Fall Semester, 2003
WebToolkit
© 2003, All Rights Reserved, SDSU & Roger Whitney
San Diego State University -- This page last updated 20-Nov-03
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CS 535 Object-Oriented Programming Fall Semester, 2003 WebToolkit |
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© 2003, All Rights Reserved, SDSU & Roger Whitney San Diego State University -- This page last updated 20-Nov-03 |
Useful VisualWorks Extras
AutoComplete
After loaded the tab key will activate
Attempts to auto complete name of class, method, and variable you currently are typing
Load parcel in Environment Enhancements in Parcel Manager
RB_Tabs
Adds tab in browser for each view you create
Minor bug – when you restart VisualWorks tabs are not shown until you select a view
Load parcel in Environment Enhancements in Parcel Manager
AddInstVarAtCompile
When you save/compile code in browser that contains a new name, the pop window will allow you to define the name as a instance variable or class in addition to the standard options
Download from the class web site
VisualWorks Web Server
Supports:
Servlets Verses Server Pages
Systems for dynamic web pages
Servlets
Configuration Files
Copy the files listed below from VisualWorks installation /web to the directory containing your image
configure-site.ini
default-site.ini
webtools.ini
These files help configure the VW web server
In default-site.ini edit the line
directory = $(VISUALWORKS)/web/examples
so that directory is set to the location you want the web server to look for web pages
Loading WebToolkit
First open the Parcel Manager by selecting “Parcel Manager” item in the “System” menu on the Launcher. Or you can click on the “Parcel Manager” iconon the Launcher.
In the “Parcel Manager” select “Application Sever” in the left pane. In the right pane select the “WebToolkit” parcel. To load the parcel select the “Load” item in the “Parcel” menu in the “Parcel Manager”.
Starting Web Server
To start the VW web server you need to use the “Server Console”. After loading the WebToolKit select the “Server Console” item of the “Web” menu item on the Launcher. The Web menu was added by the WebToolkit. One can also open the “Server Console” by clicking on the “Server Console” iconin the Launcher.
In the Server Console, click on the “Create Server” button. A pane will appear at the bottom of Server Console window. Set the “Server Type” to “TinyHttpServer”. You may use any port you wish. However, some platforms require root or administrator privileges to use ports under 1024. I will use the default port of 8008. Click on the “Create and Start” button to create and start the server.
Testing the Server Using a browser on the same machine access the url:
http://localhost:8008/echo
This should list the headers sent to the web server. On some machines you may need to use:
http://127.0.0.1:8008/echo
The address 127.0.0.1 is the local machine. Other urls to try are given below. From now on I will use 127.0.0.1 and localhost interchangeably.
http://127.0.0.1:8008/servlet/VeryBasicServlet
The first url is an example of a servlet in Smalltalk. The second provides some examples of Smalltalk server pages.
Some Useful URLS
http://localhost:8008/configure/
A page that allows you to manage and configure the web server
Creating A Servlet
VW allows you to create servlets, using an API similar to Java’s servlets. To create a new servlet create a subclass of VisualWave.HttpServlet. Note that you need to type the full name of the class, including the VisualWave namespace. Here is a simple servlet.
Smalltalk defineClass: #HelloWorld superclass: #{VisualWave.HttpServlet} indexedType: #none private: false instanceVariableNames: '' classInstanceVariableNames: '' imports: '' category: 'CS535'!
!HelloWorld methodsFor: 'servering'!
doGet: aRequest response: aResponse aResponse write: '<HTML><BODY>Hello world</BODY></HTML>'! !
