The Solid Protocol
Editor’s Draft, 2021-02-02
- This version
- https://solidproject.org/TR/protocol
- Published
- Modified
- Repository
- GitHub
- Issues
MIT License. Copyright © 2019–2021 W3C Solid Community Group.
Abstract
This document connects a set of specifications that, together, provide applications with secure and permissioned access to externally stored data in an interoperable way.
Status of This Document
This section describes the status of this document at the time of its publication.
This document was published by the Solid Community Group as an Editor’s Draft. The sections that have been incorporated have been reviewed following the Solid process. However, the information in this document is still subject to change. You are invited to contribute any feedback, comments, or questions you might have.
Publication as an Editor’s Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the W3C Community Contributor License Agreement (CLA). A human-readable summary is available.
Introduction
The aims of the Solid project are in line with those of the Web itself: empowerment towards an equitable, informed and interconnected society
. Solid adds to existing Web standards to realise a space where individuals can maintain their autonomy, control their data and privacy, and choose applications and services to fulfil their needs.
The Solid ecosystem encapsulates a set of specifications that are guided by the principles we have adopted and also the priority of our values. We acknowledge that every technical decision has ethical implications both for the end user (short-term) as well as society (long-term). To contribute towards a net positive social benefit, we use the Ethical Web Principles to orient ourselves. The consensus on the technical designs are informed by common use cases, implementation experience, and use.
An overarching design goal of the Solid ecosystem is to be evolvable and to provide fundamental affordances for decentralised Web applications for information exchange in a way that is secure and privacy respecting. In this environment, actors allocate identifiers for their content, shape and store data where they have access to, set access control policies, and use preferred applications and services to achieve them.
The general architectural principles of Solid specifications are borrowed from the Architecture of the World Wide Web. The components as described in each specification may evolve independently – according to the principle of orthogonality in order to increase the flexibility and robustness of the Solid ecosystem. With that, the specifications are loosely coupled and indicate which features overlap with those governed by another specification. Extensibility as well as variability also are taken into account in each specification.
The specifications in the ecosystem describe how Solid servers and clients can be interoperable by using Web communication protocols, global identifiers, authentication and authorization mechanisms, data formats and shapes, and query interfaces.
The specifications are accompanied with supplemental documents, such as Primers and Best Practices and Guidelines to help implementers to form a well-rounded understanding of the Solid ecosystem as well as ways to improve their implementations.
Definitions
A data pod is a place for storing documents, with mechanisms for controlling who can access what.
A Solid app is an application that reads or writes data from one or more data pods.
A read operation entails that information about a resource’s existence or its description can be known. [Source]
A write operation entails that information about resources can be created or removed. [Source]
An append operation entails that information can be added but not removed. [Source]
Namespaces
Prefix | Namespace | Description |
---|---|---|
rdf | http://www.w3.org/1999/02/22-rdf-syntax-ns# | [rdf-schema] |
ldp | http://www.w3.org/ns/ldp# | [LDP] |
solid | http://www.w3.org/ns/solid/terms# | Solid Terms |
pim | http://www.w3.org/ns/pim/space# | Workspace Ontology |
acl | http://www.w3.org/ns/auth/acl# | ACL Ontology |
Conformance
All assertions, diagrams, examples, and notes are non-normative, as are all sections explicitly marked non-normative. Everything else is normative.
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
Hypertext Transfer Protocol
Solid clients and servers need to exchange data securely over the Internet, and they do so using the HTTP Web standard. This section describes in detail which parts of HTTP must be implemented by clients and servers.
Required Server-Side Implementation
A data pod MUST be an HTTP/1.1 server [RFC7230][RFC7231]. It SHOULD additionally be an HTTP/2 server [RFC7540] to improve performance, especially in cases where individual clients are expected to send high numbers of successive requests.
A data pod SHOULD use TLS connections through the https
URI scheme in order to secure the communication between clients and servers. When both http
and https
are supported, all http
URIs MUST redirect to their https
counterparts using a response with a 301
status code and a Location
header.
