Lua Requires Chilkat v11.0.0+

REST Follow Redirects

See more REST Examples

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

local chilkat = require("chilkat")

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

local rest = chilkat.Rest.new()

local bTls = true
local port = 443
local bAutoReconnect = true
local success = rest:connect("chilkatsoft.com", port, bTls, bAutoReconnect)
if not success then
    print(rest.last_error_text)
    return
end

-- Send a POST to a URL that will respond with a 302 redirect..
rest:add_query_param("firstName", "John")
rest:add_query_param("lastName", "Doe")
local responseText = rest:full_request_form_url_encoded("POST", "/echoPost302.asp")
if not rest.last_method_success then
    print(rest.last_error_text)
    return
end

local statusCode = rest.response_status_code

-- Examine the response status code
if statusCode < 300 then
    print("Not a redirect.")
    print(responseText)
    return
end

if statusCode > 399 then
    print("Error response: Status code = " .. statusCode)
    print(responseText)
    return
end

print("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.

print(rest.response_header)

-- Get the redirect URL
local urlStr = rest.last_redirect_url
if not rest.last_method_success then
    print("No Location header found for redirect.")
    return
end

local redirectUrl = chilkat.Url.new()
redirectUrl:parse_url(urlStr)

-- Prep for the redirect..
rest:clear_all_parts()

-- Disconnect and re-connect.
-- (This can be skipped if both the host and SSL/TLS conditions are the same.)
rest:disconnect(100)
success = rest:connect(redirectUrl.host, redirectUrl.port, redirectUrl.ssl, bAutoReconnect)
if not success then
    print(rest.last_error_text)
    return
end

if (statusCode == 301) or (statusCode == 307) then
    -- Redirect using a POST, sending the same params to the new destination
    rest:add_query_param("firstName", "John")
    rest:add_query_param("lastName", "Doe")
    responseText = rest:full_request_form_url_encoded("POST", redirectUrl.path)
    if not rest.last_method_success then
        print(rest.last_error_text)
        return
    end
end

if (statusCode == 302) or (statusCode == 303) then
    -- Redirect using a GET, sending the query params found in the redirect URL.
    responseText = rest:full_request_form_url_encoded("GET", redirectUrl.path_with_query_params)
    if not rest.last_method_success then
        print(rest.last_error_text)
        return
    end
end

-- Show the final status code and the response text.
print("Final status code = " .. rest.response_status_code)

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