Thursday, August 24, 2017, 9:53:11 AM, Daniel Dekany wrote:
> Thursday, August 24, 2017, 6:19:29 AM, Woonsan Ko wrote:
>
>> On Mon, Aug 21, 2017 at 12:19 AM, Daniel Dekany <[email protected]> wrote:
>>> Monday, August 7, 2017, 9:18:36 PM, Woonsan Ko wrote:
>>>
>>>> On Mon, Aug 7, 2017 at 11:03 AM, Daniel Dekany <[email protected]> wrote:
>>>>> If you are going to implement these directly as
>>>>> TemplateDirectiveModel-s and TemplateFunctionModel-s, then you better
>>>>> wait until I merge at least the FREEMARKER-63 PR... probably also
>>>>> FREEMARKER-64. I will try to do that tonight. At least 63.
>>>>
>>>> OK, I'll watch and wait for that. :-)
>>>
>>> FREEMARKER-63, 64 and 65 has been committed. Try to use CallableUtils
>>> for argument validation and other exception creation. See
>>> AssertFailsDirective as an example. Of course, ideas for improving
>>> CallableUtils are highly welcome.
>>>
>>> BTW, certainly there are several TemplateFunctionModel and
>>> TemplateDirectiveModel implementations that could but don't yet use
>>> CallableUtils for argument validation. If you spot some, you may go
>>> ahead and improve them.
>>
>> Thank you so much! I've briefly browsed the PRs linked from the JIRA
>> tickets, and it is really great!
Though you better look at the examples in the 3.0 branch, because
FREEMARKER-65 wasn't a PR; I have committed it directly there. (Maybe
I shouldn't do that.)
>> Really easy to extend it with
>> TemplateCallableModel. Very simple but really powerful! I also saw
>> IncludePage directive (as named "include_page") in
>> freemarker-servlet; it looks really straightforward.
>> I'll try to write equivalent directives or functions from spring JSP
>> Tag Library [1] and spring-form JSP Tag Library [2].
>
> Certainly quite a few changes will be needed compared to the JSP
> taglib. One such question if when and how escaping related
> functionality will appear, as escaping is a core facility in FTL.
> Also there are strange things like `<spring:url path=... var='v'>`.
> I'm not sure why that isn't a function (used like
> <c:set v=spring:ulr(path)>)...
With correct JSP syntax that actually would be
<c:set var="v" value="${spring:url("somePath")}">
if spring:url was a function. So it's kind of understandable that they
rather go with
<spring:url path="somePath" var="v" />
But in FreeMarker it would be just:
<#assign v = spring.url("somePath")>
or if you want to print it into the HTML:
<a href="${spring.url("somePath")}">
So this was a case where what's a custom tag in JSP should be a
function in FreeMarker, not a directive.
> Also note that in FTL you can have positional parameters for
> directives, and named parameters for functions.
Usually, if a directive has a required parameter, whose meaning is
obvious for almost anybody, then that should be a positional
parameter. A very clear case of this is <#if something>. A less clear
case, but still maybe a good idea is making the "path" parameter of
form:input, form:label etc. positional:
<tr>
<td><@form.label "contactPerson">Contact person</@></td>
<td><@form.input "contactPerson"/></td>
</tr>
I think anyone who knows even a little about Spring forms will know
that "contactPerson" is the property name in the backing form bean. Or
if not, path="contactPerson" is not much more helpful either.
Another place where FreeMarker differs from the approach of the Spring
JSP tags is when you refer to a value of the model (or to any Servlet
attribute). Like, you have an "employee" bean in the Spring Model, and
as far as I see in JSP you are supposed to bind that to a form like
this:
<form:form action="/storeEmployee" modelAttribute="employee">
While technically possible, that's quote alien from FreeMarker. If the
directive wants to do something with the `emloyee` object, then pass
the object itself to it as argument, not the name of it. Like this:
<@form.form action="/storeEmployee" model=employee>
Unless, the `form` directive indeed has to know the *name* of the
variable, as opposed to just the value of it... I'm not sure if that's
the case here. But I have seen this patter a few times in JSP (pass
the name of something instead of the thing itself), and had the
feeling that often it's just to avoid the more noisy
`model="${employee}"` syntax. FreeMarker has no such problem, as it's
just `model=employee` there, which is even less verbose than passing
the name of the variable.
> Also that a value can be both a function and a directive; maybe
> useful for message printing. If called like a function, it returns a
> string, if called like a tag, it prints the message without
> escaping... maybe.
So that practically means that these two will be equivalent:
<@spring.message "foo" />
${spring.message("foo")?noEsc}
Now this is maybe too confusing for most users and thus is a bad idea.
But if spring.message will only have one type, then that's surely
function, not directive (unlike in the FM2 Spring integration).
Something that would be interesting if the spring.message function can
somehow tell if a message is plain text or HTML. Like you can
configure which messages are HTML on name patterns (or a content
pattern, like all HTML values start with "<span>"). After all, without
such a rule, how do the developers themselves know if a message should
be HTML or plain text. Hopefully the have some exact policy for that.
