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Patrons Account Information API (PAIA)

Jakob Voß

2016-12-05 (version 1.3.0+2)

Table of Contents

1 Introduction

The Patrons Account Information API (PAIA) is a HTTP based programming interface to access library patron information, such as loans, reservations, and fees. Its primary goal is to provide patron access for discovery interfaces and other third-party applications to integrated library system, as easy and open as possible.

1.1 Synopsis

PAIA consists of two independent parts:

Authentication in PAIA is based on OAuth 2.0 (RFC 6749) with bearer tokens (RFC 6750) over HTTPS (RFC 2818).

1.2 Status of this document

This specification has been created collaboratively based on use cases and taking into account existing related standards and products of integrated library systems (ILS), such as NISO Circulation Interchange Protocol (NCIP), SIP2, [X]SLNP,1 DLF-ILS recommendations, and VuFind ILS.

All sources and updates can be found in a public git repository at http://github.com/gbv/paia. See the list of releases at https://github.com/gbv/paia/releases for functional changes. The master file paia.md is written in Pandoc’s Markdown. HTML version of the specification is generated from the master file with makespec. The specification can be distributed freely under the terms of CC-BY-SA.

Additional information and references about PAIA can be found in the public PAIA Wiki at https://github.com/gbv/paia/wiki.

1.3 Conformance requirements

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

A PAIA server MUST implement PAIA core and it MAY implement PAIA auth. If PAIA auth is not implemented, another way SHOULD BE documented to distribute patron identifiers and access tokens. A PAIA server MAY support only a subset of methods but it MUST return a valid response or an error response on every method request, as defined in this document.

2 Basics

2.1 API methods

Each API method is accessed at a unique URL with a HTTP verb GET, POST, or PATCH:

PAIA core PAIA auth
GET/PATCH patron: general patron information POST login: get access token
GET items: current loans, reservations, … POST logout: invalidate access token
POST request: new reservation, delivery, … POST change: modify credentials
POST renew: existing loans, reservations, …
POST cancel: requests, reservations, …
GET fees: paid and open charges

All supported API method URLs MUST also be accessible with HTTP verb OPTIONS. All API methods with HTTP verb GET MAY also be accessible with HTTP verb HEAD.

API method URLs share a common base URL for PAIA core methods and common base URL for PAIA auth methods. A server SHOULD NOT provide additional methods at these base URLs and it MUST NOT propagate additional methods at these base URLs as belonging to PAIA.

Base URLs of PAIA auth and PAIA core are not required to share a common host, nor to include the URL path core/ or auth/. In the following, the base URL https://example.org/core/ is used for PAIA core and https://example.org/auth/ for PAIA auth.

For security reasons, PAIA methods MUST be requested via HTTPS only. A PAIA client MUST NOT ignore SSL certificate errors; otherwise access token (PAIA core) or even password (PAIA auth) are compromised by the client.

2.2 Access tokens and scopes

All PAIA API methods, except PAI auth login and HTTP OPTIONS requests require an access token as a special request parameter. The access token is a so called bearer token as described in RFC 6750. The access token can be sent either as a URL query parameter or in an HTTP header. For instance the following requests both get information about patron 123 with access token vF9dft4qmT:

curl -H "Authorization: Bearer vF9dft4qmT" https://example.org/core/123
curl -H https://example.org/core/123?access_token=vF9dft4qmT

An access token is valid for a limited set of actions, referred to as scope. The following scopes are possible for PAIA core:

read_patron
Get patron information by the patron method.
update_patron / update_patron_name / update_patron_email / update_patron_address
Update parts of the patron information by the update patron method.
read_fees
Get fees of a patron by the fees method.
read_items
Get a patron’s item information by the items method.
write_items
Request, renew, and cancel items by the request, renew, and cancel methods.

For instance a particular token with scopes read_patron and read_items may be used for read-only access to information about a patron, including its loans and requested items but not its fees.

For PAIA auth there is an additional scope:

change_password
Change the password of a patron with the PAIA auth change method.

A PAIA auth server MAY support additional scopes to share an access token with other services.

2.3 Request and response format

Each API method call expects a set of request parameters, given as URL query fields, HTTP headers, or HTTP message body and return a JSON object. Most parts of PAIA core request parameters and JSON response can be mapped to RDF as defined by the PAIA Ontology.

Request parameters and fields of response objects are defined in this document with:

Simple parameter names and response fields consist of lowercase letters a-z only.