A data pod MUST implement the server part of HTTP/1.1 Conditional Requests [RFC7232] to ensure that updates requested by clients will only be applied if given preconditions are met. It SHOULD additionally implement the server part of HTTP/1.1 Caching [RFC7234] to improve performance. A data pod MAY implement the server part of HTTP/1.1 Range Requests [RFC7233] to further improve performance for large representations.
A data pod MUST implement the server part of HTTP/1.1 Authentication [RFC7235]. When a client does not provide valid credentials when requesting a resource that requires it (see WebID), the data pod MUST send a response with a 401
status code (unless 404
is preferred for security reasons).
A Solid server MUST reject PUT
, POST
and PATCH
requests without the Content-Type
header with a status code of 400
. [Source]
Required Client-Side Implementation
A Solid client MUST be an HTTP/1.1 client [RFC7230][RFC7231]. It MAY additionally be an HTTP/2 client [RFC7540] to improve performance.
A Solid client MAY implement the client parts of HTTP/1.1 Conditional Requests [RFC7232] to only trigger updates when certain preconditions are met. It MAY implement HTTP/1.1 Caching [RFC7234] and HTTP/1.1 Range Requests [RFC7233] to improve performance.
A Solid client MUST implement the client part of HTTP/1.1 Authentication [RFC7235] if it needs to access resources requiring authentication (see WebID). When it receives a response with a 403
or 404
status code, it MAY repeat the request with different credentials.
A Solid client MUST use the Content-Type
HTTP header in PUT
, POST
and PATCH
requests [RFC7231]. [Source]
Uniform Resource Identifier
URI Slash Semantics
The slash character in the URI path indicates hierarchical relationship segments, and enables relative referencing [RFC3986]. The semantics of the slash character is shared by servers and clients. Paths ending with a slash denote a container resource. [Source]
If two URIs differ only in the trailing slash, and the server has associated a resource with one of them, then the other URI MUST NOT correspond to another resource. Instead, the server MAY respond to requests for the latter URI with a 301 redirect to the former. [Source]. Behaviour pertaining to authorization MUST precede this optional redirect [Source]
URI Persistence
Servers should not re-use URIs, regardless of the mechanism by which resources are created. Certain specific cases exist where URIs may be reinstated when it identifies the same resource, but only when consistent with Web architecture’s URI persistence [WEBARCH]. [Source]
Note: Servers that wish to disable URI re-use may want to use the 410
status code.
Resources
Storage
When a server supports a data pod, it MUST provide one or more storages (pim:Storage
) – a space of URIs in which data can be accessed. A storage is the root container for all of its contained resources (see Resource Containment).
When a server supports multiple storages, the URIs MUST be allocated to non-overlapping space.
Servers exposing the storage resource MUST advertise by including the HTTP Link
header with rel="type"
targeting http://www.w3.org/ns/pim/space#Storage
when responding to storage’s request URI.
Clients can determine a resource is of type storage by making an HTTP HEAD
or GET
request on the target URL, and checking for the Link
header with rel="type"
targeting http://www.w3.org/ns/pim/space#Storage
.
Clients can determine the storage of a resource by moving up the URI path hierarchy until the response includes a Link
header with rel="type"
targeting http://www.w3.org/ns/pim/space#Storage
. Clients may check the root path of a URI for the storage claim at any time.
Clients can discover a storage by making an HTTP GET
request on the target URL to retrieve an RDF representation [RDF11-CONCEPTS], whose encoded RDF graph contains a relation of type http://www.w3.org/ns/pim/space#storage
. The object of the relation is the storage (pim:Storage
).
When using Web Access Control (Web Access Control):
The root container (pim:Storage
) MUST have an ACL auxiliary resource directly associated to it. The associated ACL document MUST include an authorization policy with acl:Control
access privilege.
[Source]
Resource Containment
Solid has the notion of containers to represent a collection of linked resources to help with resource discovery and lifecycle management.
