Road vehicles — Extended vehicle (ExVe) web services — Part 2: Access

This document defines how to access resources on a web-services interface of an offering party using the Hypertext Transfer Protocol Secure (HTTPS). Resources can be accessed through request/reply and/or requested to be pushed. The Representational State Transfer (REST) architectural pattern is chosen as a common way to format resource paths both for request/reply and push. Some specific extensions to this pattern are defined to allow for asynchronous resource requests, such as, for example, forcing readouts of data from a connected vehicle.

Véhicules routiers — Web services du véhicule étendu (ExVe) — Partie 2: Accès

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Published
Publication Date
29-Nov-2021
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6060 - International Standard published
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30-Nov-2021
Completion Date
30-Nov-2021
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INTERNATIONAL ISO
STANDARD 20078-2
Second edition
2021-11
Road vehicles — Extended vehicle
(ExVe) web services —
Part 2:
Access
Véhicules routiers — Web services du véhicule étendu (ExVe) —
Partie 2: Accès
Reference number
ISO 20078-2:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 20078-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 20078-2:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms, definitions and abbreviated terms .............................................................................................................................. 1

3.1 Terms and definitions ...................................................................................................................................................................... 1

3.2 Abbreviated terms .............................................................................................................................................................................. 1

4 Representational state transfer-based interface ............................................................................................................. 1

4.1 General ........................................................................................................................................................................................................... 1

4.1.1 Introduction ........................................................................................................................................................................... 1

4.1.2 Request/reply ....................................................................................................................................................................... 2

4.1.3 Push................................................................................................................................................................................................ 2

4.1.4 Push with subsequent request/reply............................................................................................................... 4

4.1.5 Requirements ........................................................................................................................................................................ 6

4.2 Resources .................................................................................................................................................................................................... 7

4.3 Subscription profiles ...................................................................................................................................................................... 11

4.4 HTTP header fields .......................................................................................................................................................................... 20

4.5 Media types ............................................................................................................................................................................................ 21

4.6 Resource versioning ....................................................................................................................................................................... 21

4.7 Resources and web services .................................................................................................................................................... 22

4.7.1 General .....................................................................................................................................................................................22

4.7.2 Examples ................................................................................................................................................................................ 22

4.8 Rate limits ................................................................................................................................................................................................ 23

4.9 HTTP methods ..................................................................................................................................................................................... 24

4.10 HTTP response status codes ...................................................................................................................................................25

4.11 Error messaging ................................................................................................................................................................................. 26

4.12 Interaction pattern ..........................................................................................................................................................................29

4.12.1 Asynchronous ....................................................................................................................................................................29

4.13 Resource discovery.......................................................................................................................................................................... 33

4.14 Capability discovery .......................................................................................................................................................................34

5 Container management API ..................................................................................................................................................................35

5.1 General ........................................................................................................................................................................................................ 35

5.2 Container management operations ................................................................................................................................... 35

Annex A (informative) Container management API specification ....................................................................................45

Annex B (normative) Container management OpenAPI specification .........................................................................64

Annex C (normative) OpenAPI specification for container push notifications ...................................................65

Bibliography .............................................................................................................................................................................................................................66

iii
© ISO 2021 – All rights reserved
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ISO 20078-2:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,

Data communication.

This second edition cancels and replaces the first edition (ISO 20078-2:2019), which has been

technically revised.
The main changes are as follows:

— added definition of a push method, allowing the offering party to push resources to the accessing

party according to subscription;

— added definition of reusable subscription profiles, used to store URI locations and authorization

information from the accessing party and used by offering party to push subscribed resources;

— defined requirements for container management API;
— added Annex A and digital Annex B describing container management API;
— revised error format;
— redefined resource versioning.
A list of all parts in the ISO 20078 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO 20078-2:2021(E)
Road vehicles — Extended vehicle (ExVe) web services —
Part 2:
Access
1 Scope

This document defines how to access resources on a web-services interface of an offering party using

the Hypertext Transfer Protocol Secure (HTTPS). Resources can be accessed through request/reply

and/or requested to be pushed.

The Representational State Transfer (REST) architectural pattern is chosen as a common way to format

resource paths both for request/reply and push. Some specific extensions to this pattern are defined

to allow for asynchronous resource requests, such as, for example, forcing readouts of data from a

connected vehicle.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 20078-1, Road vehicles — Extended vehicle (ExVe) web services — Part 1: Content and definitions

ISO 8601 (all parts), Date and time — Representations for information interchange

3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20078-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.2 Abbreviated terms

For the purposes of this document, the abbreviated terms given in ISO 20078-1 apply.

