[fpc-devel] Questions and suggestions to fpWeb

[Michael Van Canneyt]

On Tue, 3 Aug 2010, Luiz Americo Pereira Camara wrote:

> Michael Van Canneyt escreveu:
>> 
>> 
>> On Tue, 3 Aug 2010, Luiz Americo Pereira Camara wrote:
>> 
>>> Michael Van Canneyt escreveu:
>>>> 
>>>> 
>>>> On Fri, 30 Jul 2010, Luiz Americo Pereira Camara wrote:
>>>> 
>>>>> Hi,
>>>>> 
>>>>> I've playing a bit with fpWeb and have some suggestions and questions:
>>>>> 
>>>>> - In TFPWebAction.DoHandleRequest if request is not handled by OnRequest 
>>>>> and inherited, the content is copied to the response and handled is 
>>>>> checked by the response content.
>>>>> - FContensts will be always created even if is not created previously
>>>>> - At this point AResponse.Contents can have some content?
>>>>> - If so the handled checking is wrong. See these conditions
>>>>>    AResponse.Contents.Text <> '';
>>>>>    Self.Contents.Text = '';
>>>>>    Handled will be true. Should be false.
>>>> 
>>>> Why ? It is handled ?
>>> 
>>> No. Because TWebAction.Contents is empty.
>> 
>> But that can be a perfectly valid result ?
>
> Yes. But in this case the appropriate way to mark as handled is to set 
> Handled in OnRequest.
>
> Moreover, how to leave Handled as false if even an empty Contents is treated 
> as a value that affects the Handled state?

Ok, you have convinced me :-)

>
>>>>> - Content and Contents properties are redundant. Also can lead to some 
>>>>> performance issues. See the code of DoGetContent:
>>>>>
>>>>>   If (Self.Content<>'') then
>>>>>     Content.Write(Self.Content[1],Length(Self.Content));
>>>>> 
>>>>> Content is computed (Contents items concatenated) three times.
>>>>> 
>>>>> Don't be surprised if users do things like
>>>>> 
>>>>> while  not ready do
>>>>> Content := Content + 'xxx';
>>>> 
>>>> I agree that the contents/content properties should be reduced to 1
>>>> property. But this is a change which will break backwards compatibility.
>>> 
>>> AFAIK the fpWeb interface is still in progress. Anyway, better change now 
>>> than later.
>> 
>> The question is: which one ?
>
> Contents is more versatile and does not lead to performance pitfalls like 
> using it as a simple AnsiString property

So you prefer Contents ?
(that would be my preference)

>
>
> [..]
>>> 
>>> OK. BTW what's the intention of adding TWebHandler AFAIK only add another 
>>> layer.
>> 
>> There is a simple reason: if you want to have a service application, there
>> will be 2 application objects. Now you can have only 1 application object
>> (service application) which uses the webhandler to process requests.
>> 
>> You can now also produce 1 binary which can be configured to run as a
>> CGI/FCGI/Service/standalone server, and which will have 1 single 
>> application
>> instance for all 4 cases.
>
> Good.
>
> Do you have an simple example of such program?

Not yet for public use.

I personally need the case of a fastcgi service application, 
for use with ExternalFastCGIServer of mod_fastcgi.
(*not* mod_fcgid, it has no such equivalent)

But I will try to cook up an application which does that.

Michael.