Go CLI: fix show variable (#16370)

### What problem does this PR solve?

```
RAGFlow(api/default)> show var 'mail.port';
+-----------+-----------+--------------+-------+
| data_type | name      | setting_type | value |
+-----------+-----------+--------------+-------+
| integer   | mail.port | config       | 30    |
+-----------+-----------+--------------+-------+
```

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/cli/admin_command.go

@@ -975,9 +975,11 @@ func (c *CLI) AdminShowVariable(cmd *Command) (ResponseIf, error) {
 		return nil, fmt.Errorf("var_name not provided")
 	}
 
-	payload := map[string]interface{}{"var_name": varName}
+	encodedVarName := common.EncodeToBase64(varName)
 
-	resp, err := c.AdminServerClient.Request("GET", "/admin/variables", "admin", nil, payload)
+	endPoint := fmt.Sprintf("/admin/variables/%s", encodedVarName)
+
+	resp, err := c.AdminServerClient.Request("GET", endPoint, "admin", nil, nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to show variable: %w", err)
 	}

internal/cli/cli_http.go

@@ -330,6 +330,8 @@ func (c *CLI) ExecuteUserCommand(cmd *Command) (ResponseIf, error) {
 		return c.APISetAPIKeyCommand(cmd)
 	case "api_set_variable":
 		return c.APISetVariableCommand(cmd)
+	case "api_show_variable":
+		return c.APIShowVariableCommand(cmd)
 	case "api_unset_api_key":
 		return c.APIUnsetAPIKeyCommand(cmd)
 	case "api_show_version":

internal/cli/user_command.go

@@ -1146,6 +1146,51 @@ func (c *CLI) APISetVariableCommand(cmd *Command) (ResponseIf, error) {
 	return &result, nil
 }
 
+// APIShowVariableCommand displays variable value
+func (c *CLI) APIShowVariableCommand(cmd *Command) (ResponseIf, error) {
+
+	if c.Config.CLIMode != APIMode {
+		return nil, fmt.Errorf("this command is only allowed in USER mode")
+	}
+
+	httpClient := c.APIServerClientMap[c.Config.APIClientConfig.CurrentAPIServer]
+
+	if httpClient.APIKey == nil && httpClient.LoginToken == nil {
+		return nil, fmt.Errorf("API key not set. Please login first")
+	}
+
+	varName, ok := cmd.Params["var_name"].(string)
+	if !ok {
+		return nil, fmt.Errorf("var_name not provided")
+	}
+
+	EncodedVarName := common.EncodeToBase64(varName)
+
+	endPoint := fmt.Sprintf("/system/variables/%s", EncodedVarName)
+
+	resp, err := httpClient.Request("GET", endPoint, "web", nil, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get variable: %w", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("failed to get variable: HTTP %d, body: %s", resp.StatusCode, string(resp.Body))
+	}
+
+	var result CommonResponse
+	if err = json.Unmarshal(resp.Body, &result); err != nil {
+		return nil, fmt.Errorf("show variable failed: invalid JSON (%w)", err)
+	}
+
+	if result.Code != 0 {
+		return nil, fmt.Errorf("%s", result.Message)
+	}
+
+	normalizeVariableRows(result.Data)
+	result.Duration = resp.Duration
+	return &result, nil
+}
+
 // APIShowAPIKeyCommand displays the current API key
 func (c *CLI) APIShowAPIKeyCommand(cmd *Command) (ResponseIf, error) {
 	if c.Config.CLIMode != APIMode {

internal/cli/user_parser.go

@@ -522,7 +522,7 @@ func (p *Parser) parseAPIShowCommands() (*Command, error) {
 	case TokenCurrent:
 		return p.parseAPIShowCurrent()
 	case TokenVar:
-		return p.parseShowVariable()
+		return p.parseAPIShowVariable()
 	case TokenProvider:
 		return p.parseAPIShowProviderCommands()
 	case TokenModel:
@@ -572,17 +572,17 @@ func (p *Parser) parseAPIShowCurrent() (*Command, error) {
 	return NewCommand("api_show_current"), nil
 }
 
-func (p *Parser) parseShowVariable() (*Command, error) {
+func (p *Parser) parseAPIShowVariable() (*Command, error) {
 	p.nextToken() // consume VAR
-	varName, err := p.parseIdentifier()
+	varName, err := p.parseQuotedString()
 	if err != nil {
 		return nil, err
 	}
+	p.nextToken()
 
-	cmd := NewCommand("show_variable")
+	cmd := NewCommand("api_show_variable")
 	cmd.Params["var_name"] = varName
 
-	p.nextToken()
 	// Semicolon is optional
 	if p.curToken.Type == TokenSemicolon {
 		p.nextToken()