If spring.message knows that rule too, then for HTML messages it
should return a TemplateMarkupOutputModel instead of a string, so it
will be automatically non-escaped. Then people can just write
${spring.message("foo")} without worrying about `?noEsc`. And then we
certainly don't need the directive "overload" either.
>> By the way, I'm wondering what the best practices are in naming those
>> models. Should it be better with 'form', 'spring_form', 'spring.form',
>> or something else? Prefixing with something sounds safer to me.
>
> In the templates they should be accessible as <@spring.bind ...> and
> such. In the case of the form tags, as it's in a separate namespace in
> JSP, maybe it should be <@form.input ...> etc. (Though I'm not 100%
> sure if its practical the structure of the JSP taglibs so closely, and
I meant: "if it's practical to follow the structure of the JSP taglibs
so closely"
> maybe we could just go with <@spring.input ...>. I don't know.)
>
>> Regards,
>>
>> Woonsan
>>
>> [1]
>> https://docs.spring.io/spring/docs/current/spring-framework-reference/html/spring-tld.html
>> [2]
>> https://docs.spring.io/spring/docs/current/spring-framework-reference/html/spring-form-tld.html
>>
>>>
>>>>> Besides, just to be absolutely clear, I would merge your current PR as
>>>>> well, if it doesn't raise licensing issues, which is of course a
>>>>> blocker.
>>>>
>>>> Sure, no worries. I was also under a concern about that and wanted to
>>>> get feedbacks before doing too much. ;-)
>>>>
>>>> Regards,
>>>>
>>>> Woonsan
>>>>
>>>>>
>>>>>
>>>>> Monday, August 7, 2017, 4:23:26 PM, Woonsan Ko wrote:
>>>>>
>>>>>> On Sun, Aug 6, 2017 at 6:14 AM, Daniel Dekany <[email protected]>
>>>>>> wrote:
>>>>>>> The big problem is that spring.ftl is copyrighted by some of the
>>>>>>> Spring authors (or the Spring project as a whole - it's not clear). So
>>>>>>> certainly we can't just copy it. It has to be reimplemented without
>>>>>>> looking at the source, or something absurd like that. Perhaps the best
>>>>>>> is to start out from the spring JSP taglib, as that's the most widely
>>>>>>> used templating solution (I assume), so certainly that's the one where
>>>>>>> all the features are exposed.
>>>>>>>
>>>>>>> I wonder if using #import + FTL is the best way of adding
>>>>>>> framework-level functionality that's used by a lot of people. It's
>>>>>>> surely an OK way, but it's not the highest performance way. The other
>>>>>>> way is using a shared variable (or some other kind of commonly visible
>>>>>>> variable) and implement the library in Java using
>>>>>>> TemplateDirectiveModel-s and TemplateFunctionModel-s. It's less
>>>>>>> convenient than doing it in FTL, but it has to be done once, while you
>>>>>>> save some resources everywhere where it's used. Though as most of
>>>>>>> these macros/functions are quite simple, I don't think the performance
>>>>>>> difference matters much. But, it also avoids the legal issue above. I
>>>>>>> mean, many of these function/macros are so trivial, that it's hard to
>>>>>>> implement them on a different way in FTL than as it is in the Spring
>>>>>>> source code, but if you implement them in Java, then it's much harder
>>>>>>> to accuse anyone with stealing. (A minor annoyance right now is that
>>>>>>> that part of the FreeMarker API is not yet settled; see FREEMARKER-63,
>>>>>>> FREEMARKER-64, FREEMARKER-65. But hopefully it will be in a good
>>>>>>> enough shape soon. And see other thread; input is welcome!)
>>>>>>>
>>>>>>> As of template aliases, at the first glance that's fine. Note that
>>>>>>> there's MultiTemplateLoader which does something similar, but I assume
>>>>>>> it would be less neat (and/or slower) to do this with that. (But if
>>>>>>> the spring functionality won't be #import-ed after all (as above), the
>>>>>>> whole thing can become unnecessary...)
>>>>>>
>>>>>> Thank you very much for sharing your insights. Greatly helpful advice.
>>>>>> I agree that it might be better with template model(s) rather than
>>>>>> library FTL in various aspects.
>>>>>> Let me try with that approach again and let you know soon with a new PR.
>>>>>>
>>>>>> Thank again,
>>>>>>
>>>>>> Woonsan
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Sunday, August 6, 2017, 7:22:00 AM, ASF GitHub Bot (JIRA) wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> [
>>>>>>>> https://issues.apache.org/jira/browse/FREEMARKER-55?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16115649#comment-16115649
>>>>>>>> ]
>>>>>>>>
>>>>>>>> ASF GitHub Bot commented on FREEMARKER-55:
>>>>>>>> ------------------------------------------
>>>>>>>>
>>>>>>>> GitHub user woonsan opened a pull request:
>>>>>>>>
>>>>>>>> https://github.com/apache/incubator-freemarker/pull/31
>>>>>>>>
>>>>>>>> FREEMARKER-55: spring.ftl marco lib support
>>>>>>>>
>>>>>>>> - Support <#import "/spring.ftl" as spring> like Spring Framework
>>>>>>>> does.
