catch error 400
lazarus / 38-Networking and Web Programming

----------------------------------------------------------------------
Nicole · 2025-07-10 14:55

Here is a nice site, which gives me free news.
It is not nice any more, if I key in anything, which is not found.
Then there pops up 2 times "error 400".
This is rather annoying to click away and I would prefer it return a
silent "nothing found" instead.
I am not familiar where I hop on an catch those replies and where
exactly to hook in.
Can you give me a hint please?
The function reads (the last line is formatting it):

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i // sucht zu
einem Ticker die Nachrichtenfunction TNews.Suche_NewsZu(Ticker:
string; abDatum, bisDatum: TDate): string;var URL, Response: string; 
 HttpClient: TFPHTTPClient;    JsonResponse: TJSONData;    ts_ab,
ts_bis: Int64;    s_from, s_to: string;begin  Result := '';   ts_ab :=
DateTimeToUnix(abDatum);  ts_bis := DateTimeToUnix(bisDatum + 1);  //
period2 ist exklusiv!   s_from := IntToStr(ts_ab);  s_to :=
IntToStr(ts_bis);  // brauche ich offenbar nicht, kam von Yahoo-
Vorlage   URL := 'https://newsapi.org/v2/everything?q=' + Ticker + 
'&from=' + s_from + '&sortBy=publishedAt&apiKey='+ APIKEY_News;  
HttpClient := TFPHTTPClient.Create(nil);  HttpClient.AddHeader('User-
Agent', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36
(KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36');  try    Response
:= HttpClient.Get(URL);    JsonResponse := GetJSON(Response);   
Ersetze.JsonWirdDatei(JsonResponse, 'myNews_json');  // ich speichere
es einmal ab    result:=JsonResponse.FormatJSON([]);    
result:=VerarbeiteArtikel(result); //VerarbeiteAntwort(result); 
finally    HttpClient.Free;  end;end;

----------------------------------------------------------------------
paweld · 2025-07-10 15:12

Use try..except block.Code: Pascal  [Select][+][-]window.onload =
function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i // sucht zu einem Ticker die Nachrichtenfunction
TNews.Suche_NewsZu(Ticker: string; abDatum, bisDatum: TDate):
string;var URL, Response: string;    HttpClient: TFPHTTPClient;   
JsonResponse: TJSONData;    ts_ab, ts_bis: Int64;    s_from, s_to:
string;begin  Result := '';   ts_ab := DateTimeToUnix(abDatum); 
ts_bis := DateTimeToUnix(bisDatum + 1);  // period2 ist exklusiv!  
s_from := IntToStr(ts_ab);  s_to := IntToStr(ts_bis);  // brauche ich
offenbar nicht, kam von Yahoo-Vorlage   URL :=
'https://newsapi.org/v2/everything?q=' + Ticker +  '&from=' + s_from +
'&sortBy=publishedAt&apiKey='+ APIKEY_News;   HttpClient :=
TFPHTTPClient.Create(nil);  HttpClient.AddHeader('User-Agent',
'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML,
like Gecko) Chrome/123.0.0.0 Safari/537.36');  try    try     
Response := HttpClient.Get(URL);    except       on E: EHttpClient do 
    begin        case HttpClient.ResponseStatusCode of          401:
Caption := 'Unauthorised';          404: Caption := 'Not found';     
   else            Caption := Format('error: %d',
[HttpClient.ResponseStatusCode]);        end;      end;    end;   
JsonResponse := GetJSON(Response);   
Ersetze.JsonWirdDatei(JsonResponse, 'myNews_json');  // ich speichere
es einmal ab    result:=JsonResponse.FormatJSON([]);    
result:=VerarbeiteArtikel(result); //VerarbeiteAntwort(result); 
finally    HttpClient.Free;  end;end;

----------------------------------------------------------------------
Nicole · 2025-07-10 16:44

Thank you, looks good, but does not work yet.
I read
"u_news.pas(218,16) Error: Identifier not found "Caption""

at
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  case
HttpClient.ResponseStatusCode of          401: Caption :=
'Unauthorised'; 
If I change caption to result, the error message comes back

Code: Text  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i [Window
Title]Fehler [Content]Projekt project_Tiger hat Exception-Klasse
»External: ACCESS VIOLATION« ausgelöst mit der Meldung:Access
violation reading from address $0000000000000000.  Bei Adresse
10011AEC3 [Ok]
followed by an access-thing because it is not json any more.

----------------------------------------------------------------------
paweld · 2025-07-10 18:42

You only showed one function, so I thought TNews was a Form and I
wanted to display message on its title.
If it is a class then instead of to Caption you can assign this
message as a function result or to some property storing the last
error etc.