Upload files to a CMIS repository with JRuby

How to upload multiple files to a CMIS repository using JRuby

Jeff Potts recently posted an article that showcases how you can upload multiple files to a CMIS repository using Java. I thought it would be a nice idea to write a similar article but using JRuby instead.

What is CMIS?

CMIS stands for Content Management Interoperability Services and it’s basically a standardized API that let’s you perform CRUD operations against a CMIS compliant server. More information about the specification can be found here. Recently, Jeff Potts also wrote a really good article that introduces CMIS.

Here are a few CMIS-compliant content repositories:

What you need

First off, you need to install a CMIS repository on your system. In this article I’m going to use Alfresco 4.2.c Community Edition. Instructions on how to download and install Alfresco can be found here

Then you need to install JRuby on your system. I’m using rbenv to manage different Ruby implementations on my Mac. I won’t go in to the details on how to get JRuby running on your system. Just search on Google if you don’t know how to setup JRuby.

When you have JRuby setup on your system you can install the CMIS gem that we need:

gem install cmis

The CMIS gem is a CMIS client for JRuby. This gem uses the Apache Chemistry OpenCMIS Java libraries under the hood.

I’m the author of this gem so if it doesn’t work as expected for you, blame me :-)

Create a session

The first thing you need to do is to create a session:

require 'cmis'
require 'rika'

atom_url = "http://localhost:8080/alfresco/cmisatom"
user = "admin"
password = "admin"
@session = CMIS::create_session(atom_url, user, password)

As you can see, creating a session is very simple and straightforward. You only have to specify a username, password and the URL to the CMIS endpoint. CMIS does support both Atom Pub binding and Web Services binding. However, the JRuby gem only supports the Atom Pub binding which is faster than the SOAP Web Services binding and usually it’s a better choice. SOAP just sucks anyway so I won’t bother implementing support for it in the CMIS gem.

Most CMIS servers only provides one repository by default that you can connect to and the code above automatically connects to the first repository that it finds. This is a different behavior compared to the OpenCMIS library where your need to specify a repository explicitly every time you want to connect to a repository. I’ve chosen to implement this behavior to make it a little bit more convenient to work with the gem. However, you can specify a different repository if you want to in JRuby. You can read about it in the documentation for the CMIS gem.

Create the target folder

So now we got a session to work with. CMIS repositories is represented as a hierarchical tree of object consisting of folders and documents just like a local file system. The example below gets the root folder of the repository and creates a new folder called Images in the root folder. We also store a reference (image_folder) to the new folder so we can use it later:

root = @session.root_folder
image_folder = root.create_cmis_folder("Images")

Upload files

Now that we got a newly created folder, we can start to upload images to the folder:

local_folder = "/Users/ricn/temp/images"
files_to_upload = Dir["#{local_folder}/*"]

files_to_upload.each do |file|
  id = image_folder.create_cmis_document(File.basename(file), file)
  doc = session.get_object(id)
  puts "#{doc.name} uploaded."
end

To upload the images we just call the create_cmis_document method on the folder object and we pass in the name of the file and the full file path. Then we store the new object id in a variable so we can grab the image object from the repository using the get_object method on the sesssion.

List the uploaded files

To list the new files in our image folder we can execute the following code:

image_folder = session.get_object_by_path("/Images")
image_folder.children.each do |child|
  puts child.name
end

First I’m just showcasing another way to get an object by using the get_object_by_path method. Then I’m just grabbing the children from the image folder and then I print out the name of the file.

Summary

This is just a very simple example of what you can do with the OpenCMIS library and the CMIS gem in JRuby. Please let me know if you build something more interesting with the CMIS gem!

The complete code example can be found here.

Richard Nyström