generated: '2026-07-27'
method: searched
source: live probes of the CER ArcGIS, Federal Geospatial Platform and Open Government Portal surfaces, 2026-07-27
note: 'The Canada Energy Regulator publishes no API style guide, because it publishes no API of its own design. Its
  machine-readable surfaces inherit the conventions of three upstream products: Esri ArcGIS REST, OGC WMS 1.3.0 and
  CKAN Action API v3. Everything below was observed on the wire rather than read off a docs page, and the conventions
  differ per surface — there is no cross-surface consistency to document.'
authentication:
  style: none (anonymous)
  artifact: authentication/canada-energy-regulator-authentication.yml
idempotency:
  supported: false
  note: 'No idempotency contract exists and none is needed: every surface is read-only. There is no write operation,
    no Idempotency-Key header and no request-replay semantics anywhere in the estate. No Idempotency pointer is emitted.'
content_negotiation:
  style: query parameter, not Accept header
  note: ArcGIS REST selects representation with f= (json, geojson, pjson, html); WMS uses request=/service=/version=;
    CKAN always returns application/json.
  arcgis_f_values:
  - json
  - geojson
  - pjson
  - html
pagination:
- surface: ArcGIS REST /query
  style: offset
  params:
  - resultOffset
  - resultRecordCount
  response_fields:
  - exceededTransferLimit
  page_ceiling: maxRecordCount per layer — 1000 on 6 of the 25 CER layers, 2000 on the other 19
  note: A layer will silently truncate at maxRecordCount and set exceededTransferLimit true. AER_Regulated_Pipelines
    holds 315,089 features against a 2,000-record ceiling, so it cannot be pulled in one call — paging through resultOffset
    is mandatory, and returnCountOnly=true is the way to size the job first.
- surface: CKAN Action API
  style: offset
  params:
  - rows
  - start
  response_fields:
  - count
  note: package_search defaults to 20 rows; rows=100 returned all 83 CER datasets in one call on 2026-07-27.
- surface: OGC WMS
  style: not applicable
  note: WMS is a tiled/BBOX image and feature-info protocol, not a paged collection API.
filtering:
- surface: ArcGIS REST /query
  params:
  - where
  - geometry
  - geometryType
  - spatialRel
  - outFields
  - returnGeometry
  - returnCountOnly
  - orderByFields
  note: where takes SQL-92 predicates; where=1=1 is the idiomatic match-all. An invalid predicate returns an error
    envelope under HTTP 200.
- surface: CKAN Action API
  params:
  - q
  - fq
  - sort
  - rows
  - start
  note: Solr syntax. fq=owner_org:A3EE9522-882F-47B0-BA7D-83420DC8577C is the filter that isolates the CER from every
    other federal department on the shared portal.
error_envelope:
  artifact: errors/canada-energy-regulator-problem-types.yml
  rfc9457: false
  note: Three different envelopes and two of them lie about the HTTP status. ArcGIS returns {"error":{"code","message","details"}}
    under HTTP 200. www.cer-rec.gc.ca returns a 4,405-byte HTML error page under HTTP 200 for every unknown path.
    CKAN is the only surface that sets a truthful status code. Status-code-only error handling will not work against
    this provider.
rate_limiting:
  documented: false
  headers_observed: []
  note: No rate-limit policy is published and no RateLimit/X-RateLimit/Retry-After header was observed on any surface.
    The practical ceilings are transfer limits (ArcGIS maxRecordCount), not request budgets.
request_tracing:
  request_id_header: null
  note: No request-id or correlation header observed on any surface.
versioning:
  artifact: lifecycle/canada-energy-regulator-lifecycle.yml
  note: 'Version is per upstream product: ArcGIS Online currentVersion 12, FGP ArcGIS Server 10.81, CKAN Action API
    v3 in the URI path, WMS 1.3.0 as a required query parameter.'
bilingualism:
  required: true
  note: The Official Languages Act shows up in the data contract itself. Field pairs are suffixed _en/_fr or _FRA
    (name_en/name_fr, Pipeline_Name/Pipeline_Name_FRA, feature_name/feature_name_fr), and the incident layer is published
    twice as separate services with translated FIELD NAMES — Incident_Data_French uses Numéro_d_i, Société, État.
    A client cannot switch language by parameter; it must switch service and remap every field.
licensing:
  name: Open Government Licence - Canada
  id: ca-ogl-lgo
  url: https://open.canada.ca/en/open-government-licence-canada
  note: All 83 CER datasets carry ca-ogl-lgo — verified across every package on 2026-07-27. Attribution required;
    no agreement to execute.
client_gotchas:
- open.canada.ca requires a browser-like User-Agent or its WAF returns an HTML "Request Rejected" body under HTTP
  200.
- ArcGIS errors arrive under HTTP 200 — parse the body, never branch on status alone.
- 'www.cer-rec.gc.ca soft-404s: every unknown path returns HTTP 200 with the same 4,405-byte HTML page.'
- Only 1 of 944 CKAN resources is loaded into the datastore, so datastore_search is effectively unavailable; the real
  pattern is metadata over the API then bulk CSV download.
- ArcGIS field names are truncated to 10 characters in several layers (Incident_N, Reported_D, What_Happe) — a shapefile-era
  artefact preserved in the JSON contract.