func ExampleGetFieldKind() {
s := MyStruct{
FirstField: "first value",
SecondField: 2,
ThirdField: "third value",
}
var firstFieldKind reflect.Kind
var secondFieldKind reflect.Kind
var err error
// GetFieldKind will return reflect.String
firstFieldKind, err = reflections.GetFieldKind(s, "FirstField")
if err != nil {
log.Fatal(err)
}
fmt.Println(firstFieldKind)
// GetFieldKind will return reflect.Int
secondFieldKind, err = reflections.GetFieldKind(s, "SecondField")
if err != nil {
log.Fatal(err)
}
fmt.Println(secondFieldKind)
}
func (r *Row) Bind(x interface{}, strategy map[string]string) error {
for src, dest := range strategy {
data, ok := r.data[src]
if ok {
k, err := reflections.GetFieldKind(x, dest)
if err != nil {
return err
}
switch k {
case reflect.String:
{
reflections.SetField(x, dest, data)
}
case reflect.Int64:
{
i, err := strconv.ParseInt(data, 10, 64)
if err != nil {
return err
}
reflections.SetField(x, dest, i)
}
case reflect.Ptr:
{
value, err := reflections.GetField(x, dest)
if err != nil {
return err
}
if reflect.TypeOf(value) == typeDec {
dec, success := new(inf.Dec).SetString(data)
if !success {
fmt.Errorf("Could not parse inf.Dec: %s", data)
}
reflections.SetField(x, dest, dec)
}
}
case reflect.Struct:
{
value, err := reflections.GetField(x, dest)
if err != nil {
return err
}
if reflect.TypeOf(value) == typeTime {
date, err := time.ParseInLocation("2006-01-02 15:04:05", data, r.opts.TimeZone)
if err != nil {
return err
}
reflections.SetField(x, dest, date)
}
}
}
}
}
return nil
}
func validFieldType(fieldName string, target interface{}, fieldType string) bool {
fieldKind, err := reflections.GetFieldKind(target, fieldName)
if err != nil {
return false
}
return fieldKind == fieldKindFromFieldType(fieldType)
}
func (l Loader) fieldValueIsEmpty(fieldName string) bool {
// We need to use the field kind to determine the type of empty test.
value, _ := reflections.GetField(l.Config, fieldName)
fieldKind, _ := reflections.GetFieldKind(l.Config, fieldName)
if fieldKind == reflect.String {
return value == ""
} else if fieldKind == reflect.Slice {
v := reflect.ValueOf(value)
return v.Len() == 0
} else if fieldKind == reflect.Bool {
return value == false
} else {
panic(fmt.Sprintf("Can't determine empty-ness for field type %s", fieldKind))
}
return false
}
// createFieldInfos creates the fieldInfos for a struct s.
// Only information from the struct (headerName, fieldName and kind) is available,
// all field positions are initialized with an invalid value of -1
func createFieldInfos(s interface{}) (fieldInfos, error) {
if reflect.TypeOf(s).Kind() != reflect.Struct {
return nil, ErrNoStruct
}
fieldInfos := []fieldInfo{}
headerNameMap := map[string]interface{}{} // to detect duplicate csv tag names
fieldNames, err := reflections.Fields(s)
if err != nil {
return nil, err
}
for _, fieldName := range fieldNames {
headerName, err := reflections.GetFieldTag(s, fieldName, "csv")
if err != nil {
return nil, err
}
// csv fieldtags that contain a dash are ignored
if strings.Contains(headerName, "-") {
continue
}
if _, ok := headerNameMap[headerName]; ok {
return nil, fmt.Errorf("duplicate csv tag name: %s", headerName)
}
headerNameMap[headerName] = nil
kind, err := reflections.GetFieldKind(s, fieldName)
if err != nil {
return nil, err
}
if len(headerName) == 0 {
return nil, fmt.Errorf("empty csv tag for field: %s", fieldName)
}
fieldInfos = append(fieldInfos, fieldInfo{
headerName: headerName,
fieldName: fieldName,
position: -1,
kind: kind,
})
}
return fieldInfos, nil
}
// SetField sets the value of the given field.
func (dc *DeepCopier) SetField(options *FieldOptions) error {
if options.Skip {
return nil
}
if dc.Reversed {
has, _ := reflections.HasField(dc.Destination, options.SourceField)
if !has {
return nil
}
}
has, _ := reflections.HasField(dc.Source, options.SourceField)
if !has {
err := dc.HandleMethod(options)
if err != nil {
has, _ = reflections.HasField(dc.Destination, options.DestinationField)
if has {
return nil
}
}
return nil
}
kind, _ := reflections.GetFieldKind(dc.Source, options.SourceField)
if kind == reflect.Struct {
if err := dc.HandleStructField(options); err != nil {
return err
}
return nil
}
if err := dc.HandleField(options); err != nil {
return err
}
return nil
}
func (l Loader) normalizeField(fieldName string, normalization string) error {
if normalization == "filepath" {
value, _ := reflections.GetField(l.Config, fieldName)
fieldKind, _ := reflections.GetFieldKind(l.Config, fieldName)
// Make sure we're normalizing a string filed
if fieldKind != reflect.String {
return fmt.Errorf("filepath normalization only works on string fields")
}
// Normalize the field to be a filepath
if valueAsString, ok := value.(string); ok {
normalizedPath := NormalizeFilePath(valueAsString)
if err := reflections.SetField(l.Config, fieldName, normalizedPath); err != nil {
return err
}
}
} else {
return fmt.Errorf("Unknown normalization `%s`", normalization)
}
return nil
}
func formTagFromField(fieldName string, target interface{}) (string, error) {
fieldKind, err := reflections.GetFieldKind(target, fieldName)
f, _ := reflections.GetField(target, fieldName)
fmt.Printf("Field %v\n", f)
if err != nil {
return "", err
}
choices, _ := reflections.GetFieldTag(target, fieldName, "choices")
switch fieldKind {
case reflect.String:
if choices != "" {
return "list", nil
}
return "input", nil
case reflect.Slice:
return "checkbox", nil
case reflect.Bool:
return "confirm", nil
}
return "", nil
}
// Reflects on the values in the commandLineOptions structure, and fills it
// with values either from the command line, or from the ENV.