4 Representational state transfer-based interface
4.1 General
4.1.1 Introduction

There are three different ways to access resources for the accessing party, request/reply, push, and

push with a subsequent request/reply. Request/reply is the recommended method, but push can be

used when needed. In most cases only one method is used for a particular resource, but sometimes both

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ISO 20078-2:2021(E)

request/reply and push are needed. Latency, message size and frequency are examples of requirements

to consider when selecting between request/reply, push, and push with subsequent request/reply.

4.1.2 Request/reply

Figure 1 shows an example of request/reply sequence, where the accessing party requests a resource

using HTTP GET and the offering party returns it in the payload.
Figure 1 — Request/reply example
4.1.3 Push

Figure 2 shows an example of push sequence, where the accessing party initiates a push of a resource

using HTTP POST. The offering party confirms the subscription and starts to push the resource using

HTTP POST. Figure 2 shows an example where the push is done two times.
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ISO 20078-2:2021(E)
Figure 2 — Push example

Figure 3 shows an example of push sequence, where there is no explicit initiation of the push from the

accessing party. It is instead initiated by for instance rules or configuration at the offering party. It is

outside the scope of this document to describe how this is agreed between the accessing party and the

offering party.
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ISO 20078-2:2021(E)
Figure 3 — Push example without explicit initiation
4.1.4 Push with subsequent request/reply

Figure 4 shows an example of push with subsequent request/reply, where the accessing party initiates

a push of a resource using HTTP POST. The offering party confirms the subscription and starts to push

the resource reference using HTTP POST. The accessing party uses the resource reference to request

the resource from the offering party.
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ISO 20078-2:2021(E)
Figure 4 — Push with subsequent request/reply example

Figure 5 shows an example of push with subsequent request/reply, where there is no explicit initiation

of the push from the accessing party. It is instead initiated by, for instance, rules or configuration at

the offering party. It is outside the scope of this document to describe how this is agreed between the

accessing and the offering party.
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ISO 20078-2:2021(E)

Figure 5 — Push with subsequent request/reply example without explicit initiation

4.1.5 Requirements
[9] [6][7]

The following defines the requirements on a REST -based web service interface using HTTPS

based on transport layer security (TLS) to give the accessing party secure access to resources provided

by the offering party. The requirements in this document are valid both for request/reply and push

unless otherwise stated.

REQ_04_01_01 The REST-based web services interface implementation shall use HTTPS as the

transport protocol with TLS.

REQ_04_01_02 HTTP shall only be used with version 1.1 or higher compatible versions.

REQ_04_01_03 TLS shall only be used with version 1.2 or higher versions.

REQ_04_01_04 The request/reply REST web service shall be a strict client-server interaction,

where the accessing party (client) sends a request and the offering party (server)

sends a response.
NOTE Resources can be transferred both in the request and the response.

REQ_04_01_05 The request/reply REST implementation shall be stateless; i.e. the offering party

server shall not maintain any accessing party client context or session information.

Due to REQ_04_01_05, each request-response pair is handled independently from one another. Each

client request by the accessing party contains all information required by the server of the offering

party to successfully respond to the request, including a representation of the client state when

necessary.
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ISO 20078-2:2021(E)

REQ_04_01_06 A push initiation REST web service shall be a strict client-server interaction, where

the accessing party (client) sends a request and the offering party (server) sends a

response.

REQ_04_01_07 The push REST web service shall be a strict client-server interaction, where the

offering party (client) sends a request and the accessing party (server) sends a
response.
4.2 Resources

REQ_04_02_01 Information on the server shall be exposed as resources expressed as plural nouns.

NOTE 1 This holds true even when the resource is only available one time on a connected vehicle (e.g.

"odometers").

REQ_04_02_02 The exposed resources shall be uniquely identified in the form of Uniform Resource

Identifiers (URIs).

The resources, the resource groups or the containers, and how to apply those on a specific presentation

or application layer of the accessing party are described in ISO 20078-1. How an accessing party

authenticates and how it is authorized for access to resources is described in ISO 20078-3.

REQ_04_02_03 The offering party shall define the base URIs of the web services offered by the

offering party.
Table 1 — Examples of possible ExVe-based URIs
Resource Description
https:// {example .com}/ exve/ URI based on sub directory
https:// exve .{example .com}/ URI based on sub domain

REQ_04_02_04 The offering party shall comply with the URI resource paths defined by specific

ExVe standard applications.
Table 2 — Examples of possible ExVe resource URIs
Resource Description
{base_URI}/{resourcePath} Resources based on path
{base URI}/vehicles A list of the available vehicles as defined by
authorization context

{base URI}/vehicles/{vehicleId}/dtcReadouts/ Read all Diagnostic Trouble Codes for a spe-

cific vehicle

{base URI}/vehicles/{vehicleId}/ecus/{ecuId}/dtcReadouts/ Read all Diagnostic Trouble Codes for a spe-

cific ECU of a specific vehicle

There are two primary elements defining an URI: entities and resources (Table 2). Entities are the

fundamental objects representing, e.g. vehicles, ECUs, drivers and fleets. Resources are the actual data,

aggregated information or functionalities associated with an entity and a specific use case.

