Custom query parser

[bompi88]

What is the feature you are proposing?

I want to be able to switch out the default query parser with something like qs.

I am able to use a validator to "hack something together", but if I'm using @hono/zod-openapi that will not be able to use the output of that validator.

Something like the getPath method would be sufficient enough for my use case.

EDIT:

Adding more context to the ticket. I'm using a special query "syntax" which is supported by qs. For example I can do ?amount[lte]=300 which resolves to:

{
  amount: {
    lte: 300
  }
}

For comparison here is how you can change the query parser in express. Not that we should follow their approach because I think that one looks messy.

var express = require('express');
var qs = require('qs');
var app = express();

app.set('query parser', function (str) {
  return qs.parse(str, opts);
});

[yusukebe]

Hi @bompi88

I like the idea of using something like the getPath method. I will also consider this issue.

[yusukebe]

It is unrelated to query parsing, but it would be interesting to allow users to specify a custom JSON serializer as a good example of using something like getPath.

[bompi88]

@yusukebe thanks! I've updated the ticket with the example from the #3565 + example how it is done in for example express (please not get too inspired by that approach).

[bompi88]

@yusukebe I know that there is currently an ongoing PR regarding the URLSearchParams that is kind of related (and not), but let me know if there anything I can facilitate regarding this ticket.

[bompi88]

Hi @yusukebe, I wanted to follow up as I haven’t heard back from you yet. We’re highly interested in adding a way to override this functionality. Would you be open to accepting contributions on this topic?

[yusukebe]

@bompi88

Sorry for the late reply! I am not eager to proceed because the implementation would be complicated. Also, as I said before, I am concerned about the behavior depending on the parameters. If you make a PR, I will review it, but that does not ensure that it will be merged.

[bompi88]

@yusukebe We've started to look into how the code is structured, and we see what concerns you have. I hope that you enable a more plugin approach for the query parser in the future.

We have an ugly hack that we currently use to get around the problem using a middleware.

// middlewares.ts
import qs from 'qs';
import { createMiddleware } from 'hono/factory';
import { URL } from 'url';

export const queryParseMiddleware = createMiddleware((c, next) => {
  const query = qs.parse(new URL(c.req.url).search, { ignoreQueryPrefix: true });
  // eslint-disable-next-line no-param-reassign, @typescript-eslint/no-explicit-any
  c.req.queries = () => query as any;
  return next();
});

// utils.ts
import { createRoute as openApiCreateRoute } from '@hono/zod-openapi';

export const createRoute: typeof openApiCreateRoute = (config) =>
  openApiCreateRoute({
    ...config,
    middleware: config.middleware
      ? [...(Array.isArray(config.middleware) ? config.middleware : [config.middleware]), queryParseMiddleware]
      : queryParseMiddleware,
  });


// routes.ts
import { createRoute } from './utils';

export const list = createRoute({
  path: '/whatever',
  method: 'get',
  request: {
    query: z.object({
      value: z.object({ lte: z.number() })
    })
  },
  tags,
  responses: {
    [StatusCodes.OK]: jsonContent(z.any(), 'The list of whatever'),
  },
});

[yusukebe]

@bompi88

Setting a value for c.req.queries is only for c.req.valid(), so it does not replace the query parsing in HonoRequest. Therefore, since this middleware is only for validation, I have no motivation to make it a built-in middleware.