Repeatable response fields are encoded as JSON arrays with irrelevant order, for instance:

{ "fee" : [ { ... }, { ... } ] }

Hierarchical JSON structures in this document are referenced with a dot (.) as separator. For instance the subfield/parameter item of the doc element is referenced as doc.item and refers to the following JSON structure:

{ "doc" : [ { "item" : "..." } ] }

2.4 URL query fields

The following special request parameters can be added to any request as URL query fields:

access_token
An access token can be sent either as URL query parameter or as HTTP request header.
callback
A JavaScript callback method name to return JSONP instead of JSON. The callback MUST only contain alphanumeric characters and underscores.
suppress_response_codes
If this parameter is present, all responses MUST be returned with a 200 OK status code, even request errors.

2.5 HTTP headers

Request headers

The following HTTP request headers SHOULD or MAY be sent by PAIA clients in particular:

User-Agent
SHOULD be sent with an appropriate client name and version number
Accept
SHOULD be sent with value application/json
Authorization
MAY be sent to provide an access token
Accept-Language
MAY be sent to indicate preferred languages of textual response fields
Content-Type
SHOULD be sent for HTTP POST with value application/json or for PAIA core and application/x-www-form-urlencoded for PAIA auth.

A OPTIONS preflight request for Cross-Origin Resource Sharing (CORS) MUST include the cross-origin request headers:

Origin
Where the cross-origin request originates from
Access-Control-Request-Method
The HTTP verb of the actual request (GET or POST)
Access-Control-Request-Headers
The value Authorization if access tokens are sent as HTTP headers

Note that PAIA specification does not require clients to respect CORS rules. CORS preflight requests in browsers can be avoided by using request format application/x-www-form-urlencoded and omitting the request headers Accept and Authorization.

Response headers

Both PAIA core and PAIA auth servers SHOULD include the following HTTP response headers:

Content-Language
The language of textual response fields
Content-Type
The value application/json or application/json; charset=utf-8 for JSON response; the value application/javascript or application/javascript; charset=utf-8 for JSONP response
X-OAuth-Scopes
A space-separated list of scopes, the current token has authorized, not limited to PAIA scopes. The change_password scope MAY be omitted in PAIA core responses.
X-Accepted-OAuth-Scopes
A space-separated list of scopes, the current method checks for
Access-Control-Expose-Headers
The value X-OAuth-Scopes X-Accepted-OAuth-Scopes
Access-Control-Allow-Origin
The value * or another origin domain in response to a Origin request header.
WWW-Authenticate
The value Bearer for request errors with status 401
Allow
A list of supported HTTP verbs (e.g. GET, HEAD, OPTIONS) for request errors with status 405

2.6 HTTP message body

All POST and PATCH requests MUST include a HTTP message body.

A PAIA Server MUST also accept the explicit charset UTF8 (content type application/json; charset=utf-8 or application/x-www-form-urlencoded; charset=utf-8). A PAIA Server MAY support additional request charsets such as ISO-8859-1.

2.7 Request errors

Malformed requests, failed authentication, unsupported methods, and unexpected server errors such as backend downtime etc. MUST result in an error response. An error response is returned with an HTTP status code 4xx (client error) or 5xx (server error) as defined in RFC 2616, unless the request parameter suppress_response_codes is given.

Document errors MUST NOT result in a request error but they are part of a normal response.

The response body of a request error is a JSON object with the following fields (compatible with OAuth error response):

name occ data type description
error 1..1 string alphanumerical error code
code 0..1 nonnegative integer HTTP status error code
error_description 0..1 string Human-readable error description
error_uri 0..1 string Human-readable web page about the error

The code field is REQUIRED with request parameter suppress_response_codes in PAIA core. It SHOULD be omitted with PAIA auth requests to not confuse OAuth clients.

The response header of a request error MUST include a WWW-Authenticate header field to indicate the need of providing a proper access token. The field MAY include a short name of the PAIA service with a “realm” parameter:

WWW-Authenticate: Bearer
WWW-Authenticate: Bearer realm="PAIA Core"

The following error responses are expected:2

error code description
not_found 404 Unknown request URL or unknown patron. Implementations SHOULD first check authentication and prefer error invalid_grant or access_denied to prevent leaking patron identifiers.
not_implemented 501 Known but unsupported request URL (for instance a PAIA auth server server may not implement http://example.org/core/change)
invalid_request 405 Unexpected HTTP verb
invalid_request 400 Malformed request (for instance error parsing JSON, unsupported request content type, etc.)
invalid_request 422 The request parameters could be parsed but they don’t match the request method (for instance missing fields, invalid values, etc.)
invalid_grant 401 The access token was missing, invalid, or expired
insufficient_scope 403 The access token was accepted but it lacks permission for the request
access_denied 403 Wrong or missing credentials to get an access token
internal_error 500 An unexpected error occurred. This error corresponds to a bug in the implementation of a PAIA auth/core server
service_unavailable 503 The request couldn’t be serviced because of a temporary failure
bad_gateway 502 The request couldn’t be serviced because of a backend failure (for instance the library system’s database)
gateway_timeout 504 The request couldn’t be serviced because of a backend failure

