fix: The argocd server api-content-type flag does not allow empty content-type header

cmd/argocd-server/commands/argocd_server.go

@@ -248,7 +248,7 @@ func NewCommand() *cobra.Command {
 	command.Flags().StringVar(&repoServerAddress, "repo-server", env.StringFromEnv("ARGOCD_SERVER_REPO_SERVER", common.DefaultRepoServerAddr), "Repo server address")
 	command.Flags().StringVar(&dexServerAddress, "dex-server", env.StringFromEnv("ARGOCD_SERVER_DEX_SERVER", common.DefaultDexServerAddr), "Dex server address")
 	command.Flags().BoolVar(&disableAuth, "disable-auth", env.ParseBoolFromEnv("ARGOCD_SERVER_DISABLE_AUTH", false), "Disable client authentication")
-	command.Flags().StringVar(&contentTypes, "api-content-types", env.StringFromEnv("ARGOCD_API_CONTENT_TYPES", "application/json"), "Semicolon separated list of allowed content types for non GET api requests. Any content type is allowed if empty.")
+	command.Flags().StringVar(&contentTypes, "api-content-types", env.StringFromEnv("ARGOCD_API_CONTENT_TYPES", "application/json", env.StringFromEnvOpts{AllowEmpty: true}), "Semicolon separated list of allowed content types for non GET api requests. Any content type is allowed if empty.")
 	command.Flags().BoolVar(&enableGZip, "enable-gzip", env.ParseBoolFromEnv("ARGOCD_SERVER_ENABLE_GZIP", true), "Enable GZIP compression")
 	command.AddCommand(cli.NewVersionCmd(cliName))
 	command.Flags().StringVar(&listenHost, "address", env.StringFromEnv("ARGOCD_SERVER_LISTEN_ADDRESS", common.DefaultAddressAPIServer), "Listen on given address")

util/env/env.go

@@ -151,8 +151,17 @@ func ParseDurationFromEnv(env string, defaultValue, min, max time.Duration) time
 	return dur
 }
 
-func StringFromEnv(env string, defaultValue string) string {
-	if str := os.Getenv(env); str != "" {
+type StringFromEnvOpts struct {
+	// AllowEmpty allows the value to be empty as long as the environment variable is set.
+	AllowEmpty bool
+}
+
+func StringFromEnv(env string, defaultValue string, opts ...StringFromEnvOpts) string {
+	opt := StringFromEnvOpts{}
+	for _, o := range opts {
+		opt.AllowEmpty = opt.AllowEmpty || o.AllowEmpty
+	}
+	if str, ok := os.LookupEnv(env); opt.AllowEmpty && ok || str != "" {
 		return str
 	}
 	return defaultValue

util/env/env_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"k8s.io/utils/pointer"
 )
 
 func TestParseNumFromEnv(t *testing.T) {
@@ -167,19 +168,25 @@ func TestStringFromEnv(t *testing.T) {
 
 	testCases := []struct {
 		name     string
-		env      string
+		env      *string
 		expected string
 		def      string
+		opts     []StringFromEnvOpts
 	}{
-		{"Some string", "true", "true", def},
-		{"Empty string with default", "", def, def},
-		{"Empty string without default", "", "", ""},
+		{"Some string", pointer.String("true"), "true", def, nil},
+		{"Empty string with default", pointer.String(""), def, def, nil},
+		{"Empty string without default", pointer.String(""), "", "", nil},
+		{"No env variable with default allow empty", nil, "default", "default", []StringFromEnvOpts{{AllowEmpty: true}}},
+		{"Some variable with default allow empty", pointer.String("true"), "true", "default", []StringFromEnvOpts{{AllowEmpty: true}}},
+		{"Empty variable with default allow empty", pointer.String(""), "", "default", []StringFromEnvOpts{{AllowEmpty: true}}},
 	}
 
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
-			t.Setenv(envKey, tt.env)
-			b := StringFromEnv(envKey, tt.def)
+			if tt.env != nil {
+				t.Setenv(envKey, *tt.env)
+			}
+			b := StringFromEnv(envKey, tt.def, tt.opts...)
 			assert.Equal(t, tt.expected, b)
 		})
 	}