PHP Document management

I am looking for a mature PHP-based, preferably Open Source, Document management solution.

Requirements:

Manage documents, preferably in a folder structure
Clean architecture
Half-way nice-looking interface (I can customize but need a clean basis)
Can fulltext index PDF, OpenOffice and ideally MS Office formats
Multi-user capable
Must be a browser-based web app, no Java clients etc.
Self-hosted solution

Nice to haves:

An API to read / write documents would be great
PHP5 based architecture
Versioning (Storage of multiple versions of a document)
Image thumbnails
Tagging

I am aware of

KnowledgeTree (about to do a test install)
OpenDocMan (very interesting, about to do a test install)

and would appreciate any additional hints and links to related projects - also in the direction of Asset Management for advertising agencies and such. For a brilliant, totally outstanding killer application that does most things out of the box I would also be ready to go beyond PHP (but it has to be a web app).

I checked through the dupes but found no question going into the right direction.

Solution

Firstly let me state that this answer is an "alternative" solution to your requirements and maybe not be the exact answer your looking for but I think the software that im about to descibe may influence you to look at other languages / platforms.

The software is called Microsoft Sharepoint 2010 which the Free Product, Links are below.

Firstly ill let you know that actual files are stored as binary within the database, and are not physical files on the system.

I have been working with sharepoint for the past few weeks few weeks now and I find it amazing, the way the application is designed is extreamly complex but the branding is not that complex, especially if you know C#.

Manage documents, preferably in a folder structure
- The document management is extremely powerful especially with the Microsoft office range, Where documents such as Excel,Word,Access can be modified and worked on by multiple people within the browser.
- You can point a folder on your desktop to your http server and the files would be stored exactly how you wish, Drag and drop within your computer.
- The collaboration of this kit will bring a "group" of people together to increase work rate and decrease work load (if required).
Interface:
- Please take a loog at the following screen: http://www.misdivision.com/blog/wp-content/uploads/2011/01/Use-Access-to-Edit-lists-in-Sharepoint-Slide-02.png
Multi-user capable
- if you had the costs to have multiple servers, creating a separate server and installing Active Directory as your main login, or you could just select Web Based Login
An API to read / write documents would be great
- If you have ever used Visual Studio you would understand that learning how to do applications is pretty simple, Well Sharepoint have integrated into Visual Studio 2010 so that you can Create/Modify/Deploy web parts to your site, you can create everything from a Youtube scraper to a complex multi segmented database analyser.

What I would recommend you doing is researching the platform in more detail and watching video cast on Youtube and Microsoft.

With foundation you do not have to scale your Sharepoint out as a farm, you can have it all in the same box such as a Server with MSSQL, Office 2007 installed, IIS, And Sharepoint on top of that.

if you do not have the resources for this then you can always rent a Sharepoint Server pre deployed.

Update 1.

Also i would like to mention that creating a network share on your PC and pointing the location to (http://pecka.com/archive) would result in being able to drag and drop files in the folder and them getting synchronizes with SharePoint, meta data automatically generated and stored in the DB.

Sorry for the rambe but i would at least look into it

Links