[AI] Server Prompt Templates (#15402)

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com> Co-authored-by: Andrew Heard <andrewheard@google.com> Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: 4 people

FirebaseAI/Sources/AILog.swift

@@ -87,6 +87,7 @@ enum AILog {
  case generateContentResponseEmptyCandidates = 4003
  case invalidWebsocketURL = 4004
  case duplicateLiveSessionSetupComplete = 4005
+ case malformedURL = 4006
 
  // SDK Debugging
  case loadRequestStreamResponseLine = 5000
@@ -138,6 +139,17 @@ enum AILog {
  log(level: .debug, code: code, message)
  }
 
+ @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+ static func makeInternalError(message: String, code: MessageCode) -> GenerateContentError {
+ let error = GenerateContentError.internalError(underlying: NSError(
+ domain: "\(Constants.baseErrorDomain).Internal",
+ code: code.rawValue,
+ userInfo: [NSLocalizedDescriptionKey: message]
+ ))
+ AILog.error(code: code, message)
+ return error
+ }
+
  /// Returns `true` if additional logging has been enabled via a launch argument.
  static func additionalLoggingEnabled() -> Bool {
  return ProcessInfo.processInfo.arguments.contains(enableArgumentKey)

FirebaseAI/Sources/Chat.swift

@@ -19,35 +19,21 @@ import Foundation
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public final class Chat: Sendable {
  private let model: GenerativeModel
+ private let _history: History
 
- /// Initializes a new chat representing a 1:1 conversation between model and user.
  init(model: GenerativeModel, history: [ModelContent]) {
  self.model = model
- self.history = history
+ _history = History(history: history)
  }
 
- private let historyLock = NSLock()
- private nonisolated(unsafe) var _history: [ModelContent] = []
  /// The previous content from the chat that has been successfully sent and received from the
  /// model. This will be provided to the model for each message sent as context for the discussion.
  public var history: [ModelContent] {
  get {
- historyLock.withLock { _history }
+ return _history.history
  }
  set {
- historyLock.withLock { _history = newValue }
- }
- }
-
- private func appendHistory(contentsOf: [ModelContent]) {
- historyLock.withLock {
- _history.append(contentsOf: contentsOf)
- }
- }
-
- private func appendHistory(_ newElement: ModelContent) {
- historyLock.withLock {
- _history.append(newElement)
+ _history.history = newValue
  }
  }
 
@@ -87,8 +73,8 @@ public final class Chat: Sendable {
  let toAdd = ModelContent(role: "model", parts: reply.parts)
 
  // Append the request and successful result to history, then return the value.
- appendHistory(contentsOf: newContent)
- appendHistory(toAdd)
+ _history.append(contentsOf: newContent)
+ _history.append(toAdd)
  return result
  }
 
@@ -136,63 +122,16 @@ public final class Chat: Sendable {
  }
 
  // Save the request.
- appendHistory(contentsOf: newContent)
+ _history.append(contentsOf: newContent)
 
  // Aggregate the content to add it to the history before we finish.
- let aggregated = self.aggregatedChunks(aggregatedContent)
- self.appendHistory(aggregated)
+ let aggregated = self._history.aggregatedChunks(aggregatedContent)
+ self._history.append(aggregated)
  continuation.finish()
  }
  }
  }
 
- private func aggregatedChunks(_ chunks: [ModelContent]) -> ModelContent {
- var parts: [InternalPart] = []
- var combinedText = ""
- var combinedThoughts = ""
-
- func flush() {
- if !combinedThoughts.isEmpty {
- parts.append(InternalPart(.text(combinedThoughts), isThought: true, thoughtSignature: nil))
- combinedThoughts = ""
- }
- if !combinedText.isEmpty {
- parts.append(InternalPart(.text(combinedText), isThought: nil, thoughtSignature: nil))
- combinedText = ""
- }
- }
-
- // Loop through all the parts, aggregating the text.
- for part in chunks.flatMap({ $0.internalParts }) {
- // Only text parts may be combined.
- if case let .text(text) = part.data, part.thoughtSignature == nil {
- // Thought summaries must not be combined with regular text.
- if part.isThought ?? false {
- // If we were combining regular text, flush it before handling "thoughts".
- if !combinedText.isEmpty {
- flush()
- }
- combinedThoughts += text
- } else {
- // If we were combining "thoughts", flush it before handling regular text.
- if !combinedThoughts.isEmpty {
- flush()
- }
- combinedText += text
- }
- } else {
- // This is a non-combinable part (not text), flush any pending text.
- flush()
- parts.append(part)
- }
- }
-
- // Flush any remaining text.
- flush()
-
- return ModelContent(role: "model", parts: parts)
- }
-
  /// Populates the `role` field with `user` if it doesn't exist. Required in chat sessions.
  private func populateContentRole(_ content: ModelContent) -> ModelContent {
  if content.role != nil {

FirebaseAI/Sources/FirebaseAI.swift

@@ -135,6 +135,28 @@ public final class FirebaseAI: Sendable {
  )
  }
 
+ /// Initializes a new `TemplateGenerativeModel`.
+ ///
+ /// - Returns: A new `TemplateGenerativeModel` instance.
+ public func templateGenerativeModel() -> TemplateGenerativeModel {
+ return TemplateGenerativeModel(
+ generativeAIService: GenerativeAIService(firebaseInfo: firebaseInfo,
+ urlSession: GenAIURLSession.default),
+ apiConfig: apiConfig
+ )
+ }
+
+ /// Initializes a new `TemplateImagenModel`.
+ ///
+ /// - Returns: A new `TemplateImagenModel` instance.
+ public func templateImagenModel() -> TemplateImagenModel {
+ return TemplateImagenModel(
+ generativeAIService: GenerativeAIService(firebaseInfo: firebaseInfo,
+ urlSession: GenAIURLSession.default),
+ apiConfig: apiConfig
+ )
+ }
+
  /// **[Public Preview]** Initializes a ``LiveGenerativeModel`` with the given parameters.
  ///
  /// - Note: Refer to [the Firebase docs on the Live

