Mega Code Archive
Making an active web-page, part 2
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This time we're going to make a Webpage that's coupled to a databasetable, and we're going to send SQL-enquiries from our Web-interface. You can use any database you like for this purpose. In this example we're going to use standard Borland db-components, so the database must be coupled through the BDE. (You can of course use other components.) We're going to use a table called "CDs", which is a tracklist of CD-recordings. The fieldnames are: Artist, Album, Track, Name, Time. Here's my table:
Create a table called "CDs" with these fieldnames in your database, and fill it with some data. Well let's get into business !
Start Delphi and select File / New / Web Server Application.
Select :CGI stand-alone executable and Delphi presents a WebModule for us to work with.
Select: Project / Options / Application and write "cgi" into Target file extension.
Select: Project / Options / Application / Directories/Conditionals and write your
servers cgi-bin library into Output Directory
Save the project as "test2.dpr"
Here's the HTML-code for the search-header:
<HTML>
<HEAD>
<TITLE>CDs</TITLE>
</HEAD>
<BODY>
<FORM ACTION="/cgi-bin/test2.cgi/search" METHOD="POST">
<FORM>
<P><FONT FACE="Arial"><B><FONT SIZE="+2"
COLOR="#0000FF">My CD:s</FONT></B></FONT></P>
<P><FONT FACE="Arial" SIZE="-1">Search for...</FONT></P>
<P><FONT FACE="Arial" SIZE="-1"></FONT></P>
<TABLE WIDTH="50%">
<TR>
<TD WIDTH="94"><FONT FACE="Arial"><B>Artist:</B></FONT></TD>
<TD WIDTH="265"> <P><INPUT TYPE="TEXT" NAME="Artist"></P>
</TD>
</TR>
<TR>
<TD WIDTH="94"><FONT FACE="Arial"><B>Volym:</B></FONT></TD>
<TD WIDTH="265"> <P><INPUT TYPE="TEXT" NAME="Album"></P>
</TD>
</TR>
<TR>
<TD WIDTH="94"><B><FONT FACE="Arial">Titel:</FONT></B></TD>
<TD WIDTH="265"> <P><INPUT TYPE="TEXT" NAME="Title"></P>
</TD>
</TR>
</TABLE>
<P><INPUT TYPE="SUBMIT" NAME="Submit1"></P>
</FORM><FONT FACE="Arial" SIZE="-2"><BR>
This code will result in a page like this:
For displaying the dbtable we'll need a TDataSetTableProducer.
Place one, (from the Internet-group), on the WebModule.
We also need a TQuery-component for making queries to the DB. Put one on your WebModule.
Put the name of your database into the Query1.DatabaseName - property.
Put "select * from CDs" into the Query1.SQL - property and set Query1.Active to true.
Paste the HTML-code above into the DataSetTableProducer.Header - property
Right-click on the DataSetTableProducer - component and select: Response Editor, and if
everything is right you would see this:
Not Bad, eh... Well let's say we want a sorted output, change the Query1.SQL - property to:
"select * from CDs order by Artist, Album, Track". Presenting this output is the first action we
want the dispatcher to take.
To make this happen:
Right-click on the DataSetTableProducer - component and select: Action Editor
Select Add New, set Default to true.
Select Events and double-click in the OnAction - event.
Put this code into the default action: Response.Content:= DataSetTableProducer1.Content;
Compile.
It's time to test. We're going to call the dispatcher's default action. To do this, put "http://<your servername>/cgi-bin/test2.cgi" into your WebBrowser. You should get an output similar to the one you got from the Response Editor.
Not much coding so far. Now it's time to make the search-action:
Right-click on the DataSetTableProducer - component and select: Action Editor
Select Add New, and put: "/search" into the PathInfo - property.
Select Events, and double-click in the OnAction - event. This will bring us into the code.
To get hold of the input parameters for the search, we will look at the Request - object, just as we did in the Part 1 example. Then we have to put these inputs into a SQL-query , and let the DataSetTableProducer reflect the query-output. Last we will send HTML-code to our WebBrowser.
Lets start with the code:
procedure TWebModule1.WebModule1WebActionItem2Action(Sender: TObject;
Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
var
Artist, Album, Title: string;
begin
// Extract the input-parameters from Request
with Request.ContentFields do
begin
Artist:= Values['Artist'];
Album:= Values['Album'];
Title:= Values['Title'];
end;
// Put them into a SQL-statement:
// "select * from CDs where Artist like '%Artist%' and Album like '%Album%' and
// Title like '%Title%' order by Artist, Album, Track"
Query1.SQL.Clear;
Query1.SQL.Add('select * from CDs where Artist like ' + Chr(39) + '%' + Artist +
'%' + Chr(39) + ' and Album like ' + Chr(39) + '%' + Album + '%' + Chr(39) +
' and Title like ' + Chr(39) + '%' + Title + '%' + Chr(39) + ' order by ' +
'Artist, Album, Track');
// Make query
Query1.Close;
Query1.Open;
// Send the response
Response.Content:= DataSetTableProducer1.Content;
end;
Compile the code. Put "http://<your servername>/cgi-bin/test2.cgi" into your WebBrowser, submit your search-entries, and the thing should be working !
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