There are currently three CGI (Common Gateway Interface) WebServer packages for Squeak, two available at the "CREATE" site under Applications. (CGI uses HTML forms to provide simple interaction on the Web. I use it for collaboration tools and surveys, and it can also be used for database access, guestbooks, shopping baskets, and a bunch of other things.) Tim Jones' (tim@thregecy.com), WebTalk, and Georg Gollmann's WebServer (gollmann@edvz.tuwien.ac.at) (at http://ftp.tuwien.ac.at/~go/Squeak/webServer.html) are both really great. A new one is the Pluggable WebServer.

WebServer

Georg's WebServer is a webserver oriented toward database applications. His Web page is where to go for the best information. I'll point out only a couple of strengths here:

• WebServer is particularly strong for database applications. Georg has taken a lot of effort to "roll-over" the image (save transactions on a daily basis), and to provide an "undo" capability.
• WebServer provides a bunch of nice features like authentication support, such as triggering unauthorized access and checking names and passwords.
• WebServer allows ANY object to be a CGI "server". You simply register the object in the WebServer dictionary, then URL's sent to WebServer will be parsed into message sends to objects in the dictionary. It's a very flexible structure.

WebTalk

WebTalk is actually three packages:

• VS-Events and VS-Exceptions provides a nice exceptions package to Squeak. You can test if errors occur and provide default blocks to execute if the errors do occur. Here's Tim's test method as a demonstration:

  test1 
  	"simple use of ensure:"
  	[Transcript show: 'do this'] ensure: [Transcript show: ' then this';cr].
  
  
  	"simple use of ifCurtailed:"
  	[Transcript show: 'do this'; cr] ifCurtailed: [Transcript show: 'but not this'; cr].
  
  
  	"ifCurtailed: within an on:do:"
  	[[Transcript show: 'do this'. self signalDumbError. Transcript show: 'not this']
  		ifCurtailed: [Transcript show: ' and this']] 
  			on: Error do: [Transcript show: ' then this'; cr].
  
  
  	"handling more than one type of exception"
  	[ self signalDumbError ] 
  		on: DumbError,StupidError 
  		do: [Transcript show: 'and finally this';cr].
    
  	"nested exception handlers"
  	[[self signalDumbError ] on: StupidError do: [Transcript show: 'not this']] 
  		on: DumbError do: [ Transcript show: 'and this too';cr].
  

• Connections is a cool package for building servers and clients. The below is quoted from Tim's comments on the Connection class:

  
  
  This class provides a high level interface to tcpip sockets. It uses stream protocol, and is implemented using ReferenceStreams so that it can work with any kind of object, not just characters. An example:
   
  server:  
  c := Connection port: 1234. 
  c nextPut: (c next storeString). 
  c close.
  
  
  client: 
  c := Connection to: ''server.free.com'' port: 1234. 
  c nextPut: #(a test).
  Transcript show: c next;cr.
  
  
  Notice that only one side needs to use the close method, the other will close automatically when all data is read. Address can be specified using either
  names or dot notation "111.111.111.111".
  
  
  By subclassing Connection you can create connection servers. For example, to create the EvaluationServer from Connection, the following method was added:
  
  
  eventRead: aString
  	self nextPut: (Compiler evaluate: aString)  
  
  
  To start the server, say the following:
  
  
  EvaluationServer service: 1234 "the port number"
  
  
  The server runs in the background and can handle any number of connections from any number of sources. To access the server, use code like the following:
  
  
  c_Connection to: ''111.111.111.111'' port: 1234.
  c nextPut: ''2+2''.
  Transcript show: c next;cr.
  c nextPut: ''200 factorial''.
  Transcript show: c next;cr.
  c close.
  
  
  To stop the server and close all current connections to it, say:
  
  
  EvaluationServer stopService.
  
  
  Also see the comment for StringConnection; it allows you to communicate with non-Smalltalk systems.
  
  
  tim jones (tim@thregecy.com)
  

• The final piece is WebTalk itself. WebTalk provides several different things:
  • It contains a number of pieces for HTML generation. These are useful in generating forms and responding to CGI requests.
  • It is possible to serve from an external Web server. There is a PERL CGI script that can server from a larger server (say, a UNIX server running Apache), and the PERL CGI script can talk to WebTalk.
  • Finally, all by itself, WebTalk can act as a Web Server and serve WebTalk CGI requests.

Extending the Existing WebServer Tools

The CGI WebServer packages provided by Tim Jones (tim@thregecy.com), WebTalk, and by Georg Gollmann (gollmann@edvz.tuwien.ac.at) (at http://ftp.tuwien.ac.at/~go/Squeak/webServer.html) are really great, but they focus on serving CGI scripts from inside of Squeak. I also wanted to serve HTML, GIF, and JPEG files. The downloads below provide subclasses which add file access capabilities to these tools. Thanks to the efforts of John Maloney, Tim, and Georg, these have become quite stable on the various Macs I've tried them on (e.g., longest run without problems has been about four days, before I had to restart the machine for other reasons), using both 1.20 and 1.22 versions of Squeak and respective versions of WebTalk and WebServer.

Caveats!

• Tim Jones' latest version of WebTalk builds in file-serving, and has been improved so that it can handle pages with multiple embedded images.
• These currently only work on Macs! I hack the URL into a Mac file reference (with ":" delimiters). One of my undergraduate students has already hacked it to work on Windows (i.e., just remove the shift from "/" to ":"), so it's pretty simple to do.
• These don't serve any default file (e.g., "index.html" on Apache, "default.html" on WebStar), so references just to a directory won't work.

For Tim's WebTalk -- No longer necessary, but will still work: WTWebServer.st is the WebServer that works with Tim's WebTalk.