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Specberus is a checker used at W3C to validate the compliance of Technical Reports with publication rules.

  1. Installation
  2. Running
  3. Testing
  4. JS API
  6. Profiles
  7. Validation events
  8. Writing rules

1. Installation

Specberus is a Node.js application, distributed through npm. Alternatively, you can clone the repository and run:

$ npm install -d

In order to get all the dependencies installed. Naturally, this requires that you have a reasonably recent version of Node.js installed.

2. Running

Currently there is no shell to run Specberus. Later we will add both Web and CLI interfaces based on the same core library.

Syntax and command-line parameters

$ W3C_API_KEY="<YOUR W3C API KEY>" npm start [PORT]

Specberus relies on the W3C API to run a few checks. You will need to provide your key in an environment variable W3C_API_KEY

Meaning of positional parameters:

  1. PORT: where Specberus will be listening for HTTP connections. (Default 80.)


$ W3C_API_KEY="<YOUR W3C API KEY>" npm start
$ W3C_API_KEY="<YOUR W3C API KEY>" npm start 3001

running specberus

Set the environment variable DEBUG to run in debug mode instead:

$ DEBUG=true W3C_API_KEY="<YOUR W3C API KEY>" npm start

This modifies the behaviour of certain parts of the application to facilitate debugging. eg, CSS and JS resources will not be loaded in their minified/uglified forms (the web UI will load bootstrap.css, bootstrap.js and jquery.js instead of bootstrap.min.css, bootstrap.min.js and jquery.min.js).

If Specberus is not going to be served from the root directory of a domain, or if it will be served through a proxy, set also BASE_URI pointing to the public root URI of Specberus; eg

$ BASE_URI= W3C_API_KEY=deadbeef npm start
$ BASE_URI=/hostname/can/be/omitted/ W3C_API_KEY=deadbeef npm start 88
  1. Auto reload when developing

Run npm run live when developing. The app will automatically reload when changes happen.

$ W3C_API_KEY="xxx" npm run live

$ W3C_API_KEY="xxx" npm run live 3001

3. Testing

Testing is done using mocha. Simply run:

$ W3C_API_KEY="<YOUR W3C API KEY>" mocha

from the root and you will be running the test suite. Mocha can be installed with:

$ npm install -g mocha

Some of the tests can on occasion take a long time, or fail outright because a remote service is unavailable. To work around this, you can set SKIP_NETWORK:



The interface you get when you require("specberus") is that from lib/validator. It returns a Specberus instance that is properly configured for operation in the Node.js environment (there is nominal support for running Specberus under other environments, but it isn't usable at this time).

(See also the REST API.)

Creating a Validator instance

const { Specberus } = require('specberus');
const specberus = new Specberus(apiKey);
// specberus.validate(...)
// specberus.extractMetadata(...)


This method takes an object with the following fields:

  • url: URL of the content to check. One of url, source, file, or document must be specified and if several are they will be used in this order.
  • source: A String with the content to check.
  • file: A file system path to the content to check.
  • document: A DOM Document object to be checked.
  • profile: A profile object which defines the validation. Required. See below.
  • events: An event sink which supports the same interface as the Node.js EventEmitter. Required. See below for the events that get generated.


This method eventually extends this with metadata inferred from the document. Once the event end-all is emitted, the metadata should be available in a new property called meta.

The options accepted are equal to those in validate(), except that a profile is not necessary and will be ignored (finding out the profile is one of the goals of this method).

this.meta will be an Object and may include up to 16 properties described below:

  • profile
  • title: The (possible) title of the document.
  • docDate: The date associated to the document.
  • thisVersion: URL of this version of the document.
  • latestVersion: URL of the latest version of the document.
  • previousVersion: URL of the previous version of the document (the last one, if multiple are shown).
  • editorsDraft: URL of the latest editor's draft.
  • delivererIDs: ID(s) of the deliverer(s); an Array of Numbers.
  • editorIDs: ID(s) of the editor(s) responsible for the document; an Array of Numbers.
  • informative: Whether the document in informative or not.
  • process: The process rules link.
  • sameWorkAs: The previous shortlink if any.
  • implementationFeedbackDue: The implementation review date for CRs.
  • prReviewsDue: The review date for PRs.
  • implementationReport: Implementation report link for CRs, PRs and RECs.
  • errata: The errata link of the document.
  • substantiveChanges: Whether the document is a REC and has proposed amendments
  • newFeatures: Whether the document is a REC and has proposed additions

If some of these pieces of metadata cannot be deduced, that key will not exist, or its value will not be defined.

This is an example of the value of Specberus.meta after the execution of Specberus.extractMetadata():

  "profile": "WD",
  "title": "Title of the spec",
  "docDate": "2016-2-3",
  "thisVersion": "",
  "latestVersion": "",
  "previousVersion": "",
  "editorsDraft": "",
  "delivererIDs": [123, 456],
  "editorIDs": [ 12345 ],
  "informative": false,
  "process": "" }


Similar to the JS API, Specberus exposes a REST API via HTTP too.

The endpoint is <host>/api/. Use either url or file to pass along the document (neither source nor document are allowed).

