@soluble/dsn-parser

@soluble/dsn-parser

DSN parser, validation utilities, and query string helper in a light and modern package.

Install

$ npm install @soluble-dsn-parser
$ yarn add @soluble/dsn-parser
$ pnpm add @soluble/dsn-parser

Features

• Parse individual fields (ie: driver, user, password, host...)
• Handle query string with casting of boolean and numeric values.
• Handle special characters like /, :... in the password (some libs won't).
• Error with indicative message / reasons (discriminative union or throwing).
• Don't leak passwords in the error message.
• Assertion and typeguard helpers (ie: easy integrate with zod).

Quick start

parseDsnOrThrow

Usage with exceptions

import { parseDsnOrThrow } from "@soluble/dsn-parser";

const dsn = "redis://user:p@/ssword@localhost:6379/0?ssl=true";

try {
  const parsedDsn = parseDsnOrThrow(dsn);
  assert.deepEqual(parsedDsn, {
    driver: "redis",
    pass: "p@/ssword",
    host: "localhost",
    user: "user",
    port: 6379,
    db: "0",
    params: {
      ssl: true,
    },
  });
} catch (e) {
  // example:
  // e -> Error("Can't parse dsn: Invalid port: 12345678 (INVALID_PORT)")
}

parseDsn

Usage with discriminated union.

import { parseDsn } from "@soluble/dsn-parser";

const dsn = "redis://user:p@/ssword@localhost:6379/0?ssl=true";

const parsed = parseDsn(dsn);

if (parsed.success) {
  assert.deepEqual(parsed.value, {
    driver: "redis",
    pass: "p@/ssword",
    host: "localhost",
    user: "user",
    port: 6379,
    db: "0",
    params: {
      ssl: true,
    },
  });
} else {
  assert.deepEqual(parsed, {
    success: false,
    // Reasons might vary
    reason: "INVALID_PORT",
    message: "Invalid http port: 12345678",
  });
}

Options

const dsn = "mySql://localhost:6379/db";
const parsed = parseDsn(dsn, {
  lowercaseDriver: true,
  overrides: {
    db: "db3",
    port: undefined,
  },
});

assert.deepEqual(parsed.value, {
  driver: "mysql",
  host: "localhost",
  db: "db3",
});

Params	Type	Description
lowercaseDriver	<boolean>	Driver name in lowercase, default false
overrides	DSN must be a string

Assertion

import { assertParsableDsn, ParsableDsn } from "@soluble/dsn-parser";

try {
  assertParsableDsn("redis:/");
  // Type is narrowed to string (ParsableDsn) if it
  // didn't throw.
} catch (e) {
  assert.equal(e.message, "Cannot parse DSN (PARSE_ERROR)");
}

Typeguard

import { isParsableDsn, type ParsableDsn } from "@soluble/dsn-parser";

const dsn = "postgresql://localhost:6379/db";

if (isParsableDsn(dsn)) {
  // known to be ParsableDSN
}

DSN parsing

Requirements

The minimum requirement for dsn parsing is to have a host and a driver (/[a-z0-9]+/i) defined. All other options are optional.

export type ParsedDsn = {
  driver: string;
  host: string;
  user?: string;
  pass?: string;
  port?: number;
  db?: string;
  /** Query params */
  params?: Record<string, number | string | boolean>;
};

DSN support

Things like:

const validExamples = [
  "postgresql://postgres:@localhost:5432/prisma-db",
  "redis://us_er-name:P@ass-_:?/ssw/[e-mail]:6379/0?cache=true",
  //...
];

should work.

Query parameters

Simple query parameters are supported (no arrays, no nested). For convenience it will cast 'true' and 'false' to booleans, parse numeric string to numbers if possible. When a query parameter does not contain a value, it will be returned as true.

const dsn = "redis://host?index=1&compress=false&ssl";
const parsed = parseDsn(dsn);
assert.deepEqual(parsed.value.params, {
  index: 1,
  compress: false,
  ssl: true,
});

Portability

parseDsn won't make any assumptions on default values (i.e: default port for mysql...).

Validation

parseDsn wraps its result in a discriminated union to allow the retrieval of validation errors. No try... catchneeded and full typescript support.

Reason codes are guaranteed in semantic versions and messages does not leak credentials

const parsed = parseDsn("redis://localhost:65636");
assert.deepEqual(parsed, {
  success: false,
  reason: "INVALID_PORT",
  message: "Invalid port: 65636",
});
if (!parsed.success) {
  // `success: false` narrows the type to
  // {
  //   reason: 'PARSE_ERROR'|'INVALID_ARGUMENT'|...
  //   message: string
  // }
  log(parsed.reason);
}

Reason	Message	Comment
'PARSE_ERROR'	Cannot parse DSN	Regexp failed
'INVALID_ARGUMENT'	DSN must be a string
'EMPTY_DSN'	DSN cannot be empty
'INVALID_PORT'	Invalid port: ${port}	[1-65535]

Faq

Zod integration example

The isParsableDsn can be easily plugged into zod custom validation. Example:

import { z } from "zod";

export const serverEnvSchema = z.object({
  PRISMA_DATABASE_URL: z.custom(
    (dsn) => isParsableDsn(dsn),
    "Invalid DSN format."
  ),
});

serverEnvSchema.parse(process.env);

Why '/' in password matters

Some libs (ioredis...) still might fail parsing a password containing '/', unfortunately they're pretty convenient, i.e:

openssl rand 60 | openssl base64 -A

# YFUXIG9INIK7dFyE9aXtxLmjmnYL0zv6YluBJJbC6alKIBema/MwEGy3VUpx0oLAvWHUFGFMagAdLxrB

Sponsors ❤️

If you are enjoying some of my OSS guides or libs for your company, I'd really appreciate a sponsorship, a coffee or a dropped star. That gives me a tasty morning boost and help me to make some of my ideas come true 🙏

Special thanks

JetBrains	Embie.be