Re: [Cppcms-users] URL dispatching help
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Re: [Cppcms-users] URL dispatching help
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From: Lee E. <lee...@gm...> - 2013-05-07 06:13:26
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I'll give a broader response:
web apps use HTTP protocol. This protocol is essentially stateless
so a client (browser) issue a request to the server (GET or POST are the
most common) with a url - now the server needs to resolve the URL in order
to find what code to run - this is dispatching
the code dispached generate a response (usually an HTML content) and that
content is sent over to the browser that renderes it.
with that a complete cycle is complete and the connection between the
server and the client is severed and they go their separate ways.
If only life where so simple :)
We usually do not write web application that only render data from URL - we
ususally have web pages that interact with one another. So if i want in the
page my code generated to provide a button for example that activates a
specific functionality in my app - i need to generate proper URL for that
button that will be dispatched to the correct code. So instead
of figuring by hand what that URL is, i can assign that piece of code a key
whe i register it with the dispatcher - and ask to get the url that match
that key - this is mapping
I hope this helps
On Fri, May 3, 2013 at 1:35 PM, Petr Janda <ele...@ex...>wrote:
> One way to use the url_mapper class is when using
> http_response::set_redirect_header() function.
>
> In combination with the url() function you can easily translate a single
> name/key to a longer url.
>
> Such as: set_response_header(url("my_key", "argument"))
>
> Which depending on the value mapped to my_key might get translated to
> something like "/some/url/with/'argument'"
>
>
>
> On 3/05/2013 6:40 PM, Troy Watson wrote:
> > <digression>
> > > 1. Read the docs.
> > I have read both the tutorials online and the API documentation
> generated
> > by Doxygen. The documentation is riddled with spelling
> > and grammatical errors making it difficult for me to comprehend in some
> > places.
> >
> > > 2. Read existing code and examples.
> > You must have missed earlier where I mentioned reading the examples and
> > looking through the code and not understanding the concept or use of the
> > url_mapper class! That's why I'm here asking people who do understand it,
> > hoping they can share some knowledge! The help so far is VERY
> appreciated.
> > :)
> >
> > > It is a walk in park if you already know C++...
> > I do.
> >
> > > ... and some basic web programming.
> > I don't. The documentation fails to educate a person new to web
> > development, like me.
> > </digression>
> >
> > Anyway, back on topic:
> > I think I'm not understanding HOW to use the url_mapper class because I
> > don't understand WHY I would need to or should. What problem does it
> solve?
> > Like I said above, I'm new to web programming. In a project larger than
> > CppBlog and WikiPP I'm not using the URL mapping functions anywhere,
> which
> > leads me to believe that either it's useless or, more likely, I'm doing
> > something wrong! :)
> >
> > According to a simple "grep -R mapper()", the url_mapper member of the
> > application class is referred to 52 times in all the examples code and
> > WikiPP and CppBlog code. Of those 52 uses, only seven are not a call to
> > mapper().assign(...). Five are to mapper().root(...) and the remaining
> two
> > are for mapper().set_value(...). I use none of those in my code, or any
> > other call to mapper(), yet the application seems to work so far!
> >
> > Perhaps the problem is that I'm generating all the HTML code in CppCMS
> > templates and none in C++ functions. Is URL mapping relevant if I'm only
> > using templates to output HTML? I assume it is, because the documentation
> > states:
> > Such system allows using "url" tag in templates system easily as"
> > <a href="<% url "/news/article" using article id %>" >...</a>
> >
> > But I've been using something like:
> > <a href="/news/<%= article.id %>">...</a>
> >
> > Which appears to work fine. I'm presuming there's some problem in my
> usage
> > that URL mapping solves?
> >
> > Thank you all for being patient with me and helping where you can!
> >
> >
> > On Fri, May 3, 2013 at 1:36 AM, Shiv Shankar Dayal <
> > shi...@gm...> wrote:
> >
> >> Two things. 1. Read the docs. 2. Read existing code and examples. It is
> a
> >> walk in park if you already know C++ and some basic web programming.
> >>
> >>
> >> On Thu, May 2, 2013 at 9:04 PM, Shiv Shankar Dayal <
> >> shi...@gm...> wrote:
> >>
> >>> look up examples directory in cppcms directory. you need cppdb for some
> >>> apps. you can also install cppwiki and cppblog for more understanding.
> It
> >>> is all there for you.
> >>>
> >>>
> >>> On Thu, May 2, 2013 at 1:08 PM, Troy Watson <dr...@gm...> wrote:
> >>>
> >>>> Nope - still not getting it :(
> >>>>
> >>>> Perhaps if you can spare some time to show me with a real, practical
> >>>> example I'll understand.
> >>>>
> >>>> I have the following line in my code: dispatcher().assign(
> >>>> "/edit/(\\d+)", &application::edit_bookmark, this, 1 );
> >>>> It correctly calls this function:
> >>>>
> >>>> void edit_bookmarks( std::string id )
> >>>>
> >>>> ...when I click links that look like /edit/10 or /edit/9239 etc.
> >>>> Dispatching I understand.
> >>>>
> >>>> Where does mapping come into this? How can my application be improved
> >>>> with a call to mapper(...)? How could it compliment the dispatcher as
> shown
> >>>> above?
