Add url parsing utility (#8)

* Add url utils

* Fix test and add to list

* Fixes based on comments

* Fix to use parens around the license

packages/opencensus-web-core/src/common/url-util.ts

@@ -0,0 +1,50 @@
+/**
+ * Copyright 2019, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Interface to represent the components of a parsed URL.
+ * The field comments below reference this sample URL:
+ *    https://example.com:3000/pathname/?search=test#hash
+ */
+export interface ParsedUrl {
+  /** Protocol of the URL including the colon. E.g. https: */
+  readonly protocol: string;
+  /** Host name only (no port). E.g. example.com */
+  readonly hostname: string;
+  /**
+   * Port number if explicitly specified (else empty string). E.g. 3000
+   * This is a string type to match the type of the field in the document <a>
+   * tag that is used to implement this.
+   */
+  readonly port: string;
+  /** Host portion of the URL including port. E.g. example.com:3000 */
+  readonly host: string;
+  /** Origin with protocol, hostname and port. E.g. https://example.com:3000 */
+  readonly origin: string;
+  /** Request URL path. E.g. /pathname/ */
+  readonly pathname: string;
+  /** Portion of the URL after and including the `#` character. E.g. #hash */
+  readonly hash: string;
+  /** Query string before the `#` char including the `?`. E.g. ?search=test */
+  readonly search: string;
+}
+
+/** Parses the given URL into components. */
+export function parseUrl(url: string): ParsedUrl {
+  const aTag = document.createElement('a');
+  aTag.href = url;
+  return aTag;
+}

packages/opencensus-web-core/test/index.ts

@@ -23,3 +23,4 @@ import './test-span';
 import './test-time-util';
 import './test-tracer';
 import './test-tracing';
+import './test-url-util';

packages/opencensus-web-core/test/test-url-util.ts

@@ -0,0 +1,47 @@
+/**
+ * Copyright 2019, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {parseUrl} from '../src/common/url-util';
+
+describe('parseUrl', () => {
+  it('parses a URL into its various components', () => {
+    const parsedUrl =
+        parseUrl('https://example.com:3000/pathname/?search=test#hash');
+
+    expect(parsedUrl.protocol).toBe('https:');
+    expect(parsedUrl.hostname).toBe('example.com');
+    expect(parsedUrl.port).toBe('3000');
+    expect(parsedUrl.host).toBe('example.com:3000');
+    expect(parsedUrl.origin).toBe('https://example.com:3000');
+    expect(parsedUrl.pathname).toBe('/pathname/');
+    expect(parsedUrl.hash).toBe('#hash');
+    expect(parsedUrl.search).toBe('?search=test');
+  });
+
+  it('correctly parases a url without a port', () => {
+    const parsedUrl =
+        parseUrl('http://example.com/path1/path2?search=test&format=json');
+
+    expect(parsedUrl.protocol).toBe('http:');
+    expect(parsedUrl.hostname).toBe('example.com');
+    expect(parsedUrl.port).toBe('');
+    expect(parsedUrl.host).toBe('example.com');
+    expect(parsedUrl.origin).toBe('http://example.com');
+    expect(parsedUrl.pathname).toBe('/path1/path2');
+    expect(parsedUrl.hash).toBe('');
+    expect(parsedUrl.search).toBe('?search=test&format=json');
+  });
+});