EGI AppDB REST API v1.0

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Introduction

This document is intended for developers who want to write applications that interact with the AppDB API over the web using HTTP commands following the REST paradigm. The API is located at http://appdb-pi.egi.eu and it allows information retrieval and modification from third party applications without having to reside on the rich user interface of the AppDB portal. Thus one is given the opportunity to design one's own front-ends.

Getting started

Operations

Starting with version 1.0, the AppDB API features write access as well, by supporting HTTP verbs such as PUT, POST, and DELETE. Verb mappings to data operations follow a CRUD convention, as depicted in the following table:

Operation

HTTP Verb

Create PUT
Read GET
Update POST
Delete DELETE


The API also supports the Listing operation (CRUDL extension), by passing the parameter listmode=listing in the querystring when performing a GET request. Please note that in order to simplify the access model, Update operations are always partial, meaning that properties of the resource that is being updated which are entirely missing from the representation, are ignored (i.e. their state in the backend does not change). Therefore, in order to unset/remove a property, one has to explicitly specify it as NULL, provided that this is permitted. This is the reason why Create and Update CRUD mappings are inverted with regards to what is usually accustomed. Finally, the API also supports the OPTIONS HTTP verb, which returns a list of the operations that are permitted, in principle, for the resource in question.
The base URI for this version of the RESTful API is

http://appdb-pi.egi.eu/rest/1.0/

and requests must be followed by at least one resource name, which may be followed by one or more optional sub-resource names, separated by slashes, as in the examples given bellow:

http://appdb-pi.egi.eu/rest/1.0/applications/
http://appdb-pi.egi.eu/rest/1.0/applications/50/

Response types

Because the API conforms to the REST paradigm, responses to all CRUD operations are always XML document representations of the resource in question. These documents are described by schema files which reside publicly in the web server. All the XML documents are enveloped in a common root element named appdb with attributes that describe request status, such as paging, or errors. These attributes are:

  • count (number) : the count of the entries found in the applications database. In case of paging, where only a subset of the results gets returned, the attribute is left unaffected.
  • pagelength, pageoffset (numbers) : paging data in case the response is a list of resources. More information follows in the next section.
  • datatype (string) : an identifier for the resource data that is enclosed in the response as defined in the XML schema.
  • type (string) : the type of the response. Possible values are:
    • list: A collection of references to entries in the applications' database. In order to obtain the referenced entry, a request should be made using the entry's id.
    • entry: Detailed information about an entry in the applications' database. Paging is never used for this type of response.
  • version (number) : The version of the API that was accessed.
  • error (string) : If an error occurs, this attribute will contain the error message.
  • host, apihost (strings) : the URIs of the host that provided the data and API access, respectively.

Paging and Filtering

The paging mechanism that the API provides, as far as Read/Listing operations are concerned, can be used through two query parameters (if allowed) and can be displayed in the attributes of the root element of the response XML document. The query parameters are:

  • pagelength : defines the count of entries to be displayed in each page.
  • pageoffset : defines the position in the list of entries from which the page will start.

So if the client wants a list of 50 entries and wants to display the first 10, then the parameters should be set as page length=10 and page offset=0. To view the next 10 entries it should change the page offset to 10, for the next 10, it should set page length to 20, etc. One must remember that paging is not valid for all resources, as documented in the query parameters section in the API reference. A final note about paging is that if the client hasn't explicitly enable paging, then the server will default to a preset paging value, in order to reduce load; this value can be retrieved from the relevant attributes of the response’s root node. If the paging parameters were set by the client but the page length exceeds that of the server's default maximum value, then the later is used. Otherwise the page length set by the client will be used.
Moreover, some of the API’s resources support filtering when doing Read/Listing operations; filter expressions may be passed in the querystring by assigning a value to the flt parameter, in order to retrieve just the subset of data that match certain criteria. These filter expressions are strings that may range from simple keywords to complex queries. For more information on the syntax, please refer to FAQ item #13 at the AppDB portal.

API Reference

Below you may find an exhaustive list of the resources v1.0 of the AppDB RESTful API offers. Details and documentation about a resource's representation may be found as XSD annotations inside the appropriate schema file, under the schemata base resource. Note that when performing POST operations, the representation must be passed as a URL-encoded string in the query-string under the parameter data, whereas when performing PUT operations, the representation must be passed as a normal text stream. Representations passed to PUT/POST operations must be enclosed within an appdb:appdb root element, with the appropriate XML namespaces declared, the same way that responses are; nevertheless, this will be omitted in all following examples, in order to reduce clutter.
Also note that since all Update (POST) operations are partial, XML elements that represent properties with a cardinality 0..* must be either

  • omitted, in which case the present state in the backend is left untouched,
  • fully disclosed, in which case entities present in the backend but absent from the POSTed representation are deleted, and vice versa
  • explicitly declared NULL by passing a single instance of the element, with no node value (is of mixed type) and the single attribute xsi:nil with value true, in which case all instances of the entity are erased from the backend.

