refactor: reorganize files in commons package

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

commons/src/parse-url/errors.ts

@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export class MissingTrailingSlashError extends Error {
+  constructor() {
+    super("Path doesn't end with a trailing slash")
+  }
+}
+
+export class WrongProtocolError extends Error {
+  constructor() {
+    super('Protocol must be HTTP or HTTPS')
+  }
+}

commons/src/parse-url/index.ts

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+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export { parseUrl } from './parse-url.js'
+export { MissingTrailingSlashError, WrongProtocolError } from './errors.js'

commons/src/parse-url/parse-url.spec.ts

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+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { MissingTrailingSlashError, WrongProtocolError } from './errors.js'
+import { parseUrl } from './parse-url.js'
+import { describe, expect, it } from '@jest/globals'
+
+describe('validate url', () => {
+  it("doesn't accept non-urls", () => {
+    expect(parseUrl('noUrl').isEmpty()).toBeTruthy()
+  })
+
+  describe('protocols', () => {
+    it('works with http', () => {
+      expect(parseUrl('http://example.org').get().toString()).toEqual(
+        'http://example.org/'
+      )
+    })
+    it('works with https', () => {
+      expect(parseUrl('https://example.org').get().toString()).toEqual(
+        'https://example.org/'
+      )
+    })
+    it("doesn't work without protocol", () => {
+      expect(() => parseUrl('example.org').isEmpty()).toBeTruthy()
+    })
+    it("doesn't work any other protocol", () => {
+      expect(() => parseUrl('git://example.org').get()).toThrowError(
+        WrongProtocolError
+      )
+    })
+  })
+
+  describe('trailing slash', () => {
+    it('accepts urls with just domain with trailing slash', () => {
+      expect(parseUrl('http://example.org/').get().toString()).toEqual(
+        'http://example.org/'
+      )
+    })
+    it('accepts urls with just domain without trailing slash', () => {
+      expect(parseUrl('http://example.org').get().toString()).toEqual(
+        'http://example.org/'
+      )
+    })
+    it('accepts urls with with subpath and trailing slash', () => {
+      expect(parseUrl('http://example.org/asd/').get().toString()).toEqual(
+        'http://example.org/asd/'
+      )
+    })
+    it("doesn't accept urls with with subpath and without trailing slash", () => {
+      expect(() => parseUrl('http://example.org/asd').get().toString()).toThrow(
+        MissingTrailingSlashError
+      )
+    })
+  })
+})

commons/src/parse-url/parse-url.ts

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+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { MissingTrailingSlashError, WrongProtocolError } from './errors.js'
+import { Optional } from '@mrdrogdrog/optional'
+
+/**
+ * Parses the given string as URL
+ *
+ * @param {String | undefined} url the raw url
+ * @return An {@link Optional} that contains the parsed URL or is empty if the raw value isn't a valid URL
+ * @throws WrongProtocolError if the protocol of the URL isn't either http nor https
+ * @throws MissingTrailingSlashError if the URL has a path that doesn't end with a trailing slash
+ */
+export function parseUrl(url: string | undefined): Optional<URL> {
+  return createOptionalUrl(url)
+    .guard(
+      (value) => value.protocol === 'https:' || value.protocol === 'http:',
+      () => new WrongProtocolError()
+    )
+    .guard(
+      (value) => value.pathname.endsWith('/'),
+      () => new MissingTrailingSlashError()
+    )
+}
+
+function createOptionalUrl(url: string | undefined): Optional<URL> {
+  try {
+    return Optional.ofNullable(url).map((value) => new URL(value))
+  } catch (error) {
+    return Optional.empty()
+  }
+}