
+ +
+ Supported fields:
+
+ * title
+
+-- [[Jon]]
+
+>> Ok, I've had a bit of a think about this. There are currently 15 supported
+>> meta fields. Of these: title, licence, copyright, author, authorurl,
+>> and robots might make sense to define globally and override on a per-page
+>> basis.
+>>
+>> Less so, description (due to its impact on map); openid (why would
+>> someone want more than one URI to act as an openid endpoint to the same
+>> place?); updated. I can almost see why someone might want to set a global
+>> updated value. Almost.
+>>
+>> Not useful are permalink, date, stylesheet (you already have a global
+>> stylesheet), link, redir, and guid.
+>>
+>> In other words, the limitations of my first patch that [[smcv]] outlined
+>> are only relevant to defined fields that you wouldn't want to specify a
+>> global default for anyway.
+>>
+>>> I generally agree with this. It is *possible* that meta would have a new
+>>> field added, that takes parameters and make sense to use globally.
+>>> --[[Joey]]
+>>
+>> Due to this, and the added complexity of the second patch (having to adjust
+>> `IkiWiki/Setup.pm`), I think the first patch makes more sense. I've thus
+>> reverted to it here.
+>>
+>> Is this merge-worthy?
diff --git a/IkiWiki/Plugin/meta.pm b/IkiWiki/Plugin/meta.pm
index b229592..3132257 100644
-- [[Jon]]
-> This doesn't support multiple-argument meta directives like
-> `link=x rel=y`, or meta directives with special side-effects like
-> `updated`.
->
-> The first could be solved (if you care) by a syntax like this:
->
-> meta_defaults => [
-> { copyright => "© me" },
-> { link => "about:blank", rel => "silly", },
-> ]
->
-> The second could perhaps be solved by invoking `meta::preprocess` from within
-> `scan` (which might be a simplification anyway), although this is complicated
-> by the fact that some (but not all!) meta headers are idempotent.
->
-> --[[smcv]]
+>>> Merry Christmas/festive season/happy new year folks. I've been away from
+>>> ikiwiki for the break, and now I've returned to watching recentchanges.
+>>> Hopefully I'll be back in the mix soon, too. In the meantime, Joey, have
+>>> you had a chance to look at this yet? -- [[Jon]]
+
+>>>> Ping :) Hi. [[Joey]], would you consider this patch for the next
+>>>> ikiwiki release? -- [[Jon]]
+
+>>> For this to work with websetup and --dumpsetup, it needs to define the
+>>> `meta_*` settings in the getsetup function.
+>>>
+>>> I also have some concerns about both these patches, since both throw
+>>> a lot of redundant data at meta, which then stores it in a very redundant
+>>> way. Specifically, meta populates a per-page `%metaheaders` hash
+>>> as well as storing per-page metadata in `%pagestate`. So, if you have
+>>> a wiki with 10 thousand pages, and you add a 1k site-wide license text,
+>>> that will bloat the memory usage of ikiwiki by in excess of 2
+>>> megabytes. It will also cause ikiwiki to write a similar amount more data
+>>> to its state file which has to be loaded back in each
+>>> run.
+>>>
+>>> Seems that this could be managed much more efficiently by having
+>>> meta special-case the site-wide settings, not store them in these
+>>> per-page data structures, and just make them be used if no per-page
+>>> metadata of the given type is present. --[[Joey]]
+
+>>>> Thanks for the review - these are all valid points. I'll get working
+>>>> on a revised patch. -- [[Jon]]