fix: The proxy URL is being altered in version 2.20.4, resulting in invalid URL

packages/core/src/__tests__/internal/fetchSettings.test.ts

@@ -281,4 +281,158 @@
       expect(setSettingsSpy).not.toHaveBeenCalled();
     }
   );
+  describe('getEndpointForSettings', () => {
+    it.each([
+      ['example.com/v1/', 'https://example.com/v1/'],
+      ['https://example.com/v1/', 'https://example.com/v1/'],
+      ['http://example.com/v1/', 'http://example.com/v1/'],
+    ])(
+      'should append projects/key/settings if proxy end with / and useSegmentEndpoint is true',
+      (cdnProxy, expectedBaseURL) => {
+        const config = {
+          ...clientArgs.config,
+          useSegmentEndpoints: true,
+          cdnProxy: cdnProxy,
+        };
+        const anotherClient = new SegmentClient({
+          ...clientArgs,
+          config,
+        });
+        const spy = jest.spyOn(
+          Object.getPrototypeOf(anotherClient),
+          'getEndpointForSettings'
+        );
+        expect(anotherClient['getEndpointForSettings']()).toBe(
+          `${expectedBaseURL}projects/${config.writeKey}/settings`
+        );
+        expect(spy).toHaveBeenCalled();
+      }
+    );
+    it.each([
+      ['example.com/v1/projects/', 'https://example.com/v1/projects/'],
+      ['https://example.com/v1/projects/', 'https://example.com/v1/projects/'],
+      ['http://example.com/v1/projects/', 'http://example.com/v1/projects/'],
+    ])(
+      'should append projects/writeKey/settings if proxy ends with projects/ and useSegmentEndpoint is true',
+      (cdnProxy, expectedBaseURL) => {
+        const config = {
+          ...clientArgs.config,
+          useSegmentEndpoints: true,
+          cdnProxy: cdnProxy,
+        };
+        const anotherClient = new SegmentClient({
+          ...clientArgs,
+          config,
+        });
+
+        const spy = jest.spyOn(
+          Object.getPrototypeOf(anotherClient),
+          'getEndpointForSettings'
+        );
+        expect(anotherClient['getEndpointForSettings']()).toBe(
+          `${expectedBaseURL}projects/${config.writeKey}/settings`
+        );
+        expect(spy).toHaveBeenCalled();
+      }
+    );
+    it.each([
+      ['example.com/v1/projects', 'https://example.com/v1/projects'],
+      ['https://example.com/v1/projects', 'https://example.com/v1/projects'],
+      ['http://example.com/v1/projects', 'http://example.com/v1/projects'],
+    ])(
+      'should append /projects/writeKey/settings if proxy ends with /projects and useSegmentEndpoint is true',
+      (cdnProxy, expectedBaseURL) => {
+        const config = {
+          ...clientArgs.config,
+          useSegmentEndpoints: true,
+          cdnProxy: cdnProxy,
+        };
+        const anotherClient = new SegmentClient({
+          ...clientArgs,
+          config,
+        });
+
+        const spy = jest.spyOn(
+          Object.getPrototypeOf(anotherClient),
+          'getEndpointForSettings'
+        );
+        expect(anotherClient['getEndpointForSettings']()).toBe(
+          `${expectedBaseURL}/projects/${config.writeKey}/settings`
+        );
+        expect(spy).toHaveBeenCalled();
+      }
+    );
+    it.each([
+      ['example.com/v1?params=xx'],
+      ['https://example.com/v1?params=xx'],
+      ['http://example.com/v1?params=xx'],
+    ])(
+      'should throw an error if proxy comes with query params and useSegmentEndpoint is true',
+      (cdnProxy) => {
+        const config = {
+          ...clientArgs.config,
+          useSegmentEndpoints: true,
+          cdnProxy: cdnProxy,
+        };
+        const anotherClient = new SegmentClient({
+          ...clientArgs,
+          config,
+        });
+
+        const spy = jest.spyOn(
+          Object.getPrototypeOf(anotherClient),
+          'getEndpointForSettings'
+        );
+        // Expect the private method to throw an error
+        expect(anotherClient['getEndpointForSettings']()).toBe(
+          `${settingsCDN}/${config.writeKey}/settings`
+        );
+        expect(spy).toHaveBeenCalled();
+      }
+    );
+    it.each([
+      ['example.com/v1/', false],
+      ['example.com/v1/projects/', false],
+      ['example.com/v1/projects', false],
+      ['example.com/v1?params=xx', false],
+    ])(
+      'should always return identical result if proxy is provided and useSegmentEndpoints is false',
+      (cdnProxy, useSegmentEndpoints) => {
+        const config = {
+          ...clientArgs.config,
+          useSegmentEndpoints: useSegmentEndpoints,
+          cdnProxy: cdnProxy,
+        };
+        const anotherClient = new SegmentClient({
+          ...clientArgs,
+          config,
+        });
+        const spy = jest.spyOn(
+          Object.getPrototypeOf(anotherClient),
+          'getEndpointForSettings'
+        );
+        const expected = `https://${cdnProxy}`;
+        expect(anotherClient['getEndpointForSettings']()).toBe(expected);
+        expect(spy).toHaveBeenCalled();
+      }
+    );
+    it('No cdn proxy provided, should return default settings CDN', () => {
+      const config = {
+        ...clientArgs.config,
+        useSegmentEndpoints: true, // No matter in this case
+      };
+      const anotherClient = new SegmentClient({
+        ...clientArgs,
+        config,
+      });
+      const spy = jest.spyOn(
+        Object.getPrototypeOf(anotherClient),
+        'getEndpointForSettings'
+      );
+      expect(anotherClient['getEndpointForSettings']()).toBe(
+        `${settingsCDN}/${config.writeKey}/settings`
+      );
+      expect(spy).toHaveBeenCalled();
+    });
+  });
 });