For instance the following response could result from a request with malformed URIs:

{
  "error": "invalid_request",
  "code": "422",
  "error_description": "malformed item identifier provided: must be an URI",
  "error_uri": "http://example.org/help/api"
}

2.8 Simple data types

The following data types are used to define request and response format:

string
A Unicode string. Strings MAY be empty.
nonnegative integer
An integer number larger than or equal to zero.
boolean
Either true or false. Note that omitted boolean values are not false by default but unknown!
date
A date value in YYYY-MM-DD format. A datetime value with time and timezone SHOULD be used instead, if possible.
datetime

A date value in YYY-MM-DD format, optionally followed by a time value. A time value consists of the letter T followed by hh:mm:ss format, and a timezone indicator (Z for UTC or +hh:mm or -hh:mm) where:

  • YYYY indicates a year (0001 through 9999)
  • MM indicates a month (01 through 12)
  • DD indicates a day (01 through 31)
  • hh indicates an hour (00 through 23)
  • mm indicates a minute (00 through 59)
  • ss indicates a second (00 through 59)

Examples of valid datetime values include 2015-03-20 (a date), 2016-03-09T11:58:19+10:00, and 2017-08-21T12:24:28-06:00.

money
A monetary value with currency (format [0-9]+\.[0-9][0-9] [A-Z][A-Z][A-Z]), for instance 0.80 USD.
email
A syntactically correct email address.
URI
A syntactically correct URI.
account state

A nonnegative integer representing the current state of a patron account. Possible values are:

  1. active
  2. inactive
  3. inactive because account expired
  4. inactive because of outstanding fees
  5. inactive because account expired and outstanding fees

A PAIA server MAY define additional states which can be mapped to 1 by PAIA clients. In JSON account states MUST be encoded as numbers instead of strings.

service status

A nonnegative integer representing the current status in fulfillment of a service. In most cases the service is related to a document, so the service status is a relation between a particular document and a particular patron. Possible values are:

  1. no relation (this applies to most combinations of document and patron, and it can be expected if no other state is given)
  2. reserved (the document is not accessible for the patron yet, but it will be)
  3. ordered (the document is being made accessible for the patron)
  4. held (the document is on loan by the patron)
  5. provided (the document is ready to be used by the patron)
  6. rejected

A PAIA server MUST NOT define any other service status. In JSON service status MUST be encoded as numbers instead of strings.

2.9 Documents

A document is a key-value structure with the following fields:

name occ data type description
status 1..1 service status status (0, 1, 2, 3, 4, or 5)
item 0..1 URI URI of a particular copy
edition 0..1 URI URI of a the document (no particular copy)
requested 0..1 URI URI that was originally requested
about 0..1 string textual description of the document
label 0..1 string call number, shelf mark or similar item label
queue 0..1 nonnegative integer number of waiting requests for the document or item
renewals 0..1 nonnegative integer number of times the document has been renewed
reminder 0..1 nonnegative integer number of times the patron has been reminded
starttime 0..1 datetime date and time when the status began
endtime 0..1 datetime date and time when the status will expire
duedate 0..1 date date when the current status will expire (deprecated)
cancancel 0..1 boolean whether an ordered or provided document can be canceled
canrenew 0..1 boolean whether a document can be renewed
error 0..1 string textual document error, for instance if a request was rejected
condition 0..1 condition condition (only in responses to request, renew, or cancel)
storage 0..1 string textual description of location of the document
storageid 0..1 URI URI of location of the document

For each document at least an item URI or an edition URI MUST be given. Together, item and edition URI MUST uniquely identify a document within the set of documents related to a patron.

The fields starttime and endtime MUST be interpreted as following:

status starttime endtime
0 - -
1 when the document was reserved when the reserved document is expected to be available
2 when the document was ordered when the ordered document is expected to be available
3 when the document was lend when the loan period ends or ended (due)
4 when the document is provided when the provision will expire
5 when the request was rejected -

Note that timezone information is mandatory in these fields. The field duedate is deprecated. Clients SHOULD only use it as endtime if no endtime was given.

If both storage and storageid are given, a PAIA server MUST return identical values of storage for identical id and identical content language. PAIA clients MAY override the value of storage based on storageid and a preferred language.

Unknown document URIs and failed attempts to request, renew, or cancel a document MUST NOT result in a request error. Instead they are indicated by a document error with field error. Form and type of document errors are not specified, so clients SHOULD use these messages for display only.

If condition is given, a PAIA server MUST also include a document error for the same document, for instance the error message “confirmation required”. This allows PAIA clients without support of conditions and conformations to treat conditions as simple, unrecoverable document errors.