REQ_04_02_05 Resources shall be named and described.
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ISO 20078-2:2021(E)

EXAMPLE Fuel level can be an example of a single data item resource, vehicle position can be an aggregated

resource consisting of several data items (e.g. latitude, longitude, sample time) and lock and unlock the vehicle

can be a functionality resource.

REQ_04_02_06 The offering party should have the possibility to extend resources, but shall not be

able to reduce resources.

Thus, by REQ_04_02_06 it is not possible to remove data items from a resource, other than through an

update of the underlying use case specification. It is however possible to add data items to a resource

(i.e. versioning).

REQ_04_02_07 Aggregated resources shall only include or cross-reference necessary data items

for the complete and correct operation of the related use case.

NOTE 2 REQ_04_02_07 ensures an accessing party only receives data items necessary for fulfilling the

intended need and nothing else when accessing the resource (i.e. data economy).
See also ISO 20078-1:2021, 8.3, for further details.

REQ_04_02_08 A resource within an already existing use case should not be redefined.

An application may extend the recommended patterns below if none of them meets the needs of the use

case.

REQ_04_02_09 Each use case shall define how the HTTP operations GET, POST, PUT, PATCH, and

DELETE are supported for each defined resource and what the response for each
operation is.
REQ_04_02_10 All URI elements shall be written in lower camel case notation.

NOTE 3 The {baseURI} in following patterns refers to the offering party root URI (see Table 3).

Table 3 — Examples of base URI expresses REQ_04_02_09 and REQ_04_02_01
Normative generic format {baseURI}/{entities}
Example {baseURI}/vehicles
Request a list of all vehicles available to the accessing party.
REQ_04_02_11 Relations of entities shall be expressed using subresources.
NOTE 4 See Table 4.
Table 4 — Examples of sub-URI’s expresses REQ_04_02_11 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/{ID}/{entities2}/{ID2}
Example {baseURI}/fleets/12/vehicles/456
Request information on vehicle with id 456 of fleet with id 12.
{baseURI}/vehicles/456/ecus/789
Request information on ECU with id 789 of vehicle with id 456.

REQ_04_02_12 A resource shall be placed after the entity to which it belongs in the URI.

© ISO 2021 – All rights reserved
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ISO 20078-2:2021(E)
NOTE 5 See Table 5.
Table 5 — Examples of descriptive URI’s expresses REQ_04_02_12 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/{ID}/{resource}
Example {baseURI}/vehicles/123/positions
Request all positions for vehicle with id 123.
{baseURI}/vehicles/456/odometers
Request the odometer value for vehicle with id 456.
{baseURI}/vehicles/456/tirePressures
Request tire pressures of all wheels on the vehicle with id 456.

REQ_04_02_13 If filtering of the response is needed, query parameters shall be used.

NOTE 6 Several query parameters can be added to a request.
NOTE 7 See Table 6.

Table 6 — Examples of filtering responses expresses REQ_04_02_13 and REQ_04_02_01

Normative generic format {baseURI}/{entities}?{filter}={filterValue}
{baseURI}/{entities}?{filter}={filterValue}&{filter2}={filterValue2}
Example {baseURI}/vehicles?ignitionState=on
Request all vehicles with ignition on.
{baseURI}/vehicles/123/positions?startDate=...&endDate=...
Request the positions for vehicle with id 123 registered in given date span in
the ISO 8601 series date-time format.
REQ_04_02_14 If sorting is needed, query parameters shall be used.
NOTE 8 See Table 7.
Table 7 — Examples of query parameters expresses REQ_04_02_14 and REQ_04_02_01
Normative generic format {baseURI}/{entities}?{sorting}={sortingValue}
{baseURI}/{entities}?{sorting}={sortingValue}&{sorting2}={sortingValue2}
Example {baseURI}/vehicles?sortField=id&sortOrder=asc

REQ_04_02_15 If selection of subsets of resources is needed, query parameters shall be used.

NOTE 9 See Table 8.
Table 8 — Examples of query parameters for subsets expresses REQ_04_02_15 and
REQ_04_02_01
Normative generic format {baseURI}/{entities}?{id}={ID}
{baseURI}/{entities}?{id}={ID}&{id2}={ID2}
Example {baseURI}/vehicles?id=123&id=124
{baseURI}/vehicles?id=YS2RX20001754836
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ISO 20078-2:2021(E)

Identifiers may come in multiple formats including, but not limited to, VIN or pseudonymized IDs.

