Home Library 2.0 API Framework Specification

Introduction

The Home Library is a library to manage and persist the user home folder that supports file sharing.

Any Home Library user is presented with a personal Workspace, where users can collaborate, share information, and access project resources using special folders. This module describes the model of Home Library 2.0 and how to use the new API interface.

Design Model

The design model for Home Library identifies a core set of capabilities to work on Jackrabbit content. The goal of Home Library 2.0 is to expose content in the content repository as HTTP resources, fostering a RESTful style of application architecture. Home Library 2.0 is 10 times faster on average in comparison with the previous version.

The Home Library 2.0 is composed by:

• HomeLibrary: the API interface.
• HomeLibrary JCR: an HomeLibrary implementation based on JCR 2.0 (Java Content Repository JSR 283).
• HomeLibrary WebApp: a webService built on the top of the Jackrabbit web application.
• Home Library Model: a library to shared information between clients and Web App. It includes ACLType, FolderItemType, NodeProperty, WorkspaceItemType, etc.

Workspace Items

Each element contained in a workspace area is a WorkspaceItem.The workspace items are the effective user objects.

The following figure shows the WorkspaceItem model.

Prior HL 2.0 Objects that have been removed

• AquaMapsItem
• Annotation
• DocumentLink
• ImageDocumentLink
• PDFDocumentLink
• Annotation
• TabularDataLink
• ExternalResourceLink
• WorkflowReport
• WorkflowTemplate

Prior HL 2.0 Objects that have been mapped to the new model (GCubeItem)

• Document
• ImageDocument
• Metadata
• PDFDocument
• UrlDocument

Use the next section to migrate your components to the new Home Library API.

Compatibility

There is some pattern to know to keep code compatible with new API.

If you were working on Document, ImageDocument, Metadata, PDFDocument or UrlDocument, using new API your are going to work on GCubeItem that is a generic gCube Object.

But old context and model are still available using the following sections.

Document

Home Library 2.0 API to retrieve Document Objects:

import org.gcube.common.homelibrary.home.workspace.folder.items.gcube.Document;
 
Document document = (Document) item;
 
becomes: 
 
import org.gcube.common.homelibary.model.items.type.NodeProperty;
import org.gcube.common.homelibrary.home.workspace.folder.items.GCubeItem;
 
GCubeItem document = (GCubeItem) item;

How to retrieve properties:

document.getAlternatives(); -> document.getProperties().getProperties().get((NodeProperty.ALTERNATIVES.toString()); 
document.getAnnotation(); -> document.getProperties().getProperties().get((NodeProperty.ANNOTATIONS.toString()); 
document.getCollectionName(); -> document.getProperties().getProperties().get((NodeProperty.COLLECTION_NAME.toString()); 
document.getData(); -> document.getProperties().getProperties().get((NodeProperty.DATA.toString());
document.getFolderItemType(); -> document.getProperties().getProperties().get((NodeProperty.FOLDER_ITEM_TYPE.toString());
document.getLength(); -> document.getProperties().getProperties().get((NodeProperty.SIZE.toString());
document.getMetadata(); -> document.getProperties().getProperties().get((NodeProperty.METADATA.toString());
document.getMimeType(); -> document.getProperties().getProperties().get((NodeProperty.MIME_TYPE.toString());  
document.getParts(); -> document.getProperties().getProperties().get((NodeProperty.PARTS.toString()); 
document.getURI(); -> document.getProperties().getProperties().get((NodeProperty.OID.toString());  
document.getWorkflowData(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_DATA.toString());  
document.getWorkflowId(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_ID.toString());  
document.getWorkflowStatus(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_STATUS.toString());

ImageDocument

New Home Library API to retrieve ImageDocument Objects:

import org.gcube.common.homelibrary.home.workspace.folder.items.gcube.ImageDocument;
 
ImageDocument document = (ImageDocument) item;
 
becomes: 
 
import org.gcube.common.homelibary.model.items.type.NodeProperty;
import org.gcube.common.homelibrary.home.workspace.folder.items.GCubeItem;
 
GCubeItem document = (GCubeItem) item;

To retrieve properties, use the API for Document Object and the following API:

document.getHeight(); -> document.getProperties().getProperties().get((NodeProperty.IMAGE_HEIGHT.toString());  
document.getWidth(); -> document.getProperties().getProperties().get((NodeProperty.IMAGE_WIDTH.toString());  
document.getThumbnailHeight(); -> document.getProperties().getProperties().get((NodeProperty.THUMBNAIL_HEIGHT.toString());    
document.getThumbnailWidth(); -> document.getProperties().getProperties().get((NodeProperty.THUMBNAIL_WIDTH.toString());  
document.getThumbnail(); -> document.getProperties().getProperties().get((NodeProperty.THUMBNAIL_DATA.toString()); 
document.getThumbnailLength(); -> document.getThumbnail().getSize();