An example of a document serialized in JSON is given below. In this case a general document (http://example.org/documents/9876543) was requested an mapped to a particular copy (http://example.org/items/barcode1234567) by the PAIA server. The copy turned out to be lost, so the request was rejected (status 5) at 2014-07-12, 14:07 UTC.

{
   "status":    5,
   "item":      "http://example.org/items/barcode1234567",
   "edition":   "http://example.org/documents/9876543",
   "requested": "http://example.org/documents/9876543",
   "starttime": "2014-07-12T14:07Z",
   "error":     "sorry, we found out that our copy is lost!"
}

The following document could result from a request for an item given by an unknown URI:

{
  "item": "http://example.org/some/uri",
  "error": "item URI not found"
}

2.10 Conditions and confirmations

Conditions and confirmations can OPTIONALLY be used to require or to select from additional options in PAIA core methods request, renew, and cancel. For instance a PAIA server MAY allow to choose among multiple delivery methods or it MAY require to explicitly agree to some terms of services when a special document is requested. A PAIA client without support of conditions and confirmations will always be assigned to the default option or it will experience a condition as document error if no default option is available.

Conditions

A condition is a key-value structure that maps condition types to condition settings.

Conditions can be included in response field condition of a document if the same document also includes a document error in field error. The error SHOULD provide a short description of the condition, for instance “delivery type must be selected” or “confirmation required”.

A condition type is an URI that identifies the purpose of a condition. A PAIA client MUST be able to handle arbitrary condition type URIs. A PAIA server SHOULD support at least the following two condition types:

A condition setting is a key-value structure with the following keys:

name occ data type description
option 1..n condition option list of condition options
multiple 0..1 boolean whether multiple options can be selected
default 0..n URI set of default option identifiers

A missing field multiple MUST be treated equal to a multiple field with value false. The field default MAY be an empty array — this case MUST NOT be confused with a missing field default. All URIs listed in field default MUST also be included as field id of one condition option.

If multiple condition options are given, they SHOULD be ordered, for instance by popularity.

A condition option is a key-value structure with the following keys:

name occ data type description
id 1..1 URI unique identifier of this option
about 1..1 string textual description or label of this option
amount 0..1 money fee implied by chosing this option

A condition setting MUST NOT contain multiple condition options with same id. A PAIA server MUST return identical values of about for identical values of id and identical content language. PAIA clients MAY override the value of about based on id and a preferred language.

Values of amout matching the regular expression /^0+\.00/ MUST be treated equal to no amount and vice versa.

A PAIA server SHOULD use the condition option id http://purl.org/ontology/dso#DocumentService or other URIs from the Document Service Ontology for condition options of type http://purl.org/ontology/paia#FeeCondition. Id and amount of the selected condition option SHOULD later occurr in response to request method fees.

Most simple condition only contain a single condition type. In the following example condition type http://purl.org/ontology/paia#FeeCondition is mapped to a condition setting with one condition option. No default option is given, so an explicit confirmation is required.

{
  "http://purl.org/ontology/paia#FeeCondition": {
    "option": [
      {
        "id": "http://purl.org/ontology/dso#Loan",
        "about": "loan",
        "amount": "0.50 EUR"
      }
    ]
  }
}

The following condition contains two condition types. The first condition type (http://purl.org/ontology/paia#StorageCondition) refers to a list of delivery places. The first place is marked as default and the third place implies a fee. The second condition type (http://example.org/purpose) lists two options which can also be selected together. An empty set is given as default option.

{
  "http://purl.org/ontology/paia#StorageCondition": {
    "option": [
      {
        "id": "http://example.org/locations/pickup-desk",
        "about": "pickup desk"
      },
      {
        "id": "http://example.org/locations/branch",
        "about": "branch office"
      },
      {
        "id": "http://example.org/services/home-delivery",
        "amount": "2.50 EUR",
        "about": "home delivery"
      }
    ],
    "default": [ "http://example.org/locations/pickup-desk" ]
  },
  "http://example.org/purpose": {
    "multiple": true,
    "option": [
      {
        "id": "http://example.org/purpose/research",
        "about": "document usage for research"
      },
      {
        "id": "http://example.org/purpose/leisure",
        "about": "document usage for leisure"
      }
    ],
    "default": [ ]
  }
}

Confirmations

Confirmations can be sent as part of a PAIA core request of methods request, renew, and cancel in field confirm of a document to choose among condition options for selected condition types.

A confirmation is a key-value structure that maps condition types to (possibly empty) sets of identifiers of selected condition options.

