feat(project): init

lib/openai.ts

@@ -0,0 +1,130 @@
+import "server-only";
+
+import { appConfig } from "@/lib/config";
+import type {
+  GenerateOutputFormat,
+  GeneratePayload,
+  GenerateResult,
+  GeneratedImage,
+  HttpError,
+} from "@/lib/types";
+
+interface OpenAiImageEntry {
+  b64_json?: string;
+  revised_prompt?: string | null;
+}
+
+interface OpenAiErrorBody {
+  message?: string;
+  [key: string]: unknown;
+}
+
+interface OpenAiImageResponse {
+  created?: number | null;
+  data?: OpenAiImageEntry[];
+  error?: OpenAiErrorBody;
+  usage?: unknown;
+}
+
+export async function generateImagesWithOpenAI(
+  payload: GeneratePayload,
+): Promise<GenerateResult> {
+  const startedAt = Date.now();
+  const response = await fetch(
+    `${appConfig.openAiBaseUrl.replace(/\/$/, "")}/images/generations`,
+    {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${appConfig.openAiApiKey}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify(payload),
+      signal: AbortSignal.timeout(appConfig.openAiTimeoutMs),
+    },
+  );
+  const responseBody = await parseJsonSafely(response);
+
+  if (!response.ok) {
+    const error = new Error(
+      responseBody?.error?.message ?? `OpenAI 返回了 ${response.status} 错误。`,
+    ) as HttpError;
+    error.statusCode = response.status;
+    error.detail = responseBody?.error ?? null;
+    throw error;
+  }
+
+  const images = Array.isArray(responseBody?.data)
+    ? responseBody.data
+        .map((entry, index) => mapGeneratedImage(entry, index, payload))
+        .filter((image): image is GeneratedImage => image !== null)
+    : [];
+
+  if (images.length === 0) {
+    const error = new Error(
+      "上游已返回成功，但没有拿到图片数据。",
+    ) as HttpError;
+    error.statusCode = 502;
+    throw error;
+  }
+
+  return {
+    images,
+    meta: {
+      model: payload.model,
+      size: payload.size,
+      quality: payload.quality,
+      outputFormat: payload.output_format,
+      background: payload.background,
+      moderation: payload.moderation,
+      outputCompression: payload.output_compression,
+      count: images.length,
+      durationMs: Date.now() - startedAt,
+      created: responseBody?.created ?? null,
+      usage: responseBody?.usage ?? null,
+    },
+  };
+}
+
+async function parseJsonSafely(
+  response: Response,
+): Promise<OpenAiImageResponse | null> {
+  try {
+    return (await response.json()) as OpenAiImageResponse;
+  } catch {
+    return null;
+  }
+}
+
+function mapGeneratedImage(
+  entry: OpenAiImageEntry,
+  index: number,
+  payload: GeneratePayload,
+): GeneratedImage | null {
+  if (!entry?.b64_json) {
+    return null;
+  }
+
+  const fileExtension =
+    payload.output_format === "jpeg" ? "jpg" : payload.output_format;
+  const mimeType = resolveMimeType(payload.output_format);
+
+  return {
+    id: `image-${index + 1}`,
+    base64: entry.b64_json,
+    mimeType,
+    fileName: `gpt-image-${Date.now()}-${index + 1}.${fileExtension}`,
+    revisedPrompt: entry.revised_prompt ?? null,
+  };
+}
+
+function resolveMimeType(outputFormat: GenerateOutputFormat): string {
+  if (outputFormat === "jpeg") {
+    return "image/jpeg";
+  }
+
+  if (outputFormat === "webp") {
+    return "image/webp";
+  }
+
+  return "image/png";
+}