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1.9.2 • Public • Published


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

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


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

Quick start


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)")


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",


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


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

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


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

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

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

DSN parsing


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 = [

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,


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


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
  // }
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]


Zod integration example

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

import { z } from "zod";

export const serverEnvSchema = z.object({
    (dsn) => isParsableDsn(dsn),
    "Invalid DSN format."


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

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Special thanks

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