import { z } from 'zod';
// --- Types ---
export type JsonRpcId = string | number | null;
interface McpRequestParams {
_meta?: Record<string, unknown>;
[key: string]: unknown;
}
interface McpRequestBody {
jsonrpc: '2.0';
method: string;
id?: JsonRpcId;
params?: McpRequestParams;
}
// --- Validation ---
const paramsSchema = z.looseObject({});
const mcpRequestSchema = z.strictObject({
jsonrpc: z.literal('2.0'),
method: z.string().min(1),
id: z.union([z.string(), z.number(), z.null()]).optional(),
params: paramsSchema.optional(),
});
export function isJsonRpcBatchRequest(body: unknown): boolean {
return Array.isArray(body);
}
export function isMcpRequestBody(body: unknown): body is McpRequestBody {
return mcpRequestSchema.safeParse(body).success;
}
function parseAcceptMediaTypes(
header: string | null | undefined
): readonly string[] {
if (!header) return [];
return header
.split(',')
.map((value) => extractAcceptMediaType(value.trim()))
.filter((value) => value.length > 0);
}
function extractAcceptMediaType(value: string): string {
return value.split(';', 1)[0]?.trim().toLowerCase() ?? '';
}
export function acceptsEventStream(header: string | null | undefined): boolean {
const mediaTypes = parseAcceptMediaTypes(header);
return mediaTypes.some((mediaType) => mediaType === 'text/event-stream');
}
function hasAcceptedMediaType(
mediaTypes: readonly string[],
exact: string,
wildcardPrefix: string
): boolean {
return mediaTypes.some(
(mediaType) =>
typeof mediaType === 'string' &&
mediaType.length > 0 &&
(mediaType === '*/*' ||
mediaType === exact ||
mediaType === wildcardPrefix)
);
}
export function acceptsJsonAndEventStream(
header: string | null | undefined
): boolean {
const mediaTypes = parseAcceptMediaTypes(header);
const acceptsJson = hasAcceptedMediaType(
mediaTypes,
'application/json',
'application/*'
);
if (!acceptsJson) return false;
return hasAcceptedMediaType(mediaTypes, 'text/event-stream', 'text/*');
}
