<?php
require_once 'OAuth.php';
// Replace this with some real function that pulls from the LMS.
function getLMSDummyData() {
$parms = array(
"resource_link_id" => "120988f929-274612",
"resource_link_title" => "Weekly Blog",
"resource_link_description" => "Each student needs to reflect on the weekly reading. These should be one paragraph long.",
"user_id" => "292832126",
"roles" => "Instructor", // or Learner
"lis_person_name_full" => 'Jane Q. Public',
"lis_person_contact_email_primary" => "user@school.edu",
"lis_person_sourcedid" => "school.edu:user",
"context_id" => "456434513",
"context_title" => "Design of Personal Environments",
"context_label" => "SI182",
);
return $parms;
}
function validateDescriptor($descriptor)
{
$xml = new SimpleXMLElement($xmldata);
if ( ! $xml ) {
echo("Error parsing Descriptor XML\n");
return;
}
$launch_url = $xml->secure_launch_url[0];
if ( ! $launch_url ) $launch_url = $xml->launch_url[0];
if ( $launch_url ) $launch_url = (string) $launch_url;
return $launch_url;
}
// Parse a descriptor
function launchInfo($xmldata) {
$xml = new SimpleXMLElement($xmldata);
if ( ! $xml ) {
echo("Error parsing Descriptor XML\n");
return;
}
$launch_url = $xml->secure_launch_url[0];
if ( ! $launch_url ) $launch_url = $xml->launch_url[0];
if ( $launch_url ) $launch_url = (string) $launch_url;
$custom = array();
if ( $xml->custom[0]->parameter )
foreach ( $xml->custom[0]->parameter as $resource) {
$key = (string) $resource['key'];
$key = strtolower($key);
$nk = "";
for($i=0; $i < strlen($key); $i++) {
$ch = substr($key,$i,1);
if ( $ch >= "a" && $ch <= "z" ) $nk .= $ch;
else if ( $ch >= "0" && $ch <= "9" ) $nk .= $ch;
else $nk .= "_";
}
$value = (string) $resource;
$custom["custom_".$nk] = $value;
}
return array("launch_url" => $launch_url, "custom" => $custom ) ;
}
function signParameters($oldparms, $endpoint, $method, $oauth_consumer_key, $oauth_consumer_secret,
$submit_text = false, $org_id = false, $org_desc = false)
{
global $last_base_string;
$parms = $oldparms;
if ( ! isset($parms["lti_version"]) ) $parms["lti_version"] = "LTI-1p0";
if ( ! isset($parms["lti_message_type"]) ) $parms["lti_message_type"] = "basic-lti-launch-request";
if ( ! isset($parms["oauth_callback"]) ) $parms["oauth_callback"] = "about:blank";
if ( $org_id ) $parms["tool_consumer_instance_guid"] = $org_id;
if ( $org_desc ) $parms["tool_consumer_instance_description"] = $org_desc;
if ( $submit_text ) $parms["ext_submit"] = $submit_text;
$test_token = '';
$hmac_method = new OAuthSignatureMethod_HMAC_SHA1();
$test_consumer = new OAuthConsumer($oauth_consumer_key, $oauth_consumer_secret, NULL);
$acc_req = OAuthRequest::from_consumer_and_token($test_consumer, $test_token, $method, $endpoint, $parms);
$acc_req->sign_request($hmac_method, $test_consumer, $test_token);
// Pass this back up "out of band" for debugging
$last_base_string = $acc_req->get_signature_base_string();
$newparms = $acc_req->get_parameters();
return $newparms;
}
function signOnly($oldparms, $endpoint, $method, $oauth_consumer_key, $oauth_consumer_secret)
{
global $last_base_string;
$parms = $oldparms;
$test_token = '';
$hmac_method = new OAuthSignatureMethod_HMAC_SHA1();
$test_consumer = new OAuthConsumer($oauth_consumer_key, $oauth_consumer_secret, NULL);
$acc_req = OAuthRequest::from_consumer_and_token($test_consumer, $test_token, $method, $endpoint, $parms);
$acc_req->sign_request($hmac_method, $test_consumer, $test_token);
// Pass this back up "out of band" for debugging
$last_base_string = $acc_req->get_signature_base_string();
$newparms = $acc_req->get_parameters();
return $newparms;
}
function postLaunchHTML($newparms, $endpoint, $debug=false, $iframeattr=false) {
global $last_base_string;
$r = "<div id=\"ltiLaunchFormSubmitArea\">\n";
