[fpc-pascal] Cannot reuse TFPHTTPClient object for 2 different POST requests

[Michael Van Canneyt]

On Sun, 18 Jan 2015, leledumbo wrote:

>> Yes, I can. The TFPHTTPClient instance is not stateless.
>>
>> Before doing a call, some headers are added to the request headers if they
>> are not there yet.
>> For example, the Content-Size header.
>>
>> But the Content-Size header is not added if is already present.
>> For calls 1 and 2 it does not matter, since the size is the same.
>>
>> For the third call, however, it does matter, since the content-size header
>> still contains the size of call 2 (93),
>> which does not match the size of call 3: call 3 has less data (57).
>>
>> So the server is waiting for more data (it expects 93 bytes as indicated
>> in Content-Size instead of 57 actually present).
>>
>> The solution is simple: Try clearing the headers before doing your calls.
>>
>>    WriteLn('Response 2:');
>>    HTTP.RequestHeaders.Clear;
>>
>> etc. then it will work. (it does here)
>
> This is the answer I need, thanks :)
>
> Looks like this needs some kind of documentation or at least comment
> somewhere in the source.

Will do.

>
> I still wonder why the header is not updated based on given parameters
> though...

Because the header may have been set on purpose by the user.

I will look at a mechanism to remove headers that were 'automatically' added.

Michael.