There is a 1-1 correspondence between containment triples and relative reference within the path name hierarchy. [Source]. It follows that all resources are discoverable from a container and that it is not possible to create orphan resources. [Source]
The representation and behaviour of containers in Solid corresponds to LDP Basic Container and MUST be supported. [Source]
Auxiliary Resources
Solid has the notion of auxiliary resources to provide supplementary information such as descriptive metadata, authorization policies, data shape constraints, digital rights or provenance record about a given resource (hereafter referred as the subject resource), and affects how resources and others associated with it are processed, served or interpreted.
Auxiliary resources are represented as RDF documents [RDF11-CONCEPTS].
Note: Where applicable, to promote self-describing resources, implementations and authors are encouraged to use the subject resource instead of the associated auxiliary resource.
Servers exposing auxiliary resources that are defined by this specification MUST have the same "origin" for both the resource and the associated auxiliary resource [RFC6454].
As per Deleting Resources, the lifecycle of auxiliary resources defined by this specification depend on the lifecycle of the subject resource.
This specification defines the following types of auxiliary resources:
Clients can discover auxiliary resources associated with a subject resource by making an HTTP HEAD
or GET
request on the target URL, and checking the HTTP Link
header with the rel
parameter [RFC8288].
Auxiliary Type | Link Relation | Definitions |
---|---|---|
Web Access Control | acl |
[Solid Protocol] |
Description Resource | describedby |
[LDP] |
The possibility of using URIs as relation types interchangeably or as alternate to the tokens above are under consideration:
|
Web Access Control
An auxiliary resource of type Web Access Control provides access control description of a subject resource (Web Access Control).
Servers MUST NOT directly associate more than one ACL auxiliary resource to a subject resource.
To discover, read, create, or modify an ACL auxiliary resource, an acl:agent
MUST have acl:Control
privileges per the ACL inheritance algorithm on the resource directly associated with it.
A Solid server SHOULD sanity check ACL auxiliary resources upon creation or update to restrict invalid changes, such as by performing shape validation against authorization statements therein.
Description Resource
An auxiliary resource of type Description Resource provides a description of a subject resource ([LDP]).
Servers MUST NOT directly associate more than one description resource to a subject resource.
To create or modify a description resource, an acl:agent
MUST have acl:Write
privileges per the ACL inheritance algorithm on the resource directly associated with it.
To discover or read a description resource, an acl:agent
MUST have acl:Read
privileges per the ACL inheritance algorithm on the resource directly associated with it.
Clients can discover resources that are described by description resources by making an HTTP HEAD
or GET
request on the target URL, and checking the HTTP Link
header with a rel
value of describes
(inverse of the describedby
relation) [RFC6892].
Reading and Writing Resources
Servers MUST respond with the 405
status code to requests using HTTP methods that are not supported by the target resource. [Source]
Resource Type Heuristics
When creating new resources, servers can determine an effective request URI’s type by examining the URI path ending (URI Slash Semantics).
Clients who want to assign a URI to a resource, MUST use PUT
and PATCH
requests.
Clients who want the server to assign a URI of a resource, MUST use the POST
request. Servers MAY allow clients to suggest the URI of a resource created through POST, using the HTTP Slug
header as defined in [RFC5023].
[Source].
Reading Resources
Servers MUST support the HTTP GET
, HEAD
and OPTIONS
methods [RFC7231] for clients to read resources or to determine communication options. [Source]
When responding to authorized requests:
Servers MUST indicate their support for HTTP Methods by responding to HTTP GET
and HEAD
requests for the target resource with the HTTP Method tokens in the HTTP response header Allow
.
Servers MUST indicate supported media types in the HTTP Accept-Patch
[RFC5789], Accept-Post
[LDP] and Accept-Put
[The Accept-Put Response Header] response headers that correspond to acceptable HTTP methods listed in Allow
header value in response to HTTP GET
and HEAD
requests.
Servers MAY include the HTTP Accept-Patch
, Accept-Post
and Accept-Put
headers in the response of a OPTIONS *
request.
