//! Crate-specific errors (using `failure`) //! //! The justification for this complexity is that we need to return correct HTTP error types as //! well as helpful error messages in API responses. // Design goals: // - be able to call '?' on random things and collect them in endpoint handlers // - be able to 'bail!()' and 'ensure!()' and have those end up as InternalErrors // - do conversion into ErrorResponse model in this file, not endpoint handlers, and ErrorReponse // should have good context about the error // // Plan: // - use .map_err() to convert to the correct type // - map to pub use failure::Error; use failure::Fail; use fatcat_api_spec::models; use std::result; /// A type alias for handling errors throughout this crate pub type Result<T> = result::Result<T, Error>; #[derive(Debug, Fail, Clone)] pub enum FatcatError { #[fail(display = "no such {} found: {}", _0, _1)] NotFound(String, String), #[fail( display = "invalid fatcat identifier (expect 26-char base32 encoded): {}", _0 )] InvalidFatcatId(String), #[fail( display = "external identifier doesn't match required pattern for a {}: {}", _0, _1 )] MalformedExternalId(String, String), #[fail( display = "checksum doesn't match required pattern ({} in hex encoding): {}", _0, _1 )] MalformedChecksum(String, String), #[fail(display = "not a valid UUID: {}", _0)] MalformedUuid(String), #[fail(display = "'{}' is not a an known/acceptable '{}' value", _1, _0)] NotInControlledVocabulary(String, String), // vocab, word #[fail( display = "attempted to accept or mutate an editgroup which was already accepted: {}", _0 )] EditgroupAlreadyAccepted(String), #[fail( display = "external identifiers missing or multiple specified; please supply exactly one: {}", _0 )] MissingOrMultipleExternalId(String), #[fail(display = "tried to mutate an entity into impossible state: {}", _0)] InvalidEntityStateTransform(String), #[fail( display = "auth token was missing, expired, revoked, or corrupt: {}", _0 )] InvalidCredentials(String), #[fail(display = "editor account doesn't have authorization: {}", _0)] InsufficientPrivileges(String), #[fail( display = "broke a constraint or made an otherwise invalid request: {}", _0 )] // Utf8Decode, StringDecode, Uuid BadRequest(String), #[fail(display = "unexpected database error: {}", _0)] // Diesel constraint that we think is a user error ConstraintViolation(String), // TODO: can these hold context instead of Inner? #[fail(display = "unexpected database error: {}", _0)] // other Diesel, R2d2 errors which we don't think are user errors (eg, connection failure) DatabaseError(String), #[fail(display = "unexpected internal error: {}", _0)] // Fmt, Io, Serde, InternalError(String), } // NOTE: this enum is not exhaustive and shouldn't be matched over! impl Into<models::ErrorResponse> for FatcatError { /// Format an error as an API response (ErrorResponse model, used by all HTTP 4xx and 5xx /// responses) fn into(self) -> models::ErrorResponse { // TODO: something more complex? context? models::ErrorResponse { success: false, // enum variant name, without fields. whew, what a pile error: format!("{:?}", self).split('(').collect::<Vec<&str>>()[0].to_string(), message: self.to_string(), } } } impl From<diesel::result::Error> for FatcatError { fn from(inner: diesel::result::Error) -> FatcatError { match inner { diesel::result::Error::NotFound => { FatcatError::NotFound("unknown".to_string(), "N/A".to_string()) } diesel::result::Error::DatabaseError(_, _) => { FatcatError::ConstraintViolation(inner.to_string()) } _ => FatcatError::InternalError(inner.to_string()), } } } impl From<std::fmt::Error> for FatcatError { fn from(inner: std::fmt::Error) -> FatcatError { FatcatError::InternalError(inner.to_string()) } } impl From<diesel::r2d2::Error> for FatcatError { fn from(inner: diesel::r2d2::Error) -> FatcatError { FatcatError::InternalError(inner.to_string()) } } impl From<uuid::ParseError> for FatcatError { fn from(inner: uuid::ParseError) -> FatcatError { FatcatError::MalformedUuid(inner.to_string()) } } impl From<serde_json::Error> for FatcatError { fn from(inner: serde_json::Error) -> FatcatError { FatcatError::InternalError(inner.to_string()) } } impl From<std::string::FromUtf8Error> for FatcatError { fn from(inner: std::string::FromUtf8Error) -> FatcatError { FatcatError::InternalError(inner.to_string()) } } impl From<data_encoding::DecodeError> for FatcatError { fn from(inner: data_encoding::DecodeError) -> FatcatError { FatcatError::InternalError(inner.to_string()) } } // A big catchall! impl From<failure::Error> for FatcatError { fn from(error: failure::Error) -> FatcatError { // TODO: I think it should be possible to match here? regardless, this is *super* janky if let Some(_) = error.downcast_ref::<FatcatError>() { return error.downcast::<FatcatError>().unwrap(); } if let Some(_) = error.downcast_ref::<std::fmt::Error>() { return error.downcast::<std::fmt::Error>().unwrap().into(); } if let Some(_) = error.downcast_ref::<diesel::result::Error>() { return error.downcast::<diesel::result::Error>().unwrap().into(); } if let Some(_) = error.downcast_ref::<uuid::ParseError>() { return error.downcast::<uuid::ParseError>().unwrap().into(); } FatcatError::InternalError(error.to_string()) } }