(PowerShell) REST Follow Redirects

Demonstrates how to follow a 302/303 redirect response.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

$rest = New-Object Chilkat.Rest

$bTls = $true
$port = 443
$bAutoReconnect = $true
$success = $rest.Connect("chilkatsoft.com",$port,$bTls,$bAutoReconnect)
if ($success -ne $true) {
    $($rest.LastErrorText)
    exit
}

# Send a POST to a URL that will respond with a 302 redirect..
$rest.AddQueryParam("firstName","John")
$rest.AddQueryParam("lastName","Doe")
$responseText = $rest.FullRequestFormUrlEncoded("POST","/echoPost302.asp")
if ($rest.LastMethodSuccess -ne $true) {
    $($rest.LastErrorText)
    exit
}

$statusCode = $rest.ResponseStatusCode

# Examine the response status code
if ($statusCode -lt 300) {
    $("Not a redirect.")
    $($responseText)
    exit
}

if ($statusCode -gt 399) {
    $("Error response: Status code = " + $statusCode)
    $($responseText)
    exit
}

$("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.

$($rest.ResponseHeader)

$redirectUrl = $rest.RedirectUrl()
if ($rest.LastMethodSuccess -eq $false) {
    $("No Location header found for redirect.")
    exit
}

# Prep for the redirect..
$rest.ClearAllParts()

# 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,$bAutoReconnect)
if ($success -ne $true) {
    $($rest.LastErrorText)
    exit
}

if (($statusCode -eq 301) -or ($statusCode -eq 307)) {
    # Redirect using a POST, sending the same params to the new destination
    $rest.AddQueryParam("firstName","John")
    $rest.AddQueryParam("lastName","Doe")
    $responseText = $rest.FullRequestFormUrlEncoded("POST",$redirectUrl.Path)
    if ($rest.LastMethodSuccess -ne $true) {
        $($rest.LastErrorText)
        exit
    }

}

if (($statusCode -eq 302) -or ($statusCode -eq 303)) {
    # Redirect using a GET, sending the query params found in the redirect URL.
    $responseText = $rest.FullRequestFormUrlEncoded("GET",$redirectUrl.PathWithQueryParams)
    if ($rest.LastMethodSuccess -ne $true) {
        $($rest.LastErrorText)
        exit
    }

}

# Show the final status code and the response text.
$("Final status code = " + $rest.ResponseStatusCode)

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