DSpace REST API - Bojan Suzic

Integration, testing, documentation and further development of DSpace REST services for 1.x and 2.0 versions. - Bojan Suzic

Not completed!

This page is not completed. The work on specifications is ongoing. Everyone is welcome to comment or contribute!

Details

Project Title:	DSpace REST API
Student:	Bojan Suzic, University of Technology Graz
Mentors:	Aaron Zeckoski, Mark Diggory
Contacting author:	bojan AT student . tugraz DOT at - using subject line DSpace
SCM Location for Project:	http://scm.dspace.org/svn/repo/modules/rest

Project description

The REST approach promotes simplification and decoupling of software architecture, enabling further scalability, portability, granularity and simplified interaction of software systems and components.
The aim of this project is to provide DSpace with REST capable API and underlying component, which will enable developers and end-users to exploit the advantages of such approach.

Some of uses this module is intended to provide could be, for instance:

interaction between DSpace systems and/or other repositories
automation of different activities, e.g. submission of packages
integrating repositories in process workflows of other applications or systems
interaction with many kinds of systems or web applications, such as CMS, LMS, LCMS, VLS, AMS etc
providing of other approaches to UI, such as client based/run UI
crawling of repositories, exposing information in structural way

This project is continuation of last year's activities, supported by Google as part of GSoC 2009. In the first stage the basic support for REST for DSpace is provided, exposing many parts of DSpace functionality to the clients.

In this year's GSoC the following activities should be primarily addressed:

integration of existing code in the system
alignment of REST API with currently available DSpace features/functionality, e.g. adding of new features
extending of existing code, in order to provide better handling of management and injection functions
providing more detailed documentation and examples for end users
testing activities, e.g. cooperation/coordination with other GSoC 10 project Unit testing
promotion of DSpace REST interaction (by taking part in integration with other systems)

Detailed activities

In the following sections main activities are elaborated in detail.

REST API Methods

Changes in comparison to existing support are marked with red color. Please note that changes may appear as:

introduction of new method
extending of existing method, by implementing new functionality (e.g. GET/PUT/DELETE)
extending of existing method, by changing its parameters, output etc

Naming convention for endpoints
DSpace 1.x and 2.x are treating the resources on different way. 2.x is more generalized, suggesting the use of RDF-like interrelation notations. The necessity to follow this approach for 1.x is to be discussed in the list or on the following page.

