Hello, On Sun, Dec 11, 2011 at 11:25 PM, Gerry Weaver <ger...@compvia.com> wrote: > Hello All, > > I am new to Racket and Lisp/Scheme in general. I am trying to write a simple > rest web service in Racket, but I'm not making much progress. Unfortunately, > I don't find the Racket docs to be very helpful. I guess my brain just isn't > wired right ;-) Asking questions on the mailing list would almost be a step > by step at this point, so I thought I would spare y'all from that. Anyway, > I'm trying to find some alternative docs or examples. I had the same problem > with the Sedna XML stuff, but once I found the scheme docs on Sedna's web > site I was able to get going. I've been searching the web for some > docs/examples, but no luck so far. Is there anything out there that would > help? >
I had a similar need recently, I developed a little library to use with Racket's web-server. There's still no documentation, so I didn't put it on PLaneT yet, but a few explanations might be enough. Don't hesitate to ask further questions. You can find the repaus.rkt file here: https://gitorious.org/repaus In a racket module, you require "repaus.rkt" and then you have three new form you can use : - define-resource - route - serve * define-resource allows you to define a… resource! It works like this: (define-resource (name path-elements ...) (http-method => procedure) ...) - name is the name of the resource. - path-elements are the request path separated by '/'. They can be strings or symbols. Strings enforce the value and symbols are "arguments". Symbols in path-elements can be preceded by #:number or #:symbol to be converted automatically (to a number or a symbol instead of a string). It can ends with ". some-symbol" to get a list of all the remaining path-elemnts. - http-method can be one of get, post, put, delete, patch, head. - procedure must be a function which takes the request as first argument, and then as many arguments as there are symbols in the path-elements. Also, it must returns someting the web-server can use as a response. Examples: (define-resource (home "") ;; / (get => (lambda (req) #;"the home page"))) (define-resource (posts "posts") ;; /posts (get => (lambda (req) #;"the n lasts posts")) (post => (lambda (req) #;"creates a new post"))) ; see the very good Racket web-server/http docs for how to get ; POST data and stuff from the request object. (define-resource (post "posts" slug) ;; /posts/your-awesome-post, /posts/foo-bar, ... (get => (lambda (req slug) #;"the slug post")) (put => (lambda (req slug) #;"update the slug post")) (delete => (lamdba (req slug) #;"delete the slug post"))) (define-resource (comments "posts" slug "comments") ;; /posts/foo-bar/comments, /posts/lalala/comments, ... (get => (lambda (req slug) #;"comments for slug")) (post => (lambda (req slug) #;"creates a comment for post slug"))) (define-resource (comment "posts" slug "comments" #:number id) ;; /posts/foo-bar/comments/42 (put => (lambda (req slug id) #;"edit comment id")) (delete => (lambda (req slug id) #;"delete comment id"))) ; here the id argument of the procedure is a number, I think for ; now it just breaks if Racket can't convert it to a number… ; (for instance /posts/foo-bar/comments/lala) (define-resource (archives "archives" #:number year #:number month) ;; now it should be clear) End examples. Of course you can (should) define the procedure in other modules that you require and just do stuff like "(get => show-posts)". * route will takes some resources defined with define-resource as arguments and make a functions which does the right dispatching that you can use with serve: (define blog (route home posts post comments comment archives)) * serve is just an alias to serve/servlet from Racket's web-server/servlet (so you don't need to require it): (serve blog #:port 8080 #:listen-ip #f #:servlet-regexp #rx"" #:stateless? #t #:command-line? #t) * Other details: - OPTIONS request are automatically handled for existing resources. - an empty response with a 404 (Not Found) status is sent if no resources given to route match the request. - an empty resources with a 405 (Method Not Allowed) status is sent if the resource exists but the method is not defined. Now, be aware that this is not quite polished as I wish it to be before really giving it to the public: it still needs some documentation, the default 404 and 405 response should be customizable, and to be a bit more robust for the string->number conversion. "I'll do that when I have some time…™" Cheers :-). -- Pablo. http://pablo.rauzy.name/ _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
