PowerBuilder

REST Follow Redirects

See more REST Examples

Demonstrates how to follow a 302/303 redirect response. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Rest
integer li_BTls
integer li_Port
integer li_BAutoReconnect
string ls_ResponseText
integer li_StatusCode
string ls_UrlStr
oleobject loo_RedirectUrl

li_Success = 0

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

loo_Rest = create oleobject
li_rc = loo_Rest.ConnectToNewObject("Chilkat.Rest")
if li_rc < 0 then
    destroy loo_Rest
    MessageBox("Error","Connecting to COM object failed")
    return
end if

li_BTls = 1
li_Port = 443
li_BAutoReconnect = 1
li_Success = loo_Rest.Connect("chilkatsoft.com",li_Port,li_BTls,li_BAutoReconnect)
if li_Success = 0 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    return
end if

// Send a POST to a URL that will respond with a 302 redirect..
loo_Rest.AddQueryParam("firstName","John")
loo_Rest.AddQueryParam("lastName","Doe")
ls_ResponseText = loo_Rest.FullRequestFormUrlEncoded("POST","/echoPost302.asp")
if loo_Rest.LastMethodSuccess = 0 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    return
end if

li_StatusCode = loo_Rest.ResponseStatusCode

// Examine the response status code
if li_StatusCode < 300 then
    Write-Debug "Not a redirect."
    Write-Debug ls_ResponseText
    destroy loo_Rest
    return
end if

if li_StatusCode > 399 then
    Write-Debug "Error response: Status code = " + string(li_StatusCode)
    Write-Debug ls_ResponseText
    destroy loo_Rest
    return
end if

Write-Debug "Redirect status code = " + string(li_StatusCode)

// The response header will contain a Location field with the redirect URL, such as this:
// Location: http://www.chilkatsoft.com/echoPostFinal.asp

// The response status code determines how the client should behave.
// Here are some common possibilities:

// 301: Moved Permanently
// This and all future requests should be directed to the given URI.  (Keep the original HTTP method for the redirect.  In this case, the 
// original request was a POST, so we POST to the redirect URL.)

// 302: Found (aka Object Moved aka Moved Temporarily)
// This is the most popular redirect code, but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945 ) required the client
// to perform a temporary redirect (the original describing phrase was �Moved Temporarily�), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1
// added status codes 303 and 307 to disambiguate between the two behaviors. However, the majority of Web applications and frameworks still use the 302 status code
// as if it were the 303.

// 303: See Other
// The response to the request can be found under another URI using a GET method. When received in response to a PUT, it should be assumed that the server has
// received the data and the redirect should be issued with a separate GET message.

// 307: Temporary Redirect
// In this occasion, the request should be repeated with another URI, but future requests can still use the original URI. In contrast to 303, the request method
// should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.

Write-Debug loo_Rest.ResponseHeader

// Get the redirect URL
ls_UrlStr = loo_Rest.LastRedirectUrl
if loo_Rest.LastMethodSuccess = 0 then
    Write-Debug "No Location header found for redirect."
    destroy loo_Rest
    return
end if

loo_RedirectUrl = create oleobject
li_rc = loo_RedirectUrl.ConnectToNewObject("Chilkat.Url")

loo_RedirectUrl.ParseUrl(ls_UrlStr)

// Prep for the redirect..
loo_Rest.ClearAllParts()

// Disconnect and re-connect.  
// (This can be skipped if both the host and SSL/TLS conditions are the same.)
loo_Rest.Disconnect(100)
li_Success = loo_Rest.Connect(loo_RedirectUrl.Host,loo_RedirectUrl.Port,loo_RedirectUrl.Ssl,li_BAutoReconnect)
if li_Success = 0 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    destroy loo_RedirectUrl
    return
end if

if (li_StatusCode = 301) OR (li_StatusCode = 307) then
    // Redirect using a POST, sending the same params to the new destination
    loo_Rest.AddQueryParam("firstName","John")
    loo_Rest.AddQueryParam("lastName","Doe")
    ls_ResponseText = loo_Rest.FullRequestFormUrlEncoded("POST",loo_RedirectUrl.Path)
    if loo_Rest.LastMethodSuccess = 0 then
        Write-Debug loo_Rest.LastErrorText
        destroy loo_Rest
        destroy loo_RedirectUrl
        return
    end if

end if

if (li_StatusCode = 302) OR (li_StatusCode = 303) then
    // Redirect using a GET, sending the query params found in the redirect URL.
    ls_ResponseText = loo_Rest.FullRequestFormUrlEncoded("GET",loo_RedirectUrl.PathWithQueryParams)
    if loo_Rest.LastMethodSuccess = 0 then
        Write-Debug loo_Rest.LastErrorText
        destroy loo_Rest
        destroy loo_RedirectUrl
        return
    end if

end if

// Show the final status code and the response text.
Write-Debug "Final status code = " + string(loo_Rest.ResponseStatusCode)

Write-Debug "Final response text (HTML, XML, JSON, or whatever..)"
Write-Debug ls_ResponseText


destroy loo_Rest
destroy loo_RedirectUrl