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In the case of Shibboleth Service Provider software, applications or protected scripts have access to the identity provider's entityID via the Shib-Identity-Provider variable/header. Other information in the IdP's metadata, such as the errorURL, user interface extensions, and contact information, are not easily accessible except by parsing the metadata directly. The Federated Error Handling Service offers a simplified mechanism for obtaining the errorURL value from metadata.
To integrate a Shibboleth SP with the Federated Error Handling Service, follow the error-handling instructions in the Shib wiki carefully.