4chan · API Governance Rules

4chan API Rules

Spectral linting rules defining API design standards and conventions for 4chan.

45 Rules error 14 warn 23 info 8
Authorship not recorded No authorship marker is recorded for this file. It is not presented as the provider's; it was most likely written by an API Evangelist pass before outputs were stamped.
View Rules File View on GitHub

Rule Categories

external get info no openapi operation parameter paths response schema security servers tag tags

Rules

warn
info-title-4chan-prefix
API title MUST begin with "4chan ".
$.info.title
warn
info-description-required
API description MUST be present and non-trivial.
$.info
error
info-version-required
API version MUST be declared in info.version.
$.info
warn
info-contact-required
A contact block with an email MUST be present (api@4chan.org).
$.info
warn
info-terms-of-service-required
termsOfService MUST be set since 4chan publishes API ToS.
$.info
info
openapi-version-3-0-3
OpenAPI version SHOULD be 3.0.3.
$.openapi
error
servers-defined
At least one server entry MUST be present and reference a.4cdn.org.
$.servers
warn
servers-https-preferred
HTTPS server entry SHOULD be present first.
$.servers[0].url
warn
servers-description-required
Every server entry MUST have a description.
$.servers[*]
error
paths-no-trailing-slash
Paths MUST NOT end with a trailing slash.
$.paths.*~
warn
paths-must-end-in-json
4chan paths terminate in `.json` (or use a `{thread}.json` template).
$.paths.*~
error
paths-no-query-strings
Paths MUST NOT include a query string — the 4chan API does not accept GET parameters.
$.paths.*~
warn
paths-lowercase-segments
Path segments (other than `{params}`) MUST be lowercase.
$.paths.*~
error
operation-operationid-required
Every operation MUST declare an operationId.
$.paths.*[get,post,put,patch,delete]
warn
operation-operationid-camelcase
operationId MUST be camelCase, lead with `get`/`list`/`fetch`.
$.paths.*[get,post,put,patch,delete].operationId
error
operation-summary-required
Every operation MUST have a summary.
$.paths.*[get,post,put,patch,delete]
warn
operation-summary-4chan-prefix
Operation summary SHOULD start with "4chan ".
$.paths.*[get,post,put,patch,delete].summary
warn
operation-description-required
Every operation MUST have a description (min 40 chars).
$.paths.*[get,post,put,patch,delete]
error
operation-tags-required
Every operation MUST declare at least one tag.
$.paths.*[get,post,put,patch,delete]
error
operation-only-get-allowed
Only GET operations are supported by the 4chan read-only JSON API.
$.paths.*
info
operation-microcks-extension-present
Each operation SHOULD declare `x-microcks-operation` for mock compatibility.
$.paths.*[get]
warn
tags-defined-globally
Global `tags` array MUST be defined.
$.tags
warn
tag-description-required
Every global tag MUST have a description.
$.tags[*]
info
tag-title-case
Tag names SHOULD use Title Case.
$.tags[*].name
warn
parameter-description-required
Every path parameter MUST have a description.
$.components.parameters[*]
error
parameter-schema-required
Every path parameter MUST declare a schema with a concrete type.
$.components.parameters[*]
info
parameter-example-required
Every path parameter SHOULD provide an example value.
$.components.parameters[*]
info
parameter-snake-case-names
Path parameter names SHOULD be short and lowercase.
$.components.parameters[*].name
error
response-200-required
Every operation MUST define a `200` response.
$.paths.*[get].responses
warn
response-304-recommended
GET operations SHOULD document the `304 Not Modified` response, since clients are required to use If-Modified-Since.
$.paths.*[get].responses
warn
response-404-required
GET operations MUST document `404 Not Found`.
$.paths.*[get].responses
warn
response-503-recommended
GET operations SHOULD document `503 Service Unavailable` (rate-limit back-pressure).
$.paths.*[get].responses
error
response-description-required
Every response MUST have a description.
$.paths.*[get].responses.*
error
response-json-content-type
2xx responses MUST use `application/json`.
$.paths.*[get].responses.200.content
info
response-200-example-required
200 responses SHOULD include a named example for Microcks mocking.
$.paths.*[get].responses.200.content.application/json
warn
schema-snake-case-properties
Schema property names MUST be snake_case (mirrors the actual 4chan JSON wire format).
$.components.schemas[*].properties.*~
warn
schema-description-required
Every top-level schema MUST have a description.
$.components.schemas[*]
error
schema-type-required
Every top-level schema MUST declare a type.
$.components.schemas[*]
warn
schema-properties-have-types
Every object property MUST declare a type (or be a $ref).
$.components.schemas[?(@.type=='object')].properties[?(!@.['$ref'])]
info
schema-properties-have-descriptions
Every object property SHOULD have a description.
$.components.schemas[?(@.type=='object')].properties[?(!@.['$ref'])]
warn
security-must-be-absent
The 4chan API is anonymous — `security` MUST NOT be declared.
$.security
warn
security-schemes-must-be-absent
No `securitySchemes` should be defined — there is no auth surface.
$.components.securitySchemes
error
get-no-request-body
GET operations MUST NOT define a request body.
$.paths.*[get]
warn
no-empty-descriptions
Descriptions MUST NOT be empty strings.
$..description
info
external-docs-encouraged
An `externalDocs` block linking to https://github.com/4chan/4chan-API is encouraged.
$

