Get logs for a contract (#99)

* Add ability to fetch logs for a contract and a block

* Test contract related code against Infura, so can run on Travis

* Add godo task for getLogs

pkg/config/config.go

@@ -12,6 +12,8 @@ import (
 
 	"errors"
 
+	"net/url"
+
 	"github.com/BurntSushi/toml"
 )
 
@@ -24,6 +26,10 @@ var NewErrConfigFileNotFound = func(environment string) error {
 	return errors.New(fmt.Sprintf("No configuration found for environment: %v", environment))
 }
 
+var NewErrBadConnectionString = func(connectionString string) error {
+	return errors.New(fmt.Sprintf("connection string is invalid: %v", connectionString))
+}
+
 func NewConfig(environment string) (Config, error) {
 	filenameWithExtension := fmt.Sprintf("%s.toml", environment)
 	absolutePath := filepath.Join(ProjectRoot(), "environments", filenameWithExtension)
@@ -31,7 +37,7 @@ func NewConfig(environment string) (Config, error) {
 	if err != nil {
 		return Config{}, NewErrConfigFileNotFound(environment)
 	} else {
-		if !filepath.IsAbs(config.Client.IPCPath) {
+		if !filepath.IsAbs(config.Client.IPCPath) && !isUrl(config.Client.IPCPath) {
 			config.Client.IPCPath = filepath.Join(ProjectRoot(), config.Client.IPCPath)
 		}
 		return config, nil
@@ -43,16 +49,31 @@ func ProjectRoot() string {
 	return path.Join(path.Dir(filename), "..", "..")
 }
 
+func isUrl(s string) bool {
+	_, err := url.ParseRequestURI(s)
+	if err == nil {
+		return true
+	}
+	return false
+}
+
+func fileExists(s string) bool {
+	_, err := os.Stat(s)
+	if err == nil {
+		return true
+	}
+	return false
+}
+
 func parseConfigFile(filePath string) (Config, error) {
 	var cfg Config
-	_, err := os.Stat(filePath)
-	if err != nil {
-		return Config{}, err
+	if !isUrl(filePath) && !fileExists(filePath) {
+		return Config{}, NewErrBadConnectionString(filePath)
 	} else {
 		_, err := toml.DecodeFile(filePath, &cfg)
 		if err != nil {
 			return Config{}, err
 		}
-		return cfg, err
+		return cfg, nil
 	}
 }