DataFlex

Duplicating a Simple HTML Form Submission (POST)

This example shows how to duplicate a simple HTML form submission. The HTML to be duplicated is shown below, and may be tested in a browser by going to this URL: http://www.chilkatsoft.com/postSample.html


<html>
<body>
<form action="echoPost.asp" method="post">
<p>First name: <input name="firstname"></p>
<p>Last name: <input name="lastname"></p>
<p>Your favorite color:
<select name="color">
<option>Blue</option>
<option>Green</option>
<option>Red</option>
<option>Yellow</option>
<option>Pink</option>
</select>
</p>
<input type="hidden" name="myHiddenField1", value="Hidden Value 1">
<input type="hidden" name="myHiddenField2", value="Hidden Value 2">
<p><input type="submit" value="Send POST"></p>
</form>

</body>
</html>

By default, a browser will send a form POST as an HTTP reqeuest using a Content-Type of "application/x-www-form-urlencoded". This is because the form parameters are sent in the body of the HTTP POST using the URL encoding. Therefore, one should use the PostUrlEncoded method to duplicate the form submission.

Each "input" or "select" tag found in the HTML is a form parameter having a name and value. These are duplicated in code by calling AddParam on the HTTP Request object for each parameter.

The target URL is indicated by the "action" attribute on the "form" tag. In the HTML form shown above, it is "echoPost.asp". The URL specified in the "action" attribute may be an absolute or relative URL. In this case, it is a relative URL, and since there is no directory path, the full URL of the POST target is "http://www.chilkatsoft.com/echoPost.asp". This will be the 1st argument passed to the PostUrlEncoded method.

The raw HTTP POST sent to the web server in this example is shown below. The form parameters are located in the body of the request (i.e. under the header fields), and they are URL encoded.

POST /echoPost.asp HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Host: www.chilkatsoft.com
Content-Length: 87

firstname=John&lastname=Doe&myHiddenField1=Hidden+Value+1&myHiddenField2=Hidden+Value+2

Note: An HTTP file upload is a form submission having an "input" tag w/ "type=file". In this case, a browser will send the POST using a content-type of "multipart/form-data". The PostUrlEncoded method should not be called for HTTP file uploads. The SynchronousRequest would instead be called.

Chilkat DataFlex Downloads

Download Chilkat for DataFlex

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoHttp
    Variant vReq
    Handle hoReq
    Variant vResp
    Handle hoResp
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    Get Create (RefClass(cComChilkatHttpRequest)) To hoReq
    If (Not(IsComObjectCreated(hoReq))) Begin
        Send CreateComObject of hoReq
    End

    // Add the form parameters to the HTTP request:
    Send ComAddParam To hoReq "firstname" "John"
    Send ComAddParam To hoReq "lastname" "Doe"
    Send ComAddParam To hoReq "myHiddenField1" "Hidden Value 1"
    Send ComAddParam To hoReq "myHiddenField2" "Hidden Value 2"

    Set ComHttpVerb Of hoReq To "POST"
    Set ComContentType Of hoReq To "application/x-www-form-urlencoded"

    Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
    If (Not(IsComObjectCreated(hoResp))) Begin
        Send CreateComObject of hoResp
    End
    Get pvComObject of hoReq to vReq
    Get pvComObject of hoResp to vResp
    Get ComHttpReq Of hoHttp "http://www.chilkatsoft.com/echoPost.asp" vReq vResp To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Display the Body of the HTTP resp
    // (This is the HTML that the browser would receive if it
    // had been an interactive form submission from the browser.)
    Get ComBodyStr Of hoResp To sTemp1
    Showln sTemp1


End_Procedure