Lianja

REST Follow Redirects

See more REST Examples

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

llSuccess = .F.

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

loRest = createobject("CkRest")

llBTls = .T.
lnPort = 443
llBAutoReconnect = .T.
llSuccess = loRest.Connect("chilkatsoft.com",lnPort,llBTls,llBAutoReconnect)
if (llSuccess = .F.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

// Send a POST to a URL that will respond with a 302 redirect..
loRest.AddQueryParam("firstName","John")
loRest.AddQueryParam("lastName","Doe")
lcResponseText = loRest.FullRequestFormUrlEncoded("POST","/echoPost302.asp")
if (loRest.LastMethodSuccess = .F.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

lnStatusCode = loRest.ResponseStatusCode

// Examine the response status code
if (lnStatusCode < 300) then
    ? "Not a redirect."
    ? lcResponseText
    release loRest
    return
endif

if (lnStatusCode > 399) then
    ? "Error response: Status code = " + str(lnStatusCode)
    ? lcResponseText
    release loRest
    return
endif

? "Redirect status code = " + str(lnStatusCode)

// 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.

? loRest.ResponseHeader

// Get the redirect URL
lcUrlStr = loRest.LastRedirectUrl
if (loRest.LastMethodSuccess = .F.) then
    ? "No Location header found for redirect."
    release loRest
    return
endif

loRedirectUrl = createobject("CkUrl")
loRedirectUrl.ParseUrl(lcUrlStr)

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

// Disconnect and re-connect.  
// (This can be skipped if both the host and SSL/TLS conditions are the same.)
loRest.Disconnect(100)
llSuccess = loRest.Connect(loRedirectUrl.Host,loRedirectUrl.Port,loRedirectUrl.Ssl,llBAutoReconnect)
if (llSuccess = .F.) then
    ? loRest.LastErrorText
    release loRest
    release loRedirectUrl
    return
endif

if ((lnStatusCode = 301) or (lnStatusCode = 307)) then
    // Redirect using a POST, sending the same params to the new destination
    loRest.AddQueryParam("firstName","John")
    loRest.AddQueryParam("lastName","Doe")
    lcResponseText = loRest.FullRequestFormUrlEncoded("POST",loRedirectUrl.Path)
    if (loRest.LastMethodSuccess = .F.) then
        ? loRest.LastErrorText
        release loRest
        release loRedirectUrl
        return
    endif

endif

if ((lnStatusCode = 302) or (lnStatusCode = 303)) then
    // Redirect using a GET, sending the query params found in the redirect URL.
    lcResponseText = loRest.FullRequestFormUrlEncoded("GET",loRedirectUrl.PathWithQueryParams)
    if (loRest.LastMethodSuccess = .F.) then
        ? loRest.LastErrorText
        release loRest
        release loRedirectUrl
        return
    endif

endif

// Show the final status code and the response text.
? "Final status code = " + str(loRest.ResponseStatusCode)

? "Final response text (HTML, XML, JSON, or whatever..)"
? lcResponseText


release loRest
release loRedirectUrl