get webpage content
lazarus / 38-Networking and Web Programming

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apeoperaio · 2017-12-11 17:06

I am trying to get a webpage content. I used in the past both
TFPHTTPClient from fphttpclient and THTTPSend from synapse httpsend.

Anyway I have some issues.
I am trying to resolve url like:
https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/smiles/CCNCC/cids

I I use TFPHTTPClient I am able to download the url content:
urlrequest:= TFPHTTPClient.Create(nil);
try
inputstr:= 'https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/smiles/
CCNCC/cids';
urlrequest.SimpleGet(inputstr);
finally
end;

but if the webpage does not exists or if I get some messages I am not
able to catch the exceptions (an error is raised by my application
even if the request is under try finaly).

Using THTTPSend  I am not able to resolve the url:
httpClient:= THTTPSend.Create;
try
    inputstr:= 'https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/smi
les/CCNCC/cids';
    getResult:= httpClient.HTTPMethod('GET', inputstr);
finally
end;

getresult is always false, even if the url is correct.
What am I doing wrong?

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molly · 2017-12-11 17:29

see this thread for a recent discussion on the subject.

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avra · 2017-12-11 22:39

Quote from: apeoperaio on December 11, 2017, 06:06:36 pman error is
raised by my application even if the request is under try finalyTo
catch an exception you need try..except not try..finally.
For more info take a look at
http://www.delphibasics.co.uk/RTL.asp?Name=Finally:
QuoteHowever, the Finally clause does not actually handle any
exceptions
You probably want to combine try..finally as outer scope with
try..except as inner scope.
Unfortunately there is no single try..except..finally scope yet in
FreePascal, which is a little annoying and stays in the way of code
readability.

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Leledumbo · 2017-12-12 05:49

You don't always have to use SimpleGet, as it has some predetermined
values set, including allowed status code, which is only 200 by
default, everything else will raise exception. Set up the properties
and parameters yourself and use Get, so you can handle it yourself.
Otherwise, what avra suggested should work.

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apeoperaio · 2017-12-12 08:54

Quote from: avra on December 11, 2017, 11:39:08 pmTo catch an
exception you need try..except not try..finally.

Thanks!