(Delphi DLL) Creating an application/json HTTP POST Request

Demonstrates how to create an HTTP POST request having the Content-Type application/json, where the body of the HTTP request is the following JSON:

{
   "username" : "my_username",
   "password" : "my_password",
   "validation-factors" : {
      "validationFactors" : [
         {
            "name" : "remote_address",
            "value" : "127.0.0.1"
         }
      ]
   }
}

The generated HTTP request looks like this:

POST /something HTTP/1.1
Content-Type: application/json
Accept: application/json
Host: domain
Content-Length: 216

{
  "username": "my_username",
  "password": "my_password",
  "validation-factors": {
    "validationFactors": [
      {
        "name": "remote_address",
        "value": "127.0.0.1"
      }
    ]
  }
}

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
req: HCkHttpRequest;
json: HCkJsonObject;
vFactors: HCkJsonObject;
vArray: HCkJsonArray;
factorObj: HCkJsonObject;
requestMime: PWideChar;

begin
// This example demonstrates building an application/json request.

req := CkHttpRequest_Create();

// The ContentType, HttpVerb, and Path properties should
// always be explicitly set.
CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putPath(req,'/something');
CkHttpRequest_putContentType(req,'application/json');

// We may wish to add an "Accept" header to the request.
// This tells the server we'll accept an application/json response.
CkHttpRequest_AddHeader(req,'Accept','application/json');

// We'll use Chilkat's JSON API to create the JSON body of the HTTP request.
json := CkJsonObject_Create();
CkJsonObject_AppendString(json,'username','my_username');
CkJsonObject_AppendString(json,'password','my_password');
vFactors := CkJsonObject_AppendObject(json,'validation-factors');
vArray := CkJsonObject_AppendArray(vFactors,'validationFactors');
CkJsonArray_AddObjectAt(vArray,0);
factorObj := CkJsonArray_ObjectAt(vArray,0);
CkJsonObject_AppendString(factorObj,'name','remote_address');
CkJsonObject_AppendString(factorObj,'value','127.0.0.1');
CkJsonObject_Dispose(factorObj);
CkJsonArray_Dispose(vArray);
CkJsonObject_Dispose(vFactors);

// Use the JSON for the HTTP request body
// By default, the Emit method will output compact JSON.
// This is best for generating the smallest size request.
// To generate a more human-readable (pretty-printed) JSON request body,
// set the EmitCompact property to FALSE
CkJsonObject_putEmitCompact(json,False);
CkHttpRequest_LoadBodyFromString(req,CkJsonObject__emit(json),'utf-8');

// View the request that would be sent if SynchronousRequest was called:
requestMime := CkHttpRequest__generateRequestText(req);
Memo1.Lines.Add(requestMime);

// A few important comments about the HTTP request that is generated:
// 
// 1) The Content-Length header is automatically generated based on the actual length of the MIME message
//    that follows the intial (topmost) MIME header.
// 2) The HOST header will automatically get filled in with the actual domain when SynchronousRequest
//    is called

CkHttpRequest_Dispose(req);
CkJsonObject_Dispose(json);

end;