⚠️ 待更新·2026-08-29核验 · 更新时间待核验 · 本文信息可能已过期，请以官方文档为准
更新时间：2026-08-29 · 核验状态：待更新 · 官方溯源待补
背景
移动端调模型有三个独有问题:网络抖动(地铁、电梯)、电量预算(后台不能持续跑)、首屏延迟敏感(用户对 >2s 等待容忍度极低)。直接用 openai-python 不可行——它是为服务器写的,没有重试退避、流式回压、离线缓存。需要为 iOS / Android 各做一个轻量 SDK,封装到统一网关。
SDK 设计要点
- 统一接口:
chat(messages, model, stream=True) 是唯一入口,内部根据平台选 HTTP 实现(iOS 用 URLSession,Android 用 OkHttp)。
- 弱网重试:网络层用 exponential backoff + jitter,3 次内重试;对
timeout / connection reset 可重试,对 4xx 不重试。
- 流式渲染:SSE chunk 接到后立即推到 UI 线程,用
DispatchQueue.Main / MainScope 隔离,避免 UI 卡顿。
- 电量预算:大模型调用标记为
opportunistic,低电量模式下自动降级到更便宜的模型;后台调用要求充电 + WiFi 双条件。
- 离线缓存:同一 prompt 的响应落 SQLite,断网时返回最近缓存 + 透明提示"离线结果"。
- Token 安全:用户 token 用 Keychain / Keystore 存,不进 NSUserDefaults / SharedPreferences。
代码示例 (Swift 伪代码)
class APIShareClient {
let session = URLSession(configuration: .default)
let cache = ResponseCache() // SQLite-backed
let token = Keychain.read("apshare_token")
func chat(_ messages: [Message], model: String,
onChunk: @escaping (String) -> Void) async throws {
// 1. try cache
if let cached = cache.get(messages, model) {
onChunk(cached); return
}
// 2. streaming request with retry
let req = try buildRequest(messages, model)
for attempt in 0..<3 {
do {
let (bytes, _) = try await session.bytes(for: req)
var buffer = ""
for try await line in bytes.lines {
guard line.hasPrefix("data: ") else { continue }
let json = try JSON(line.dropFirst(6))
let delta = json.choices[0].delta.content
await MainActor.run { onChunk(delta) }
buffer += delta
}
cache.set(messages, model, buffer)
return
} catch let e as URLError where e.isRetryable {
try await Task.sleep(nanoseconds: backoffNs(attempt))
continue
}
}
throw APIError.timeout
}
}
App 更新粒度与 SDK 兼容
移动 SDK 的最大约束是"用户不更新 App":你发了新版 SDK 修复了 bug,但 30% 用户还在用 1 个月前的版本。SDK 必须做向后兼容承诺:大版本号 3 年不变,小版本只加字段不删字段,字段语义不改。同时利用"配置下发"机制,网关可以下发开关控制 SDK 行为(如禁用某个 Provider、调整重试次数),不需要用户更新 App。
最佳实践
- 二进制体积:SDK <500KB,避免被 App 主包拖大。
- 隐私清单:iOS 17+ 要求 SDK 声明
PrivacyInfo.xcprivacy,模型调用 SDK 必须声明"无数据采集"。
- A/B 路由:SDK 支持
apshare-config 下发的实验分组,方便灰度新模型。
- 崩溃兜底:网关返回的 JSON 解析失败时返回一个固定 fallback 文本,而不是 crash。
- 网络分级:WiFi 走高质量模型,蜂窝走轻量模型,节省电量的同时保持体验。
让 App 也享受统一网关:一套接口、一组重试、一份缓存策略,跨平台一致。
⚠️ Pending Update · 2026-08-29 Verification · Content may be outdated, please refer to official docs
Updated: 2026-08-29 · Status: Pending Verification
Background
Calling models from mobile has three unique problems: network jitter (subway, elevator), battery budget (no sustained background runs), and first-screen latency sensitivity (users tolerate >2s waits poorly). Using openai-python directly does not work — it was written for servers, with no retry backoff, no streaming backpressure, no offline cache. iOS and Android each need a lightweight SDK wrapping the unified gateway.
SDK Design Points
- Unified interface:
chat(messages, model, stream=True) is the only entry; internally it picks the platform HTTP implementation (URLSession on iOS, OkHttp on Android).
- Weak-network retries: exponential backoff + jitter at the network layer, up to 3 retries; retryable on
timeout / connection reset, not on 4xx.
- Streaming rendering: push SSE chunks to the UI thread immediately, isolated via
DispatchQueue.Main / MainScope to prevent UI stutter.
- Battery budget: model calls are tagged
opportunistic; in low-battery mode they auto-degrade to a cheaper model; background calls require charging + Wi-Fi.
- Offline cache: responses for the same prompt land in SQLite; when offline, return the latest cache with a transparent "offline result" hint.
- Token security: the user token lives in Keychain / Keystore, never in NSUserDefaults / SharedPreferences.
Code Example (Swift pseudocode)
class APIShareClient {
let session = URLSession(configuration: .default)
let cache = ResponseCache() // SQLite-backed
let token = Keychain.read("apshare_token")
func chat(_ messages: [Message], model: String,
onChunk: @escaping (String) -> Void) async throws {
// 1. try cache
if let cached = cache.get(messages, model) {
onChunk(cached); return
}
// 2. streaming request with retry
let req = try buildRequest(messages, model)
for attempt in 0..<3 {
do {
let (bytes, _) = try await session.bytes(for: req)
var buffer = ""
for try await line in bytes.lines {
guard line.hasPrefix("data: ") else { continue }
let json = try JSON(line.dropFirst(6))
let delta = json.choices[0].delta.content
await MainActor.run { onChunk(delta) }
buffer += delta
}
cache.set(messages, model, buffer)
return
} catch let e as URLError where e.isRetryable {
try await Task.sleep(nanoseconds: backoffNs(attempt))
continue
}
}
throw APIError.timeout
}
}
App Update Granularity and SDK Compatibility
The biggest constraint on mobile SDKs is "users do not update": you ship a new SDK version fixing a bug, but 30% of users are still on last month's build. The SDK must make a backward compatibility promise: major version stays stable for 3 years, minor versions only add fields (never remove), and field semantics never change. Combined with a "config push" mechanism — the gateway pushes flags that control SDK behavior (disable a provider, tune retry counts) without requiring an app update.
Best Practices
- Binary footprint: keep the SDK under 500KB so it does not bloat the app's main bundle.
- Privacy manifest: iOS 17+ requires SDKs to declare
PrivacyInfo.xcprivacy; a model-calling SDK must declare "no data collection."
- A/B routing: the SDK supports experiment groups from
apshare-config for easy model canarying.
- Crash fallback: when JSON parsing of the gateway response fails, return a fixed fallback text instead of crashing.
- Network tiering: route over Wi-Fi to high-quality models, over cellular to lightweight ones, saving battery without losing the experience.
Let apps share the unified gateway too: one interface, one set of retries, one cache strategy, consistent across platforms.