This confirmation confirms condition type http://purl.org/ontology/paia#FeeCondition with condition option identified by http://purl.org/ontology/dso#DocumentService and confirms another condition type with two options from the example condition given above:

{
  "http://purl.org/ontology/paia#FeeCondition": [
    "http://purl.org/ontology/dso#DocumentService"
  ],
  "http://example.org/purpose": [
    "http://example.org/purpose/research",
    "http://example.org/purpose/leisure"
  ]
}

Valid confirmations can be empty, which is distinct from a missing confirmation. Confirmations can also contain empty lists of option identifiers:

{ }
{ "http://purl.org/ontology/paia#FeeCondition": [ ] }

How conditions are met

A PAIA server MUST use the following algorithm or an equivalent mechanism to check whether a given condition is met by a given confirmation or by a missing confirm field. If a condition is not met, the server MUST return a document error for the given document.

  1. If no confirmation is given, a default confirmation is created by mapping all condition types to the default values of their condition settings.

  2. All condition types in the conformation are removed, unless they have a correspondence in the condition.

  3. All condition option identifiers in the conformation are removed, unless they also occur in the condition settings of the corresponding condition.

  4. If the confirmation contains multiple condition option identifiers for a condition type that does not have a condition setting with field multiple set to true, all but the first identifier are removed.

  5. The condition is not met, if there is a condition type in the condition without correspondence in the confirmation.

  6. The condition is met if for each condition setting either field default is set to the empty array ([ ]) or the corresponding list of remaining option identifiers in the confirmation is not empty.

To not select any default confirmation options, a PAIA client can send an empty object ({ }).

Non applying condition types or options in a confirmation are ignored, so a PAIA client can choose to always sent some custom default confirmation.

The following condition contains the empty set as default value, so it is met by any confirmation except a confirmation that does not include condition type http://example.org/purpose (for instance { }):

{
  "http://example.org/purpose": {
    "multiple": true,
    "option": [
      { "id": "http://example.org/research", "about": "for research" },
      { "id": "http://example.org/leisure", "about": "for leisure" }
    ],
    "default": [ ]
  }

All other possible confirmations are reduced to one of this cases (the first also used if no confirmation is given):

{ "http://example.org/purpose": [ ] }
{ "http://example.org/purpose": [ "http://example.org/research" ] }
{ "http://example.org/purpose": [ "http://example.org/leisure" ] }
{ "http://example.org/purpose": [ "http://example.org/research", "http://example.org/leisure" ] }

3 PAIA core

Each API method of PAIA core is accessed at a URL that includes the URI escaped patron identifier.

3.1 patron

purpose
Get general information about a patron
HTTP verb and URL
GET https://example.org/core/{uri_escaped_patron_identifier}
scope
read_patron
response fields
name occ data type description
name 1..1 string full name of the patron
email 0..1 email email address of the patron
address 0..1 string freeform address of the patron
expires 0..1 datetime patron account expiry
status 0..1 account state current state (0, 1, 2, or 3)
type 0..n URI list of custom URIs to identify patron types

PAIA server documentation SHOULD refer to a specialized API, such as LDAP, to get more detailed patron information.

GET /core/123 HTTP/1.1
Host: example.org
User-Agent: MyPAIAClient/1.0
Accept: application/json
Authorization: Bearer a0dedc54bbfae4b
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
X-Accepted-OAuth-Scopes: read_patron
X-OAuth-Scopes: read_fees read_items read_patron write_items
{
  "name": "Jane Q. Public",
  "email": "jane@example.org",
  "address": "Park Street 2, Springfield",
  "expires": "2015-05-18",
  "status": 0,
  "type": ["http://example.org/usertypes/default"]
}

3.2 update patron

purpose
Update general information about a patron
HTTP verb and URL
PATCH https://example.org/core/{uri_escaped_patron_identifier}
scopes
update_patron / update_patron_name / update_patron_email / update_patron_address
request parameters
name occ data type description
name 0..1 string new full name of the patron
email 0..1 email new email address of the patron
address 0..1 string new freeform address of the patron
response fields
Same as patron method on success, error otherwise.

This PAIA core method can be used to modify parts of the general patron information: Fields “name”, “email”, and “address” can be changed with scope update_patron for all of these fields, or with the scopes update_patron_name, update_patron_email, and/or update_patron_address for each corresponding field.

This PAIA core method will be introduced with PAIA 1.4.0. A PAIA server MAY chose not not implement this method and return an error response with error code access_denied (403), invalid_request (405), or not_implemented (501) instead.

Update of patron fields expires, status, and type via this method is not supported. To change a patron password see method change of PAIA auth.