REQ_04_02_16 Pseudonymized IDs may be simple numerical IDs, UUIDs or any other alphanumerical

scheme.
NOTE 10 See Table 9.
Table 9 — Examples of pseudonymized IDs represented by numerical IDs expresses
REQ_04_02_16 and REQ_04_02_01
Normative generic {baseURI}/{entities}?{id}={ID}
format
{baseURI}/{entities}?{id}={ID}&{id2}={ID2}

Example {baseURI}/vehicles?id=ce5d5e3d-28bc-475f-8ef7-b5cb9c8039d4&id=f95ce756-42fc-

48b2-8873-86553f6df5cc
{baseURI}/vehicles?id=456
REQ_04_02_17 For large resource responses pagination may be used.
NOTE 11 See Table 10.
Table 10 — Examples of pagination expresses REQ_04_02_17 and REQ_04_02_01
Normative generic format {baseURI}/{entities}?start={value}&limit={count}
Example {baseURI}/vehicles?start=20&limit=10

REQ_04_02_18 A GET request on the returned location may return the total amount of results. If

used, it shall be part of the message body using the keyword “exveTotal”.
EXAMPLE The following example expresses REQ_04_02_18:
"results": {
"exveTotal": "150",
… }

REQ_04_02_19 If wildcards are used, a wildcard (*) shall access all subentities or resources of all

parent entities.
NOTE 12 See Table 11.
Table 11 — Examples of wildcards in URIs expresses REQ_04_02_19 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/*/{entities2}
Example {baseURI}/vehicles/*/positions
Request all positions for all vehicles.
{baseURI}/vehicles/*/ecus
Request all ECU’s of all vehicles.
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ISO 20078-2:2021(E)

REQ_04_02_20 If wildcards are used, a wildcard (*) may be combined with other filtering, includ-

ing IDs, to access a smaller number of entities.
NOTE 13 See Table 12.

Table 12 — Examples of wildcards in URIs while filtering by IDs expresses REQ_04_02_20 and

REQ_04_02_01

Normative generic {baseURI}/{entities}/*/{resource}?{id}={ID}&{id2}={ID2}&{filter}={filterValue}&{-

format filter2}={filterValue2}
Example {baseURI}/vehicles/*/odometers?id=456&id=789& startDate=...&endDate=...

Request all odometer values from vehicles with id 456 and 789 registered within the

given time span in the ISO 8601 series date-time format.

REQ_04_02_21 For fully anonymized access, no entity IDs shall be used in the URIs.

NOTE 14 See Table 13.

Table 13 — Examples of an anonymized access expresses REQ_04_02_21 and REQ_04_02_01

Normative generic format {baseURI}/{entities}/{entities2}
Example {baseURI}/vehicles/hazardWarnings?isActive=true
REQ_04_02_22 A push resource shall be suffixed with subscriptions.
NOTE 15 See Table 14.
Table 14 — Examples of push resources regarding REQ_04_02_22
Normative generic format {baseURI}/{resource}Subscriptions
Example POST {baseURI}/positionSubscriptions?vehicleId=123
Subscribe to positions for vehicle with id 123.
GET {baseURI}/positionSubscriptions
Request a list of all position subscriptions.
POST {baseURI}/vehicles/456/tirePressureSubscriptions?pressure=low
Subscribe to low tire pressures of all wheels on the vehicle with id 456.

REQ_04_02_23 The accessing party shall define the base URIs of the web services offered by the

accessing party. (Compare with REQ_04_02_03).
4.3 Subscription profiles

Push of subscribed resources requires URI locations and authorization information from the accessing

party. This information is stored in subscription profiles. Subscription profiles can be created in a

separate step before creating subscriptions or directly when creating a subscription. In both cases the

subscription profile will be assigned an id and can be reused by any number of subscriptions.

© ISO 2021 – All rights reserved
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ISO 20078-2:2021(E)
REQ_04_03_01 A subscription profile shall contain:
— profileId (assigned at creation),
— callback baseURI,
— token information according to REQ_04_03_02 or REQ_04_03_03.
REQ_04_03_02 A subscription profile for refresh token shall contain:
— an OAuth2 refresh token,
— the OAuth2 refresh token lifetime,
— the OAuth2 endpoint for renewing access tokens.
NOTE 1 See Table 15.
REQ_04_03_03 A subscription profile for bearer token shall contain:
— a bearer token,
— the bearer token lifetime.

NOTE 2 It is the responsibility of the accessing party to renew the subscription profile before the bearer token

expires.
NOTE 3 See Table 16.
REQ_04_03_04 A subscription shall contain a subscription profile.

REQ_04_03_05 The full subscription profile information can be provided when the subscription is

created.

