response to response

[git.ikiwiki.info.git] / doc / todo / allow_site-wide_meta_definitions.mdwn

diff --git a/doc/todo/allow_site-wide_meta_definitions.mdwn b/doc/todo/allow_site-wide_meta_definitions.mdwn
index 5b7a5bea53d493cbce126af21f14d0c8a58ed30e..82670250e54df00b79d8419fe1cbdf3dc5ae6311 100644 (file)
--- a/doc/todo/allow_site-wide_meta_definitions.mdwn
+++ b/doc/todo/allow_site-wide_meta_definitions.mdwn
@@ -1,44 +1,192 @@
+[[!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.
 
 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[[!tag 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
 
     diff --git a/IkiWiki/Plugin/meta.pm b/IkiWiki/Plugin/meta.pm

-    index b229592..a307db4 100644
+    index 6fe9cda..2f8c098 100644

     --- a/IkiWiki/Plugin/meta.pm
     +++ b/IkiWiki/Plugin/meta.pm
     --- a/IkiWiki/Plugin/meta.pm
     +++ b/IkiWiki/Plugin/meta.pm

-    @@ -13,6 +13,7 @@ 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);
+    @@ -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 () {
      }
      
      sub getsetup () {

-    @@ -302,6 +303,15 @@ sub match {
-            }
+    @@ -305,6 +307,15 @@ sub match {
+       }

      }
      
     +sub scan() {
      }
      
     +sub scan() {

-    +       my %params = @_;
-    +       my $page = $params{page};
-    +    foreach my $type (map { s/^meta_//; $_ } grep /^meta_/, keys %config) {
-    +               $pagestate{$page}{meta}{$type} = $config{"meta_$type"}
-    +                       unless defined $pagestate{$page}{meta}{$type};
-    +       }
+    +  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 ($$;@) {
     +}
     +
      package IkiWiki::PageSpec;
      
      sub match_title ($$;@) {

-    @@ -324,4 +334,5 @@ sub match_copyright ($$;@) {
-            IkiWiki::Plugin::meta::match("copyright", @_);
+    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 `&quot;` 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
+    --- a/IkiWiki/Plugin/meta.pm
+    +++ b/IkiWiki/Plugin/meta.pm
+    @@ -13,6 +13,7 @@ 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);

      }
      
      }
      

+     sub getsetup () {
+    @@ -302,6 +303,15 @@ sub match {
+       }
+     }
+     
+    +sub scan() {
+    +  my %params = @_;
+    +  my $page = $params{page};
+    +    foreach my $type (map { s/^meta_//; $_ } grep /^meta_/, keys %config) {
+    +          $pagestate{$page}{meta}{$type} = $config{"meta_$type"}
+    +                  unless defined $pagestate{$page}{meta}{$type};
+    +  }
+    +}

     +
     +

-     1
+     package IkiWiki::PageSpec;
+     
+     sub match_title ($$;@) {

     diff --git a/doc/ikiwiki/directive/meta.mdwn b/doc/ikiwiki/directive/meta.mdwn
     index 000f461..200c4b2 100644
     --- a/doc/ikiwiki/directive/meta.mdwn
     diff --git a/doc/ikiwiki/directive/meta.mdwn b/doc/ikiwiki/directive/meta.mdwn
     index 000f461..200c4b2 100644
     --- a/doc/ikiwiki/directive/meta.mdwn


@@ -50,11 +198,49 @@ my github ikiwiki fork):
     +You can also define site-wide defaults for meta values by including them
     +in your setup file, e.g.
     +
     +You can also define site-wide defaults for meta values by including them
     +in your setup file, e.g.
     +

-    +       meta_copyright => "Copyright 2007 by Joey Hess",
-    +       meta_license   => "GPL v2+",
+    +  meta_copyright => "Copyright 2007 by Joey Hess",
+    +  meta_license   => "GPL v2+",

     +
      Supported fields:
      
      * title
 
 -- [[Jon]]
     +
      Supported fields:
      
      * title
 
 -- [[Jon]]

+
+>>> 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 think this will be problematic with the current implementation of this
+>>>> patch. The datatype here is an array of hash references, with each hash
+>>>> having a variable (and arbitrary) number of key/value pairs.  I can't
+>>>> think of an intuitive way of implementing a way of editing such a
+>>>> datatype in the web interface, let alone registering the option in
+>>>> getsetup.
+>>>> 
+>>>> Perhaps a limited set of defined meta values could be exposed via
+>>>> websetup (the obvious ones: author, copyright, license, etc.) -- [[Jon]]
+>>>
+>>> 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]]
+>>>> 
+>>>> that should be easy enough to do. I will work on a patch. -- [[Jon]]