Note: If you want to use the public W3C instance of Specberus, you can replace <host> with

There are three GET methods available.


Returns the version string, eg 1.5.3.


Extract all known metadata from a document; see below for information about the return value.


Check the document (syntax). Many of the options understood by the JS method validate are accepted.

The special profile auto is also available.


1. Get API version of Pubrules


2. Get metadata of one document.

Metadata is a bunch of data extracted from the document. It includes the type (profile) of the document, publish date, editors' names, Patent Policy version the document is under, etc...


3. Validate the document using profile: auto

auto profile is the easiest way to validate a document. The validation relies on the automatically extracted data.

The validation result contains both the metadata and the errors/warnings regarding the document.


4. Validate the document using manual configs

Pubrules supports advanced configs to make the validation more accurate.

Config Explanation Supported value
validation Recursively validate multipart documents no-validation, simple-validation, recursive
informativeOnly If the document is informative true, false
echidnaReady Check that the document is valid for automatic publication with Echidna true, false
patentPolicy Patent Policy version pp2020, pp2004


Return values

Methods metadata and validate return a JSON object with these properties:

  • success (boolean): whether the operation succeeded, or not.
  • errors (array): all errors found.
  • warnings (array): all warnings.
  • info (array): additional, informative messages.
  • metadata (object): extracted metadata; see structure here.

If there is an internal error, the document cannot be retrieved or is not recognised, or validation fails, both methods would return HTTP status code 400. Also, in the case of validate, success would be false and errors.length > 0.

This is an example of a successful validation of a document, with profile auto:

    "success": true,
    "errors": [],
    "warnings": [
    "info": [
    "metadata": {
        "profile": "WD",
        "title": "Character Model for the World Wide Web: String Matching and Searching",
        "docDate": "2016-4-7",
        "thisVersion": "",
        "latestVersion": "",
        "previousVersion": "",
        "editorsDraft": "",
        "delivererIDs": [32113],
        "editorIDs": [33573],
        "informative": false,
        "process": "",
        "url": ""

When the profile is given by the user (instead of being set to auto), fewer items of metadata are returned.

metadata returns a similar structure, where all values are empty arrays, except for the key metadata which contains the metadata object.

6. Profiles

Profiles are simple objects that support the following API:

  • name: A String being the name of this profile.
  • rules: An Array of rule objects which are checked in this profile.

A profile is basically a configuration of what to check. You can load a specific profile from under lib/profiles or create your own.

Here follows the current hierarchy of profiles. Each profile inherits all rules from its parent profile. Profiles that are identical to its parent profile, ie that do not add any new rules, are marked too.

  • base
    • TR
      • WD
        • WD-Echidna
      • FPWD (identical)
      • PR
      • CR
        • CR-Echidna
      • CRD
        • CRD-Echidna
      • REC
      • REC-RSCND
      • DNOTE
      • DNOTE-Echidna
      • NOTE
      • NOTE-Echidna
      • STMT
      • DRY
      • CRY
      • CRYD
      • RY
    • Submission
      • SUBM
      • MEM-SUBM

7. Validation events

For a given checking run, the event sink you specify will be receiving a bunch of events as indicated below. Events are shown as having parameters since those are passed to the event handler.

  • start-all(profile-name): Fired first to indicate that the profile's checking has started.
  • end-all(profile-name): Fired last to indicate that the profile's checking has completed. When you receive this you are promised that all testing operations, including asynchronous ones, have terminated.
  • done(rule-name): Fired when a specific rule has finished processing, including its asynchronous tasks.
  • ok(rule-name): Fired to indicate that a rule has succeeded. There is only one ok per rule. There cannot also be err events but there can be warning events.
  • err(error-name, data): Fired when an error is detected. The data contains further details, that depend on the error but should feature a message field. There can be multiple errors for a given rule. There cannot also be ok events but there can be warnings.
  • warning(warnings-name, data): Fired for non-fatal problems with the document that may nevertheless require investigation. There may be several for a rule.
  • info(info-name, data): Fired for additional information items detected by the validator.
  • metadata(key, value): Fired for every piece of document metadata found by the validator.
  • exception(message): Fired when there is a system error, such as a File not found error. message contains details about this error. All exceptions are displayed on the error console in addition to this event being fired.

8. Writing rules

Rules are simple modules that just expose a check(sr, cb) method. They receive a Specberus object and a callback, use the Specberus object to fire validation events and call the callback when they're done.

The Specberus object exposes the following API that's useful for validation:

  • loader. The loader object that loaded the content, which exposes the content's url and source if they are known.
  • sink. The event target on which to fire validation events.
  • version. The Specberus version.
  • checkSelector(selector, rule-name, cb). Some rules need to do nothing other than to check that a selector returns some content. For this case, the rule can just call this method with the selector and its callback, and Specberus will conveniently take care of all the rest.
  • norm(text). Returns a whitespace-normalised version of the text.
  • getDocumentDate(). Returns a Date object that matches the document's date as specified in the headers' stateElement (id="w3c-state").
  • getDocumentStateElement(). Returns the element that contains the document's date.


Checker used at W3C to validate the compliance of Technical Reports with publication rules







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