PATCH /core/123 HTTP/1.1
Host: example.org
User-Agent: MyPAIAClient/1.0
Accept: application/json
Content-Type: application/json
Authorization: Bearer 08568be488a2539
{
  "email": "janes-new-mail@example.com"
}
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
X-Accepted-OAuth-Scopes: update_patron update_patron_email
X-OAuth-Scopes: read_patron update_patron
{
  "name": "Jane Q. Public",
  "email": "janes-new-mail@example.com",
  "address": "Park Street 2, Springfield",
  "expires": "2015-05-18",
  "status": 0,
  "type": ["http://example.org/usertypes/default"]
}

3.3 items

purpose
Get a list of loans, reservations and other items related to a patron
HTTP verb and URL
GET https://example.org/core/{uri_escaped_patron_identifier}/items
scope
read_item
response fields
name occ data type description
doc 0..n document list of documents (order is irrelevant)

In most cases, each document will refer to a particular copy (doc.item), but users may also have requested (doc.requested) and/or reserved (doc.edition) an edition.

GET /core/123/items HTTP/1.1
Host: example.org
User-Agent: MyPAIAClient/1.0
Accept: application/json
Authorization: Bearer a0dedc54bbfae4b
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
X-Accepted-OAuth-Scopes: read_patron
X-OAuth-Scopes: read_items read_patron
{
  "doc": [{
    "status": 3,
    "item": "http://bib.example.org/105359165",
    "edition": "http://bib.example.org/9782356",
    "about": "Maurice Sendak (1963): Where the wild things are",
    "label": "Y B SEN 101",
    "queue": 0,
    "renewals": 0,
    "reminder": 0,
    "starttime": "2014-05-08T12:37Z",
    "endtime": "2014-06-09",
    "cancancel": false,
  },{
    "status": 1,
    "item": "http://bib.example.org/8861930",
    "about": "Janet B. Pascal (2013): Who was Maurice Sendak?",
    "label": "BIO SED 03",
    "queue": 1,
    "starttime": "2014-05-12T18:07Z",
    "endtime": "2014-05-24",
    "cancancel": true,
    "storage": "pickup service desk",
    "storageid": "http://bib.example.org/library/desk/7",
  }]
}

3.4 request

purpose
Request one or more items for reservation or delivery.
HTTP verb and URL
POST https://example.org/core/{uri_escaped_patron_identifier}/request
scope
write_item
request parameters
name occ data type description
doc 1..n array list of documents requested
doc.item 0..1 URI URI of a particular item
doc.edition 0..1 URI URI of a particular edition
doc.confirm 0..1 confirmation Confirmation
doc.storageid 0..1 URI Requested document location (deprecated)
response fields
name occ data type description
doc 1..n document list of documents (order is irrelevant)

The response SHOULD include the same documents as requested. A client MAY also use the items method to get the service status after request.

The field doc.storageid is deprecated and MUST be ignored if field doc.confirm is given. Otherwise a PAIA core server SHOULD map the value of field doc.storageid (e.g http://example.org/a/location) to a corresponding confirmation in field doc.confirm:

{
  "http://purl.org/ontology/paia#StorageCondition": [
    "http://example.org/a/location"
  ]
}

3.5 renew

purpose
Renew one or more documents usually held by the patron. PAIA servers MAY also allow renewal of reserved, ordered, and provided documents.
HTTP verb and URL
POST https://example.org/core/{uri_escaped_patron_identifier}/renew
scope
write_item
request parameters
doc 1..n array list of documents to renew
doc.item 0..1 URI URI of a particular item
doc.edition 0..1 URI URI of a particular edition
doc.confirm 0..1 confirmation Confirmation
response fields
name occ data type description
doc 1..n document list of documents (order is irrelevant)

The response SHOULD include the same documents as requested. A client MAY also use the items method to get the service status after renewal.

3.6 cancel

purpose
Cancel requests for items.
HTTP verb and URL
POST https://example.org/core/{uri_escaped_patron_identifier}/cancel
scope
write_item
request parameters
name occ data type
doc 1..n array list of documents to cancel
doc.item 0..1 URI URI of a particular item
doc.edition 0..1 URI URI of a particular edition
doc.confirm 0..1 confirmation Confirmation
response fields
name occ data type description
doc 1..n document list of documents (order is irrelevant)

3.7 fees

purpose
Look up current fees of a patron.
HTTP verb and URL
GET https://example.org/core/{uri_escaped_patron_identifier}/fees
scope
read_fees
response fields
name occ data type description
amount 0..1 money sum of all fees. May also be negative.
fee 0..n array list of fees
fee.amount 1..1 money amount of a single fee
fee.date 0..1 date date when the fee was claimed
fee.about 0..1 string textual information about the fee
fee.item 0..1 URI item that caused the fee
fee.edition 0..1 URI edition that caused the fee
fee.feetype 0..1 string textual description of the type of service that caused the fee
fee.feeid 0..1 URI URI of the type of service that caused the fee

A PAIA server MUST return identical values of fee.feetype for identical fee.feeid and identical content language. PAIA clients MAY override the value of fee.feetype based on fee.feeid and a preferred language.

