add URL

check_test.go

@@ -157,6 +157,42 @@ func TestIsDialAddr(t *testing.T) {
 	}
 }
 
+func TestURL(t *testing.T) {
+	tests := []struct {
+		in      string
+		wantErr bool
+	}{
+		// Valid
+		{"http://localhost", false},
+		{"http://localhost:1234", false},
+		{"http://192.168.0.1:1234", false},
+		{"https://example.com", false},
+		{"https://example.com/home", false},
+		{"https://example.com/home?a=b", false},
+
+		// Invalid
+		{"", true},
+		{"ht tp://foo.com", true}, // invalid character in schema
+		{"http://a b.com/", true}, // no space in host name please
+		{"cache_object:foo", true},
+	}
+
+	env.ResetForTesting()
+	prefix := env.CmdVar.Name()
+	_ = env.URL("URL", "URL test")
+	name := strings.ToUpper(prefix) + "_URL"
+
+	for _, tt := range tests {
+		t.Run(tt.in, func(t *testing.T) {
+			os.Setenv(name, tt.in)
+
+			if err := env.Parse(); (err != nil) != tt.wantErr {
+				t.Errorf("env.Parse() = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
 func TestIsPath(t *testing.T) {
 	env.ResetForTesting()
 

env.go

@@ -5,6 +5,7 @@ package env // import "code.sajari.com/env"
 import (
 	"errors"
 	"fmt"
+	"net/url"
 	"os"
 	"path"
 	"strconv"
@@ -128,6 +129,30 @@ func (v *boolValue) String() string {
 	return strconv.FormatBool(bool(*v))
 }
 
+type urlValue url.URL
+
+func newURLValue(x url.URL, p *url.URL) *urlValue {
+	*p = x
+	return (*urlValue)(p)
+}
+
+func (v *urlValue) Set(x string) error {
+	if x == "" {
+		return errors.New("empty")
+	}
+	u, err := url.Parse(x)
+	if err != nil {
+		return err
+	}
+	*v = urlValue(*u)
+	return err
+}
+
+func (v *urlValue) String() string {
+	u := url.URL(*v)
+	return u.String()
+}
+
 // NewVarSet creates a new variable set with given name.
 //
 // If name is non-empty, then all variables will have a strings.ToUpper(name)+"_"
@@ -249,6 +274,14 @@ func (v *VarSet) DialAddr(name, usage string) *string {
 	return p
 }
 
+// URL defines a string variable with specified name, usage string validated as a URL.
+// The return value is the address of a URL variable that stores the value of the variable.
+func (v *VarSet) URL(name, usage string) *url.URL {
+	p := new(url.URL)
+	v.Var(newURLValue(url.URL{}, p), name, usage)
+	return p
+}
+
 // Path defines a string variable with specified name, usage string validated as a local path.
 // The return value is the address of a string variable that stores the value of the variable.
 func (v *VarSet) Path(name, usage string) *string {
@@ -356,6 +389,12 @@ func DialAddr(name, usage string) *string {
 	return CmdVar.DialAddr(name, usage)
 }
 
+// URL defines a string variable with specified name, usage string validated as a URL.
+// The return value is the address of a URL variable that stores the value of the variable.
+func URL(name, usage string) *url.URL {
+	return CmdVar.URL(name, usage)
+}
+
 // Path defines a string variable with specified name, usage string validated as a
 // local path.
 // The return value is the address of a string variable that stores the value of the variable.

env_test.go

@@ -20,6 +20,7 @@ func TestAll(t *testing.T) {
 	env.Int("INT", "int test")
 	env.BindAddr("LISTEN", "bindaddr test")
 	env.DialAddr("ADDR", "dialaddr test")
+	env.URL("URL", "URL test")
 	env.String("STRING", "string test")
 	env.Duration("TIMEOUT", "timeout test")
 
@@ -28,6 +29,7 @@ func TestAll(t *testing.T) {
 		"TEST_INT":     "1",
 		"TEST_LISTEN":  ":1234",
 		"TEST_ADDR":    "localhost:1234",
+		"TEST_URL":     "http://localhost:1234/api",
 		"TEST_STRING":  "name",
 		"TEST_TIMEOUT": "1m1s",
 	}