Spectral Ruleset

Raw ↑ 
# 4chan Spectral Ruleset
#
# Enforces conventions observed across the 4chan Read-Only JSON API specification
# at openapi/4chan-api.yml.
#
# Convention summary (dominant patterns):
#   OpenAPI version : 3.0.3
#   Title prefix    : "4chan ..."
#   Path casing     : lowercase (paths are static JSON file names + a board / page / thread id)
#   OperationId     : camelCase
#   Schema props    : snake_case (mirrors the actual JSON wire format)
#   Security        : none — fully anonymous, read-only
#   Methods         : GET only (HEAD and OPTIONS are also supported but not modeled)
#   Required errors : 304, 404, 503
extends:
  - "spectral:oas"
formats:
  - oas3
rules:

  # ─── INFO / METADATA ────────────────────────────────────────────────────────
  info-title-4chan-prefix:
    description: API title MUST begin with "4chan ".
    message: "{{property}} must start with '4chan ' (e.g. '4chan Read-Only JSON API')."
    severity: warn
    given: $.info.title
    then:
      function: pattern
      functionOptions:
        match: "^4chan .+"

  info-description-required:
    description: API description MUST be present and non-trivial.
    message: "{{property}} description is required (min 60 chars)."
    severity: warn
    given: $.info
    then:
      - field: description
        function: truthy
      - field: description
        function: length
        functionOptions:
          min: 60

  info-version-required:
    description: API version MUST be declared in info.version.
    severity: error
    given: $.info
    then:
      field: version
      function: truthy

  info-contact-required:
    description: A contact block with an email MUST be present (api@4chan.org).
    severity: warn
    given: $.info
    then:
      - field: contact
        function: truthy
      - field: contact.email
        function: truthy

  info-terms-of-service-required:
    description: termsOfService MUST be set since 4chan publishes API ToS.
    severity: warn
    given: $.info
    then:
      field: termsOfService
      function: truthy

  # ─── OPENAPI VERSION ────────────────────────────────────────────────────────
  openapi-version-3-0-3:
    description: OpenAPI version SHOULD be 3.0.3.
    severity: info
    given: $.openapi
    then:
      function: pattern
      functionOptions:
        match: "^3\\.0\\.3$"

  # ─── SERVERS ────────────────────────────────────────────────────────────────
  servers-defined:
    description: At least one server entry MUST be present and reference a.4cdn.org.
    severity: error
    given: $.servers
    then:
      - function: truthy
      - field: "0.url"
        function: pattern
        functionOptions:
          match: "^https?://a\\.4cdn\\.org/?$"

  servers-https-preferred:
    description: HTTPS server entry SHOULD be present first.
    severity: warn
    given: $.servers[0].url
    then:
      function: pattern
      functionOptions:
        match: "^https://"

  servers-description-required:
    description: Every server entry MUST have a description.
    severity: warn
    given: $.servers[*]
    then:
      field: description
      function: truthy

