add client option for literal URLs

client_options.go

@@ -22,9 +22,10 @@ type ClientOption func(*ClientOptions)
 
 // ClientOptions encapsulate the configurable parameters on a Twirp client.
 type ClientOptions struct {
-	Interceptors []Interceptor
-	Hooks        *ClientHooks
-	pathPrefix   *string
+	Interceptors       []Interceptor
+	Hooks              *ClientHooks
+	UseLiteralCaseURLs bool
+	pathPrefix         *string
 }
 
 func (opts *ClientOptions) PathPrefix() string {
@@ -130,3 +131,13 @@ func WithClientPathPrefix(prefix string) ClientOption {
 		o.pathPrefix = &prefix
 	}
 }
+
+// WithClientLiteralCase sets twirp client to use exact names for service and method names as defined the protobuf file.
+// Example: for Service name `haberdasher` and method name `make_hat`, the default URL is `/<prefix>/<package>.Haberdasher/MakeHat`
+// using this option will make the client send requests to `/<prefix>/<package>.haberdasher/make_hat` instead.
+// This is required when working with spec-compatible servers in other languages.
+func WithClientLiteralCase() ClientOption {
+	return func(o *ClientOptions) {
+		o.UseLiteralCaseURLs = true
+	}
+}

client_options_test.go

@@ -112,3 +112,21 @@ func TestWithClientPathPrefix(t *testing.T) {
 		t.Errorf("unexpected value after WithClientPathPrefix, have: %q, want: %q", have, want)
 	}
 }
+
+func TestWithClientLiteralCase(t *testing.T) {
+	opts := &ClientOptions{}
+
+	// Default value
+	if have, want := opts.UseLiteralCaseURLs, false; have != want {
+		t.Errorf("unexpected default UseLiteral on ClientOptions, have: %t, want: %t", have, want)
+		return
+	}
+
+	// Set a different prefix
+	WithClientLiteralCase()(opts)
+	if have, want := opts.UseLiteralCaseURLs, true; have != want {
+		t.Errorf("unexpected value after WithClientLiteralCase, have: %t, want: %t", have, want)
+		return
+	}
+
+}