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On Wed, May 1, 2013 at 12:59 AM, Shiv Shankar Dayal <
> >>>> shi...@gm...> wrote:
> >>>>
> >>>>> It is simple actually. You click a link some function on server is
> >>>>> invoked and output is displayed on another link. One is mapping
> another is
> >>>>> dispatching.
> >>>>>
> >>>>>
> >>>>> Best regards,
> >>>>> Shiv
> >>>>>
> >>>>>
> >>>>> On Tue, Apr 30, 2013 at 2:16 PM, Troy Watson <dr...@gm...>
> wrote:
> >>>>>
> >>>>>> I've read that page several times, messed about with the url_mapping
> >>>>>> example, and it still makes no sense to me what you mean by "the
> opposite
> >>>>>> of dispatching". I appreciate the help, but please explain it like
> I've
> >>>>>> never written a webapp before... because I haven't!
> >>>>>>
> >>>>>>
> >>>>>> On Mon, Apr 29, 2013 at 4:28 PM, Artyom Beilis <art...@ya...
> >wrote:
> >>>>>>
> >>>>>>>> What is mapper().assign( "...", "..." ) used for? All my URL
> >>>>>>> dispatching seems to work by only calling
> >>>>>>>> dispatcher().assign(...) to set up the URLs with a callback
> >>>>>>> function.
> >>>>>>>> What concept am I not understanding that would require the
> mapper()?
> >>>>>>>
> >>>>>>> The opposite of dispatching :-)
> >>>>>>>
> >>>>>>>
> >>>>>>> See: http://cppcms.com/wikipp/en/page/cppcms_1x_tut_url_mapping
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> Artyom Beilis
> >>>>>>> --------------
> >>>>>>> CppCMS - C++ Web Framework: http://cppcms.com/
> >>>>>>> CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
> >>>>>>>
> >>>>>>>
> >>>>>>>
> ------------------------------------------------------------------------------
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> >>>>>>> _______________________________________________
> >>>>>>> Cppcms-users mailing list
> >>>>>>> Cpp...@li...
> >>>>>>> https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> ------------------------------------------------------------------------------
> >>>>>> Introducing AppDynamics Lite, a free troubleshooting tool for
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> >>>>>>
> >>>>>> _______________________________________________
> >>>>>> Cppcms-users mailing list
> >>>>>> Cpp...@li...
> >>>>>> https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> Best regards,
> >>>>> Shiv Shankar Dayal
> >>>>>
> >>>>>
> >>>>>
> ------------------------------------------------------------------------------
> >>>>> Introducing AppDynamics Lite, a free troubleshooting tool for
> Java/.NET
> >>>>> Get 100% visibility into your production application - at no cost.
> >>>>> Code-level diagnostics for performance bottlenecks with <2% overhead
> >>>>> Download for free and get started troubleshooting in minutes.
> >>>>> http://p.sf.net/sfu/appdyn_d2d_ap1
> >>>>> _______________________________________________
> >>>>> Cppcms-users mailing list
> >>>>> Cpp...@li...
> >>>>> https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>
> ------------------------------------------------------------------------------
> >>>> Introducing AppDynamics Lite, a free troubleshooting tool for
> Java/.NET
> >>>> Get 100% visibility into your production application - at no cost.
> >>>> Code-level diagnostics for performance bottlenecks with <2% overhead
> >>>> Download for free and get started troubleshooting in minutes.
> >>>> http://p.sf.net/sfu/appdyn_d2d_ap1
> >>>> _______________________________________________
> >>>> Cppcms-users mailing list
> >>>> Cpp...@li...
> >>>> https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >>>>
> >>>>
> >>>
> >>>
> >>> --
> >>> Best regards,
> >>> Shiv Shankar Dayal
> >>>
> >>
> >>
> >>
> >> --
> >> Best regards,
> >> Shiv Shankar Dayal
> >>
> >>
> >>
> ------------------------------------------------------------------------------
> >> Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET
> >> Get 100% visibility into your production application - at no cost.
> >> Code-level diagnostics for performance bottlenecks with <2% overhead
> >> Download for free and get started troubleshooting in minutes.
> >> http://p.sf.net/sfu/appdyn_d2d_ap1
> >> _______________________________________________
> >> Cppcms-users mailing list
> >> Cpp...@li...
> >> https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >>
> >>
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> > Get 100% visibility into Java/.NET code with AppDynamics Lite
> > It's a free troubleshooting tool designed for production
> > Get down to code-level detail for bottlenecks, with <2% overhead.
> > Download for free and get started troubleshooting in minutes.
> > http://p.sf.net/sfu/appdyn_d2d_ap2
> >
> >
> >
> > _______________________________________________
> > Cppcms-users mailing list
> > Cpp...@li...
> > https://lists.sourceforge.net/lists/listinfo/cppcms-users
> >
>
>
> --
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>
>
>
> ------------------------------------------------------------------------------
> Get 100% visibility into Java/.NET code with AppDynamics Lite
> It's a free troubleshooting tool designed for production
> Get down to code-level detail for bottlenecks, with <2% overhead.
> Download for free and get started troubleshooting in minutes.
> http://p.sf.net/sfu/appdyn_d2d_ap2
> _______________________________________________
> Cppcms-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/cppcms-users
>
>
--
--
lee
Lee Elenbaas
lee...@gm...
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