Once you add this to your image you can access the servlet using the url:
http://127.0.0.1:8008/servlet/HelloWorld
The basic format is
http://serverAddress/servlet/ClassName
Important Servlet Methods
initialize
doGet:response:
doPost:response:
initialize is called when an instance of the servlet class is called
doGet:response:
Response
doGet: aRequest response: aResponse
aResponse is an instance of VisualWave.Response
Useful methods
write: anObject
cr
space
redirectTo: aUri
Form Example
Form <HTML> <title>Create a Survey</title> <BODY> <p> <center>CS 535 Surveys </center> <HR size=1 noshade> <h2 align="center">Add a new Survey</h2> <form action="http://127.0.0.1:8008/servlet/NewSurvey" method="post"> <textarea name="definition" rows="20" cols="80"> </textarea> <BR> <input type="submit"></input> </form> </BODY></HTML>
Servlet
Smalltalk defineClass: #NewSurvey superclass: #{VisualWave.HttpServlet} indexedType: #none private: false instanceVariableNames: '' classInstanceVariableNames: '' imports: '' category: 'CS535'
doPost: aRequest response: aResponse | surveyString | surveyString := aRequest anyFormValueAt: 'definition'. "Here we can do anything we want. Just return it for demonstration" aResponse write: '<html><body>You entered: '; write: surveyString; write: '</body></html>'
Connections
<form action="http://127.0.0.1:8008/servlet/NewSurvey" method="post">
Html form action contains the url to the servlet
Uses post method
doPost: aRequest response: aResponse
Servlet implements doPost:response: method
<textarea name="definition" rows="20" cols="80"> </textarea>
Textarea name is “definition”
surveyString := aRequest anyFormValueAt: 'definition'.
Use the name of the textarea to get the value form the request
Request & Forms
VisualWave.Request>>allFormValuesAt: aString
"Return all the form values associated with aString"
VisualWave.Request>>anyFormValueAt: aString
"Return the first form value associated with aString. If there are none, return nil"
VisualWave.Request>>form
"Return a dictionary of all form data, with the name of the data as a key, and a collection of all values by that name as the value"
Query Data
Forms sent using get rather than post
Url format:
http://127.0.0.1:8008/foo/bar?name=roger&office=561
VisualWave.Request>>allQueryValuesAt: aString
"Return all the query data associated with aString"
VisualWave.Request>>anyQueryValueAt: aString
"Return the first query data associated with aString. If there are none, return nil"
VisualWave.Request>>query
"Return the query data associated with this request.
This is a dictionary, mapping from the name of a query parameter to the collection of values associated with it."
Example
Smalltalk defineClass: #Information superclass: #{VisualWave.HttpServlet} indexedType: #none private: false instanceVariableNames: '' classInstanceVariableNames: '' imports: '' category: 'CS535'Instance Method
doGet: aRequest response: aResponse | answer userRequest | userRequest := aRequest anyQueryValueAt: 'type'. answer := 'No valid request given'. userRequest = 'time' ifTrue:[answer := Time now printString]. userRequest = 'date' ifTrue:[answer := Date today printString]. aResponse write: '<html><body>Answer: '; write: answer; write: '</body></html>'
Example URLs
http://127.0.0.1:8008/servlet/Information?type=date
http://127.0.0.1:8008/servlet/Information?type=time
Form & Query Data
The following method work with post and get data
VisualWave.Request>>allParameterValuesAt: aString
VisualWave.Request>>anyParameterValueAt: aString
VisualWave.Request>>parameters
Unused Path Information
Smalltalk defineClass: #Information superclass: #{VisualWave.HttpServlet} indexedType: #none private: false instanceVariableNames: '' classInstanceVariableNames: '' imports: '' category: 'CS535'
Instance Method
doGet: aRequest response: aResponse | pathString pathComponents answer | pathString := aRequest pathInfo. pathComponents := pathString tokensBasedOn: $/. answer := 'No valid request given'. pathComponents last = 'time' ifTrue:[answer := Time now printString]. pathComponents last = 'date' ifTrue:[answer := Date today printString]. aResponse write: '<html><body>Answer: '; write: answer; write: '</body></html>Example URLs
http://127.0.0.1:8008/servlet/Information/time
http://127.0.0.1:8008/servlet/Information/date
Servlet Debugging
There is no need to stop & start the server to:
Templates
Generating html in servlets can be difficult
Often much of the html is static
Example @@@ indicates start/end of placeholder
Can have different place holders in one file
Same placeholder can occur in multiple places
<HTML> <BODY> <p> <center> CS 535 Surveys <br> Fall Semester, 2003 </center> <HR size=1 noshade> @@@body@@@ </BODY> </HTML>
Using the Template
Smalltalk defineClass: #HelloWorld superclass: #{VisualWave.HttpServlet} indexedType: #none private: false instanceVariableNames: '' classInstanceVariableNames: 'template ' imports: '' category: 'CS55Servlets'
Instance Methods
doGet: aRequest response: aResponse | template | template := Template fromFile: 'hello.html'. template at: 'body' put: 'Hello World'. aResponse write: template asString.
Copyright ©, All rights reserved.
2003 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA.
OpenContent license defines the copyright on this document.
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