Multiple rewrites not supported

[tgrassl]

Hi,

There's an error in the rewritePath method. It already returns after the first replacement and thus never checks other rewrites.

Example:
Wrong: rewritePath('/api/test/xy/', { '/$': '', '^/api/test/': '' }) -> /api/test/xy
Correct: rewritePath('/api/test/xy/', { '/$': '', '^/api/test/': '' }) -> xy

export const rewritePath = (
  url: string,
  pathRewrite: { [key: string]: string }
) => {
  for (let patternStr in pathRewrite) {
    const pattern = RegExp(patternStr);
    const path = pathRewrite[patternStr];
    if (pattern.test(url as string)) {
      return url.replace(pattern, path); <--- returns to early
    }
  }
  return url;
};

possible fix:

export const rewritePath = (url: string, pathRewrite: { [key: string]: string }): string => {
  let rewrittenUrl = url;
  for (let patternStr in pathRewrite) {
    const pattern = new RegExp(patternStr);
    const path = pathRewrite[patternStr];
    if (pattern.test(url as string)) {
      rewrittenUrl = rewrittenUrl.replace(pattern, path);
    }
  }
  return rewrittenUrl;
};

[stegano]

Hi @tgrassl
Thanks for your reporting

Cases like the above issue can happen enough, and I agree.

In the above case, since pathRewrite is an object(map) type that does not guarantee the order, different results may be produced depending on the nodejs version or execution environment.

To solve the above issue, in the next version, we plan to modify the rewritePath argument value to be passed as an object or an array so that the entered rule can be applied first.

Thanks 😄

[stegano]

@all-contributors please add @tgrassl for bug

[allcontributors]

@stegano

I've put up a pull request to add @tgrassl! 🎉

[stegano]

I just released a package.

You can now use it like this(Pattern checks are run in the order they are entered into the array first.)

// pages/[...all].ts
...
export default (req: NextApiRequest, res: NextApiResponse) => (
  isDevelopment
    ? httpProxyMiddleware(req, res, {
      // You can use the `http-proxy` option
      target: 'https://www.example.com',
      // In addition, you can use the `pathRewrite` option provided by `next-http-proxy-middleware`
      pathRewrite: [{
        patternStr: '^/api/new',
        replaceStr: '/v2'
      }, {
        patternStr: '^/api',
        replaceStr: ''
      }],
    })
    : res.status(404).send(null)
);