  # ─── PATHS — NAMING CONVENTIONS ────────────────────────────────────────────
  paths-no-trailing-slash:
    description: Paths MUST NOT end with a trailing slash.
    severity: error
    given: $.paths.*~
    then:
      function: pattern
      functionOptions:
        notMatch: "/$"

  paths-must-end-in-json:
    description: 4chan paths terminate in `.json` (or use a `{thread}.json` template).
    severity: warn
    given: $.paths.*~
    then:
      function: pattern
      functionOptions:
        match: "\\.json$"

  paths-no-query-strings:
    description: Paths MUST NOT include a query string — the 4chan API does not accept GET parameters.
    severity: error
    given: $.paths.*~
    then:
      function: pattern
      functionOptions:
        notMatch: "\\?"

  paths-lowercase-segments:
    description: Path segments (other than `{params}`) MUST be lowercase.
    severity: warn
    given: $.paths.*~
    then:
      function: pattern
      functionOptions:
        match: "^(/(\\{[a-zA-Z_]+\\}|[a-z0-9._-]+))+$"

  # ─── OPERATIONS ─────────────────────────────────────────────────────────────
  operation-operationid-required:
    description: Every operation MUST declare an operationId.
    severity: error
    given: "$.paths.*[get,post,put,patch,delete]"
    then:
      field: operationId
      function: truthy

  operation-operationid-camelcase:
    description: operationId MUST be camelCase, lead with `get`/`list`/`fetch`.
    severity: warn
    given: "$.paths.*[get,post,put,patch,delete].operationId"
    then:
      function: pattern
      functionOptions:
        match: "^(get|list|fetch)[A-Z][A-Za-z0-9]*$"

  operation-summary-required:
    description: Every operation MUST have a summary.
    severity: error
    given: "$.paths.*[get,post,put,patch,delete]"
    then:
      field: summary
      function: truthy

  operation-summary-4chan-prefix:
    description: Operation summary SHOULD start with "4chan ".
    severity: warn
    given: "$.paths.*[get,post,put,patch,delete].summary"
    then:
      function: pattern
      functionOptions:
        match: "^4chan .+"

  operation-description-required:
    description: Every operation MUST have a description (min 40 chars).
    severity: warn
    given: "$.paths.*[get,post,put,patch,delete]"
    then:
      - field: description
        function: truthy
      - field: description
        function: length
        functionOptions:
          min: 40

  operation-tags-required:
    description: Every operation MUST declare at least one tag.
    severity: error
    given: "$.paths.*[get,post,put,patch,delete]"
    then:
      field: tags
      function: length
      functionOptions:
        min: 1

  operation-only-get-allowed:
    description: Only GET operations are supported by the 4chan read-only JSON API.
    message: "The 4chan API only accepts GET, HEAD, and OPTIONS — write methods MUST NOT appear."
    severity: error
    given: "$.paths.*"
    then:
      function: undefined
      field: post
    where:
      field: post
      function: truthy

  operation-microcks-extension-present:
    description: Each operation SHOULD declare `x-microcks-operation` for mock compatibility.
    severity: info
    given: "$.paths.*[get]"
    then:
      field: x-microcks-operation
      function: truthy

  # ─── TAGS ───────────────────────────────────────────────────────────────────
  tags-defined-globally:
    description: Global `tags` array MUST be defined.
    severity: warn
    given: $.tags
    then:
      function: truthy

  tag-description-required:
    description: Every global tag MUST have a description.
    severity: warn
    given: $.tags[*]
    then:
      field: description
      function: truthy

  tag-title-case:
    description: Tag names SHOULD use Title Case.
    severity: info
    given: $.tags[*].name
    then:
      function: pattern
      functionOptions:
        match: "^[A-Z][A-Za-z0-9 -]*$"

  # ─── PARAMETERS ─────────────────────────────────────────────────────────────
  parameter-description-required:
    description: Every path parameter MUST have a description.
    severity: warn
    given: $.components.parameters[*]
    then:
      field: description
      function: truthy

  parameter-schema-required:
    description: Every path parameter MUST declare a schema with a concrete type.
    severity: error
    given: $.components.parameters[*]
    then:
      - field: schema
        function: truthy
      - field: schema.type
        function: truthy

  parameter-example-required:
    description: Every path parameter SHOULD provide an example value.
    severity: info
    given: $.components.parameters[*]
    then:
      field: example
      function: truthy

  parameter-snake-case-names:
    description: Path parameter names SHOULD be short and lowercase.
    severity: info
    given: $.components.parameters[*].name
    then:
      function: pattern
      functionOptions:
        match: "^[a-z][a-z0-9_]*$"

