feat: add constructServiceURL function

v5/core/parameterized_url.go

@@ -0,0 +1,83 @@
+package core
+
+// (C) Copyright IBM Corp. 2021.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+//
+// constructServiceURL returns a service URL that is constructed by formatting a parameterized URL.
+//
+// Parameters:
+//
+// parameterizedUrl: URL that contains variable placeholders, e.g. "{scheme}://ibm.com".
+//
+// defaultUrlVariables: map from variable names to default values.
+//		Each variable in the parameterized URL must have a default value specified in this map.
+//
+// providedUrlVariables: map from variable names to desired values.
+// 		If a variable is not provided in this map,
+// 		the default variable value will be used instead.
+//
+func constructServiceURL(
+	parameterizedUrl string,
+	defaultUrlVariables map[string]string,
+	providedUrlVariables map[string]string,
+) (string, error) {
+
+	// If null was passed, we set the variables to an empty map.
+	// This results in all default variable values being used.
+	if providedUrlVariables == nil {
+		providedUrlVariables = map[string]string{}
+	}
+
+	// Verify the provided variable names.
+	for providedName := range providedUrlVariables {
+		if _, ok := defaultUrlVariables[providedName]; !ok {
+			// Get all variable names (the keys of the default variables map).
+			acceptedNames := make([]string, len(defaultUrlVariables))
+
+			i := 0
+			for name := range defaultUrlVariables {
+				acceptedNames[i] = name
+				i++
+			}
+			sort.Strings(acceptedNames)
+
+			return "", fmt.Errorf(
+				"'%s' is an invalid variable name.\nValid variable names: %s.",
+				providedName,
+				acceptedNames,
+			)
+		}
+	}
+
+	// Format the URL with provided or default variable values.
+	formattedUrl := parameterizedUrl
+
+	for name, defaultValue := range defaultUrlVariables {
+		providedValue, ok := providedUrlVariables[name]
+
+		// Use the default variable value if none was provided.
+		if !ok {
+			providedValue = defaultValue
+		}
+		formattedUrl = strings.Replace(formattedUrl, "{"+name+"}", providedValue, 1)
+	}
+	return formattedUrl, nil
+}

v5/core/parameterized_url_test.go

@@ -0,0 +1,78 @@
+// +build all fast
+
+package core
+
+// (C) Copyright IBM Corp. 2021.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const parameterizedUrl = "{scheme}://{domain}:{port}"
+
+var defaultUrlVariables = map[string]string{
+	"scheme": "http",
+	"domain": "ibm.com",
+	"port":   "9300",
+}
+
+func TestConstructServiceURLWithNil(t *testing.T) {
+	url, err := constructServiceURL(parameterizedUrl, defaultUrlVariables, nil)
+
+	assert.Equal(t, url, "http://ibm.com:9300")
+	assert.Nil(t, err)
+}
+
+func TestConstructServiceURLWithSomeProvidedVariables(t *testing.T) {
+	providedUrlVariables := map[string]string{
+		"scheme": "https",
+		"port":   "22",
+	}
+
+	url, err := constructServiceURL(parameterizedUrl, defaultUrlVariables, providedUrlVariables)
+
+	assert.Equal(t, url, "https://ibm.com:22")
+	assert.Nil(t, err)
+}
+
+func TestConstructServiceURLWithAllProvidedVariables(t *testing.T) {
+	var providedUrlVariables = map[string]string{
+		"scheme": "https",
+		"domain": "google.com",
+		"port":   "22",
+	}
+
+	url, err := constructServiceURL(parameterizedUrl, defaultUrlVariables, providedUrlVariables)
+
+	assert.Equal(t, url, "https://google.com:22")
+	assert.Nil(t, err)
+}
+
+func TestConstructServiceURLWithInvalidVariable(t *testing.T) {
+	var providedUrlVariables = map[string]string{
+		"server": "value",
+	}
+
+	url, err := constructServiceURL(parameterizedUrl, defaultUrlVariables, providedUrlVariables)
+
+	assert.Equal(t, url, "")
+	assert.EqualError(
+		t,
+		err,
+		"'server' is an invalid variable name.\nValid variable names: [domain port scheme].",
+	)
+}