packages/core/src/__tests__/util.test.ts

@@ -172,7 +172,7 @@ describe('getURL function', () => {
   });
 
   it('should return the root URL when the path is empty', () => {
-    expect(getURL('www.example.com', '')).toBe('https://www.example.com/');
+    expect(getURL('www.example.com', '')).toBe('https://www.example.com');
   });
 
   it('should handle query parameters correctly in the URL path', () => {
@@ -188,13 +188,13 @@ describe('getURL function', () => {
   });
 
   // Negative Test Cases
-  it('should handle empty host gracefully', () => {
-    expect(getURL('', '/home')).toBe('https:///home');
+  it('should throw an error for empty host', () => {
+    expect(() => getURL('', '/home')).toThrow('Invalid URL has been passed');
   });
 
-  it('should handle invalid characters in the host', () => {
-    expect(getURL('invalid host.com', '/path')).toBe(
-      'https://invalid host.com/path'
+  it('should throw an error for invalid characters in the host', () => {
+    expect(() => getURL('invalid host.com', '/path')).toThrow(
+      'Invalid URL has been passed'
     );
   });
 });

packages/core/src/analytics.ts

@@ -320,22 +320,37 @@ export class SegmentClient {
 
     return map;
   }
-
-  async fetchSettings() {
-    const settingsPrefix: string = this.config.cdnProxy ?? settingsCDN;
+  private getEndpointForSettings(): string {
+    let settingsPrefix = '';
+    let settingsEndpoint = '';
     const hasProxy = !!(this.config?.cdnProxy ?? '');
     const useSegmentEndpoints = Boolean(this.config?.useSegmentEndpoints);
-    let settingsEndpoint = '';
+
     if (hasProxy) {
+      settingsPrefix = this.config.cdnProxy ?? '';
       if (useSegmentEndpoints) {
-        settingsEndpoint = `/projects/${this.config.writeKey}/settings`;
-      } else {
-        settingsEndpoint = '';
+        const isCdnProxyEndsWithSlash = settingsPrefix.endsWith('/');
+        settingsEndpoint = isCdnProxyEndsWithSlash
+          ? `projects/${this.config.writeKey}/settings`
+          : `/projects/${this.config.writeKey}/settings`;
       }
     } else {
+      settingsPrefix = settingsCDN;
       settingsEndpoint = `/${this.config.writeKey}/settings`;
     }
-    const settingsURL = getURL(settingsPrefix, settingsEndpoint);
+    try {
+      return getURL(settingsPrefix, settingsEndpoint);
+    } catch (error) {
+      console.error(
+        'Error in getEndpointForSettings:',
+        `fallback to ${settingsCDN}/${this.config.writeKey}/settings`
+      );
+      return `${settingsCDN}/${this.config.writeKey}/settings`;
+    }
+  }
+
+  async fetchSettings() {
+    const settingsURL = this.getEndpointForSettings();
     try {
       const res = await fetch(settingsURL, {
         headers: {

packages/core/src/plugins/SegmentDestination.ts

@@ -92,17 +92,24 @@ export class SegmentDestination extends DestinationPlugin {
     const config = this.analytics?.getConfig();
     const hasProxy = !!(config?.proxy ?? '');
     const useSegmentEndpoints = Boolean(config?.useSegmentEndpoints);
-
+    let baseURL = '';
     let endpoint = '';
-
     if (hasProxy) {
-      endpoint = useSegmentEndpoints ? '/b' : '';
+      //baseURL is always config?.proxy if hasProxy
+      baseURL = config?.proxy ?? '';
+      if (useSegmentEndpoints) {
+        const isProxyEndsWithSlash = baseURL.endsWith('/');
+        endpoint = isProxyEndsWithSlash ? 'b' : '/b';
+      }
     } else {
-      endpoint = '/b'; // If no proxy, always append '/b'
+      baseURL = this.apiHost ?? defaultApiHost;
+    }
+    try {
+      return getURL(baseURL, endpoint);
+    } catch (error) {
+      console.error('Error in getEndpoint:', `fallback to ${defaultApiHost}`);
+      return defaultApiHost;
     }
-
-    const baseURL = config?.proxy ?? this.apiHost ?? defaultApiHost;
-    return getURL(baseURL, endpoint);
   }
   configure(analytics: SegmentClient): void {
     super.configure(analytics);
@@ -128,7 +135,7 @@ export class SegmentDestination extends DestinationPlugin {
       segmentSettings?.apiHost !== null
     ) {
       //assign the api host from segment settings (domain/v1)
-      this.apiHost = segmentSettings.apiHost;
+      this.apiHost = `https://${segmentSettings.apiHost}/b`;
     }
     this.settingsResolve();
   }