Wed, 29 Apr 2009
/Coding/php:
Accessing the KnowledgeTree API
KnowledgeTree[1] is a very popular server-based Open Source document
management system. Something that some users (like me, or rather my clients)
need to do is allow certain people to add or manipulate documents in
KnowledgeTree without having to have a login ID and knowledge of the
KnowledgeTree user interface. Enter the API, and a little custom PHP
scripting....
Oddly enough, I found at least three different documents on the wiki[2]
that seemed to talk about three different approaches to using the API. Oddly
(should I say suspiciously?) because the level of detail was just enough to
be interesting, but just short of being useful. Ie. for two of them, I just
could not figure it out. I even saw a post on the KnowledgeTree forum asking
for more detail / a concrete example (me too! me too!) and the only reply
was a curt link to one of the near useless wiki pages that I have already
mentioned. And needless to say, my own post was ignored. Whats up? (Some
conspiratorial possibilities come to mind....)
The only API approach that I have been able to get working is the "REST
web service framework"[3], which, for better or worse, only works as of the
currently bleeding edge KnowledgeTree version 3.6.0 (will NOT work with
current stable 3.5.4a). [3] is also sorely lacking in detail, but in
combination with a little code surfing in
knowledgetree/ktwebservice/webservice.php
I was able to divine what was needed to get it working. Here I will
hopefully provide some missing detail for Google to find....
One can of course play with the KnowledgeTree REST web service through a
browser, as the means of communication with the server is via POST
parameters attached to the server URL. This is also a good way to see the
exact format of the XML response the server gives back.
To achieve the same result with PHP one must use libcurl through the PHP
curl extension[4]. Since [4] is also a little skimpy on detail, [5] is a
very useful supplement. To cut to the chase, I created a function as
follows:
<![CDATA[
<?php
function curlPost($site, $fields){
$ch = curl_init(); // initialize curl handle
curl_setopt($ch, CURLOPT_URL,$site); // set url to post to
curl_setopt($ch, CURLOPT_FAILONERROR, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);// allow redirects
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); // return into a variable
curl_setopt($ch, CURLOPT_TIMEOUT, 9); // times out after 10s
curl_setopt($ch, CURLOPT_POST, 1); // set POST method
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
$answer = curl_exec($ch); // run the whole process
// print_r(curl_getinfo($ch));
// echo "\n\ncURL error number:" .curl_errno($ch);
// echo "\n\ncURL error:" . curl_error($ch);
curl_close($ch);
return $answer;
}
?>
]]>
$site is the REST URL of the KnowledgeTree server, and $fields are the
POST parameters that are to go along with it. This function simply POSTs
these parameters to the URL (exactly the same as entering $site?$fields into
your web browser).
Here is a concrete and currently working example of how to get the
contents of the KnowledgeTree root directory:
<![CDATA[
<?php
$url =
'https://www.server.com/kt-dms-oss-3.6.0/ktwebservice/KTWebService.php';
require_once('funCurlPost.php');
// **************************
// Login
// **************************
$postfields = "method=login&password=123456&username=admin";
$response = curlPost($url, $postfields);
$xml = new SimpleXMLElement($response);
if( $xml->status_code != 0 ){
echo 'Error - authentication failed: ' . $xml->message;
} else {
$session_id = $xml->results;
echo "Login successful, session ID = " . $session_id;
}
// ***********************************
// List contents of root folder (id=1)
// ***********************************
$postfields =
"method=get_folder_contents&session_id=$session_id&folder_id=1";
$response = curlPost($url, $postfields);
$xml = new SimpleXMLElement($response);
echo "<p>Get root folder contents:<br>";
if( $xml->status_code != 0 ){
echo 'Error - get_folder_contents failed: ' . $xml->message;
} else {
// print_r($xml); // to see data structure
echo "<p>folder ID = " . $xml->results->folder_id . "<br>";
echo "folder name = " . $xml->results->folder_name . "<br>";
echo "folder path = " . $xml->results->full_path . "<p>";
foreach ($xml->results->items->item as $value) {
echo "item type = " . $value->item_type . " ";
echo "item ID = " . $value->id . " ";
echo "item name = " . $value->filename . "<br>";
}
}
// ***********************************
// Logout
// ***********************************
$postfields = "method=logout&session_id=$session_id";
$response = curlPost($url, $postfields);
$xml = new SimpleXMLElement($response);
echo "<p>Logging out....<br>";
if( $xml->status_code != 0 ){
echo 'Error - get_folder_contents failed: ' . $xml->message;
} else {
echo 'successful!';
}
?>
]]>
The key point is that there were three operations in the above script,
with three corresponding POST strings:
| Operation | POST string |
| Login | login&password=123456&username=admin |
| List Directory
| get_folder_contents&session_id=$session_id&folder_id=1 |
| Logout | method=logout&session_id=$session_id |
And something else that is already working -- to add a document to
KnowledgeTree, use this POST string:
$document = "bodybg.jpg"; // located in /var/uploads
$postfields =
"method=add_document&session_id=$session_id&folder_id=1&title=$document&filename=$document&documenttype=Default&tempfilename=/vol/www/vsc/apps/kt-dms-oss-3.6.0/var/uploads/$document";
[1] http://www.knowledgetree.com/
[2] http://wiki.knowledgetree.com/
[3] http://wiki.knowledgetree.com/REST_Web_Service
[4] http://php.net/manual/en/book.curl.php
[5] http://devzone.zend.com/article/1081-Using-cURL-and-libcurl-with-PHP
posted at: 00:08 | path: /Coding/php | permanent link to this entry