  # ─── RESPONSES ──────────────────────────────────────────────────────────────
  response-200-required:
    description: Every operation MUST define a `200` response.
    severity: error
    given: "$.paths.*[get].responses"
    then:
      field: "200"
      function: truthy

  response-304-recommended:
    description: GET operations SHOULD document the `304 Not Modified` response, since clients are required to use If-Modified-Since.
    severity: warn
    given: "$.paths.*[get].responses"
    then:
      field: "304"
      function: truthy

  response-404-required:
    description: GET operations MUST document `404 Not Found`.
    severity: warn
    given: "$.paths.*[get].responses"
    then:
      field: "404"
      function: truthy

  response-503-recommended:
    description: GET operations SHOULD document `503 Service Unavailable` (rate-limit back-pressure).
    severity: warn
    given: "$.paths.*[get].responses"
    then:
      field: "503"
      function: truthy

  response-description-required:
    description: Every response MUST have a description.
    severity: error
    given: "$.paths.*[get].responses.*"
    then:
      field: description
      function: truthy

  response-json-content-type:
    description: 2xx responses MUST use `application/json`.
    severity: error
    given: "$.paths.*[get].responses.200.content"
    then:
      field: "application/json"
      function: truthy

  response-200-example-required:
    description: 200 responses SHOULD include a named example for Microcks mocking.
    severity: info
    given: "$.paths.*[get].responses.200.content.application/json"
    then:
      field: examples
      function: truthy

  # ─── SCHEMAS — PROPERTY NAMING ─────────────────────────────────────────────
  schema-snake-case-properties:
    description: Schema property names MUST be snake_case (mirrors the actual 4chan JSON wire format).
    severity: warn
    given: $.components.schemas[*].properties.*~
    then:
      function: pattern
      functionOptions:
        match: "^[a-z][a-z0-9_]*$"

  schema-description-required:
    description: Every top-level schema MUST have a description.
    severity: warn
    given: $.components.schemas[*]
    then:
      field: description
      function: truthy

  schema-type-required:
    description: Every top-level schema MUST declare a type.
    severity: error
    given: $.components.schemas[*]
    then:
      field: type
      function: truthy

  schema-properties-have-types:
    description: Every object property MUST declare a type (or be a $ref).
    severity: warn
    given: $.components.schemas[?(@.type=='object')].properties[?(!@.['$ref'])]
    then:
      field: type
      function: truthy

  schema-properties-have-descriptions:
    description: Every object property SHOULD have a description.
    severity: info
    given: $.components.schemas[?(@.type=='object')].properties[?(!@.['$ref'])]
    then:
      field: description
      function: truthy

  # ─── SECURITY ───────────────────────────────────────────────────────────────
  security-must-be-absent:
    description: The 4chan API is anonymous — `security` MUST NOT be declared.
    message: "4chan is fully read-only and anonymous; do not declare security requirements."
    severity: warn
    given: $.security
    then:
      function: falsy

  security-schemes-must-be-absent:
    description: No `securitySchemes` should be defined — there is no auth surface.
    severity: warn
    given: $.components.securitySchemes
    then:
      function: falsy

  # ─── HTTP METHOD CONVENTIONS ───────────────────────────────────────────────
  get-no-request-body:
    description: GET operations MUST NOT define a request body.
    severity: error
    given: "$.paths.*[get]"
    then:
      field: requestBody
      function: falsy

  # ─── GENERAL QUALITY ───────────────────────────────────────────────────────
  no-empty-descriptions:
    description: Descriptions MUST NOT be empty strings.
    severity: warn
    given: "$..description"
    then:
      function: truthy

  external-docs-encouraged:
    description: An `externalDocs` block linking to https://github.com/4chan/4chan-API is encouraged.
    severity: info
    given: $
    then:
      field: externalDocs
      function: truthy

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