Help with FreeSpider Web Page builder
lazarus / 38-Networking and Web Programming

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tjpren · 2011-12-21 07:35

Hi Forum,

I'm now looking to develop a web application with lazarus, and am
trying FreeSpider.

I've tried putting the example Freespider.exe in the cgi-bin directory
of IIS, Apache, and TinyWeberServer.  In all of them, I can get the
first screen to show up, but not the secondary screens (eg Hello
world).

All I get is the Http 404 error (page cannot be found).

The application seems to compile correctly.

I am using Laz ver 0.9.3.0, and FPC 2.4.2

Any thoughts?

Regards

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jamhitz · 2011-12-22 13:20

Works for me. This is a simplified sample of how I did it.

Start off with the first demo in the official documentation
(http://code.sd/freespider.pdf). Make sure you can get as far as
getting a response from http://localhost/cgi-bin/first

Create your html documents (mine are info.html:

Code: [Select]<html></head><title>Info</title></head><body>
<h1>Information</h1>
<p>You are logged in as @user;</p>
</body></html>

...and about.html):

Code: [Select]<html></head><title>About Us</title></head><body>
<h1>About Us</h1>
<p>You are logged in as @user;</p>
<br>
<p>Generated on: @date;</p>
</body></html>

On the data module, add two TSpiderPage components assigning them
different PathFileName to the respective file. Mine were:

Code: [Select]Name: pgInfo
PageFileName: info.html

Name: pgAbout
PageFileName: pgAbout.html

And assign then these event handlers:

Code: [Select]procedure TDataModule1.pgAboutTag(Sender: TObject; ATag:
string; var TagReplacement: string);
begin
    if aTag = 'user' then
        TagReplacement := 'FreePascal User'
    else if aTag = 'date' then
        TagReplacement := FormatDateTime('dd MMMM yyyy', Date());
end;

procedure TDataModule1.pgInfoTag(Sender: TObject; ATag: string; var
TagReplacement: string);
begin
    if aTag = 'user' then TagReplacement := 'FreePascal User';
end; 

Also, add two TSpiderAction components acInfo (path = /info) and
acAbout (path = /about) and add the following event handlers to the
OnRequest handlers:

Code: [Select]procedure TDataModule1.acInfoRequest(Sender: TObject;
Request: TSpiderRequest; var Response: TSpiderResponse);
begin
    Response.Add(pgInfo.Contents);
end; 

procedure TDataModule1.acAboutRequest(Sender: TObject; Request:
TSpiderRequest; var Response: TSpiderResponse);
begin
    Response.Add(pgAbout.Contents);
end;

That's it. You can access the two pages as http://localhost/cgi-
bin/first/about and http://localhost/cgi-bin/first/info respectively.

Good luck!

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tjpren · 2012-01-02 11:01

Hi,

Thanks - I've managed to get it working - I quite like it.

It took some googling to get IIS and Apache working with cgi-bin.  A
useful tutorial is at:
http://www.chromicdesign.com/2009/05/setting-up-perl-for-wampp.html

I then set about modifying the freeSpider example, and jamhitz code to
make a test.

Now, I'm wondering if there is any documentation on the TMemdataset. 
The Freespider example connects to a sub.dat.  I'm wondering if it
could connect to a text file, or an access database; and if so how?  I
couldn't find a link to any examples of the TMemdataset.

Regards

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Leledumbo · 2012-01-03 01:52

QuoteI'm wondering if it could connect to a text file, or an access
database; and if so how?You can still use everything that Object
Pascal has, so is database connectivity. Search the wiki.

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tjpren · 2012-01-03 07:37

Hello,

Yes I saw the wiki, but it didn't help me sufficiently.

The following code from the WebSpider example works fine:

Code: [Select]procedure TDataModule1.SpiderPage1Tag(Sender: TObject;
ATag: string;
  var TagReplacement: string);
begin
  if ATag = 'time' then
    TagReplacement:= DateTimeToStr(Now)
  else
  if ATag = 'table' then
  begin
    if FileExists('sub.dat') then
      MemDataset1.LoadFromFile('sub.dat');
    MemDataset1.Open;
    MemDataset1.FieldByName('SubName').DisplayLabel:= 'Name';
    MemDataset1.FieldByName('Address').Visible:= False;
    TagReplacement:= SpiderTable2.Contents;
  end
  else
  if ATag = 'home' then
    TagReplacement:= '<a href="./">Main</a>'
  else
  if ATag = 'month' then
    TagReplacement:= FormatDateTime('mmm', Now)
  else
  if ATag = 'year' then
    TagReplacement:= FormatDateTime('yyyy', Now);
end;                              
But if I try exactly the same code with - say a text or csv file - I
get an error in the web page.

"Wrong data stream marker at position 0. Got 33648643, expected 1".

I think it has something to do with the format of the data, and the
way the MemDataset reads the data.

Any thoughts?

Regards

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Leledumbo · 2012-01-03 08:52

Have you seen this page?

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tjpren · 2012-01-03 09:37

Hello Leledumbo,

Yes I did, but it was sufficiently different to the example, I could
see the connection.  I note that the link shows memdataset loading
from a csv, but any csv, or txt I create gives me an error.  The only
thing that loads is the .dat file that was originally created in the
application.

I've been trying to see what sort of flat file the .dat file is, and
what 3rd party app might create it the hope that I can see what the
record structures are like.

My ultimate aim is to create flat files, and read from them to a web
page using the freespider.  My stumbling block is that the example
has:
       Code: [Select]MemDataset1.LoadFromFile('sub.dat');and I'd like
to use something like
Code: [Select]MemDataset1.LoadFromFile('sub.txt');

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tjpren · 2012-01-04 08:23

Hello all,

I've had success - couldn't get memdataset working.  I couldn't find
what the format of the data was, so I changed to a Dbf data set. 
Hardly any code change, and it worked.  The web page displays the
contents of a standard dbf file - brilliant!!.


Code: [Select]procedure TDataModule1.SpiderPage1Tag(Sender: TObject;
ATag: string;
  var TagReplacement: string);
begin
  if ATag = 'time' then
    TagReplacement:= DateTimeToStr(Now)
  else
  if ATag = 'table' then
  begin
    if FileExists('test.dbf') then
    Dbf1.TableName:= 'test.dbf';
    Dbf1.Open;

    TagReplacement:= SpiderTable2.Contents;
  end
  else
  if ATag = 'home' then
    TagReplacement:= '<a href="./">Main</a>'
  else
  if ATag = 'month' then
    TagReplacement:= FormatDateTime('mmm', Now)
  else
  if ATag = 'year' then
    TagReplacement:= FormatDateTime('yyyy', Now);
end;