✨ getPage()の実装と型判定周りの改善

まだ甘い部分がある

Author: takker99

deps/scrapbox.ts

@@ -4,5 +4,7 @@ export type {
   ImportedData,
   NotFoundError,
   NotLoggedInError,
+  NotMemberError,
   NotPrivilegeError,
+  Page,
 } from "https://pax.deno.dev/scrapbox-jp/types@0.0.8";

rest/page-data.ts

@@ -6,7 +6,12 @@ import type {
   NotLoggedInError,
   NotPrivilegeError,
 } from "../deps/scrapbox.ts";
-import { cookie, getCSRFToken } from "./utils.ts";
+import {
+  cookie,
+  getCSRFToken,
+  makeCustomError,
+  tryToErrorLike,
+} from "./utils.ts";
 import type { Result } from "./utils.ts";
 
 /** `importPages`の認証情報 */
@@ -49,8 +54,9 @@ export async function importPages(
     csrf = result.csrfToken;
   }
 
+  const path = `https://scrapbox.io/api/page-data/import/${project}.json`;
   const res = await fetch(
-    `https://scrapbox.io/api/page-data/import/${project}.json`,
+    path,
     {
       method: "POST",
       headers: {
@@ -64,12 +70,15 @@ export async function importPages(
 
   if (!res.ok) {
     if (res.status === 503) {
-      const error = new Error();
-      error.name = "ServerError";
-      error.message = "503 Service Unavailable";
-      throw error;
+      throw makeCustomError("ServerError", "503 Service Unavailable");
+    }
+    const error = tryToErrorLike(await res.text());
+    if (!error) {
+      throw makeCustomError(
+        "UnexpectedError",
+        `Unexpected error has occuerd when fetching "${path}"`,
+      );
     }
-    const error = (await res.json()) as ErrorLike;
     return { ok: false, ...error };
   }
   const result = (await res.json()) as { message: string };
@@ -94,8 +103,10 @@ export async function exportPages<withMetadata extends true | false>(
     NotFoundError | NotPrivilegeError | NotLoggedInError
   >
 > {
+  const path =
+    `https://scrapbox.io/api/page-data/export/${project}.json?metadata=${metadata}`;
   const res = await fetch(
-    `https://scrapbox.io/api/page-data/export/${project}.json?metadata=${metadata}`,
+    path,
     {
       headers: {
         Cookie: cookie(sid),
@@ -104,12 +115,22 @@ export async function exportPages<withMetadata extends true | false>(
   );
 
   if (!res.ok) {
-    const error = (await res.json()) as
-      | NotFoundError
-      | NotPrivilegeError
-      | NotLoggedInError;
+    const error = (await res.json());
     return { ok: false, ...error };
   }
+  if (!res.ok) {
+    const error = tryToErrorLike(await res.text());
+    if (!error) {
+      throw makeCustomError(
+        "UnexpectedError",
+        `Unexpected error has occuerd when fetching "${path}"`,
+      );
+    }
+    return {
+      ok: false,
+      ...(error as NotFoundError | NotPrivilegeError | NotLoggedInError),
+    };
+  }
   const result = (await res.json()) as ExportedData<withMetadata>;
   return { ok: true, ...result };
 }

rest/pages.ts

@@ -0,0 +1,66 @@
+import type {
+  NotFoundError,
+  NotLoggedInError,
+  NotMemberError,
+  Page,
+} from "../deps/scrapbox.ts";
+import {
+  cookie,
+  encodeTitle,
+  makeCustomError,
+  tryToErrorLike,
+} from "./utils.ts";
+import type { Result } from "./utils.ts";
+
+/** Options for `getPage()` */
+export interface GetPageOption {
+  /** use `followRename` */ followRename?: boolean;
+  /** connect.sid */ sid?: string;
+}
+/** 指定したページのJSONデータを取得する
+ *
+ * @param project 取得したいページのproject名
+ * @param title 取得したいページのtitle 大文字小文字は問わない
+ * @param options オプション
+ */
+export async function getPage(
+  project: string,
+  title: string,
+  options?: GetPageOption,
+): Promise<
+  Result<
+    Page,
+    NotFoundError | NotLoggedInError | NotMemberError
+  >
+> {
+  const path = `https://scrapbox.io/api/pages/${project}/${
+    encodeTitle(title)
+  }?followRename=${options?.followRename ?? true}`;
+
+  const res = await fetch(
+    path,
+    options?.sid
+      ? {
+        headers: {
+          Cookie: cookie(options.sid),
+        },
+      }
+      : undefined,
+  );
+
+  if (!res.ok) {
+    const error = tryToErrorLike(await res.text());
+    if (!error) {
+      throw makeCustomError(
+        "UnexpectedError",
+        `Unexpected error has occuerd when fetching "${path}"`,
+      );
+    }
+    return {
+      ok: false,
+      ...(error as (NotFoundError | NotLoggedInError | NotMemberError)),
+    };
+  }
+  const result = (await res.json()) as Page;
+  return { ok: true, ...result };
+}

rest/utils.ts

@@ -6,6 +6,7 @@ import type { ErrorLike } from "../deps/scrapbox.ts";
  */
 export const cookie = (sid: string) => `connect.sid=${sid}`;
 
+export type Result<T, E> = ({ ok: true } & T) | ({ ok: false } & E);
 /** CSRF tokenを取得する
  *
  * @param sid - connect.sidに入っている文字列。不正な文字列を入れてもCSRF tokenを取得できるみたい
@@ -24,4 +25,42 @@ export async function getCSRFToken(
   return { ok: true, csrfToken };
 }
 
-export type Result<T, E> = ({ ok: true } & T) | ({ ok: false } & E);
+// cf. https://blog.uhy.ooo/entry/2021-04-09/typescript-is-any-as/#%E3%83%A6%E3%83%BC%E3%82%B6%E3%83%BC%E5%AE%9A%E7%BE%A9%E5%9E%8B%E3%82%AC%E3%83%BC%E3%83%89%E3%81%AE%E5%BC%95%E6%95%B0%E3%81%AE%E5%9E%8B%E3%82%92%E3%81%A9%E3%81%86%E3%81%99%E3%82%8B%E3%81%8B
+function isNotNullish(data: unknown): data is Record<string, unknown> {
+  return data != null;
+}
+function isErrorLike(e: unknown): e is ErrorLike {
+  if (!isNotNullish(e)) return false;
+  return (e.name === undefined || typeof e.name === "string") &&
+    typeof e.message === "string";
+}
+/** 与えられたobjectもしくはJSONテキストをErrorLikeに変換できるかどうか試す
+ *
+ * @param e 試したいobjectもしくはテキスト
+ */
+export function tryToErrorLike(e: unknown): false | ErrorLike {
+  try {
+    const json = typeof e === "string" ? JSON.parse(e) : e;
+    if (!isErrorLike(json)) return false;
+    return json;
+  } catch (e2: unknown) {
+    if (e2 instanceof SyntaxError) return false;
+    throw e2;
+  }
+}
+
+/** classを使わずにカスタムエラーを作る */
+export function makeCustomError(name: string, message: string) {
+  const error = new Error();
+  error.name = name;
+  error.message = message;
+  return error;
+}
+
+export const toTitleLc = (title: string) =>
+  title.toLowerCase().replaceAll(" ", "_");
+export const encodeTitle = (title: string) =>
+  title.replaceAll(" ", "_").replace(
+    /[/?#\{}^|<>]/g,
+    (char) => encodeURIComponent(char),
+  );