Writing Resources
When a server supports the HTTP PUT
, POST
and PATCH
methods [RFC7231] this specification imposes the following requirements: [Source]
Servers MUST create intermediate containers and include corresponding containment triples in container representations derived from the URI path component of PUT
and PATCH
requests. [Source]
Servers MUST allow creating new resources with a POST
request to URI path ending /
. Servers MUST create a resource with URI path ending /{id}
in container /
. Servers MUST create a container with URI path ending /{id}/
in container /
for requests including the HTTP Link
header with rel="type"
targeting a valid LDP container type. Servers MUST handle subsequent requests to the newly created container’s URI as if it is a valid LDP container type by including the HTTP response’s Link
header. [Source]
When a POST
method request targets a resource without an existing representation, the server MUST
respond with the 404
status code. [Source]
When a PUT
or PATCH
method request targets an auxiliary resource, the server MUST create or update it. When a POST
method request with the Slug
header targets an auxiliary resource, the server MUST respond with the 403
status code and response body describing the error. [Source]
Servers MUST NOT allow HTTP POST
, PUT
and PATCH
to update a container’s containment triples; if the server receives such a request, it MUST respond with a 409
status code. [Source]
Clients MAY use the HTTP If-None-Match
header with a value of "*"
to prevent an unsafe request method (eg. PUT
, PATCH
) from inadvertently modifying an existing representation of the target resource when the client believes that the resource does not have a current representation. [Source] [Source]
Servers MAY use the HTTP ETag
header with a strong validator for RDF bearing representations in order to encourage clients to opt-in to using the If-Match
header in their requests.
When using Web Access Control (Web Access Control):
To create or update an ACL resource (see Web Access Control), an acl:agent
MUST have acl:Control
privileges per the ACL inheritance algorithm on the resource directly associated with it. [Source]
Deleting Resources
When a server supports the HTTP DELETE
method [RFC7231] this specification imposes the following requirements: [Source]
When a DELETE
request targets storage’s root container or its associated ACL resource, the server MUST respond with the 405
status code. Server MUST exclude the DELETE
method in the HTTP response header Allow
in response to requests [RFC7231]. [Source]
When a contained resource is deleted, the server MUST also remove the corresponding containment triple, which has the effect of removing the deleted resource from the containing container. [Source]
When a contained resource is deleted, the server MUST also delete the associated auxiliary resources (see the Auxiliary Resources section).
When a DELETE
request is made to a container, the server MUST delete the container if it contains no resources. If the container contains resources, the server MUST respond with the 409
status code and response body describing the error. [Source]
When using Web Access Control (Web Access Control):
To delete a resource, an acl:agent
MUST have acl:Write
privilege per the ACL inheritance algorithm on the resource and the containing container. [Source]
To delete an ACL resource (see Web Access Control), an acl:agent
MUST have acl:Control
privileges per the ACL inheritance algorithm on the resource directly associated with it. [Source]
This section is non-normative.
The server might perform additional actions, as described in the normative references like [RFC7231]. For example, the server could remove membership triples referring to the deleted resource, perform additional cleanup tasks for resources it knows are no longer referenced or have not been accessed for some period of time, and so on.
Subsequent GET
requests to the deleted resource usually result in a 404
or 410
status code, although HTTP allows others. [Source] [Source]
As deleted resources can be reinstated with the same URI, access controls on the reinstated resource can change per the ACL inheritance algorithm. [Source]
Pertaining to events and loss of control mitigation: https://github.com/solid/specification/issues/41#issuecomment-534679278
Resource Representations
When a server creates a resource on HTTP PUT
, POST
or PATCH
requests such that the request’s representation data encodes an RDF document [RDF11-CONCEPTS] (as determined by the Content-Type
header), the server MUST accept GET
requests on this resource when the value of the Accept
header requests a representation in text/turtle
or application/ld+json
[Turtle] [JSON-LD11]. [Source] Source] [Source] [Source]
When a PUT
, POST
, PATCH
or DELETE
method request targets a representation URL that is different than the resource URL, the server MUST respond with a 307
or 308
status code and Location
header specifying the preferred URI reference. [Source]
Notifications
A Solid server MUST conform to the LDN specification by implementing the Receiver parts to receive notifications and make Inbox contents available [LDN].
