Add ReadJSONConfigFromFile for jsoncfg parser, it allows reading conf…

…ig file from where the executable file resides as well. See #49, #52

_examples/032-jsoncfg/main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"os"
+
+	"github.com/mkideal/cli"
+)
+
+type argT struct {
+	cli.Helper
+	Self *argT `json:"-" cli:"c,config" usage:"parse json config from file" parser:"jsoncfg" dft:"test.json"`
+	A    string
+	B    int
+	C    bool
+}
+
+func newArgT() *argT {
+	var argv = new(argT)
+	argv.Self = argv
+	return argv
+}
+
+func main() {
+	os.Exit(cli.Run(newArgT(), func(ctx *cli.Context) error {
+		argv := ctx.Argv().(*argT)
+		ctx.JSONIndentln(argv, "", "    ")
+		return nil
+	}))
+}

_examples/032-jsoncfg/test.json

@@ -0,0 +1,5 @@
+{
+	"A": "a string",
+	"B": 12,
+	"C": true
+}

builtin.go

@@ -14,6 +14,16 @@ func (h Helper) AutoHelp() bool {
 	return h.Help
 }
 
+// Helper2 is builtin Help flag
+type Helper2 struct {
+	Help bool `cli:"!h,help" usage:"Display help information" json:"-"`
+}
+
+// AutoHelp implements AutoHelper interface
+func (h Helper2) AutoHelp() bool {
+	return h.Help
+}
+
 // Deprecated: Addr is builtin host,port flag
 type Addr struct {
 	Host string `cli:"host" usage:"specify host" dft:"0.0.0.0"`

cliutil.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 
 	"github.com/labstack/gommon/color"
@@ -93,7 +94,7 @@ func ReadJSON(r io.Reader, argv interface{}) error {
 	return json.NewDecoder(r).Decode(argv)
 }
 
-// ReadJSONFromFile is similar to ReadJSONFromFile, but read from file
+// ReadJSONFromFile is similar to ReadJSON, but read from file
 func ReadJSONFromFile(filename string, argv interface{}) error {
 	file, err := os.Open(filename)
 	if err == nil {
@@ -102,3 +103,24 @@ func ReadJSONFromFile(filename string, argv interface{}) error {
 	}
 	return err
 }
+
+// ReadJSONConfigFromFile is similar to ReadJSONFromFile, but allows reading file from where the executable file resides as well
+func ReadJSONConfigFromFile(filename string, argv interface{}) error {
+	file, err := os.Open(filename)
+	if err == nil {
+		defer file.Close()
+		err = ReadJSON(file, argv)
+	} else {
+		exe, e := os.Executable()
+		if e != nil {
+			return e
+		}
+		// allow self-config .json files to go with the executable file, #40
+		file, err = os.Open(filepath.Dir(exe) + string(filepath.Separator) + filename)
+		if err == nil {
+			defer file.Close()
+			err = ReadJSON(file, argv)
+		}
+	}
+	return err
+}

parser.go

@@ -26,6 +26,7 @@ func RegisterFlagParser(name string, creator FlagParserCreator) {
 func init() {
 	RegisterFlagParser("json", newJSONParser)
 	RegisterFlagParser("jsonfile", newJSONFileParser)
+	RegisterFlagParser("jsoncfg", newJSONConfigFileParser)
 	RegisterFlagParser("url", newURLParser)
 }
 
@@ -55,6 +56,19 @@ func (p JSONFileParser) Parse(s string) error {
 	return ReadJSONFromFile(s, p.ptr)
 }
 
+// JSON config file parser
+type JSONConfigFileParser struct {
+	ptr interface{}
+}
+
+func newJSONConfigFileParser(ptr interface{}) FlagParser {
+	return &JSONConfigFileParser{ptr}
+}
+
+func (p JSONConfigFileParser) Parse(s string) error {
+	return ReadJSONConfigFromFile(s, p.ptr)
+}
+
 // URL parser
 type URLParser struct {
 	ptr *url.URL