added --method flag for HTTP request method

Signed-off-by: Vivek Singh <vivekkmr45@yahoo.in>

changed method to httpMethod, and uppercase to camelCase

Signed-off-by: Vivek Singh <vivekkmr45@yahoo.in>

commands/invoke.go

@@ -18,6 +18,7 @@ var (
 	query       []string
 	headers     []string
 	invokeAsync bool
+	httpMethod  string
 )
 
 func init() {
@@ -29,12 +30,13 @@ func init() {
 	invokeCmd.Flags().StringArrayVar(&query, "query", []string{}, "pass query-string options")
 	invokeCmd.Flags().StringArrayVarP(&headers, "header", "H", []string{}, "pass HTTP request header")
 	invokeCmd.Flags().BoolVarP(&invokeAsync, "async", "a", false, "Invoke the function asynchronously")
+	invokeCmd.Flags().StringVarP(&httpMethod, "method", "m", "POST", "pass HTTP request method")
 
 	faasCmd.AddCommand(invokeCmd)
 }
 
 var invokeCmd = &cobra.Command{
-	Use:   `invoke FUNCTION_NAME [--gateway GATEWAY_URL] [--content-type CONTENT_TYPE] [--query PARAM=VALUE] [--header PARAM=VALUE]`,
+	Use:   `invoke FUNCTION_NAME [--gateway GATEWAY_URL] [--content-type CONTENT_TYPE] [--query PARAM=VALUE] [--header PARAM=VALUE] [--method HTTP_METHOD]`,
 	Short: "Invoke an OpenFaaS function",
 	Long:  `Invokes an OpenFaaS function and reads from STDIN for the body of the request`,
 	Example: `  faas-cli invoke echo --gateway https://domain:port
@@ -42,7 +44,8 @@ var invokeCmd = &cobra.Command{
   faas-cli invoke env --query repo=faas-cli --query org=openfaas
   faas-cli invoke env --header X-Ping-Url=http://request.bin/etc
   faas-cli invoke resize-img --async -H "X-Callback-Url=http://gateway:8080/function/send2slack" < image.png
-  faas-cli invoke env -H X-Ping-Url=http://request.bin/etc`,
+  faas-cli invoke env -H X-Ping-Url=http://request.bin/etc
+  faas-cli invoke flask --method GET`,
 	RunE: runInvoke,
 }
 
@@ -79,7 +82,7 @@ func runInvoke(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("unable to read standard input: %s", err.Error())
 	}
 
-	response, err := proxy.InvokeFunction(gatewayAddress, functionName, &functionInput, contentType, query, headers, invokeAsync)
+	response, err := proxy.InvokeFunction(gatewayAddress, functionName, &functionInput, contentType, query, headers, invokeAsync, httpMethod)
 	if err != nil {
 		return err
 	}

proxy/invoke.go

@@ -15,7 +15,7 @@ import (
 )
 
 // InvokeFunction a function
-func InvokeFunction(gateway string, name string, bytesIn *[]byte, contentType string, query []string, headers []string, async bool) (*[]byte, error) {
+func InvokeFunction(gateway string, name string, bytesIn *[]byte, contentType string, query []string, headers []string, async bool, httpMethod string) (*[]byte, error) {
 	var resBytes []byte
 
 	gateway = strings.TrimRight(gateway, "/")
@@ -40,9 +40,14 @@ func InvokeFunction(gateway string, name string, bytesIn *[]byte, contentType st
 		functionEndpoint = "/async-function/"
 	}
 
+	httpMethodErr := validateHTTPMethod(httpMethod)
+	if httpMethodErr != nil {
+		return nil, httpMethodErr
+	}
+
 	gatewayURL := gateway + functionEndpoint + name + qs
 
-	req, err := http.NewRequest(http.MethodPost, gatewayURL, reader)
+	req, err := http.NewRequest(httpMethod, gatewayURL, reader)
 	if err != nil {
 		fmt.Println()
 		fmt.Println(err)
@@ -133,3 +138,23 @@ func parseHeaders(headers []string) (map[string]string, error) {
 	}
 	return headerMap, nil
 }
+
+// validateMethod validates the HTTP request method
+func validateHTTPMethod(httpMethod string) error {
+	var allowedMethods = []string{http.MethodGet, http.MethodPost}
+	helpString := strings.Join(allowedMethods, "/")
+
+	if !contains(allowedMethods, httpMethod) {
+		return fmt.Errorf("the --method or -m flag must take one of these values (%s)", helpString)
+	}
+	return nil
+}
+
+func contains(s []string, item string) bool {
+	for _, value := range s {
+		if value == item {
+			return true
+		}
+	}
+	return false
+}

proxy/invoke_test.go

@@ -27,6 +27,7 @@ func Test_InvokeFunction(t *testing.T) {
 		[]string{},
 		[]string{},
 		false,
+		http.MethodPost,
 	)
 
 	if err != nil {
@@ -47,6 +48,7 @@ func Test_InvokeFunction_Async(t *testing.T) {
 		[]string{},
 		[]string{},
 		true,
+		http.MethodPost,
 	)
 
 	if err != nil {
@@ -67,6 +69,7 @@ func Test_InvokeFunction_Not2xx(t *testing.T) {
 		[]string{},
 		[]string{},
 		false,
+		http.MethodPost,
 	)
 
 	if err == nil {
@@ -90,6 +93,7 @@ func Test_InvokeFunction_MissingURLPrefix(t *testing.T) {
 		[]string{},
 		[]string{},
 		false,
+		http.MethodPost,
 	)
 
 	if err == nil {