A Solid client MUST conform to the LDN specification by implementing the Sender or Consumer parts to discover the location of a resource’s Inbox, and to send notifications to an Inbox or to retrieve the contents of an Inbox [LDN].
Cross-Origin Resource Sharing
Solid apps typically access data from multiple sources. However, Web browsers by default prevent apps that run on one origin from accessing data on other origins. This cross-origin protection is a security mechanism that ensures malicious websites cannot simply read your profile or banking details from other websites. However, this reasonable default poses a problem even for benevolent Solid apps, which might have good reasons to access data from different places. For instance, a Solid app at https://app.example/
would be prevented from accessing data on https://alice-data-pod.example/
or https://bob-data-pod.example/
, even when Alice and Bob have given the user of the app their permission to see some of their data.
For cases where the other origins have their own access protection mechanism—
Fortunately, Web servers can indicate to the browser that certain documents do not require cross-origin protection. This mechanism to selectively disable that protection is called Cross-Origin Resource Sharing or CORS [FETCH]. By responding to browser requests with a specific combination of HTTP headers, servers can indicate which actions are allowed for a given resource. For a Solid data pod, the goal is to allow all actions on the CORS level, such that the deeper access control layer can exert full control over the app’s allowed permissions. The next section describes how to achieve this through the right HTTP header configuration.
Required Server-Side Implementation
A data pod MUST implement the CORS protocol [FETCH] such that, to the extent possible, the browser allows Solid apps to send any request and combination of request headers to the data pod, and the Solid app can read any response and response headers received from the data pod. If the data pod wishes to block access to a resource, this MUST NOT happen via CORS but MUST instead be communicated to the Solid app in the browser through HTTP status codes such as 401
, 403
, or 404
[RFC7231].
Note: Since the CORS protocol is part of a Living Standard, it might be changed at any point, which might necessitate changes to data pod implementations for continued prevention of undesired blocking. A proposal to mitigate this has been suggested.
Concretely, whenever a data pod receives an HTTP request containing a valid Origin
header [RFC6454], the server MUST respond with the appropriate Access-Control-*
headers as specified in the CORS protocol [FETCH]. In particular, the data pod MUST set the Access-Control-Allow-Origin
header to the valid Origin
value from the request and list Origin
in the Vary
header value. The data pod MUST make all used response headers readable for the Solid app through Access-Control-Expose-Headers
(with the possible exception of the Access-Control-*
headers themselves). A data pod MUST also support the HTTP OPTIONS
method [RFC7231] such that it can respond appropriately to CORS preflight requests.
Careful attention is warranted, especially because of the many edge cases. For instance, data pods SHOULD explicitly enumerate all used response headers under Access-Control-Expose-Headers
rather than resorting to *
, which does not cover all cases (such as credentials mode set to include
). Data pods SHOULD also explicitly list Accept
under Access-Control-Allow-Headers
, because values longer than 128 characters (not uncommon for RDF-based Solid apps) would otherwise be blocked, despite shorter Accept
headers being allowed without explicit mention.
Identity
WebID
A WebID is a HTTP URI denoting an agent, for example a person, organisation, or software [WEBID]. When a WebID is dereferenced, server provides a representation of the WebID Profile in an RDF document [RDF11-CONCEPTS] which uniquely describes an agent denoted by a WebID. The WebID Profile can be used by controlling agents to link with others to grant access to identity resources as they see fit. WebIDs are an underpinning component in the Solid ecosystem and are used as the primary identifier for users and client application.
When using Web Access Control (Web Access Control):
Agents accessing non-public Solid resources need to authenticate with a WebID.
Authentication
Solid-OIDC
The Solid OpenID Connect (Solid OIDC) specification defines how resource servers verify the identity of relying parties and end users based on the authentication performed by an OpenID provider [SOLID-OIDC].
WebID-TLS
This section is non-normative.
The Solid ecosystem initially relied on WebID-TLS for authenticated resource access [WEBID-TLS]. The current recommendation for authentication relies on Solid-OIDC (Solid-OIDC). Implementations can use WebID-TLS just as any other mechanism as an additional authentication method.