FirebaseAI/Sources/GenerateContentRequest.swift

@@ -73,15 +73,23 @@ extension GenerateContentRequest {
 extension GenerateContentRequest: GenerativeAIRequest {
  typealias Response = GenerateContentResponse
 
- var url: URL {
+ func getURL() throws -> URL {
  let modelURL = "\(apiConfig.service.endpoint.rawValue)/\(apiConfig.version.rawValue)/\(model)"
+ let urlString: String
  switch apiMethod {
  case .generateContent:
- return URL(string: "\(modelURL):\(apiMethod.rawValue)")!
+ urlString = "\(modelURL):\(apiMethod.rawValue)"
  case .streamGenerateContent:
- return URL(string: "\(modelURL):\(apiMethod.rawValue)?alt=sse")!
+ urlString = "\(modelURL):\(apiMethod.rawValue)?alt=sse"
  case .countTokens:
- fatalError("\(Self.self) should be a property of \(CountTokensRequest.self).")
+ throw AILog.makeInternalError(
+ message: "\(Self.self) should be a property of \(CountTokensRequest.self).",
+ code: .malformedURL
+ )
  }
+ guard let url = URL(string: urlString) else {
+ throw AILog.makeInternalError(message: "Malformed URL: \(urlString)", code: .malformedURL)
+ }
+ return url
  }
 }

FirebaseAI/Sources/GenerativeAIRequest.swift

@@ -18,7 +18,7 @@ import Foundation
 protocol GenerativeAIRequest: Sendable, Encodable {
  associatedtype Response: Sendable, Decodable
 
- var url: URL { get }
+ func getURL() throws -> URL
 
  var options: RequestOptions { get }
 }

FirebaseAI/Sources/GenerativeAIService.swift

@@ -26,7 +26,7 @@ struct GenerativeAIService {
  /// The Firebase SDK version in the format `fire/<version>`.
  static let firebaseVersionTag = "fire/\(FirebaseVersion())"
 
- private let firebaseInfo: FirebaseInfo
+ let firebaseInfo: FirebaseInfo
 
  private let urlSession: URLSession
 
@@ -167,7 +167,7 @@ struct GenerativeAIService {
  // MARK: - Private Helpers
 
  private func urlRequest<T: GenerativeAIRequest>(request: T) async throws -> URLRequest {
- var urlRequest = URLRequest(url: request.url)
+ var urlRequest = try URLRequest(url: request.getURL())
  urlRequest.httpMethod = "POST"
  urlRequest.setValue(firebaseInfo.apiKey, forHTTPHeaderField: "x-goog-api-key")
  urlRequest.setValue(

FirebaseAI/Sources/History.swift

@@ -0,0 +1,94 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+final class History: Sendable {
+ private let historyLock = NSLock()
+ private nonisolated(unsafe) var _history: [ModelContent] = []
+ /// The previous content from the chat that has been successfully sent and received from the
+ /// model. This will be provided to the model for each message sent as context for the discussion.
+ public var history: [ModelContent] {
+ get {
+ historyLock.withLock { _history }
+ }
+ set {
+ historyLock.withLock { _history = newValue }
+ }
+ }
+
+ init(history: [ModelContent]) {
+ self.history = history
+ }
+
+ func append(contentsOf: [ModelContent]) {
+ historyLock.withLock {
+ _history.append(contentsOf: contentsOf)
+ }
+ }
+
+ func append(_ newElement: ModelContent) {
+ historyLock.withLock {
+ _history.append(newElement)
+ }
+ }
+
+ func aggregatedChunks(_ chunks: [ModelContent]) -> ModelContent {
+ var parts: [InternalPart] = []
+ var combinedText = ""
+ var combinedThoughts = ""
+
+ func flush() {
+ if !combinedThoughts.isEmpty {
+ parts.append(InternalPart(.text(combinedThoughts), isThought: true, thoughtSignature: nil))
+ combinedThoughts = ""
+ }
+ if !combinedText.isEmpty {
+ parts.append(InternalPart(.text(combinedText), isThought: nil, thoughtSignature: nil))
+ combinedText = ""
+ }
+ }
+
+ // Loop through all the parts, aggregating the text.
+ for part in chunks.flatMap({ $0.internalParts }) {
+ // Only text parts may be combined.
+ if case let .text(text) = part.data, part.thoughtSignature == nil {
+ // Thought summaries must not be combined with regular text.
+ if part.isThought ?? false {
+ // If we were combining regular text, flush it before handling "thoughts".
+ if !combinedText.isEmpty {
+ flush()
+ }
+ combinedThoughts += text
+ } else {
+ // If we were combining "thoughts", flush it before handling regular text.
+ if !combinedThoughts.isEmpty {
+ flush()
+ }
+ combinedText += text
+ }
+ } else {
+ // This is a non-combinable part (not text), flush any pending text.
+ flush()
+ parts.append(part)
+ }
+ }
+
+ // Flush any remaining text.
+ flush()
+
+ return ModelContent(role: "model", parts: parts)
+ }
+}