feat(project): init

lib/request-schema.ts

@@ -0,0 +1,155 @@
+import type {
+  GenerateOutputFormat,
+  GeneratePayload,
+  HttpError,
+} from "@/lib/types";
+
+const SIZE_OPTIONS = ["auto", "1024x1024", "1536x1024", "1024x1536"] as const;
+const QUALITY_OPTIONS = ["auto", "low", "medium", "high"] as const;
+const OUTPUT_FORMAT_OPTIONS = ["png", "jpeg", "webp"] as const;
+const BACKGROUND_OPTIONS = ["auto", "transparent", "opaque"] as const;
+const MODERATION_OPTIONS = ["auto", "low"] as const;
+
+export function parseGenerateRequest(
+  body: unknown,
+  model: string,
+): GeneratePayload {
+  if (!isRecord(body)) {
+    throw createRequestError(400, "请求体必须是 JSON 对象。");
+  }
+
+  const prompt = normalizePrompt(body.prompt);
+  const size = normalizeEnum(body.size, SIZE_OPTIONS, "size");
+  const quality = normalizeEnum(body.quality, QUALITY_OPTIONS, "quality");
+  const outputFormat = normalizeEnum(
+    body.outputFormat,
+    OUTPUT_FORMAT_OPTIONS,
+    "outputFormat",
+  );
+  const background = normalizeEnum(
+    body.background,
+    BACKGROUND_OPTIONS,
+    "background",
+  );
+  const moderation = normalizeEnum(
+    body.moderation,
+    MODERATION_OPTIONS,
+    "moderation",
+  );
+  const count = normalizeCount(body.count);
+  const outputCompression = normalizeCompression(
+    body.outputCompression,
+    outputFormat,
+  );
+  const user = normalizeUser(body.user);
+
+  if (outputFormat === "jpeg" && background === "transparent") {
+    throw createRequestError(
+      400,
+      "JPEG 不支持透明背景，请改为 PNG / WEBP 或将背景改成不透明。",
+    );
+  }
+
+  const payload: GeneratePayload = {
+    model,
+    prompt,
+    size,
+    quality,
+    n: count,
+    moderation,
+    output_format: outputFormat,
+    background,
+  };
+
+  if (typeof outputCompression === "number") {
+    payload.output_compression = outputCompression;
+  }
+
+  if (user) {
+    payload.user = user;
+  }
+
+  return payload;
+}
+
+export function createRequestError(
+  statusCode: number,
+  message: string,
+): HttpError {
+  const error = new Error(message) as HttpError;
+  error.statusCode = statusCode;
+  return error;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return Boolean(value) && typeof value === "object" && !Array.isArray(value);
+}
+
+function normalizePrompt(value: unknown): string {
+  const prompt = String(value ?? "").trim();
+
+  if (!prompt) {
+    throw createRequestError(400, "Prompt 不能为空。");
+  }
+
+  if (prompt.length > 32000) {
+    throw createRequestError(400, "Prompt 不能超过 32000 个字符。");
+  }
+
+  return prompt;
+}
+
+function normalizeEnum<T extends string>(
+  value: unknown,
+  options: readonly T[],
+  fieldName: string,
+): T {
+  const normalizedValue = (String(value ?? "").trim() || options[0]) as T;
+
+  if (!options.includes(normalizedValue)) {
+    throw createRequestError(400, `字段 ${fieldName} 的取值不合法。`);
+  }
+
+  return normalizedValue;
+}
+
+function normalizeCount(value: unknown): number {
+  const numericValue = Number.parseInt(String(value ?? "1"), 10);
+
+  if (!Number.isFinite(numericValue) || numericValue < 1 || numericValue > 4) {
+    throw createRequestError(400, "单次最多生成 4 张图片。");
+  }
+
+  return numericValue;
+}
+
+function normalizeCompression(
+  value: unknown,
+  outputFormat: GenerateOutputFormat,
+): number | undefined {
+  if (outputFormat === "png") {
+    return undefined;
+  }
+
+  const numericValue = Number.parseInt(String(value ?? "90"), 10);
+
+  if (
+    !Number.isFinite(numericValue) ||
+    numericValue < 0 ||
+    numericValue > 100
+  ) {
+    throw createRequestError(400, "压缩质量必须在 0 到 100 之间。");
+  }
+
+  return numericValue;
+}
+
+function normalizeUser(value: unknown): string | undefined {
+  const user = String(value ?? "").trim();
+
+  if (!user) {
+    return undefined;
+  }
+
+  return user.slice(0, 64);
+}