HTTP Definitions
HTTP Headers
The Accept-Put Response Header
This specification introduces a new HTTP response header Accept-Put
used to specify the document formats accepted by the server on HTTP PUT requests. It is modelled after the Accept-Patch
header defined in [RFC5789] and the Accept-Post
header defined in [LDP].
The syntax for Accept-Put
, using the ABNF syntax defined in Section 1.2 of [RFC7231], is:
Accept-Put = "Accept-Put" ":" # media-range
The Accept-Put
header specifies a comma-separated list of media ranges (with optional parameters) as defined by [RFC7231], Section 5.3.2. The Accept-Put
header, in effect, uses the same syntax as the HTTP Accept
header minus the optional accept-params
BNF production, since the latter does not apply to Accept-Put
.
The presence of the Accept-Put
header in response to any method is an implicit indication that PUT
is allowed on the resource identified by the request URI. The presence of a specific document format in this header indicates that that specific format is allowed on PUT
requests to the resource identified by the request URI.
IANA Registration Template:
The Accept-Put
response header must be added to the permanent registry (see [RFC3864]).
- Header field name
- Accept-Put
- Applicable Protocol
- HTTP
- Author/Change controller
- W3C Solid Community Group
- Specification document
- This specification
Link Relations
The intent is that these link relations will be registered with IANA per [RFC8288].
acl
The contents of this section were originally taken from Web Access Control.
The following Link Relationship will be submitted to IANA for review, approval, and inclusion in the IANA Link Relations registry.
- Relation Name
acl
- Description
- The relationship
A acl B
asserts that resource B provides access control description of resource A. There are no constraints on the format or representation of either A or B, neither are there any further constraints on either resource. - Reference
- This specification.
- Notes
- Consumers of ACL resources should be aware of the source and chain of custody of the data.
Shape of ACL: https://github.com/solid/specification/issues/169
Considerations
This section details security, privacy, accessibility and internationalization considerations.
Security Considerations
Some of the normative references with this specification point to documents with a Living Standard or Draft status, meaning their contents can still change over time. It is advised to monitor these documents, as such changes might have security implications.
A data pod MUST NOT assume that HTTP request headers sent by a client are valid, and MUST reject or sanitize invalid header values before processing them or incorporating them in messages sent to others. For example, values for Host
and Origin
MUST NOT be assumed to be free of possibly malicious sequences such as /..
or others, and invalid Origin
values MUST NOT be echoed into the Access-Control-Allow-Origin
response header.
A data pod MUST NOT assume that the user agent is a regular Web browser, even when requests contain familiar values in headers such as User-Agent
or Origin
. Such an assumption could lead to incorrect conclusions about the security model of the application making the request, since the request might actually come from a non-browser actor unaffected by browser security constraints.
Solid data pods disable all cross-origin protections in browsers because resource access is governed explicitly by Web Access Control. As such, data pods MUST NOT rely on browser-based cross-origin protection mechanisms for determining the authentication status or representation of a resource. In particular, they MUST ignore HTTP cookies from untrusted origins. Additional security measures MAY be taken to prevent metadata in error responses from leaking. For instance, a malicious app could probe multiple servers to check whether the response status code is 401
or 403
, or could try to access an error page from an intranet server within the user agent’s private network to extract company names or other data. To mitigate this, when a request from an untrusted Origin
arrives, the data pod MAY set the status code of error responses to 404
and/or anonymize or censor their contents.
Data pods SHOULD use TLS connections to protect the contents of requests and responses from eavesdropping and modification by third parties. Unsecured TCP connections without TLS MAY be used in testing environments or when the data pod is behind a reverse proxy that terminates a secure connection.
Privacy Considerations
Identifiable Information
In order to prevent leakage of non-resource data, error responses SHOULD NOT contain identifiable information.
Accessibility Considerations
..
Internationalization Considerations
..
Security and Privacy Review
..
