3 files changed, 22 insertions, 5 deletions
diff --git a/packages/connect/CHANGELOG.md b/packages/connect/CHANGELOG.md
index 2d9e2d89f..19d38df5f 100644
--- a/packages/connect/CHANGELOG.md
+++ b/packages/connect/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## v0.x.x - _TBD, 2017_
+
+    * Sanitize api endpoint url and remove trailing slashes (#315)
+    * Improve error message text in HttpClient (#315)
+
 ## v0.4.0 - _January 11, 2017_
 
     * Prevent getFeesAsync method on HttpClient from mutating input (#296)
diff --git a/packages/connect/src/http_client.ts b/packages/connect/src/http_client.ts
index 5604a9607..c30b499a2 100644
--- a/packages/connect/src/http_client.ts
+++ b/packages/connect/src/http_client.ts
@@ -20,6 +20,7 @@ import {
 } from './types';
 import { relayerResponseJsonParsers } from './utils/relayer_response_json_parsers';
 
+const TRAILING_SLASHES_REGEX = /\/+$/;
 /**
  * This class includes all the functionality related to interacting with a set of HTTP endpoints
  * that implement the standard relayer API v0
@@ -33,7 +34,7 @@ export class HttpClient implements Client {
      */
     constructor(url: string) {
         assert.isHttpUrl('url', url);
-        this._apiEndpointUrl = url;
+        this._apiEndpointUrl = url.replace(TRAILING_SLASHES_REGEX, ''); // remove trailing slashes
     }
     /**
      * Retrieve token pair info from the API
@@ -134,16 +135,18 @@ export class HttpClient implements Client {
         const headers = new Headers({
             'content-type': 'application/json',
         });
-
         const response = await fetch(url, {
             method: requestType,
             body: JSON.stringify(payload),
             headers,
         });
+        const json = await response.json();
         if (!response.ok) {
-            throw Error(response.statusText);
+            const errorString = `${response.status} - ${response.statusText}\n${requestType} ${url}\n${JSON.stringify(
+                json,
+            )}`;
+            throw Error(errorString);
         }
-        const json = await response.json();
         return json;
     }
 }
diff --git a/packages/connect/test/http_client_test.ts b/packages/connect/test/http_client_test.ts
index e7096edad..38d00d849 100644
--- a/packages/connect/test/http_client_test.ts
+++ b/packages/connect/test/http_client_test.ts
@@ -29,6 +29,15 @@ describe('HttpClient', () => {
     afterEach(() => {
         fetchMock.restore();
     });
+    describe('#constructor', () => {
+        it('should remove trailing slashes from api url', async () => {
+            const urlWithTrailingSlash = 'https://slash.com/';
+            const urlWithoutTrailingSlash = 'https://slash.com';
+            const client = new HttpClient(urlWithTrailingSlash);
+            const sanitizedUrl = (client as any)._apiEndpointUrl;
+            expect(sanitizedUrl).to.be.deep.equal(urlWithoutTrailingSlash);
+        });
+    });
     describe('#getTokenPairsAsync', () => {
         const url = `${relayUrl}/v0/token_pairs`;
         it('gets token pairs', async () => {
@@ -36,7 +45,7 @@ describe('HttpClient', () => {
             const tokenPairs = await relayerClient.getTokenPairsAsync();
             expect(tokenPairs).to.be.deep.equal(tokenPairsResponse);
         });
-        it('gets specfic token pairs for request', async () => {
+        it('gets specific token pairs for request', async () => {
             const tokenAddress = '0x323b5d4c32345ced77393b3530b1eed0f346429d';
             const tokenPairsRequest = {
                 tokenA: tokenAddress,