Confidential Client and Network Errors

Table of contents

  1. Confidential Client and Network Errors
    1. Dynamic Client Registration Errors
      1. DiscoveryError: Server does not advertise a registration endpoint
      2. RegistrationError: Server rejected the registration request
      3. RegistrationError: 2xx response missing client_id
    2. Confidential Symmetric Client Errors
      1. ConfigurationError: Missing client_secret
      2. 401 Unauthorized with Basic Auth
    3. Confidential Asymmetric Client Errors
      1. ConfigurationError: Missing private_key or kid
      2. 401 Unauthorized with JWT assertion
    4. Backend Services Errors
      1. ConfigurationError: Missing private_key or kid
    5. Network Errors
      1. NetworkError: Connection refused or timeout
      2. NetworkError: Blocked redirect to non-HTTPS URL

Dynamic Client Registration Errors

DiscoveryError: Server does not advertise a registration endpoint

Safire::Errors::DiscoveryError: Failed to discover SMART configuration from https://...: server does not advertise a 'registration_endpoint'

The server either does not support Dynamic Client Registration or its registration endpoint is not published in /.well-known/smart-configuration. Pass the endpoint explicitly or register manually through the server’s developer portal:

registration = client.register_client(
  metadata,
  registration_endpoint: 'https://auth.example.com/register'
)

RegistrationError: Server rejected the registration request

Safire::Errors::RegistrationError: Client registration failed — HTTP 400 — invalid_redirect_uri — Redirect URI must use HTTPS

The server returned an OAuth 2.0 error response. Check e.error_code and e.error_description for the specific reason, correct the metadata, and retry:

rescue Safire::Errors::RegistrationError => e
  puts e.status            # 400
  puts e.error_code        # "invalid_redirect_uri"
  puts e.error_description # "Redirect URI must use HTTPS"

RegistrationError: 2xx response missing client_id

Safire::Errors::RegistrationError: Registration response missing client_id; received fields: error, error_description

The server returned a successful HTTP status but did not include client_id. This typically means the server returned an error body with a 2xx status code, which is a server-side bug. Check e.received_fields to see what was returned.


Confidential Symmetric Client Errors

ConfigurationError: Missing client_secret

Safire::Errors::ConfigurationError: Configuration missing: client_secret

client_secret must be present when using :confidential_symmetric:

config = Safire::ClientConfig.new(
  client_secret: ENV.fetch('SMART_CLIENT_SECRET'),
  # ...
)
client = Safire::Client.new(config, client_type: :confidential_symmetric)

You can also pass it as an override directly to the token call — useful when rotating secrets:

tokens = client.request_access_token(
  code: code, code_verifier: verifier,
  client_secret: ENV.fetch('SMART_CLIENT_SECRET')
)

401 Unauthorized with Basic Auth

Causes: incorrect credentials, or the server does not support client_secret_basic.

Verify the server supports Basic Auth before debugging credentials:

metadata = client.server_metadata
unless metadata.token_endpoint_auth_methods_supported.include?('client_secret_basic')
  raise 'Server does not support client_secret_basic'
end

Safire encodes credentials with Base64.strict_encode64 — special characters in secrets are handled automatically.


Confidential Asymmetric Client Errors

ConfigurationError: Missing private_key or kid

Safire::Errors::ConfigurationError: Configuration missing: private_key, kid

Both are required for :confidential_asymmetric:

config = Safire::ClientConfig.new(
  private_key: OpenSSL::PKey::RSA.new(File.read(ENV['SMART_PRIVATE_KEY_PATH'])),
  kid:         ENV.fetch('SMART_KEY_ID'),
  # ...
)
client = Safire::Client.new(config, client_type: :confidential_asymmetric)

401 Unauthorized with JWT assertion

Causes: key mismatch, wrong kid, clock skew, or server does not support private_key_jwt.

Verify private_key_jwt is supported:

metadata = client.server_metadata
unless metadata.token_endpoint_auth_methods_supported.include?('private_key_jwt')
  raise 'Server does not support private_key_jwt'
end

Verify the public key registered with the server matches the private key you are using, and that the kid value matches the key ID the server expects. Safire sets JWT exp to 5 minutes from iat — if your system clock is significantly skewed from the server, assertions will be rejected.


Backend Services Errors

ConfigurationError: Missing private_key or kid

Safire::Errors::ConfigurationError: Configuration missing: private_key, kid

request_backend_token validates private_key and kid when building the JWT assertion. Ensure both are in config or passed as overrides:

# In config (preferred)
config = Safire::ClientConfig.new(
  private_key: OpenSSL::PKey::RSA.new(File.read(ENV['SMART_PRIVATE_KEY_PATH'])),
  kid:         ENV.fetch('SMART_KEY_ID'),
  # ...
)
client = Safire::Client.new(config)

# Or override per call
client.request_backend_token(
  private_key: OpenSSL::PKey::RSA.new(File.read(ENV['SMART_PRIVATE_KEY_PATH'])),
  kid:         ENV.fetch('SMART_KEY_ID')
)

See Backend Services — Prerequisites for key generation steps.


Network Errors

NetworkError: Connection refused or timeout

Safire::Errors::NetworkError: HTTP request failed: Connection refused

Verify server connectivity before debugging Safire configuration:

curl -v https://fhir.example.com/.well-known/smart-configuration

For transient network failures, implement retry with exponential backoff in your application — see Advanced Examples for a reusable pattern.

NetworkError: Blocked redirect to non-HTTPS URL

Safire::Errors::NetworkError: Blocked redirect to non-HTTPS URL: http://fhir.example.com/...

Safire blocks redirects to non-HTTPS URLs (except localhost). Configure base_url with the final HTTPS URL directly, bypassing any HTTP-to-HTTPS redirect the server may use:

# ✅ Use the final HTTPS URL directly
base_url: 'https://fhir.example.com/r4'

# ❌ Will fail if the server redirects HTTP → HTTPS
base_url: 'http://fhir.example.com/r4'

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