[Haskell-cafe] Bits and pieces needed to build a web server

[Jason Dagit]

On 8/3/06, Johan Tibell <johan.tibell at gmail.com> wrote:
> I've got an idea for a web server model I would like to try and since
> I'm quite new to Haskell it would be great if someone could enumerate
> a couple of useful libraries to me.
>
> Here's what I need (I've put what I've found so far inside parenthesis):
>
> * Parsing of incoming HTTP request and creation of replies
> (http://www.haskell.org/http/)

I can't comment here.

> * XML parsing and generating (http://www.cs.york.ac.uk/fp/HaXml/)

I've been using HaXml lately and I'm not real excited about the code
generated by dtd2haskell. I have a large schema and I found it
unweildy to work with the generated types. I wish it generated all of
its data types using record syntax plus generating minimal
instantiation functions.  I guess there are two things I could try to
make this nicer.   1) I could add these features (record syntax w/all
data types & minimal constructors) 2) try creating instances by
parsing xml fragments instead of using the data constructors directly.
 I haven't used the other features much, yet.  Hopefully they are
nice.  HaXml is not your only option in the xml department:

http://www.fh-wedel.de/~si/HXmlToolbox/
http://www.flightlab.com/~joe/hxml/

I've heard the arrows interface with HXmlToolbox is very nice.

> * Database support (mainly SQLite but perhaps also MySQL/PostgreSQL)
> (There seems to be several options for this one. I don't know the
> names of the table nor the columns at compile time so I need something
> that doesn't require that.)

I had the same requirement about tables/columns recently and after
trying out several database libraries I found HDBC to handle that
fairly nicely. One of the features I like is that you can choose lazy
queries if you like.  This is very nice for manipulating large
datasets.  I'm not sure if it has drivers for SQLite/MySQL/PostgreSQL
but hopefully yes.

http://quux.org:70/devel/hdbc

> A big plus if the library is still being developed/maintained.

I can't tell if HXmlToolkit is more active than HaXml.  HDBC does seem
to have some activity, at least recently, although the website appears
to be down most of the time.

HTH,
Jason