References
Normative References
- [FETCH]
- Anne van Kesteren. Fetch Standard. Living Standard. URL: https://fetch.spec.whatwg.org/
- [JSON-LD11]
- Gregg Kellogg; Pierre-Antoine Champin. JSON-LD 1.1. 9 September 2019. WD. URL: https://www.w3.org/TR/json-ld11/
- [LDN]
- Sarven Capadisli; Amy Guy. Linked Data Notifications. 2 May 2017. REC. URL: https://www.w3.org/TR/ldn/
- [LDP]
- Steve Speicher; John Arwe; Ashok Malhotra. Linked Data Platform 1.0. 26 February 2015. REC. URL: https://www.w3.org/TR/ldp/
- [RDF-SCHEMA]
- Dan Brickley; Ramanathan Guha. RDF Schema 1.1. 25 February 2014. REC. URL: https://www.w3.org/TR/rdf-schema/
- [RDF11-CONCEPTS]
- Richard Cyganiak; David Wood; Markus Lanthaler. RDF 1.1 Concepts and Abstract Syntax. 25 February 2014. REC. URL: https://www.w3.org/TR/rdf11-concepts/
- [RFC2119]
- S. Bradner. Key words for use in RFCs to Indicate Requirement Levels. March 1997. Best Current Practice. URL: https://tools.ietf.org/html/rfc2119
- [RFC3864]
- G. Klyne; M. Nottingham; J. Mogul. Registration Procedures for Message Header Fields. September 2004. Best Current Practice. URL: https://tools.ietf.org/html/rfc3864
- [RFC3986]
- T. Berners-Lee; R. Fielding; L. Masinter. Uniform Resource Identifier (URI): Generic Syntax. January 2005. Internet Standard. URL: https://tools.ietf.org/html/rfc3986
- [RFC5023]
- J. Gregorio, Ed.; B. de hOra, Ed.. The Atom Publishing Protocol. October 2007. Proposed Standard. URL: https://tools.ietf.org/html/rfc5023
- [RFC5789]
- L. Dusseault; J. Snell. PATCH Method for HTTP. March 2010. Proposed Standard. URL: https://tools.ietf.org/html/5789
- [RFC6454]
- A. Barth. The Web Origin Concept. December 2011. Proposed Standard. URL: https://tools.ietf.org/html/rfc6454
- [RFC6892]
- E. Wilde. The 'describes' Link Relation Type. March 2013. Informational. URL: https://tools.ietf.org/html/rfc6892
- [RFC7230]
- R. Fielding, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7230
- [RFC7231]
- R. Fielding, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7231
- [RFC7232]
- R. Fielding, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7232
- [RFC7233]
- R. Fielding, Ed.; Y. Lafon, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Range Requests. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7233
- [RFC7234]
- R. Fielding, Ed.; M. Nottingham, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Caching. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7234
- [RFC7235]
- R. Fielding, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Authentication. June 2014. Proposed Standard. URL: https://tools.ietf.org/html/7235
- [RFC7540]
- M. Belshe; R. Peon; M. Thomson, Ed.. Hypertext Transfer Protocol Version 2 (HTTP/2). May 2015. Proposed Standard. URL: https://tools.ietf.org/html/7540
- [RFC8174]
- Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words. B. Leiba. IETF. May 2017. Best Current Practice. URL: https://tools.ietf.org/html/rfc8174
- [RFC8288]
- M. Nottingham. Web Linking. October 2017. Proposed Standard. URL: https://tools.ietf.org/html/8288
- [SOLID-OIDC]
- Solid-OIDC. URL: https://solid.github.io/authentication-panel/solid-oidc/
- [Turtle]
- Eric Prud'hommeaux; Gavin Carothers. RDF 1.1 Turtle. 25 February 2014. REC. URL: https://www.w3.org/TR/turtle/
- [WAC]
- Web Access Control. URL: https://solid.github.io/web-access-control-spec/
- [WEBARCH]
- Ian Jacobs; Norman Walsh. Architecture of the World Wide Web, Volume One. 15 December 2004. REC. URL: https://www.w3.org/TR/webarch/