Difference between revisions of "API:EPrints/Apache/CRUD"

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Revision as of 09:06, 2 April 2012

EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects


Latest Source Code (3.3, 3.2) | Revision Log | Before editing this page please read Pod2Wiki




$crud = EPrints::Apache::CRUD->new(
		repository => $repo,
		request => $r,
		datasetid => "eprint",
		dataobjid => "23",


The CRUD (Create/Read/Update/Delete) module provides the Web API for manipulating content on the server. The API is an AtomPub implementation that exposes Import and Export plugins via simple URLs and HTTP content type negotiation.

You should use the <link> entries in the repository's home page to locate the CRUD endpoint, as they may change in the future:

  <link rel="Sword" href="https://myrepo/sword-app/servicedocument" />
  <link rel="SwordDeposit" href="https://myrepo/id/contents" />


Create a new eprint based on a single file:

  curl -x POST \
    -i \
    -u user:password \
    -d 'Hello, World!' \
    -H 'Content-Type: text/plain' \
  HTTP/1.1 201 Created
  Content-Type: application/atom+xml;charset=utf-8

Add a file to an existing eprint:

  curl -X POST \
    -i \
    -u user:password \
    -d 'Hello, World!' \
    -H 'Content-Disposition: attachment; filename=hello.txt' \
    -H 'Content-Type: text/plain' \
  HTTP/1.1 201 Created
  Content-Type: application/atom+xml;charset=utf-8

Get an eprint's metadata in Atom XML:

  curl -X GET \
    -i \
    -u user:password \
    -H 'Accept: application/atom+xml' \
  HTTP/1.1 200 OK
  Content-Type: application/atom+xml;charset=utf-8

Get the list of contents (documents) of an eprint in Atom XML:

  curl -X GET \
    -i \
    -u user:password \
    -H 'Accept: application/atom+xml' \
  HTTP/1.1 200 OK
  Content-Type: application/atom+xml;charset=utf-8

HTTP Content Negotiation

GET/HEAD requests are processed using Export plugins. POST/PUT requests are processed using Import plugins.

When GETing, your repository should support at least:

  application/vnd.eprints.data+xml - EPrints XML
  application/atom+xml - Atom XML

Depending on the object type requested (eprint, document etc.) additional formats may be available. These are defined by the 'mime-type' in the plugin. See EPrints::Plugin::Import/accept

EPrint objects are always available as text/html, which will result in a 303 Redirect to the EPrint's abstract page or, if the EPrint is not public, the View page.

Requesting the /contents of a Document will return the content of the main file. Requesting a File with no Accept header (or '*/*') will return the file content.

When creating new records via POST content negotiation is performed against the Import plugins. If no Import plugin supports the given Content-Type the content will be treated as binary and stored in a new, blank object. The returned Atom entry will describe the new object (e.g. the root 'eprint' object, in which the new document and file were created).

If the POSTed content is in a recognised format the resulting object(s) will depend on what the Import plugin outputs. This may be a single object, if the output is only an object, or an object plus content file(s).

If no Content-Type is given the MIME type defaults to application/octet-stream. If no Content-Disposition with a 'filename' argument is given the filename will be set to 'main.bin'.

Updating complex objects using PUT

EPrint objects contain zero or more documents, which each contain zero or more files. When you update (PUT) an EPrint object the contained documents will only be replaced if the Import plugin defines new documents e.g. the Atom Import plugin will never define new documents so PUTing Atom content will only update the EPrint's metadata. PUTing EPrints XML will replace the documents if you include a <documents> XML element.

PUTing to /contents will always replace all contents e.g. PUTing to /eprint/23/contents is equivalent to DELETE /eprint/23/contents then POST /eprint/23/contents.


  • /id/contents GET,HEAD,OPTIONS,POST
Requires authentication.
GET a list of the eprints owned by the user. POST to create a new EPrint object.
  • /id/[datasetid]/[dataobjid] DELETE,GET,HEAD,OPTIONS,PUT
Requires authentication depending on user's privileges and object visibility.
GET an object's metadata or, for File objects, the file content. PUT to replace the metadata and/or contents (see Updating complex objects using PUT). If the object does not exist will attempt to create it with the given dataobjid (requires 'upsert' privilege).
  • /id/[datasetid]/[dataobjid]/contents DELETE,GET,HEAD,OPTIONS,POST,PUT
Requires authentication depending on user's privileges and object visibility.
GET the logical contents of the object: documents for eprints or files for documents. PUT to replace the existing contents or POST to add to the existing contents.


Browsers only allow GET and POST requests. To perform other requests use the 'X-Method' header with POST to specify the actual method you want.

  POST /id/eprint/23 HTTP/1.1
  X-Method: PUT



$repo = $crud->repository()

Returns the current repository.


$r = $crud->request()

Returns the current Apache2::RequestUtil.


$method = $crud->method()

Returns the HTTP method.


$scope = $crud->scope()

Returns the scope of the action being performed.


$dataset = $crud->dataset()

Returns the current dataset (if any).


$dataobj = $crud->dataobj()

Returns the current dataobj (if any).


$field = $crud->field()

Returns the current field (if available);


$headers = $crud->headers()

Get the processed headers.


@verbs = $crud->options()

Returns the available HTTP verbs for the current request.


$plugin = $crud->plugin()

Returns the current plugin (if available).


$bool = $crud->is_write()

Returns true if the request is not a read-only method.


$accept_type = $crud->accept_type()

Returns the EPrints type for the current request.


$rc = $crud->check_packaging()

Check the Packaging header is ok, if given.


$list = $crud->parse_input( $plugin, $f [, %params ] )

Parse the content submitted by the user using the given $plugin. $f is called by epdata_to_dataobj to convert epdata to a dataobj.  %params are passed to the plugin's input_fh method.

Returns undef on error.


@plugins = $crud->import_plugins( [ %params ] )

Returns all matching import plugins against %params ordered by descending 'q' score.


@plugins = $crud->export_plugins( [ %params ] )

Returns all matching export plugins against %params ordered by descending 'q' score.


$plugin = $crud->content_negotiate_best_plugin()

Work out the best plugin to export/update an object based on the client-headers.





Copyright 2000-2011 University of Southampton.

This file is part of EPrints http://www.eprints.org/.

EPrints is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

EPrints is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with EPrints. If not, see http://www.gnu.org/licenses/.