Tcl Requires Chilkat v11.0.0+

REST Follow Redirects

See more REST Examples

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

load ./chilkat.dll

set success 0

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

set rest [new_CkRest]

set bTls 1
set port 443
set bAutoReconnect 1
set success [CkRest_Connect $rest "chilkatsoft.com" $port $bTls $bAutoReconnect]
if {$success == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    exit
}

#  Send a POST to a URL that will respond with a 302 redirect..
CkRest_AddQueryParam $rest "firstName" "John"
CkRest_AddQueryParam $rest "lastName" "Doe"
set responseText [CkRest_fullRequestFormUrlEncoded $rest "POST" "/echoPost302.asp"]
if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    exit
}

set statusCode [CkRest_get_ResponseStatusCode $rest]

#  Examine the response status code
if {$statusCode < 300} then {
    puts "Not a redirect."
    puts "$responseText"
    delete_CkRest $rest
    exit
}

if {$statusCode > 399} then {
    puts "Error response: Status code = $statusCode"
    puts "$responseText"
    delete_CkRest $rest
    exit
}

puts "Redirect status code = $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.

puts [CkRest_responseHeader $rest]

#  Get the redirect URL
set urlStr [CkRest_lastRedirectUrl $rest]
if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
    puts "No Location header found for redirect."
    delete_CkRest $rest
    exit
}

set redirectUrl [new_CkUrl]

CkUrl_ParseUrl $redirectUrl $urlStr

#  Prep for the redirect..
CkRest_ClearAllParts $rest

#  Disconnect and re-connect.  
#  (This can be skipped if both the host and SSL/TLS conditions are the same.)
CkRest_Disconnect $rest 100
set success [CkRest_Connect $rest [CkUrl_host $redirectUrl] [CkUrl_get_Port $redirectUrl] [CkUrl_get_Ssl $redirectUrl] $bAutoReconnect]
if {$success == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkUrl $redirectUrl
    exit
}

if {expr [$statusCode == 301]  ||  [$statusCode == 307]} then {
    #  Redirect using a POST, sending the same params to the new destination
    CkRest_AddQueryParam $rest "firstName" "John"
    CkRest_AddQueryParam $rest "lastName" "Doe"
    set responseText [CkRest_fullRequestFormUrlEncoded $rest "POST" [CkUrl_path $redirectUrl]]
    if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkUrl $redirectUrl
        exit
    }

}

if {expr [$statusCode == 302]  ||  [$statusCode == 303]} then {
    #  Redirect using a GET, sending the query params found in the redirect URL.
    set responseText [CkRest_fullRequestFormUrlEncoded $rest "GET" [CkUrl_pathWithQueryParams $redirectUrl]]
    if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkUrl $redirectUrl
        exit
    }

}

#  Show the final status code and the response text.
puts "Final status code = [CkRest_get_ResponseStatusCode $rest]"

puts "Final response text (HTML, XML, JSON, or whatever..)"
puts "$responseText"

delete_CkRest $rest
delete_CkUrl $redirectUrl