Metadata

New Home Library API to retrieve Metadata Objects:

import org.gcube.common.homelibrary.home.workspace.folder.items.gcube.Metadata;
 
Metadata document = (Metadata) item;
 
becomes: 
 
import org.gcube.common.homelibary.model.items.type.NodeProperty;
import org.gcube.common.homelibrary.home.workspace.folder.items.GCubeItem;
 
GCubeItem document = (GCubeItem) item;

To retrieve properties:

document.getURI(); -> document.getProperties().getProperties().get((NodeProperty.OID.toString());  
document.getWorkflowData(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_DATA.toString());  
document.getWorkflowId(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_ID.toString());  
document.getWorkflowStatus(); -> document.getProperties().getProperties().get((NodeProperty.WORKFLOW_STATUS.toString());
 
document.getSchemaName(); -> document.getProperties().getProperties().get((NodeProperty.SCHEMA.toString()); 
document.getXML(); -> document.getProperties().getProperties().get((NodeProperty.ALTERNATIVES.toString()); 
document.getCollectionName(); -> document.getProperties().getProperties().get((NodeProperty.COLLECTION_NAME.toString()); 
document.getURI(); -> document.getProperties().getProperties().get((NodeProperty.OID.toString());

PDFDocument

New Home Library API to retrieve PDFDocument Objects:

import org.gcube.common.homelibrary.home.workspace.folder.items.gcube.PDFDocument;
 
PDFDocument document = (PDFDocument) item;
 
becomes: 
 
import org.gcube.common.homelibary.model.items.type.NodeProperty;
import org.gcube.common.homelibrary.home.workspace.folder.items.GCubeItem;
 
GCubeItem document = (GCubeItem) item;

To retrieve properties, use the API for Document Object and the following API:

document.getNumberOfPages(); -> document.getProperties().getProperties().get((NodeProperty.NUMBER_OF_PAGES.toString());  
document.getVersion(); -> document.getProperties().getProperties().get((NodeProperty.VERSION.toString());  
document.getAuthor(); -> document.getProperties().getProperties().get((NodeProperty.AUTHOR.toString());  
document.getTitle(); -> document.getProperties().getProperties().get((NodeProperty.PDF_TITLE.toString());  
document.getProducer(); -> document.getProperties().getProperties().get((NodeProperty.PRODUCER.toString());

UrlDocument

New Home Library API to retrieve UrlDocument Objects:

import org.gcube.common.homelibrary.home.workspace.folder.items.gcube.UrlDocument;
 
UrlDocument document = (UrlDocument) item;
 
becomes: 
 
import org.gcube.common.homelibary.model.items.type.NodeProperty;
import org.gcube.common.homelibrary.home.workspace.folder.items.GCubeItem;
 
GCubeItem document = (GCubeItem) item;

To retrieve properties, use the API for Document Object and the following API:

document.getUrl(); -> document.getProperties().getProperties().get((NodeProperty.URL.toString());

Properties and Types

Properties and Types are in Home Library Model, so update the package as follows:

org.gcube.common.homelibrary.home.workspace.WorkspaceItemType -> org.gcube.common.homelibary.model.items.type.WorkspaceItemType
org.gcube.common.homelibrary.home.workspace.folder.FolderItemType -> org.gcube.common.homelibary.model.items.type.FolderItemType
org.gcube.common.homelibrary.home.workspace.accessmanager.ACLType -> org.gcube.common.homelibary.model.items.type.ACLType

Implementation Framework

The Home Library 2.0 API is a set of components that uses Apache Jackrabbit, to store and manage content.

Home Library 2.0 uses Java servlets to process HTTP requests in a RESTful way.

Home Library is implemented in terms of the JCR API. The default implementation for Apache Jackrabbit is provided out of the box.

Through code sharing, the framework reduces development costs and ensures the consistency and correctness of library implementations.

Management Model

The core of Home Library 2.0 is a web application built on top of Jackrabbit.

