[racket] doc request for serve/servlet

There's a more direct way to do that, which IS an example in the docs:

http://docs.racket-lang.org/web-server-internal/web-server.html#%28def._%28%28lib._web-server%2Fweb-server..rkt%29._serve%29%29

I use this very often and have a little program that command-line-izes it:

https://github.com/jeapostrophe/exp/blob/master/dir-serve.rkt

Jay

On Fri, Mar 22, 2013 at 6:55 AM, Greg Hendershott
<greghendershott at gmail.com> wrote:
> This is slightly off-topic, but:
>
> If you want to launch the web server _just_ to serve static files (as
> I wanted to do for a "preview" mode for Frog), then it's simply this:
>
> (serve/servlet (lambda (_) (next-dispatcher))
>                #:servlet-path "/"
>                #:extra-files-paths (list path/to/files)
>                #:port 8080              ;or whatever
>                #:launch-browser? #t)    ;if you wish
>
> Although this isn't a very interesting use case, I think it might be a
> handy example for the docs.
>
> On Fri, Mar 22, 2013 at 8:06 AM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:
>> I'm willing to change the docs, but I'd like to try to explain it in
>> an email to make sure the explanation is okay.
>>
>> The key sentence of the documentation is: "start is loaded as a
>> servlet and responds to requests that match servlet-regexp."
>>
>> The default for servlet-regexp is such that the ONLY path that the
>> servlet responds to is "/servlets/standalone.rkt" and ALL other paths
>> are handled by the static file handlers.
>>
>> It is common to change the servlet-regexp to something like #rx"",
>> which causes ALL requests to be handled by the servlet. When you do
>> this, the documentation is still correct, but you may not realize the
>> consequence of what you've done.
>>
>> Throughout the Web server infrastructure, and serve/servlet does not
>> change this, if you call (next-dispatcher) then the current responder
>> FAILS and the next responder gets a chance. In the context of
>> serve/servlet, if you call (next-dispatcher) after using #rx"" to take
>> over all requests, then for that particular request where
>> (next-dispatcher) was dynamically called, the static handlers take
>> over.
>>
>> It so happens that the default "else" clause in web-server/dispatch is
>> to call (next-dispatcher). From the documentation: "If else-fun is
>> left out, one is provided that calls (next-dispatcher) to signal to
>> the Web Server that this dispatcher does not apply."
>>
>> Thus, if you use the #rx"" regexp AND dispatch-rules, then it is
>> likely that the "right" thing will happen without you trying because
>> you won't write an else and then if your servlet doesn't handle the
>> request, the static handler will be in control.
>>
>> Overall, I don't know what the documentation should be changed to say.
>> All this is in the documentation right now: you just might not realize
>> you are telling the servlet to handle everything, but once you realize
>> that you just need to know how to turn that off, and that isn't
>> specific in any way to serve/servlet, so I don't feel like it is
>> appropriate to put it there. (Alternatively, you should just be more
>> specific in your servlet-regexp, by using something like
>> (re-complement #rx"/static/.+"), and that's reasonable to expect a
>> user to realize, IMHO.)
>>
>> Jay
>>
>>
>> On Thu, Mar 21, 2013 at 10:55 PM, John Clements
>> <clements at brinckerhoff.org> wrote:
>>> The serve/servlet function has several flags that allude to the ability to serve static files (#:extra-files-paths, etc.). However, nowhere in that documentation does it say under what circumstances the web-server serves content from that pool of files.  After much struggling and cursing, I finally found a post by Matt Jadud.  Even then, it took me quite a while to realize that the 'dispatch-rules' function was the key to actually allowing some requests to reach the static content. Perhaps the serve/servlet documentation should explicitly specify when content is served from static files, or at least provide a pointer to the dispatch-rules documentation.
>>>
>>> Thoughts?
>>>
>>> John
>>>
>>>
>>> ____________________
>>>   Racket Users list:
>>>   http://lists.racket-lang.org/users
>>
>>
>>
>> --
>> Jay McCarthy <jay at cs.byu.edu>
>> Assistant Professor / Brigham Young University
>> http://faculty.cs.byu.edu/~jay
>>
>> "The glory of God is Intelligence" - D&C 93
>>
>> ____________________
>>   Racket Users list:
>>   http://lists.racket-lang.org/users



-- 
Jay McCarthy <jay at cs.byu.edu>
Assistant Professor / Brigham Young University
http://faculty.cs.byu.edu/~jay

"The glory of God is Intelligence" - D&C 93