if ( $iframeattr ) {
$r = "<form action=\"".$endpoint."\" name=\"ltiLaunchForm\" id=\"ltiLaunchForm\" method=\"post\" target=\"basicltiLaunchFrame\" encType=\"application/x-www-form-urlencoded\">\n" ;
} else {
$r = "<form action=\"".$endpoint."\" name=\"ltiLaunchForm\" id=\"ltiLaunchForm\" method=\"post\" encType=\"application/x-www-form-urlencoded\">\n" ;
}
$submit_text = $newparms['ext_submit'];
foreach($newparms as $key => $value ) {
$key = htmlspecialchars($key);
$value = htmlspecialchars($value);
if ( $key == "ext_submit" ) {
$r .= "<input type=\"submit\" name=\"";
} else {
$r .= "<input type=\"hidden\" name=\"";
}
$r .= $key;
$r .= "\" value=\"";
$r .= $value;
$r .= "\"/>\n";
}
if ( $debug ) {
$r .= "<script language=\"javascript\"> \n";
$r .= " //<![CDATA[ \n" ;
$r .= "function basicltiDebugToggle() {\n";
$r .= " var ele = document.getElementById(\"basicltiDebug\");\n";
$r .= " if(ele.style.display == \"block\") {\n";
$r .= " ele.style.display = \"none\";\n";
$r .= " }\n";
$r .= " else {\n";
$r .= " ele.style.display = \"block\";\n";
$r .= " }\n";
$r .= "} \n";
$r .= " //]]> \n" ;
$r .= "</script>\n";
$r .= "<a id=\"displayText\" href=\"javascript:basicltiDebugToggle();\">";
$r .= get_stringIMS("toggle_debug_data","basiclti")."</a>\n";
$r .= "<div id=\"basicltiDebug\" style=\"display:none\">\n";
$r .= "<b>".get_stringIMS("basiclti_endpoint","basiclti")."</b><br/>\n";
$r .= $endpoint . "<br/>\n <br/>\n";
$r .= "<b>".get_stringIMS("basiclti_parameters","basiclti")."</b><br/>\n";
foreach($newparms as $key => $value ) {
$key = htmlspecialchars($key);
$value = htmlspecialchars($value);
$r .= "$key = $value<br/>\n";
}
$r .= " <br/>\n";
$r .= "<p><b>".get_stringIMS("basiclti_base_string","basiclti")."</b><br/>\n".$last_base_string."</p>\n";
$r .= "</div>\n";
}
$r .= "</form>\n";
if ( $iframeattr ) {
$r .= "<iframe name=\"basicltiLaunchFrame\" id=\"basicltiLaunchFrame\" src=\"\"\n";
$r .= $iframeattr . ">\n<p>".get_stringIMS("frames_required","basiclti")."</p>\n</iframe>\n";
}
if ( ! $debug ) {
$ext_submit = "ext_submit";
$ext_submit_text = $submit_text;
$r .= " <script type=\"text/javascript\"> \n" .
" //<![CDATA[ \n" .
" document.getElementById(\"ltiLaunchForm\").style.display = \"none\";\n" .
" nei = document.createElement('input');\n" .
" nei.setAttribute('type', 'hidden');\n" .
" nei.setAttribute('name', '".$ext_submit."');\n" .
" nei.setAttribute('value', '".$ext_submit_text."');\n" .
" document.getElementById(\"ltiLaunchForm\").appendChild(nei);\n" .
" document.ltiLaunchForm.submit(); \n" .
" //]]> \n" .
" </script> \n";
}
$r .= "</div>\n";
return $r;
}
/* This is a bit of homage to Moodle's pattern of internationalisation */
function get_stringIMS($key,$bundle) {
return $key;
}
function do_post_request($url, $data, $optional_headers = null)
{
$params = array('http' => array(
'method' => 'POST',
'content' => $data
));
if ($optional_headers !== null) {
$header = $optional_headers . "\r\n";
}
// $header = $header . "Content-type: application/x-www-form-urlencoded\r\n";
$params['http']['header'] = $header;
$ctx = stream_context_create($params);
$fp = @fopen($url, 'rb', false, $ctx);
if (!$fp) {
echo @stream_get_contents($fp);
< throw new Exception("Problem with $url, $php_errormsg");
> $message = "(No error message provided.)";
> if ($error = error_get_last()) {
> $message = $error["message"];
> }
> throw new Exception("Problem with $url, $message");
}
$response = @stream_get_contents($fp);
if ($response === false) {
< throw new Exception("Problem reading data from $url, $php_errormsg");
> $message = "(No error message provided.)";
> if ($error = error_get_last()) {
> $message = $error["message"];
> }
> throw new Exception("Problem reading data from $url, $message");
}
return $response;
}