writeFileSync 不创建和写入文件

Question

所以，我在 Next.js 中有一堆 SSG 页面，因此，我正在创建包含一堆路线的导航。所以，我想“缓存”第一个 api 调用，然后获取缓存（写入文件数据）。我正在使用它，它没有创建文件。我收到以下错误，因此，我总是点击 api。

我登录catch，它给出了错误。永远不会创建文件。

错误：

Error: ENOENT: no such file or directory, open '/Users/jim/company/clientapp/.next/server/pages/Users/jim/company/clientapp/.routes'

我的代码：

import fs from 'fs';
import path from 'path';

/* api */
import routes from '@api/rest/routes';

const ROUTE_CACHE_PATH = path.resolve('.routes');

export default async function getCacheRoutes() {
  let cachedData

  try {
    cachedData = JSON.parse(
      fs.readFileSync(path.join(__dirname, ROUTE_CACHE_PATH), 'utf8')
    )
      } catch (error) {
    // logger here
  }

  if (!cachedData) {    
    const data = await routes() // this is the api request, it works

    try {
      fs.writeFileSync(
        path.join(__dirname, ROUTE_CACHE_PATH),
        JSON.stringify(data),
        { flag: 'w' }. // With or without this, doesn't work.
      )
    } catch (error) {
      // Logger here
    }

    cachedData = data
  }

  return cachedData
}

Answer 1

失败是因为ROUTE_CACHE_PATH和readFileSync中的文件路径始终不正确。

尝试设置正确的路径，然后在整个过程中使用它：

// setup the correct path to file, use it throughout
// writes to the file `routes` in CWD
const ROUTE_CACHE_PATH = path.resolve(path.join(process.cwd(), 'routes'));

现在通篇引用它：

fs.readFileSync(ROUTE_CACHE_PATH, 'utf8')

和

fs.writeFileSync(
ROUTE_CACHE_PATH,

请记住，如果您发送的数据不可解析，JSON.parse 也可能在此处失败，因此您也可以考虑为此添加处理程序，或者可能在发送方部分。

使用此代码，读取和写入有点独立。因此，更好的方法可能是将文件写入错误部分，恕我直言：

try {
    readFile
} catch() {
    writeFile
}

这是重新排列的代码：

import fs from 'fs';
import path from 'path';

/* api */
import routes from '@api/rest/routes';

// setup the correct path to file, use it throughout
// writes to the file `routes` in CWD
const ROUTE_CACHE_PATH = path.resolve(path.join(process.cwd(), 'routes'));

export default async function getCacheRoutes() {

  // setup variables to be accessible for later
  let cachedData;
  let data;    

  // first, read the file
  // if it fails, there is no file
  // so move the file writing to the error part
  // note that parsing might also fail, so handle that there too
  try {
    // parsing might fail here though..
    cachedData = JSON.parse(
      fs.readFileSync(ROUTE_CACHE_PATH, 'utf8')
    )
  } catch (error) {

    // reading failed, handle file writing
    // parsing and other errors here
    console.log(error);

    // if there is no file, get data and write a fresh file
    if (error.code === 'ENOENT') {

      // todo: make sure it's always a JSON as string,
      // otherwise parsing will fail..
      data = await routes();

      try {
        fs.writeFileSync(
          ROUTE_CACHE_PATH,
          JSON.stringify(data), {
            flag: 'w'
          }
        )
      } catch (error) {
        // parsing might fail..
        console.log(error);
      }
    } else {
      // or some other error: JSON parsing failed, for example
      console.log('handle some other error', error);
    }

    cachedData = data;

  }

  return cachedData

}