Comrades I'm in a perplexing situation and I'd like to appeal to the sages. I've never written anything other than static HTML in my life, and I'd like to make a wee web service: I've heard some abbreviations, but I don't really know what they mean. I've got a function (possibly the identity, possibly const "", who knows?) assistant :: String -> String and I want to make a webpage with an edit box and a submit button. If I press the submit button with the edit box containing string s, I'd like the page to reload with the edit box reset to (assistant s). Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose. In general, what's an easy way to put a web front end on functionality implemented in Haskell? Hoping this isn't a hard question Conor
On Fri, Jun 5, 2009 at 5:18 PM, Conor McBride
Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose.
In general, what's an easy way to put a web front end on functionality implemented in Haskell?
For something this simple, I'd use CGI. I've never used the Haskell cgi package, but the basic idea is that the webserver runs an arbitrary script which reads the HTTP request information from environment variables, and outputs the response (in the simple case, just "Content-Type: text/html\r\n\r\n"++html). The cgi package probably provides easy access to those environment variables; this is what Python's cgi module does, for instance. --Max
On Fri, Jun 5, 2009 at 8:18 AM, Conor McBride
Comrades
I'm in a perplexing situation and I'd like to appeal to the sages.
I've never written anything other than static HTML in my life, and I'd like to make a wee web service: I've heard some abbreviations, but I don't really know what they mean.
I've got a function (possibly the identity, possibly const "", who knows?)
assistant :: String -> String
and I want to make a webpage with an edit box and a submit button. If I press the submit button with the edit box containing string s, I'd like the page to reload with the edit box reset to (assistant s).
Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose.
In general, what's an easy way to put a web front end on functionality implemented in Haskell?
Several of us cobbled together a web service version of lambdabot at one point. We used fast cgi plus apache on the unix side. In the program we used the fastcgi haskell bindings (I forget which package), and excuted lambdabot as a subprocess and communicated over pipes, I think. Then on the web page side there was a bit of ajax that executed the cgi request and spliced the value into the webpage. It no longer works due to changes in lambdabot, but all lambdabot knew was that it was running as a normal unix process. In a simpler world the code that used the cgi bindings could directly import your assistant function. I can try to dig up the sources if you want to see the code. It was pretty slick. And I'd say the bottom line is, you just need (fast) cgi bindings and you're good on any host where cgi is supported. Jason
I bet they have PHP on the server already. Write your program so it
takes input from standard in and writes to standard out. Then just
run your executable from PHP and write to its pipe. Instant web
service!
On Fri, Jun 5, 2009 at 8:18 AM, Conor McBride
Comrades
I'm in a perplexing situation and I'd like to appeal to the sages.
I've never written anything other than static HTML in my life, and I'd like to make a wee web service: I've heard some abbreviations, but I don't really know what they mean.
I've got a function (possibly the identity, possibly const "", who knows?)
assistant :: String -> String
and I want to make a webpage with an edit box and a submit button. If I press the submit button with the edit box containing string s, I'd like the page to reload with the edit box reset to (assistant s).
Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose.
In general, what's an easy way to put a web front end on functionality implemented in Haskell?
Hoping this isn't a hard question
Conor
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
On Fri, 2009-06-05 at 16:18 +0100, Conor McBride wrote:
I've got a function (possibly the identity, possibly const "", who knows?)
assistant :: String -> String
and I want to make a webpage with an edit box and a submit button. If I press the submit button with the edit box containing string s, I'd like the page to reload with the edit box reset to (assistant s).
Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose.
In general, what's an easy way to put a web front end on functionality implemented in Haskell?
You don't need a web server so long as you've got a compiler -
Network.CGI ought to work nicely for your purposes, you just have a
binary that's called by the web server, processes the request and yields
input. If you're not doing disk I/O, pretty much the entire program's
plain functional stuff.
--
Philippa Cowderoy
Hi Conor,
As someone pointed out, CGI is one way to go.
Another option is to write a small Haskell web server. This path is
better if you have an app that needs to keep state, ans uses the
browser mostly as a GUI.
I have just made a package that should make doing this fairly easy. I
have not uploaded it to hackage yet because I want to make some small
changes still. You can try out the "pre-release" from here (the usual
cabal steps should work for making a package/installing)
git clone git://code.galois.com/http-server.git
For an example, take a look in the "example" directory, there is a
small web-server there, which shows how to all kinds of things,
including ajax interactions with javascript using jQuery. For
processing form data there is the module:
Network.HTTP.Server.HtmlForm.
Let me know if you have questions, comments, or other feed-back!
-Iavor
On Fri, Jun 5, 2009 at 8:18 AM, Conor McBride
Comrades
I'm in a perplexing situation and I'd like to appeal to the sages.
I've never written anything other than static HTML in my life, and I'd like to make a wee web service: I've heard some abbreviations, but I don't really know what they mean.
I've got a function (possibly the identity, possibly const "", who knows?)
assistant :: String -> String
and I want to make a webpage with an edit box and a submit button. If I press the submit button with the edit box containing string s, I'd like the page to reload with the edit box reset to (assistant s).
Will I need to ask systems support to let me install some haskelly sort of web server? Looks likely, I suppose.
In general, what's an easy way to put a web front end on functionality implemented in Haskell?
Hoping this isn't a hard question
Conor
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
participants (6)
-
Conor McBride -
Iavor Diatchki -
Jason Dagit -
Justin Bailey -
Max Rabkin -
Philippa Cowderoy