Repository browsing

Earlier Implementation Description - GSoC09

C	Verb	URL	Description	Mandatory parameters	Optional parameters	Sorting fields	Response Data	Formats	Response codes
	`GET`	`/communities`	Returns a list of all communities on the system or return just top level communities.	-	`topLevelOnly=true` `idOnly=false`	`id` `name` `countitems`	By default contains item count, identifier, handle and name and other referencing data, or 204 if none. Additionaly, based on parameter `idOnly=true` the method returns only identifiers.	`json` `xml`	200, 400, 500
	`GET`	`/communities/{id`}	Return information about `id` community.	-	-	-	TBD	`json` `xml`	200, 204, 400, 500
•	`PUT`	`/communities/{id`}	Change description of `id` community	`name`	-	-	TBD	`json` `xml`	200, 204, 500, 501
•	`POST`	`/communities`	Add community to the system	`name`	`logo` `parrent` other metadata	-	TBD	`json` `xml`	200, 201, 204, 500, 501
	`GET`	`/communities/{id}/parents`	Return a list of all parent communities of the `id` community.	-	idOnly=false immediateOnly=true	`id` `name` `countitems`	Contains item count, identifiers, handle and name or 204 if id is already top-level. Additionaly, based on parameter idOnly=true the method returns only identifiers.	`json` `xml`	200, 204, 400, 500
	`GET`	`/communities/{id}/children`	Returns a list of immediate sub-communities (children) of the `id` community.	-	idOnly=false	`id` `name` `countitems`	Contains item count, identifiers, handle and name or 204 if none. Additionaly, based on parameter `idOnly=true` the method returns only identifiers.	`json` `xml`	200, 204, 400, 500
	`GET`	`/communities/{id}/collections`	Return a list of collections in the `id` community.	-	idOnly=false	`id` `name` `countitems`	Contains item count, identifiers, name, archival status, last modification and handle of collections, or 204 if there are none of them. Additionaly with idOnly=true only identifiers are returned.	`json` `xml`	200, 204, 400, 500
	`GET`	`/communities/{id}/recent`	Return a list of recent submissions to a community.	-	idOnly=false	`id` `name` `lastmodified` `submitter`	Contains complete items from recent submissions in community. Additionaly, contains only identifiers when `idOnly=true` is used.	`json` `xml`	200, 204, 400, 500
	`GET`	`/collections`	Return a list of all collections in the system.	-	idOnly=false	`id` `name` `countitems`	Contains item count, identifiers, name and handle of collections, or 204 if there are none of them. In the case idOnly=true is used, returns only identifiers of collections.	`json` `xml`	200, 204, 400, 500
	`GET`	`/collections/{id}/communities`	Return a list of all communities a collection with `id` belongs to.	-	idOnly=false	`id` `name` `countitems`	Contains item count, identifier, name and handle of collections, or 204 if there are none of them. Additionaly, when idOnly=true is used, return only identifiers.	`json` `xml`	200, 204, 400, 500
	`GET`	`/collections/{id}/items`	Returns a list of all items from the collection `id`.	-	idOnly=false in_archive=false	`id` `name` `lastmodified` `submitter`	Contains full information info including name, submitter, collections related or 204 if there are none of them. In the case idOnly=true is used, return only identifiers of results.	`json` `xml`	200, 204, 400, 500

Parameter	Description
`topLevelOnly`	returns only top level communities
`idOnly`	if true return only the identifiers for the record

Content searching

C	Verb	URL	Description	Mandatory parameters	Optional parameters	Sorting fields	Response Data	Formats	Response codes
	`GET`	`/search`	Return a list of all objects found by searching criteria. Notice: community and collection are mutually exclusive options.	-	TBD modifiers{{query=`query`}}&(community=`id` or \\{{collection=`id`}} {{idOnly=false}}	`id` `name` `lastmodified` `submitter`	Item info with basic metadata for the search results. Additionally return only identifiers when `idOnly=true` is used.	`json` `xml`	200, 204, 400, 500

Name and description	Value and notes
Base URI:	/harvest?startdate=`startdate`&enddate=`enddate`?(community=`id`!collection=`id`)&idOnly=false&withdrawn=false
Description:	Returns a list of all objects that have been created, modified or withdrawn within specified time range
HTTP method:	`GET`
Optional parameters:	`startdate`: start date `enddate`: end date date is defined with ISO 8601 format, e.g. YYYY-MM-DD or 2009-08- 20T21:15Z; if the date parameters are ommited, then from_beginning/to_current_time are assumed community=`id`: the id of community limiting search to collection=`id`: the id of collection limiting search to Notice: community and collection are mutually exclusive options idOnly=false: using true returns only identifiers of the results withdrawn=false: with true includes withdrawn items too
Sorting/ordering modifiers:	`id, name, lastmodified, submitter`: information on item returned
Response formats:	`json`, `xml`
Status codes	200: OK 204: no content 400: bad request 500: internal server error
Response details	Contains item info including id, name, handle, metadata, bitstreams according to the defined requirements. Additionally when idOnly=true only identifiers of results are returned. If the date is in incompatible format, error 400 is returned.

