Read username from ENV var as a default option

Author: qba73

README.md

@@ -22,13 +22,26 @@ import github.com/qba73/geonames
 
 ## Creating a client
 
-Export ENV Var or read the username from your app config
+Export ENV Var ```GEONAMES_USER```
+```go
+client, err := geonames.NewClient()
+if err != nil {
+    // handle error
+}
+```
 
+Provide username :
 ```go
-user := os.Getenv("GEO_USER")
-client := geonames.NewClient(user)
+client, err := geonames.NewClient(
+    geonames.WithUserName("dummy_user")
+)
+if err != nil {
+    // handle error
+}
 ```
 
+
+
 ## Bugs and feature request
 
 If you find a bug in the ```geonames``` client library, please [open an issue](https://github.com/qba73/geonames/issues). If you'd like a feature added or improved, let me know via an issue.

geonames.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"os"
 	"time"
 )
 
@@ -45,9 +46,18 @@ func WithHTTPHeaders(header http.Header) option {
 	}
 }
 
+func WithUserName(username string) option {
+	return func(c *Client) error {
+		if username == "" {
+			return errors.New("nil username")
+		}
+		c.userName = username
+		return nil
+	}
+}
+
 // Client is a client used for communicating with GeoNames web service.
 type Client struct {
-	// UserName is a user name chosen when registered for GeoNames.org
 	userName   string
 	userAgent  string
 	baseURL    string
@@ -58,11 +68,11 @@ type Client struct {
 }
 
 // NewClient knows how to create a client for GeoNames Web service.
-// The user name has to be registered at the GeoNames.org website.
-// HTTP requests without a valid username param will return 403 HTTP errors.
-func NewClient(username string, options ...option) (*Client, error) {
+// The username has to be registered at the GeoNames.org website.
+// HTTP requests without a valid username will return 403 HTTP errors.
+func NewClient(options ...option) (*Client, error) {
 	c := Client{
-		userName:  username,
+		userName:  os.Getenv("GEONAMES_USER"),
 		userAgent: userAgent,
 		baseURL:   "http://api.geonames.org",
 		httpClient: &http.Client{

geonames_test.go

@@ -69,7 +69,10 @@ func TestWikipediaResolvesGeoNameOnValidInput(t *testing.T) {
 	defer ts.Close()
 
 	name, country := "Castlebar", "IE"
-	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	client, err := geonames.NewClient(
+		geonames.WithUserName("DummyUser"),
+		geonames.WithBaseURL(ts.URL),
+	)
 	if err != nil {
 		t.Fatal(err)
 	}

postal_test.go

@@ -18,7 +18,10 @@ func TestGetPostalCodes_ReturnsSingleValueOnValidInput(t *testing.T) {
 	)
 	defer ts.Close()
 
-	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	client, err := geonames.NewClient(
+		geonames.WithUserName("DummyUser"),
+		geonames.WithBaseURL(ts.URL),
+	)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -61,7 +64,10 @@ func TestGetPostalCodes_ReturnsMultipleValuesOnValidInput(t *testing.T) {
 	)
 	defer ts.Close()
 
-	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	client, err := geonames.NewClient(
+		geonames.WithUserName("DummyUser"),
+		geonames.WithBaseURL(ts.URL),
+	)
 	if err != nil {
 		t.Fatal(err)
 	}

wikipedia_test.go

@@ -15,7 +15,10 @@ func TestGetPlace_RetrievesSingleGeoNameOnValidInput(t *testing.T) {
 	ts := newTestServer(testFile, wantReqURI, t)
 	defer ts.Close()
 
-	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	client, err := geonames.NewClient(
+		geonames.WithUserName("DummyUser"),
+		geonames.WithBaseURL(ts.URL),
+	)
 	if err != nil {
 		t.Fatal(err)
 	}