Table 15 — Examples of REQ_04_03_05 providing subscription profile information for refresh

token
Normative generic format POST {baseURI}/{resource}Subscriptions
“profile:”
“token_type”:”refresh_token”
“token”:”{token}”
“expires_in”:{lifetime in seconds for refresh token}
“tokenEndpoint”:”{accessingPartyTokenEndpoint}”
“callbackBaseURI”:”{accessingPartyBaseURI}
Response:
HTTP 201
Location: {URI of created subscription}
Response payload: "profileId": "{Subscription profile id}"
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ISO 20078-2:2021(E)
Table 15 (continued)
Example POST {baseURI}/positionSubscriptions?vehicleId=123
“profile”:
“token_type”:”refresh_token”,
“token”:”VGhpcyBpcaCB0b2tlbiwg … cm1hdHRlZA==”,
“expires_in”: 31536000,
“tokenEndpoint”: “https:// oauth2 .example .com/ token”,
“callBackBaseURI”: “https:// ap .example .com/ exVe”
Subscribe to positions for vehicle with id 123.
Response:
HTTP 201 (created) response returns location header of the new subscription

resource (id 2233) and implicitly created subscription profile id in the response

body:
Location: {baseURI}/positionSubscriptions/2233
Response payload: {"profileId": "1234"}
Table 16 — Examples of REQ_04_03_05 providing subscription profile informati
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 20078-2
ISO/TC 22/SC 31
Road vehicles — Extended vehicle
Secretariat: DIN
(ExVe) web services —
Voting begins on:
2021-08-23
Part 2:
Voting terminates on:
Access
2021-10-18
Véhicules routiers — Web services du véhicule étendu (ExVe) —
Partie 2: Accès
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 20078-2:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 20078-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 20078-2:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and abbreviated terms ................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviated terms ............................................................................................................................................................................... 1

4 Representational state transfer-based interface ................................................................................................................ 1

4.1 General ........................................................................................................................................................................................................... 1

4.1.1 Introduction ......................................................................................................................................................................... 1

4.1.2 Request/reply ..................................................................................................................................................................... 2

4.1.3 Push ............................................................................................................................................................................................. 2

4.1.4 Push with subsequent request/reply ............................................................................................................ 4

4.1.5 Requirements ..................................................................................................................................................................... 6

4.2 Resources ..................................................................................................................................................................................................... 7

4.3 Subscription profiles .......................................................................................................................................................................12

4.4 HTTP header fields ...........................................................................................................................................................................20

4.5 Media types .............................................................................................................................................................................................21

4.6 Resource versioning ........................................................................................................................................................................21

4.7 Resources and web services .....................................................................................................................................................22

4.7.1 General...................................................................................................................................................................................22

4.7.2 Examples ..............................................................................................................................................................................22

4.8 Rate limits ................................................................................................................................................................................................23

4.9 HTTP methods ......................................................................................................................................................................................24

4.10 HTTP response status codes ....................................................................................................................................................25

4.11 Error messaging ..................................................................................................................................................................................26

4.12 Interaction pattern ...........................................................................................................................................................................29

4.12.1 Asynchronous ..................................................................................................................................................................29

4.13 Resource discovery ..........................................................................................................................................................................33

4.14 Capability discovery ........................................................................................................................................................................34

5 Container management API ...................................................................................................................................................................35

5.1 General ........................................................................................................................................................................................................35

5.2 Container management operations ...................................................................................................................................35

Annex A (informative) Container management API specification ......................................................................................45

Annex B (normative) Container management OpenAPI specification ...........................................................................64

Annex C (normative) OpenAPI specification for container push notifications .....................................................65

Bibliography .............................................................................................................................................................................................................................66

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ISO/FDIS 20078-2:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,

Data communication.

This second edition cancels and replaces the first edition (ISO 20078-2:2019), which has been

technically revised.
The main changes compared to the previous edition are as follows:

— added definition of a push method, allowing the offering party to push resources to the accessing

party according to subscription;

— added definition of reusable subscription profiles, used to store URI locations and authorization

information from the accessing party and used by offering party to push subscribed resources;

— defined requirements for container management API;
— added Annex A and digital Annex B describing container management API;
— revised error format;
— redefined resource versioning.
A list of all parts in the ISO 20078 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 20078-2:2021(E)
Road vehicles — Extended vehicle (ExVe) web services —
Part 2:
Access
1 Scope

This document defines how to access resources on a web-services interface of an offering party using

the Hypertext Transfer Protocol Secure (HTTPS). Resources can be accessed through request/reply

and/or requested to be pushed.

The Representational State Transfer (REST) architectural pattern is chosen as a common way to format

resource paths both for request/reply and push. Some specific extensions to this pattern are defined

to allow for asynchronous resource requests, such as, for example, forcing readouts of data from a

connected vehicle.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 20078-1, Road vehicles — Extended vehicle (ExVe) web services — Part 1: Content and definitions

ISO 8601 (all parts), Date and time — Representations for information interchange

3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20078-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.2 Abbreviated terms

For the purposes of this document, the abbreviated terms given in ISO 20078-1 apply.

