in FirebaseMLModelDownloader/Sources/ModelInfoRetriever.swift [138:468]
func downloadModelInfo(completion: @escaping (Result<DownloadModelInfoResult, DownloadError>)
-> Void) {
authTokenProvider { result in
switch result {
// Successfully received FIS token.
case let .success(authToken):
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.DebugDescription
.receivedAuthToken,
messageCode: .validAuthToken)
// Get model info fetch URL with appropriate HTTP headers.
guard let request = self.getModelInfoFetchURLRequest(token: authToken) else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.invalidModelInfoFetchURL,
messageCode: .invalidModelInfoFetchURL)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(name: self.modelName,
size: 0,
path: "",
hash: ""),
modelInfoErrorCode: .connectionFailed)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.invalidModelInfoFetchURL)))
return
}
// Download model info.
self.session.getModelInfo(with: request) {
data, response, error in
if let downloadError = error {
let description = ModelInfoRetriever.ErrorDescription
.failedModelInfoRetrieval(downloadError.localizedDescription)
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .modelInfoRetrievalError)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .connectionFailed)
completion(.failure(.internalError(description: description)))
} else {
guard let httpResponse = response as? HTTPURLResponse else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.invalidHTTPResponse,
messageCode: .invalidHTTPResponse)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .connectionFailed)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.invalidHTTPResponse)))
return
}
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.DebugDescription
.receivedServerResponse,
messageCode: .validHTTPResponse)
switch httpResponse.statusCode {
case 200:
guard let modelHash = httpResponse
.allHeaderFields[ModelInfoRetriever.etagHTTPHeader] as? String else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription.missingModelHash,
messageCode: .missingModelHash)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .noHash)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.missingModelHash)))
return
}
guard let data = data else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.invalidHTTPResponse,
messageCode: .invalidHTTPResponse)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .unknown)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.invalidHTTPResponse)))
return
}
do {
// Parse model info from HTTP response.
let modelInfo = try self.getRemoteModelInfoFromResponse(data, modelHash: modelHash)
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.DebugDescription
.modelInfoDownloaded,
messageCode: .modelInfoDownloaded)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalSucceeded,
model: CustomModel(
name: self.modelName,
size: modelInfo.size,
path: "",
hash: modelInfo.modelHash
),
modelInfoErrorCode: .noError)
completion(.success(.modelInfo(modelInfo)))
} catch {
let description = ModelInfoRetriever.ErrorDescription
.invalidModelInfoJSON(error.localizedDescription)
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .invalidModelInfoJSON)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .unknown)
completion(
.failure(.internalError(description: description))
)
}
case 304:
// For this case to occur, local model info has to already be available on device.
guard let localInfo = self.localModelInfo else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.unexpectedModelInfoDeletion,
messageCode: .modelInfoDeleted)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .unknown)
completion(
.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.unexpectedModelInfoDeletion))
)
return
}
guard let modelHash = httpResponse
.allHeaderFields[ModelInfoRetriever.etagHTTPHeader] as? String else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.missingModelHash,
messageCode: .noModelHash)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .noHash)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.missingModelHash)))
return
}
// Ensure that there is local model info on device with matching hash.
guard modelHash == localInfo.modelHash else {
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.modelHashMismatch,
messageCode: .modelHashMismatchError)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: modelHash
),
modelInfoErrorCode: .hashMismatch)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.modelHashMismatch)))
return
}
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.DebugDescription
.modelInfoUnmodified,
messageCode: .modelInfoUnmodified)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalSucceeded,
model: CustomModel(
name: self.modelName,
size: localInfo.size,
path: "",
hash: localInfo.modelHash
),
modelInfoErrorCode: .noError)
completion(.success(.notModified))
case 400:
let errorMessage = self.getErrorFromResponse(data)
let description = errorMessage ?? ModelInfoRetriever.ErrorDescription
.invalidArgument(self.modelName)
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .invalidArgument)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .httpError(code: httpResponse
.statusCode))
completion(.failure(.invalidArgument))
case 401, 403:
// Error could be due to FirebaseML API not enabled for project, or invalid permissions.
let errorMessage = self.getErrorFromResponse(data)
let description = errorMessage ?? ModelInfoRetriever.ErrorDescription.permissionDenied
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .permissionDenied)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .httpError(code: httpResponse
.statusCode))
completion(.failure(.permissionDenied))
case 404:
let errorMessage = self.getErrorFromResponse(data)
let description = errorMessage ?? ModelInfoRetriever.ErrorDescription
.modelNotFound(self.modelName)
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .modelNotFound)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .httpError(code: httpResponse
.statusCode))
completion(.failure(.notFound))
case 429:
let errorMessage = self.getErrorFromResponse(data)
let description = errorMessage ?? ModelInfoRetriever.ErrorDescription
.resourceExhausted
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .resourceExhausted)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .httpError(code: httpResponse
.statusCode))
completion(.failure(.resourceExhausted))
default:
let errorMessage = self.getErrorFromResponse(data)
let description = errorMessage ?? ModelInfoRetriever.ErrorDescription
.modelInfoRetrievalFailed(httpResponse.statusCode)
DeviceLogger.logEvent(level: .debug,
message: description,
messageCode: .modelInfoRetrievalError)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .httpError(code: httpResponse
.statusCode))
completion(.failure(.internalError(description: description)))
}
}
}
// Error retrieving auth token.
case .failure:
DeviceLogger.logEvent(level: .debug,
message: ModelInfoRetriever.ErrorDescription
.authTokenError,
messageCode: .authTokenError)
self.telemetryLogger?.logModelInfoRetrievalEvent(eventName: .modelDownload,
status: .modelInfoRetrievalFailed,
model: CustomModel(
name: self.modelName,
size: 0,
path: "",
hash: ""
),
modelInfoErrorCode: .unknown)
completion(.failure(.internalError(description: ModelInfoRetriever.ErrorDescription
.authTokenError)))
return
}
}
}