This way, it is possible to perform modifications to a resource's properties without having to re-declare all instances of other properties with 0..* cardinality, lest they were to be erased. Properties of 0..1 cardinality may also be declared NULL in a similar fasion, in which case their value in the backed becomes undefined.
Moreover, one should also note that the response of all PUT/POST/DELETE operations equivalent to that of a GET operation, with the state of the resource

  • after the operation, in case of PUT/POST
  • before the operation, in case of DELETE

This way, it is possible - as well as advised - to differentiate the response with the input to such operations, in order to verify that the result is what was intended, since properties that are malformed or invalid will not break the operation, but rather be ignored, as long as the representation is well-formed (i.e. passes the XSD compilation).

Application List

  • Resource: applications/
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: yes
  • Public Operations: GET
  • Authenticated Operations: PUT POST

List of all application entries registered in the database

Examples:

  • GET http://appdb.egi.eu/rest/1.0/applications?flt=country:Greece

will return all applications that are in any way related to Greece

  • POST http://appdb.egi.eu/rest/1.0/applications?data={data}&username={username}&passwd={passwd}

where {data} is

<application:application id="123">
&#13;	<application:description>some new description</application:description>
&#13;</application:application>

will update application with ID 123 setting it description to "some new description" and leaving all other properties as-is.
Similarly, providing

<application:application id="123">
&#13;	<application:subdiscipline xsi:nil="true" />
&#13;</application:application>

as {data} will remove all subdiscipline associations from the application

Application Entry

  • Resource: applications/{id}
  • Type: entry
  • Datatype: application
  • Schema: application
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: DELETE

Detailed description of a specific application entry

Moderated Application List

  • Resource: applications/moderated
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET PUT

List of applications that have been moderated some some particular reason, and thus hidden from public view until the issue gets resolved.
Administrative access only.

Examples:

  • echo {data} | PUT http://appdb.egi.eu/rest/1.0/applications/moderated?username={username}&passwd={passwd}

where {data} is

<application:application id="123">
&#13;	<application:moderationReason>copyright violation</application:moderationReason>
&#13;</application:application>

will moderate the application with ID 123, providing "copyright violation" as the reason

Application Publication List

  • Resource: applications/{id}/publications
  • Type: list
  • Datatype: publication
  • Schema: publication
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: PUT POST

List of scientific publications related to an application entry. Publications can be individually managed from this resource (and its sub-resources), or collectively defined directly from application/{id} resources

Application Publication Entry

  • Resource: applications/{id}/publications/{id}
  • Type: entry
  • Datatype: publication
  • Schema: publication
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: DELETE

Detailed description of a publication related to an application entry

Application Tag List

  • Resource: applications/{id}/tags
  • Type: list
  • Datatype: tag
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: PUT

List of tags applied to an application entry

Application Tag Entry

  • Resource: applications/{id}/tags/{id}
  • Type: entry
  • Datatype: tag
  • Schema: application
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: DELETE

Detailed description of a tag applied to an application

Related Application List

  • Resource: applications/{id}/relatedapps
  • Type: list
  • Datatype: relatedapp
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of applications related to an application entry

Application Rating Report

  • Resource: applications/{id}/ratingsreport
  • Type: entry
  • Datatype: ratingreport
  • Schema: appratingreport
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Report on all user ratings of an application entry

External Application Rating Report

  • Resource: applications/{id}/ratingsreport/internal
  • Type: entry
  • Datatype: ratingreport
  • Schema: appratingreport
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Report on user ratings of an application entry made by registered users

Internal Application Rating Report

  • Resource: applications/{id}/ratingsreport/external
  • Type: entry
  • Datatype: ratingreport
  • Schema: appratingreport
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Report on user ratings of an application entry made by anonymous users

Application Rating List

  • Resource: applications/{id}/ratings
  • Type: list
  • Datatype: rating
  • Schema: apprating
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of user rating entries applied to an application entry

Application Rating Entry

  • Resource: applications/{id}/ratings/{id}
  • Type: entry
  • Datatype: rating
  • Schema: application
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Detailed description of a rating entry applied to an application entry

Application State History List

  • Resource: applications/{id}/history
  • Type: list
  • Datatype: history
  • Schema: history
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

List of previous states of an application entry.
Administrative access only.

