(Delphi ActiveX) REST with Query Params

See more REST Examples

Demonstrates how to add query params for a REST request.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: TChilkatRest;
bTls: Integer;
port: Integer;
bAutoReconnect: Integer;
success: Integer;
responseJson: WideString;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Let's say we want to send a GET request to 
// https://example.com/search?query=hello%20world&category=books&sortBy=price&filterBy=inStock

// Notice that the query parameter values must be URL encoded.

// Let's also explain the parts of the above URL:

//     Scheme: https
//         The scheme specifies the protocol used to access the resource. 
//         In this case, it is "https," which indicates that the resource is accessed using the Hypertext Transfer Protocol Secure (HTTPS).
// 
//     Host: example.com
//         The host part of the URL identifies the domain name or IP address of the server hosting the resource. In this case, "example.com" is the host.
// 
//     Path: /search
//         The path is the specific location or resource on the server that the client wants to access. 
//         In this URL, the path is "/search," indicating that the client is requesting the "search" resource on the server.
// 
//     Query Parameters:
//         Query parameters are used to send additional data to the server as key-value pairs. 
//         They are separated from the path by a question mark ? and each parameter is separated by an ampersand &.
// 
//         The above URL has four query parameters:
//             query=hello%20world: The "query" parameter with the value "hello world". The %20 represents the URL-encoded space character in the value.
//             category=books: The "category" parameter with the value "books".
//             sortBy=price: The "sortBy" parameter with the value "price".
//             filterBy=inStock: The "filterBy" parameter with the value "inStock".

rest := TChilkatRest.Create(Self);

// Connect to the REST server.

// The Host part of the URL is passed in the 1st argument.
// The Scheme part of the URL ("https") is indicated by the 2nd and 3rd arguments (port and bTls).
bTls := 1;
port := 443;
bAutoReconnect := 1;
success := rest.Connect('example.com',port,bTls,bAutoReconnect);

// There are 3 ways to send the above GET request.

// 1) Send the request with path and query params pre-built, where the query param values are URL encoded.
responseJson := rest.FullRequestNoBody('GET','/search?query=hello%20world&category=books&sortBy=price&filterBy=inStock');
if (rest.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// 2) Pass only the Path part of the URL, and specify the query params separately by calling AddQueryParams beforehand.
//    Again, the query params must be already URL encoded when passed to AddQueryParams
rest.ClearAllQueryParams();
rest.AddQueryParams('query=hello%20world&category=books&sortBy=price&filterBy=inStock');
responseJson := rest.FullRequestNoBody('GET','/search');
// ...
// ...

// 3) Pass each query parameter separately by calling AddQueryParam.  In this case, the query param value should be passed without URL encoding.
//    (ClearAllQueryParams ensures any params set for previous request are cleared.)
rest.ClearAllQueryParams();
rest.AddQueryParam('query','hello world');
rest.AddQueryParam('category','books');
rest.AddQueryParam('sortBy','price');
rest.AddQueryParam('filterBy','inStock');
responseJson := rest.FullRequestNoBody('GET','/search');
// ...
// ...
end;