4 Representational state transfer-based interface
4.1 General
4.1.1 Introduction

There are three different ways to access resources for the accessing party, request/reply, push, and

push with a subsequent request/reply. Request/reply is the recommended method, but push can be

used when needed. In most cases only one method is used for a particular resource, but sometimes both

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request/reply and push are needed. Latency, message size and frequency are examples of requirements

to consider when selecting between request/reply, push, and push with subsequent request/reply.

4.1.2 Request/reply

Figure 1 shows an example of request/reply sequence, where the accessing party requests a resource

using HTTP GET and the offering party returns it in the payload.
Figure 1 — Request/reply example
4.1.3 Push

Figure 2 shows an example of push sequence, where the accessing party initiates a push of a resource

using HTTP POST. The offering party confirms the subscription and starts to push the resource using

HTTP POST. Figure 2 shows an example where the push is done two times.
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Figure 2 — Push example

Figure 3 shows an example of push sequence, where there is no explicit initiation of the push from the

accessing party. It is instead initiated by for instance rules or configuration at the offering party. It is

outside the scope of this document to describe how this is agreed between the accessing party and the

offering party.
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Figure 3 — Push example without explicit initiation
4.1.4 Push with subsequent request/reply

Figure 4 shows an example of push with subsequent request/reply, where the accessing party initiates

a push of a resource using HTTP POST. The offering party confirms the subscription and starts to push

the resource reference using HTTP POST. The accessing party uses the resource reference to request

the resource from the offering party.
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Figure 4 — Push with subsequent request/reply example

Figure 5 shows an example of push with subsequent request/reply, where there is no explicit initiation

of the push from the accessing party. It is instead initiated by, for instance, rules or configuration at

the offering party. It is outside the scope of this document to describe how this is agreed between the

accessing and the offering party.
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Figure 5 — Push with subsequent request/reply example without explicit initiation

4.1.5 Requirements
[9] [6][7]

The following defines the requirements on a REST -based web service interface using HTTPS

based on transport layer security (TLS) to give the accessing party secure access to resources provided

by the offering party. The requirements in this document are valid both for request/reply and push

unless otherwise stated.

REQ_04_01_01 The REST-based web services interface implementation shall use HTTPS as the

transport protocol with TLS.

REQ_04_01_02 HTTP shall only be used with version 1.1 or higher compatible versions.

REQ_04_01_03 TLS shall only be used with version 1.2 or higher versions.

REQ_04_01_04 The request/reply REST web service shall be a strict client-server interaction,

where the accessing party (client) sends a request and the offering party (server)

sends a response.
NOTE Resources can be transferred both in the request and the response.

REQ_04_01_05 The request/reply REST implementation shall be stateless; i.e. the offering party

server shall not maintain any accessing party client context or session information.

Due to REQ_04_01_05, each request-response pair is handled independently from one another. Each

client request by the accessing party contains all information required by the server of the offering

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party to successfully respond to the request, including a representation of the client state when

necessary.

REQ_04_01_06 A push initiation REST web service shall be a strict client-server interaction, where

the accessing party (client) sends a request and the offering party (server) sends a

response.

REQ_04_01_07 The push REST web service shall be a strict client-server interaction, where the

offering party (client) sends a request and the accessing party (server) sends a
response.
4.2 Resources

REQ_04_02_01 Information on the server shall be exposed as resources expressed as plural nouns.

NOTE 1 This holds true even when the resource is only available one time on a connected vehicle (e.g.

"odometers").

REQ_04_02_02 The exposed resources shall be uniquely identified in the form of Uniform Resource

Identifiers (URIs).

The resources, the resource groups or the containers, and how to apply those on a specific presentation

or application layer of the accessing party are described in ISO 20078-1. How an accessing party

authenticates and how it is authorized for access to resources is described in ISO 20078-3.

REQ_04_02_03 The offering party shall define the base URIs of the web services offered by the

offering party.
Table 1 — Examples of possible ExVe-based URIs
Resource Description
https:// {example .com}/ exve/ URI based on sub directory
https:// exve .{example .com}/ URI based on sub domain

REQ_04_02_04 The offering party shall comply with the URI resource paths defined by specific

ExVe standard applications.
Table 2 — Examples of possible ExVe resource URIs
Resource Description
{base_URI}/{resourcePath} Resources based on path
{base URI}/vehicles A list of the available vehicles as defined by
authorization context

{base URI}/vehicles/{vehicleId}/dtcReadouts/ Read all Diagnostic Trouble Codes for a spe-

cific vehicle

{base URI}/vehicles/{vehicleId}/ecus/{ecuId}/dtcReadouts/ Read all Diagnostic Trouble Codes for a spe-

cific ECU of a specific vehicle
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There are two primary elements defining an URI: entities and resources (Table 2). Entities are the

fundamental objects representing, e.g. vehicles, ECUs, drivers and fleets. Resources are the actual data,

aggregated information or functionalities associated with an entity and a specific use case.