Application State History Entry

  • Resource: applications/{id}/history/{id}
  • Type: entry
  • Datatype: history
  • Schema: history
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

Detailed description of a previous state of an application entry.
Administrative access only.

Bookmarked Application List

  • Resource: people/{id}/applications/bookmarked
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET PUT

List of application entries bookmarked by a user

Bookmarked Application Entry

  • Resource: people/{id}/applications/bookmarked/{id}
  • Type: entry
  • Datatype: application
  • Schema: application
  • Filtering: N/A
  • Public Operations: none
  • Authenticated Operations: GET DELETE

Detailed description of an application entry bookmarked by a user

Editable Application List

  • Resource: people/{id}/applications/editable
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

List of application entries that a user has permission to edit

Owned Application List

  • Resource: people/{id}/applications/owned
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

List of application entries that a user holds ownership of

Associated Application List

  • Resource: people/{id}/applications/associated
  • Type: list
  • Datatype: application
  • Schema: application
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

List of application entries that a user is associated to, as a member of the application's contact list

People List

  • Resource: people/
  • Type: list
  • Datatype: person
  • Schema: person
  • Filtering: yes
  • Public Operations: GET
  • Authenticated Operations: PUT POST

List of users (people) that have registered with the database

Person Entry

  • Resource: people/{id}
  • Type: entry
  • Datatype: person
  • Schema: person
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Detailed description of a user entry

Regional Information List

  • Resource: regional/
  • Type: list
  • Datatype: regional
  • Schema: regional
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of countries, regions, and service providers participating in the EGI project and available to application and user entries

Application Category List

  • Resource: categories/
  • Type: list
  • Datatype: category
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of category types available for application entries

Discipline/Subdiscipline List

  • Resource: disciplines/
  • Type: list
  • Datatype: discipline
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of discipline and subdiscipline types available for application entries

Middleware List

  • Resource: middlewares/
  • Type: list
  • Datatype: middleware
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of grid middlewares supported by application entries and VOs

Application Status List

  • Resource: statuses/
  • Type: list
  • Datatype: status
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of status states available to application entries

VO List

  • Resource: vos/
  • Type: list
  • Datatype: vo
  • Schema: vo
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of VOs registered with the EGI Operations Portal and available to application entries

VO Entry

  • Resource: vos/{id}
  • Type: entry
  • Datatype: vo
  • Schema: vo
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

Detailed description of a VO registered with the EGI Operations Portal and available to application entries

User Role List

  • Resource: roles/
  • Type: list
  • Datatype: role
  • Schema: person
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of user roles available, which define base user privileges

Available Tag List

  • Resource: tags/
  • Type: list
  • Datatype: tag
  • Schema: application
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of all tag entries that have been attached at least once on any application entry

Contact Type List

  • Resource: contacttypes/
  • Type: list
  • Datatype: tag
  • Schema: person
  • Filtering: no
  • Public Operations: GET
  • Authenticated Operations: none

List of contact types available to user contact information entries

Application Filter Normalization

  • Resource: applications/filter/normalize
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Validates and normalizes a filter expression for application searches, defined by the querystring parameter flt

Application Filter Reflection

  • Resource: applications/filter/reflect
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Returns a nested representation of the filtering expression specifiers available to application searches

Person Filter Normalization

  • Resource: people/filter/normalize
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Validates and normalizes a filter expression for user searches, defined by the querystring parameter flt

Person Filter Reflection

  • Resource: people/filter/reflect
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Returns a nested representation of the filtering expression specifiers available to user searches

VO Filter Normalization

  • Resource: vos/filter/normalize
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Validates and normalizes a filter expression for VO searches, defined by the querystring parameter flt

VO Filter Reflection

  • Resource: vos/filter/reflect
  • Type: entry
  • Datatype: filter
  • Schema: filter
  • Filtering: N/A
  • Public Operations: GET
  • Authenticated Operations: none

Returns a nested representation of the filtering expression specifiers available to VO searches

Dissemination Log List

  • Resource: dissemination/
  • Type: list
  • Datatype: dissemination
  • Schema: dissemination
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

List of dissemination messages that have been dispatched to registered users.
Administrative access only.

Dissemination Log Entry

  • Resource: dissemination/{id}
  • Type: entry
  • Datatype: dissemination
  • Schema: dissemination
  • Filtering: no
  • Public Operations: none
  • Authenticated Operations: GET

Detailed description of a dissemination message that has been dispatched to registered users.
Administrative access only.