If a fee was caused by a document (fee.item or fee.edition is set) then fee.feeid SHOULD be taken as http://purl.org/ontology/dso#DocumentService if not given and SHOULD be a class URI from the Document Service Ontology otherwise. If the fee was confirmed with a confirmation, the value of fee.feeid SHOULD be the value of the confirmed condition option.

4 PAIA auth

PAIA auth defines three methods for authentication based on username and password. These methods can be used to get access tokens and patron identifiers, which are required to access PAIA core methods. There MAY be additional or alternative ways to distribute and manage access tokens and patron identifiers.

There is no strict one-to-one relationship between username/password and patron identifier/access token, but a username SHOULD uniquely identify a patron identifier. A username MAY even be equal to a patron identifier, but this is NOT RECOMMENDED. An access token MUST NOT be equal to the password of the same user.

A PAIA auth server acts as OAuth authorization server (RFC 6749) with password credentials grant, as defined in section 4.3 of the OAuth 2.0 specification. The access tokens provided by the server are so called OAuth 2.0 bearer tokens (RFC 6750).

A PAIA auth server MUST protect against brute force attacks (e.g. using rate-limitation or generating alerts). It is RECOMMENDED to further restrict access to PAIA auth to specific clients, for instance by additional authorization.

4.1 login

The PAIA auth login method is the only PAIA method that does not require an access token as part of the query.

purpose
Get a patron identifier and access token to access patron information
URL
POST https://example.org/auth/login (in addition a PAIA auth server MAY support HTTP GET requests)
request parameters
name occ data type
username 1..1 string User name of a patron
password 1..1 string Password of a patron
grant_type 1..1 string Fixed value set to “password”
scope 0..1 string Space separated list of scopes

If no scope parameter is given, it is set to the default value read_patron read_fees read_items write_items for full access to all PAIA core methods (see access tokens and scopes).

The response format is a JSON structure as defined in section 5.1 (successful response) and section 5.2 (error response) of OAuth 2.0. The PAIA auth server MAY grant different scopes than requested for, for instance if the account of a patron has expired, so the patron should not be allowed to request and renew new documents.

response fields
name occ data type description
patron 1..1 string Patron identifier
access_token 1..1 string The access token issued by the PAIA auth server
token_type 1..1 string Fixed value set to “Bearer” or “bearer”
scope 1..1 string Space separated list of granted scopes
expires_in 0..1 nonnegative integer The lifetime in seconds of the access token

A successful login request:

POST /auth/login
Host: example.org
User-Agent: MyPAIAClient/1.0
Accept: application/json
Content-Type: application/x-www-form-urlencoded
grant_type=password&username=alice02&password=jo-!97kdl%2B0tt
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
X-OAuth-Scopes: read_patron read_fees read_items write_items
Cache-Control: no-store
Pragma: no-cache
{
  "access_token": "2YotnFZFEjr1zCsicMWpAA",
  "token_type": "Bearer",
  "expires_in": 3600,
  "patron": "8362432",
  "scope": "read_patron read_fees read_items write_items"
}

Response to a rejected login request:

HTTP/1.1 403 Forbidden
Content-Type: application/json; charset=utf-8
Cache-Control: no-store
Pragma: no-cache
WWW-Authenticate: Bearer realm="PAIA auth example"
{
  "error": "access_denied",
  "error_description": "invalid patron or password"
}

4.2 logout

purpose
Invalidate an access token
URL
POST https://example.org/auth/logout (in addition a PAIA auth server MAY support HTTP GET requests)
request parameters
name occ data type description
patron 1..1 string patron identifier
response fields
name occ data type description
patron 1..1 string patron identifier

The logout method invalidates an access token, independent from the previous lifetime of the token. On success, the server MUST invalidate at least the access token that was used to access this method. The server MAY further invalidate additional access tokens that were created for the same patron.

4.3 change

purpose
Change password of a patron
URL
POST https://example.org/auth/change
scope
change_password
request parameters
name occ data type description
patron 1..1 string Patron identifier
username 1..1 string User name of the patron
old_password 1..1 string Password of the patron
new_password 1..1 string New password of the patron
response fields
name occ data type description
patron 1..1 string patron identifier

The server MUST check

A PAIA server MAY reject this method and return an error response with error code access_denied (403) or error code not_implemented (501). On success, the patron identifier is returned.