Home Library WebApp uses Java servlets to process HTTP requests coming from clients. The servlets are a frontend to the actual operations and they support the following operations:

• retrieve content
• create content
• modify existing content
• remove existing content
• move existing content to a new location
• copy existing content to a new location

Using the Home Library

To use Home Library 2.0, import the following dependencies:

<dependency>
<groupId>org.gcube.common</groupId>
<artifactId>home-library-jcr</artifactId>
<version>[2.0.0-SNAPSHOT,3.0.0-SNAPSHOT)</version>
</dependency>
 
<dependency>
<groupId>org.gcube.common</groupId>
<artifactId>home-library</artifactId>
<version>[2.0.0-SNAPSHOT,3.0.0-SNAPSHOT)</version>
</dependency>

How to retrieve the user Home

Firs of all is necessary to retrieve an instance of HomeManagerFactory, this can be done using the static methods from HomeLibrary class.

HomeManagerFactory factory = HomeLibrary.getHomeManagerFactory();

Obtained the factory you can retrieve the HomeManager:

HomeManager manager = factory.getHomeManager();

Then we retrieve the User home:

User user = manager.createUser(portalLogin);
Home home = manager.getHome(user);

Where portalLogin is the user username used to login into the portal (for test you can use any username).

At this point we can get the Workspace with his root:

Workspace ws = home.getWorkspace();
WorkspaceFolder root = ws.getRoot();

Examples

There are some example of HomeLibrary use.

Creating folders

Generate an unique name for a folder item

To generate an unique item name for a given folder:

// Get a destination folder
WorkspaceFolder destionationFolder = ...
 
String nameCandidate = "My first item";
 
String name = WorkspaceUtil.getUniqueName(nameCandidate, destionationFolder);

If an item with name My first item already exists, a new name My first item(n) will be assigned to the folder.

Create a workspace folder

// Get the user workspace
Workspace ws = ...
 
String name = "MyFolder";
String description = "description";
 
WorkspaceFolder folder;
if (!ws.exists(name, destinationFolderId))
	folder = ws.createFolder(name, description, destinationFolderId);
else
	folder = (WorkspaceFolder) ws.find(name, destinationFolderId);

If the folder "MyFolder" does not exist in the destination folder, it will be created. Otherwise "MyFolder" will be retrieved.

Writing items

Create a generic item into a workspace folder

After retrieving the user workspace root:

// Get a destination folder
WorkspaceFolder destinationFolder = ...
 
String name = "filename";
String description = "description";
String mimeType = null;
InputStream is = new FileInputStream("/home/user/file.txt");	
FolderItem folderItem = WorkspaceUtil.createExternalFile(destinationFolder, name, description, mimeType, is);

If the mimetype is null, it will be automatically detected.

If the file is already in the Storage, the workspace item can be created by storageId:

String storageId = ...
FolderItem folderItem = WorkspaceUtil.createExternalFile(destinationFolder, name, description, mimeType, storageId);

Add properties to an item

After retrieving the user workspace root:

String name = "key";
String value = "value";
 
// Get an item
FolderItem folderItem = ...
 
// Add properties
folderItem.getProperties().addProperty(name, value);

Create a gCubeItem into a workspace folder

import org.gcube.common.homelibrary.home.workspace.WorkspaceItem;
import java.util.ArrayList;
import java.util.List;
import java.util.HashMap;
import java.util.Map;
 
String name = "name";
String description = "description";
List<String> scopes = new ArrayList<String>();
scopes.add("/myscope/");
 
String creator = "test.user";
String itemType = "myType";
 
Map<String, String> properties = new HashMap<String, String>();
properties.put("key00", "value00");
properties.put("key01", "value01");
 
// Get a destination folder id
String destinationFolderId = ...
 
WorkspaceItem item = ws.createGcubeItem(name, description, scopes, creator, itemType, properties, destinationFolderId);

Searching items

Search items by properties

To search WorkspaceItem by properties:

import java.util.ArrayList;
import java.util.List;
import org.gcube.common.homelibrary.home.workspace.WorkspaceItem;
 
// Get the user workspace
Workspace ws = ...
 
List<String> keys = new ArrayList<String>();
keys.add("key00");
keys.add("key01");
 
// Get WorkspaceItem that contain certain keys
List<WorkspaceItem> properties = ws.searchByProperties(keys);

Advance Search on gCubeItems

To search gCubeItems by properties:

import java.util.ArrayList;
import java.util.List;
import org.gcube.common.homelibrary.home.workspace.search.util.SearchQueryBuilder;
 
// Get the user workspace
Workspace ws = ...
 
// Create a SearchQuery
SearchQueryBuilder query = new SearchQueryBuilder();
 
// Get gCubeItems that contain a certain key
query.contains("key00");
 
// Get gCubeItems where key01 = value01
query.contains("key01","value01");
 
// Get gCubeItems where type = myType
query.ofType("myType");
 
List<GCubeItem> myItems = ws.searchGCubeItems(query.build());