func parseArgs(opts *commandLineOptions, args []string) {
// Create a flag set for args
flags := flag.NewFlagSet(commandLineName, flag.ExitOnError)
// Get the fields for the strucutre
fields, _ := reflections.Fields(opts)
// Loop through each field of the structure, and define a flag for it
for i := 0; i < len(fields); i++ {
fieldName := fields[i]
flagName, _ := reflections.GetFieldTag(opts, fieldName, "flag")
fieldKind, _ := reflections.GetFieldKind(opts, fieldName)
if fieldKind == reflect.String {
flags.String(flagName, "", "")
} else if fieldKind == reflect.Bool {
flags.Bool(flagName, false, "")
} else {
exitAndError(fmt.Sprintf("Could not create flag for %s", fieldName))
}
}
// Define our custom usage text
flags.Usage = func() {
fmt.Printf("%s\n", commandLineUsage)
}
// Search the args until we find a "--", which signifies the user has started
// defining options.
var argumentFlags []string
started := false
for i := 0; i < len(args); i++ {
if strings.HasPrefix(args[i], "--") {
started = true
}
if started {
argumentFlags = append(argumentFlags, args[i])
}
}
// Now parse the flags
flags.Parse(argumentFlags)
// Now the flag set has been populated with values, retrieve them and
// set them (or use the ENV variable if empty)
for i := 0; i < len(fields); i++ {
fieldName := fields[i]
fieldKind, _ := reflections.GetFieldKind(opts, fieldName)
// Grab the flags we need
flagName, _ := reflections.GetFieldTag(opts, fieldName, "flag")
envName, _ := reflections.GetFieldTag(opts, fieldName, "env")
required, _ := reflections.GetFieldTag(opts, fieldName, "required")
// Grab the value from the flag
value := flags.Lookup(flagName).Value.String()
// If the value of the flag is empty, try the ENV
if value == "" {
value = os.Getenv(envName)
}
// Do validation
if required == "true" && value == "" {
exitAndError(fmt.Sprintf("missing %s", flagName))
}
// Set the value in the right way
if fieldKind == reflect.String {
reflections.SetField(opts, fieldName, value)
} else if fieldKind == reflect.Bool {
// The bool is converted to a string above
if value == "true" {
reflections.SetField(opts, fieldName, true)
} else {
reflections.SetField(opts, fieldName, false)
}
} else {
exitAndError(fmt.Sprintf("Could not set value of %s", fieldName))
}
}
}
func (l Loader) setFieldValueFromCLI(fieldName string, cliName string) error {
// Get the kind of field we need to set
fieldKind, err := reflections.GetFieldKind(l.Config, fieldName)
if err != nil {
return fmt.Errorf(`Failed to get the type of struct field %s`, fieldName)
}
var value interface{}
// See the if the cli option is using the special format i.e. (arg:1)
special := CLISpecialNameRegex.FindStringSubmatch(cliName)
if len(special) == 3 {
// Should this cli option be loaded from the CLI arguments?
if special[1] == "arg" {
// Convert the arg position to an integer
i, err := strconv.Atoi(special[2])
if err != nil {
return fmt.Errorf("Failed to convert string to int: %s", err)
}
// Only set the value if the args are long enough for
// the position to exist.
if len(l.CLI.Args()) > i {
// Get the value from the args
value = l.CLI.Args()[i]
}
}
} else {
// If the cli name didn't have the special format, then we need to
// either load from the context's flags, or from a config file.
// We start by defaulting the value to what ever was provided
// by the configuration file
if l.File != nil {
if configFileValue, ok := l.File.Config[cliName]; ok {
// Convert the config file value to it's correct type
if fieldKind == reflect.String {
value = configFileValue
} else if fieldKind == reflect.Slice {
value = strings.Split(configFileValue, ",")
} else if fieldKind == reflect.Bool {
value, _ = strconv.ParseBool(configFileValue)
} else {
return fmt.Errorf("Unable to convert string to type %s", fieldKind)
}
}
}
// If a value hasn't been found in a config file, but there
// _is_ one provided by the CLI context, then use that.
if value == nil || l.cliValueIsSet(cliName) {
if fieldKind == reflect.String {
value = l.CLI.String(cliName)
} else if fieldKind == reflect.Slice {
value = l.CLI.StringSlice(cliName)
} else if fieldKind == reflect.Bool {
value = l.CLI.Bool(cliName)
} else {
return fmt.Errorf("Unable to handle type: %s", fieldKind)
}
}
}
// Set the value to the cfg
if value != nil {
err = reflections.SetField(l.Config, fieldName, value)
if err != nil {
return fmt.Errorf("Could not set value `%s` to field `%s` (%s)", value, fieldName, err)
}
}
return nil
}
