Add a first cut at an express-based backend

express/http-codes.ts

@@ -0,0 +1,43 @@
+import { Extensible } from "./interfaces";
+
+export type HttpCode = {
+    code: number;
+    name: string;
+    description?: string;
+};
+type Group = "success" | "redirection" | "clientErrors" | "serverErrors";
+type CodeDefinitions = {
+    [K in Group]: {
+        [K: string]: HttpCode;
+    };
+};
+// FIXME: Figure out how to brand CodeDefinitions in a way that isn't
+// tedious.
+
+const httpCodes: CodeDefinitions = {
+    success: {
+        OK: { code: 200, name: "OK", description: "" },
+        Created: { code: 201, name: "Created" },
+        Accepted: { code: 202, name: "Accepted" },
+        NoContent: { code: 204, name: "No content" },
+    },
+    redirection: {
+        // later
+    },
+    clientErrors: {
+        BadRequest: { code: 400, name: "Bad Request" },
+        Unauthorized: { code: 401, name: "Unauthorized" },
+        Forbidden: { code: 403, name: "Forbidden" },
+        NotFound: { code: 404, name: "Not Found" },
+        MethodNotAllowed: { code: 405, name: "Method Not Allowed" },
+        NotAcceptable: { code: 406, name: "Not Acceptable" },
+        // More later
+    },
+    serverErrors: {
+        InternalServerError: { code: 500, name: "Internal Server Error" },
+        NotImplemented: { code: 500, name: "Not implemented" },
+        // more later
+    },
+};
+
+export { httpCodes };