Hostname can now be set via env var (#10)

* Hostname can now be set via env var

* Added 'Changing the hostname' to the readme

Author: laconc

README.md

@@ -16,6 +16,7 @@ go get github.com/datadotworld/dwapi-go/dwapi
 ```
 
 ## Usage
+
 The full package documentation is available at https://godoc.org/github.com/datadotworld/dwapi-go/dwapi.
 
 You can also check out the API documentation at https://apidocs.data.world/api for specifics on the endpoints.
@@ -140,3 +141,16 @@ func main() {
 	*/
 }
 ```
+
+## Changing the hostname
+
+The API calls are made to `https://api.data.world` by default, but the URL can be changed by setting the `DW_API_HOST` environment variable.
+
+For customers in a single-tenant environment, you can also use the `DW_ENVIRONMENT` variable to alter the default URL. For example, for the customer `customer`, setting it will alter the URL to `https://api.customer.data.world`.
+
+Additionally, the hostname can also be changed by explicitly setting the `BaseURL` property of the client, i.e.:
+```
+dw = dwapi.NewClient("token")
+dw.BaseURL = "http://localhost:1010/v0"
+```
+_Notice that the stage also needs to be set if going down this path._

dwapi/api.go

@@ -42,7 +42,7 @@ const (
 	POST   = "POST"
 	PUT    = "PUT"
 
-	defaultBaseURL = "https://api.data.world/v0"
+	defaultBaseURL = "https://api.data.world"
 )
 
 type Client struct {
@@ -75,7 +75,7 @@ type paginatedResponse struct {
 
 func NewClient(token string) *Client {
 	c := &Client{
-		BaseURL: defaultBaseURL,
+		BaseURL: getBaseURL(),
 		Token:   token,
 	}
 	c.Dataset = &DatasetService{c}
@@ -90,6 +90,16 @@ func NewClient(token string) *Client {
 	return c
 }
 
+func getBaseURL() string {
+	baseURL := defaultBaseURL
+	if host := os.Getenv("DW_API_HOST"); host != "" {
+		baseURL = host
+	} else if env := os.Getenv("DW_ENVIRONMENT"); env != "" {
+		baseURL = fmt.Sprintf("https://api.%s.data.world", env)
+	}
+	return baseURL + "/v0"
+}
+
 func (c *Client) buildHeaders(method, endpoint string) *headers {
 	return &headers{
 		Method:   method,

dwapi/api_test.go

@@ -132,7 +132,21 @@ func teardown() {
 
 func TestNewClient(t *testing.T) {
 	dw = getTestClient()
-	assert.Equal(t, dw.BaseURL, defaultBaseURL)
+	assert.NotEmpty(t, dw.BaseURL)
+	assert.Equal(t, dw.Token, "secret.token")
+}
+
+func TestGetBaseURL(t *testing.T) {
+	dw := getTestClient()
+	assert.Equal(t, dw.BaseURL, defaultBaseURL+"/v0")
+
+	_ = os.Setenv("DW_ENVIRONMENT", "sparklesquad")
+	dw = getTestClient()
+	assert.Equal(t, dw.BaseURL, "https://api.sparklesquad.data.world/v0")
+
+	_ = os.Setenv("DW_API_HOST", "http://localhost:1010")
+	dw = getTestClient()
+	assert.Equal(t, dw.BaseURL, "http://localhost:1010/v0")
 }
 
 func TestClient_RequestMultiplePages(t *testing.T) {