5 Glossary

access token
A confidential random string that must be sent with each PAIA request for authentication.
document
A concrete or abstract document, such as a work, or an edition.
item
A concrete copy of a document, for instance a particular physical book.
PAIA auth server
HTTP endpoint that implements the PAIA auth specification, so all PAIA auth methods can be accessed at a common base URL.
PAIA core server
HTTP endpoint that implements the PAIA core specification, so all PAIA core methods can be accessed at a common base URL.
patron
An account of a library user
patron identifier
A Unicode string that identifies a library patron account.

6 Security considerations

Security of OAuth 2.0 with bearer tokens relies on correct application of HTTPS. It is known that SSL certificate errors are often ignored just because of laziness. It MUST be clear to all implementors that this breaks the chain of trust and is as secure as sending access tokens in plain text.

To limit the risk of spoiled access tokens, PAIA servers SHOULD put limits on the lifetime of access tokens and on the number of allowed requests per minute among other security limitations.

It is also known that several library systems allow weak passwords. For this reason PAIA auth servers MUST follow appropriate security measures, such as protecting against brute force attacks and blocking accounts with weak passwords or with passwords that have been sent unencrypted.

7 Informative parts

This non-normative section contains additional examples and explanations to illustrate the semantics of PAIA concepts and methods and usage.

7.1 Transitions of service states

Six service status data type values are possible. One document can have different status for different patrons and for different times. The following table illustrates reasonable transitions of service status with time for a fixed patron. For instance some document held by another patron is first requested (0 → 1) with PAIA method request, made available after return (1 → 4), picked up (4 → 3), renewed after some time with PAIA method renew (3 → 3) and later returned (3 → 0).

transition → 0 1: reserved 2: ordered 3: held 4: provided 5: rejected
0 = request request loan request request
1: reserved cancel = available loan available patron inactive, document lost …
2: ordered cancel / = loan available patron inactive, document lost …
3: held return / / renew / /
4: provided not picked up / / loan = patron inactive, …
5: rejected time passed patron active patron active / patron active =

Transitions marked with “/” may also be possible in special circumstances: for instance a book ordered from the stacks (status 2) may turn out to be damaged, so it is first repaired and reserved for the patron meanwhile (status 1). Transitions for digital publications may also be different. Note that a PAIA server does not need to implement all service status. A reasonable subset is to only support 0, 1, 3, and 5.

7.2 Digital documents

The handling of digital documents is subject to frequently asked questions. The following rules of thumb may help:

7.3 PAIA core extensions to non-document services

A future version of PAIA may be extended to support services not related to documents. For instance a patron may reserve a cabin or some other facility. The following methods may be added to PAIA core for this purpose:

services
List non-document services related to a patron - similar to method items.
servicetypes
Get a list of services that a patron may request, each with URI, name, and short description.

8 References

8.1 Normative References

8.2 Informative References

8.3 Revision history

This is version 1.3.0+2 of PAIA specification, last modified at 2016-12-05 with revision c5e4755.

Version numbers follow Semantic Versioning: each number consists of three numbers, optionally followed by + and a suffix:

Releases

Releases with functional changes are tagged with a version number and included at https://github.com/gbv/paia/releases with release notes.

1.4.0 (not released yet)

  • added PAIA core method to update patron

1.3.0 (2015-11-06)

  • introduced conditions and confirmations
  • clarified uniqueness of storage/fee/condition id and textual description
  • removed experimental reference to service ontology

1.2.0 (2015-04-28)

  • PAIA auth MUST support content type application/x-www-form-urlencoded to align with OAuth 2.0 (issue #50)

1.1.0 (2015-04-21)

  • added mandatory HTTP OPTIONS and optional HTTP HEAD requests
  • extended CORS headers (Access-Control-...)
  • fixed name of WWW-Authenticate header
  • removed request field doc.storage and deprecate field doc.storageid
  • improved documentation

1.0.8 (2015-04-16)

  • support content-negotiation for languages (issue #32)
  • allow additional scopes not part of PAIA
  • split PAIA ontology from PAIA specification

1.0.7 (2015-04-14)

  • added patron field type

1.0.6 (2014-11-10)

  • added patron field address

1.0.5 (2014-07-16)

  • added CORS HTTP headers

1.0.4 (2014-07-14)

  • extended definition of datetime fields

1.0.3 (2014-07-11)

  • added document fields starttime and endtime

1.0.1 (2013-11-20)

  • added User-Agent header

Full changelog


  1. The Simple Library Network Protocol (SLNP) and its variant XSLNP is an internal protocol of the the SISIS-Sunrise™ library system, providing access to patron information, among other functionality. OCLC does not allow publication of the specification or public use of SLNP.

  2. The error list was compiled from the HTTP and OAuth 2.0 specifications, the Twitter API, the StackExchange API, and the GitHub API.