REQ_04_02_05 Resources shall be named and described.

EXAMPLE Fuel level can be an example of a single data item resource, vehicle position can be an aggregated

resource consisting of several data items (e.g. latitude, longitude, sample time) and lock and unlock the vehicle

can be a functionality resource.

REQ_04_02_06 The offering party should have the possibility to extend resources, but shall not be

able to reduce resources.

Thus, by REQ_04_02_06 it is not possible to remove data items from a resource, other than through an

update of the underlying use case specification. It is however possible to add data items to a resource

(i.e. versioning).

REQ_04_02_07 Aggregated resources shall only include or cross-reference necessary data items

for the complete and correct operation of the related use case.

NOTE 2 REQ_04_02_07 ensures an accessing party only receives data items necessary for fulfilling the

intended need and nothing else when accessing the resource (i.e. data economy).
See also ISO 20078-1:2021, 8.3, for further details.

REQ_04_02_08 A resource within an already existing use case should not be redefined.

An application may extend the recommended patterns below if none of them meets the needs of the use

case.

REQ_04_02_09 Each use case shall define how the HTTP operations GET, POST, PUT, PATCH, and

DELETE are supported for each defined resource and what the response for each
operation is.
REQ_04_02_10 All URI elements shall be written in lower camel case notation.

NOTE 3 The {baseURI} in following patterns refers to the offering party root URI (see Table 3).

Table 3 — Examples of base URI expresses REQ_04_02_09 and REQ_04_02_01
Normative generic format {baseURI}/{entities}
Example {baseURI}/vehicles
Request a list of all vehicles available to the accessing party.
REQ_04_02_11 Relations of entities shall be expressed using subresources.
NOTE 4 See Table 4.
Table 4 — Examples of sub-URI’s expresses REQ_04_02_11 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/{ID}/{entities2}/{ID2}
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Table 4 (continued)
Example {baseURI}/fleets/12/vehicles/456
Request information on vehicle with id 456 of fleet with id 12.
{baseURI}/vehicles/456/ecus/789
Request information on ECU with id 789 of vehicle with id 456.

REQ_04_02_12 A resource shall be placed after the entity to which it belongs in the URI.

NOTE 5 See Table 5.
Table 5 — Examples of descriptive URI’s expresses REQ_04_02_12 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/{ID}/{resource}
Example {baseURI}/vehicles/123/positions
Request all positions for vehicle with id 123.
{baseURI}/vehicles/456/odometers
Request the odometer value for vehicle with id 456.
{baseURI}/vehicles/456/tirePressures
Request tire pressures of all wheels on the vehicle with id 456.

REQ_04_02_13 If filtering of the response is needed, query parameters shall be used.

NOTE 6 Several query parameters can be added to a request.
NOTE 7 See Table 6.

Table 6 — Examples of filtering responses expresses REQ_04_02_13 and REQ_04_02_01

Normative generic format {baseURI}/{entities}?{filter}={filterValue}
{baseURI}/{entities}?{filter}={filterValue}&{filter2}={filterValue2}
Example {baseURI}/vehicles?ignitionState=on
Request all vehicles with ignition on.
{baseURI}/vehicles/123/positions?startDate=...&endDate=...
Request the positions for vehicle with id 123 registered in given date span in
the ISO 8601 series date-time format.
REQ_04_02_14 If sorting is needed, query parameters shall be used.
NOTE 8 See Table 7.
Table 7 — Examples of query parameters expresses REQ_04_02_14 and REQ_04_02_01
Normative generic format {baseURI}/{entities}?{sorting}={sortingValue}
{baseURI}/{entities}?{sorting}={sortingValue}&{sorting2}={sortingValue2}
Example {baseURI}/vehicles?sortField=id&sortOrder=asc
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REQ_04_02_15 If selection of subsets of resources is needed, query parameters shall be used.

NOTE 9 See Table 8.
Table 8 — Examples of query parameters for subsets expresses REQ_04_02_15 and
REQ_04_02_01
Normative generic format {baseURI}/{entities}?{id}={ID}
{baseURI}/{entities}?{id}={ID}&{id2}={ID2}
Example {baseURI}/vehicles?id=123&id=124
{baseURI}/vehicles?id=YS2RX20001754836

Identifiers may come in multiple formats including, but not limited to, VIN or pseudonymized IDs.

