Fixes #260: Adds URL checking

cmd/snapctl/main.go

@@ -21,6 +21,7 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	"os"
 	"sort"
 	"time"
@@ -33,6 +34,7 @@ var (
 	gitversion string
 	pClient    *client.Client
 	timeFormat = time.RFC1123
+	err        error
 )
 
 func main() {
@@ -90,7 +92,11 @@ func init() {
 			}
 		}
 	}
-	pClient = client.New(url, ver, secure)
+	pClient, err = client.New(url, ver, secure)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
 	resp := pClient.ListAgreements()
 	if resp.Err == nil {
 		commands = append(commands, tribeCommands...)

mgmt/rest/client/client.go

@@ -35,6 +35,8 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/asaskevich/govalidator"
+
 	"github.com/intelsdi-x/snap/mgmt/rest/rbody"
 )
 
@@ -72,9 +74,20 @@ type Client struct {
 	prefix string
 }
 
+// Checks validity of URL
+func parseURL(url string) error {
+	if !govalidator.IsURL(url) || !strings.HasPrefix(url, "http") {
+		return fmt.Errorf("URL %s is not in the format of http(s)://<ip>:<port>", url)
+	}
+	return nil
+}
+
 // New returns a pointer to a snap api client
 // if ver is an empty string, v1 is used by default
-func New(url, ver string, insecure bool) *Client {
+func New(url, ver string, insecure bool) (*Client, error) {
+	if err := parseURL(url); err != nil {
+		return nil, err
+	}
 	if ver == "" {
 		ver = "v1"
 	}
@@ -91,8 +104,7 @@ func New(url, ver string, insecure bool) *Client {
 		},
 	}
 	c.prefix = url + "/" + ver
-	// TODO (danielscottt): assert that path is valid and target is available
-	return c
+	return c, nil
 }
 
 // String returns the string representation of the content type given a content number.