(Perl) SharePoint -- Get Server Form Digest Value

Demonstrates how to get a server form digest value to be placed in the X-RequestDigest HTTP request header for POST, PUT, MERGE, and DELETE requests. A form digest value is typically valid for 1800 seconds (i.e. 30 minutes). This example persists the value to a file, and only requests a new form digest value if the existing one is near expiration.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

# First, let's see if we already have a persisted form digest value
# that hasn't yet expired.
$fac = chilkat::CkFileAccess->new();
$xml = chilkat::CkXml->new();

# My example code (below) persists the form digest XML in this format:
# 
# 	<savedFormDigestValue>
# 	<d:ExpireDateTime>2017-04-12T20:46:39Z</d:ExpireDateTime>
# 	<d:FormDigestValue>0x3059FFB920651834540F3E6792EA73F5746B302E953FF4E808E485DB1E6C2836C7CF924644995F092453B02A94DE14A7962674B7B16780AF16EAFB8C246BCDC7,12 Apr 2017 17:08:22 -0000</d:FormDigestValue>
# 	</savedFormDigestValue>
# 

$dtExpire = chilkat::CkDateTime->new();
$dtNow = chilkat::CkDateTime->new();

$formDigestXmlFile = "qa_data/sharepoint/savedFormDigestValue.xml";
if ($fac->FileExists($formDigestXmlFile) == 1) {

    $xml->LoadXmlFile($formDigestXmlFile);

    # Get the expire date/time
    $dtExpire->SetFromTimestamp($xml->getChildContent("d:ExpireDateTime"));

    # Get the current date/time
    $dtNow->SetFromCurrentSystemTime();

    # Get both times as Unix time values
    $tNow = $dtNow->GetAsUnixTime(0);
    $tExpire = $dtExpire->GetAsUnixTime(0);

    # If tNow >= tExpire, then fall through.
    # Otherwise, just use the cached digest value.
    if ($tNow < $tExpire) {
        print "Cached digest value is not yet expired." . "\r\n";
        print "X-RequestDigest: " . $xml->getChildContent("d:FormDigestValue") . "\r\n";
        exit;
    }

}

# If we got to this point, the cached digest value either does not exist, or expired.

$http = chilkat::CkHttp->new();

# If SharePoint Windows classic authentication is used, then set the 
# Login, Password, LoginDomain, and NtlmAuth properties.
$http->put_Login("SHAREPOINT_USERNAME");
$http->put_Password("SHAREPOINT_PASSWORD");
$http->put_LoginDomain("SHAREPOINT_NTLM_DOMAIN");
$http->put_NtlmAuth(1);

# The more common case is to use SharePoint Online authentication (via the SPOIDCRL cookie).
# If so, do not set Login, Password, LoginDomain, and NtlmAuth, and instead
# establish the cookie as shown at SharePoint Online Authentication

# When creating, updating, and deleting SharePoint entities, we'll need
# to first get the server's form digest value to send in the X-RequestDigest header.
# This can be retrieved by making a POST request with an empty body to
# http://<site url>/_api/contextinfo and extracting the value of the
# d:FormDigestValue node in the XML that the contextinfo endpoint returns.

# Apparently, SharePoint needs an "Accept" request header equal to "application/xml",
# otherwise SharePoint will return an utterly incomprehensible and useless error message.
$savedAccept = $http->ck_accept();
$http->put_Accept("application/xml");

# Note: The last argument ("utf-8") is meaningless here because the body is empty.
# resp is a HttpResponse
$resp = $http->PostXml("https://SHAREPOINT_HTTPS_DOMAIN/_api/contextinfo","","utf-8");
if ($http->get_LastMethodSuccess() != 1) {
    print $http->lastErrorText() . "\r\n";
    exit;
}

# Restore the default Accept header
$http->put_Accept($savedAccept);

if ($resp->get_StatusCode() != 200) {
    # A response status code not equal to 200 indicates failure.
    print "Response status code = " . $resp->get_StatusCode() . "\r\n";
    print "Response body:" . "\r\n";
    print $resp->bodyStr() . "\r\n";

    exit;
}

$xml->LoadXml($resp->bodyStr());

# The response XML looks like this:

# <?xml version="1.0" encoding="utf-8" ?>
# <d:GetContextWebInformation xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:georss="http://www.georss.org/georss" xmlns:gml="http://www.opengis.net/gml" m:type="SP.ContextWebInformation">
#     <d:FormDigestTimeoutSeconds m:type="Edm.Int32">1800</d:FormDigestTimeoutSeconds>
#     <d:FormDigestValue>0x3059FFB920651834540F3E6792EA73F5746B302E953FF4E808E485DB1E6C2836C7CF924644995F092453B02A94DE14A7962674B7B16780AF16EAFB8C246BCDC7,12 Apr 2017 17:08:22 -0000</d:FormDigestValue>
#     <d:LibraryVersion>15.0.4569.1000</d:LibraryVersion>
#     <d:SiteFullUrl>https://SHAREPOINT_HTTPS_DOMAIN</d:SiteFullUrl>
#     <d:SupportedSchemaVersions m:type="Collection(Edm.String)">
#         <d:element>14.0.0.0</d:element>
#         <d:element>15.0.0.0</d:element>
#     </d:SupportedSchemaVersions>
#     <d:WebFullUrl>https://SHAREPOINT_HTTPS_DOMAIN</d:WebFullUrl>
# </d:GetContextWebInformation>
# 

# Cache the digest value, and also an expiration time.  If this code is run again
# before the digest expires, we'll just get it from the file.
$xml2 = chilkat::CkXml->new();

$xml2->put_Tag("savedFormDigestValue");
$xml2->NewChild2("d:FormDigestValue",$xml->getChildContent("d:FormDigestValue"));

$timeoutInSec = $xml->GetChildIntValue("d:FormDigestTimeoutSeconds");
print "Timeout in seconds = " . $timeoutInSec . "\r\n";

# Convert this to an expire timestamp.
# Let's make it expire 30 seconds prior to the actual timeout, just to be safe.
if ($timeoutInSec > 30) {
    $timeoutInSec = $timeoutInSec - 30;
}

$dtExpire->SetFromCurrentSystemTime();
$dtExpire->AddSeconds($timeoutInSec);
$xml2->NewChild2("d:ExpireDateTime",$dtExpire->getAsTimestamp(0));

# Persist the digest and expire time to a file.
$xml2->SaveXml($formDigestXmlFile);

print "Here is the new form digest value:" . "\r\n";
print "X-RequestDigest: " . $xml->getChildContent("d:FormDigestValue") . "\r\n";