REQ_04_02_16 Pseudonymized IDs may be simple numerical IDs, UUIDs or any other alphanumerical

scheme.
NOTE 10 See Table 9.
Table 9 — Examples of pseudonymized IDs represented by numerical IDs expresses
REQ_04_02_16 and REQ_04_02_01
Normative generic {baseURI}/{entities}?{id}={ID}
format
{baseURI}/{entities}?{id}={ID}&{id2}={ID2}

Example {baseURI}/vehicles?id=ce5d5e3d-28bc-475f-8ef7-b5cb9c8039d4&id=f95ce756-42fc-

48b2-8873-86553f6df5cc
{baseURI}/vehicles?id=456
REQ_04_02_17 For large resource responses pagination may be used.
NOTE 11 See Table 10.
Table 10 — Examples of pagination expresses REQ_04_02_17 and REQ_04_02_01
Normative generic format {baseURI}/{entities}?start={value}&limit={count}
Example {baseURI}/vehicles?start=20&limit=10

REQ_04_02_18 A GET request on the returned location may return the total amount of results. If

used, it shall be part of the message body using the keyword “exveTotal”.
EXAMPLE The following example expresses REQ_04_02_18:
"results": {
"exveTotal": "150", …
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REQ_04_02_19 If wildcards are used, a wildcard (*) shall access all subentities or resources of all

parent entities.
NOTE 12 See Table 11.
Table 11 — Examples of wildcards in URIs expresses REQ_04_02_19 and REQ_04_02_01
Normative generic format {baseURI}/{entities}/*/{entities2}
Example {baseURI}/vehicles/*/positions
Request all positions for all vehicles.
{baseURI}/vehicles/*/ecus
Request all ECU’s of all vehicles.

REQ_04_02_20 If wildcards are used, a wildcard (*) may be combined with other filtering, includ-

ing IDs, to access a smaller number of entities.
NOTE 13 See Table 12.

Table 12 — Examples of wildcards in URIs while filtering by IDs expresses REQ_04_02_20 and

REQ_04_02_01

Normative generic {baseURI}/{entities}/*/{resource}?{id}={ID}&{id2}={ID2}&{filter}={filterValue}&{-

format filter2}={filterValue2}
Example {baseURI}/vehicles/*/odometers?id=456&id=789& startDate=...&endDate=...

Request all odometer values from vehicles with id 456 and 789 registered within the

given time span in the ISO 8601 series date-time format.

REQ_04_02_21 For fully anonymized access, no entity IDs shall be used in the URIs.

NOTE 14 See Table 13.

Table 13 — Examples of an anonymized access expresses REQ_04_02_21 and REQ_04_02_01

Normative generic format {baseURI}/{entities}/{entities2}
Example {baseURI}/vehicles/hazardWarnings?isActive=true
REQ_04_02_22 A push resource shall be suffixed with subscriptions.
NOTE 15 See Table 14.
Table 14 — Examples of push resources regarding REQ_04_02_22
Normative generic format {baseURI}/{resource}Subscriptions
Example POST {baseURI}/positionSubscriptions?vehicleId=123
Subscribe to positions for vehicle with id 123.
GET {baseURI}/positionSubscriptions
Request a list of all position subscriptions.
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Table 14 (continued)
POST {baseURI}/vehicles/456/tirePressureSubscriptions?pressure=low
Subscribe to low tire pressures of all wheels on the vehicle with id 456.

REQ_04_02_23 The accessing party shall define the base URIs of the web services offered by the

accessing party. (Compare with REQ_04_02_03).
4.3 Subscription profiles

Push of subscribed resources requires URI locations and authorization information from the accessing

party. This information is stored in subscription profiles. Subscription profiles can be created in a

separate step before creating subscriptions or directly when creating a subscription. In both cases the

subscription profile will be assigned an id and can be reused by any number of subscriptions.

REQ_04_03_01 A subscription profile shall contain:
— profileId (assigned at creation),
— callback baseURI,
— token information according to REQ_04_03_02 or REQ_04_03_03.
REQ_04_03_02 A subscription profile for refresh token shall contain:
— an OAuth2 refresh token,
— the OAuth2 refresh token lifetime,
— the OAuth2 endpoint for renewing access tokens.
NOTE 1 See Table 15.
REQ_04_03_03 A subscription profile for bearer token shall contain:
— a bearer token,
— the bearer token lifetime.

NOTE 2 It is the responsibility of the accessing party to renew the subscription profile before the bearer token

expires.
NOTE 3 See Table 16.
REQ_04_03_04 A subscription shall contain a subscription profile.

REQ_04_03_05 The full subscription profile information can be provided when the subscription is

created.
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Table 15 — Examples of REQ_04_03_05 providing subscription profile information for refresh

token
Normative generic format POST {baseURI}/{resource}Subscriptions
...

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