>>>>>>>> - By default, the system lib from /spring.ftl is read from the
>>>>>>>> specific classpath, not from app's template path.
>>>>>>>> The system template aliases map can be customized through
>>>>>>>> SpringResourceTemplateLoader.systemTemplateAliases property.
>>>>>>>> - The same macros and functions are defined in /spring.ftl as
>>>>>>>> Spring Framework's, with syntax changes to comply with FM3.
>>>>>>>> - Note: As the system template lib support is handled by
>>>>>>>> SpringTemplateLoader in this PR, it means developers should always
>>>>>>>> use SpringTemplateLoader directly or indirectly in order to use the
>>>>>>>> system macro library. Please review this decision.
>>>>>>>> - TODOs: review/test/refine each macro and functions in spring.ftl.
>>>>>>>>
>>>>>>>> You can merge this pull request into a Git repository by running:
>>>>>>>>
>>>>>>>> $ git pull https://github.com/woonsan/incubator-freemarker
>>>>>>>> feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> Alternatively you can review and apply these changes as the patch at:
>>>>>>>>
>>>>>>>> https://github.com/apache/incubator-freemarker/pull/31.patch
>>>>>>>>
>>>>>>>> To close this pull request, make a commit to your master/trunk branch
>>>>>>>> with (at least) the following in the commit message:
>>>>>>>>
>>>>>>>> This closes #31
>>>>>>>>
>>>>>>>> ----
>>>>>>>> commit 8e0f33c419d982279d7fb22a9dfdc66f47abaf2c
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-07-14T15:27:17Z
>>>>>>>>
>>>>>>>> FREEMARKER-55: Renaming Freemarker to FreeMarker
>>>>>>>>
>>>>>>>> commit ec8d687d4ce2c0e1bb3e3ca073b139eacc198527
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-07-14T15:53:51Z
>>>>>>>>
>>>>>>>> Merge branch '3' into feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> commit e7cb6f7cfc241689c85527971bf6e1ea7ced9127
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-07-14T17:57:29Z
>>>>>>>>
>>>>>>>> Merge branch '3' into feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> commit c6eb09de91e57035c1e0e3c4d3490b3b96622bab
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-07-16T18:24:55Z
>>>>>>>>
>>>>>>>> Merge branch '3' into feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> commit 870209fa8e0acd0bb3186053dfd549b5c758e37d
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-07-18T00:38:03Z
>>>>>>>>
>>>>>>>> Merge branch '3' into feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> commit 4481406a2f4eeb30d6d044a4ac158efab7ba7a7b
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-08-06T01:28:54Z
>>>>>>>>
>>>>>>>> Merge branch '3' into feature/FREEMARKER-55
>>>>>>>>
>>>>>>>> commit fcd9e672ec515e3042bc5efd229b7d12c23e7d88
>>>>>>>> Author: Woonsan Ko <[email protected]>
>>>>>>>> Date: 2017-08-06T05:09:12Z
>>>>>>>>
>>>>>>>> FREEMARKER-55: system template lib for spring app: spring.ftl.
>>>>>>>>
>>>>>>>> ----
>>>>>>>>
>>>>>>>>
>>>>>>>>> FM3 freemarker-spring module, Web MVC support
>>>>>>>>> ---------------------------------------------
>>>>>>>>>
>>>>>>>>> Key: FREEMARKER-55
>>>>>>>>> URL:
>>>>>>>>> https://issues.apache.org/jira/browse/FREEMARKER-55
>>>>>>>>> Project: Apache Freemarker
>>>>>>>>> Issue Type: Task
>>>>>>>>> Affects Versions: 3.0.0
>>>>>>>>> Reporter: Daniel Dekany
>>>>>>>>>
>>>>>>>>> Add Spring "Web MVC framework" functionality to freemarker-spring.
>>>>>>>>> This can be complex task (and the issue possibly has to be
>>>>>>>>> subdivided), as it involves things like:
>>>>>>>>> * Some aspects of the FreeMarker 2 integration (developed by the
>>>>>>>>> Spring developers) are quite confusing ({{FreemarerConfigurer}},
>>>>>>>>> etc.), and we are looking into if it needs to be like that.
>>>>>>>>> * See if we can support {{@EnableWebMvc}} (note that FreeMarker 2
>>>>>>>>> support is hard coded into {{ViewResolverRegistry}}, which we can't
>>>>>>>>> modify)
>>>>>>>>> * Creating custom directives/methods to expose Spring features like
>>>>>>>>> the Spring JSP Tag Library does (but in a way that firs FreeMarker
>>>>>>>>> better)
>>>>>>>>> * Expose JSP custom tag support from the {{freemarker-servlet}}
>>>>>>>>> module.
>>>>>>>>> Depends on: FREEMARKER-54
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> This message was sent by Atlassian JIRA
>>>>>>>> (v6.4.14#64029)
>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Thanks,
>>>>>>> Daniel Dekany
>>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> Thanks,
>>>>> Daniel Dekany
>>>>>
>>>>
>>>
>>> --
>>> Thanks,
>>> Daniel Dekany
>>>
>>
>
--
Thanks,
Daniel Dekany