Item status and retrieval

Name and description	Value and notes
Base URI:	`/items/{id`}
Description:	Returns detailed information about an item
HTTP method:	`GET`
Required parameters:	{`id`}: item id
Sorting fields supported:	`id, name, lastmodified, submitter`: sorting by id, name, last modifed date or submitter of item
Response formats:	`json`, `xml`
Status codes	200: OK 204: no content 400: bad request 500: internal server error
Response details	Contains an information about an item including resource name, metadata, owning collection, collections stored in, communities stored in, bundle ids, last modified date, archival/withdrawn status and submitter of an item

Name and description	Value and notes
Base URI:	`/items/{id}/permissions`
Description:	Returns status of user permissions on this item
HTTP method:	`GET`
Required parameters:	{`id`}: item id
Response formats:	`json`, `xml`
Status codes	200: OK 400: bad request 500: internal server error
Response details	Boolean variable, stating can user edit the listed item

Name and description	Value and notes
Base URI:	/items/`id`/communities?idOnly=false&immediateOnly=true
Description:	Returns communities this item is part of
HTTP method:	`GET`
Required parameters:
Sorting fields supported:	`id, name, countitems`: community properties used for sorting
Response formats:	`json`, `xml`
Status codes	200: OK 400: bad request 500: internal server error
Response details	Communities listed

Name and description	Value and notes
Base URI:	/items/`id`/collections?idOnly=false
Description:	Returns collections this item is part of
HTTP method:	`GET`
Required parameters:
Sorting fields supported:	`id, name, countitems`: collection parameters
Response formats:	`json`, `xml`
Status codes	200: OK 400: bad request 500: internal server error
Response details	Collections listed

Name and description	Value and notes
Base URI:	`/bitstream/{id`}
Description:	Returns bitstream object - usually the library item file
HTTP method:	`GET`
Required parameters:	{`id`}: bitstream item id
Response formats:	`json`, `xml` (not yet complete)
Status codes	200: OK 404: Not found 400: bad request 401: Unauthorized 403: Forbidden 500: internal server error
Response details	Includes all information about referenced bitstream, including file name, licence, corresponding ittem etc. It is possible only to get information for particular bitstreams. When the request is made without parameters/references, the blank list is presented (there is no list of all bitstreams in the system available).

Name and description	Value and notes
Base URI:	`/bitstream/{id}/receive`
Description:	Returns checksum of bitstream
HTTP method:	`GET`
Required parameters:	{`id`}: bitstreamitem id
Response formats:	`binary`
Status codes	200: OK 400: bad request 401: Unauthorized 403: Forbidden 500: internal server error
Response details	Receive full bitstream

User oriented functions

Name and description	Value and notes
Base URI:	/users?query=`query`&idOnly=false
Description:	Returns list containing id, name and email of persons (optionally matching a query)
HTTP method:	`GET`
Optional parameters:
Sorting fields supported:	`id, name, lastname, fullname, language`: sorting properties of user(submitter) supported
Response formats:	`json`, `xml`
Status codes	200: OK 204: no content 400: bad request 500: internal server error
Response details	List with information on particular user. Additionaly only identifiers are sent if idOnly is true.

Statistical info

Name and description	Value and notes
Base URI:	`/stats`
Description:	Returns general statistics
HTTP method:	`GET`
Response formats:	`json`, `xml`
Status codes	200: OK 400: bad request (if there is no stats package available) 500: internal server error
Response details	Returns cummulative list of statistics data for the system currently available

Items ingestion

Administrative tasks

Workflow related tasks

Visitors' suggestions or wishes

Here the visitors and stakeholders can insert their suggestions or describe the needs for their applications in detail.

Integration in the system

It is planned to consult two external subjects for cooperation and the assistance during integration process (LMS and national library internal automation process). More information coming soon - awaiting approval of other parties.

Documentation tasks

Although provided software module exposes basic documentation automatically to the end user, in order to make it easier for other developers and users the documentation in the following forms is additionaly to be provided:

Confluence pages, current location
integrated documentation in PDF form (manual)
short slides containing technology overview, advocacy/facts, configuration and usage guideliens and examples
code will be additionally commented

Example of usage

At the end of the current stage of this project as a bonus task (if time constraints allow) the examples of usage will be provided for several languages, the use-cases will be presented (example of integration in other software, e.g. LMS) and optionally simple client system demonstrating UI customization will be demonstrated (e.g. Flex or JavaFX like).

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GSOC10 - DSpace REST API