The "context" object is missing from within several templates

[ilias@…]

Problem:

A call to "wiki_to_html" needs the "context" object as a first parameter.

The context object is missing from within several templates, e.g. the "timeline", thus "wiki_to_html" cannot be used within those.

Reproduction:

add the following to "timeline.html"

${wiki_to_html(context, "WikiStart test")

clicking on "timeline" results in an error.

 Trac detected an internal error:

UndefinedError: "context" not defined

Trac should create a default "context" object, thus calls to wiki_to_html work fine (note that in other places the same happens, e.g. "admin")

For the case this will not fix: Is there any simple way to obtain a default context-object (e.g. the wiki root) within a template, thus "wiki_to_html" works?

[ThurnerRupert]

why would you need to call wiki_to_html in a template, i thought you write html directly there?

pls reopen if i am wrong.

[ilias@…]

Replying to ThurnerRupert:

why would you need to call wiki_to_html in a template, i thought you write html directly there?

pls reopen if i am wrong.

With all respect: "Thinking" something about the trac design is no a valid reason to close a ticket as 'invalid' (see the TracTicketTriage).

As to your question: One standard use-case of "wiki_to_html" within the standard trac-templates (ticket/templates/report-view.html):

      <div py:if="report.description" id="description" xml:space="preserve">
        ${wiki_to_html(context, report.description)}
      </div>

You will see that "wiki_to_html" is used in many different standard templates, but where it's not used, a "context" object is missing, which makes template customization difficult (especially an overall customization within "layout.html").

[ilias@…]

I've noticed the document TracDev/ContextRefactoring, but I am still not able to create a workaround.

How can I obtain a default root-context object within a template programatically (if context is not provided)?

[Christian Boos]

For now, you can't, as this would require to do Context(env, req) and the "Context" symbol is not available.

With the new proposal, it will always be possible to create a RenderingContext easily from within a template, by doing either context() (the toplevel context), or context(resource) (for some resource).

[ilias@…]

Replying to cboos:

For now, you can't, as this would require to do Context(env, req) and the "Context" symbol is not available.

I understand. I may have missunderstood something, but shouldnt it be possible to do something like (pseudo code)

<?python>
import trac.context.Context as Context
if not (defined context):
    context = Context(env, req)
<?>

# usage of context

With the new proposal, it will always be possible to create a RenderingContext easily from within a template, by doing either context() (the toplevel context), or context(resource) (for some resource).

ok, sounds good.

As I'm currently within a dead-lock situation:

would it be possible to make "wiki_to_html" use the root context by default? (e.g. passing and undefined "context" makes "wiki_to_html" create internally the wiki root object.

As said, I may have missunderstood something of the current design. I use wiki_to_html just for template customization.

[ilias@…]

After some problems with genshi (see ​genshi:#153 and ​genshi:#154 ) I'm able to have full access to code within the templates.

So, I have the context symbol available now.

I place this code before the body tag (of the wiki_view.html template):

<?python
      from trac.context import Context as C
      def w2h(wikitext,env, req):
        ctxx = C(env, req)('wiki','WikiStart')
        return wiki_to_html(ctxx, wikitext)
?>
  
${w2h('Test WikiStart',trac.xenv,req)}

but I get an error:

AttributeError: 'Context' object has no attribute 'id'

Most possibly I've overseen a detail.

If not, isn't at this point any lower level function available, which converts wiki to html, without any need to pass a context? Such a simpler function would be useful.

[ilias@…]

correction:

${w2h('Test WikiStart', env, req)}

[ilias@…]

related: #6144

[Christian Boos]

After the context-refactoring, there will actually be a context object (trac.mimeview.api.Context) available in the data dictionary.

[Christian Boos]

Now in trunk (r6139).