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- // Copyright © 2014 Steve Francia <spf@spf13.com>.
- //
- // Use of this source code is governed by an MIT-style
- // license that can be found in the LICENSE file.
-
- package cast
-
- import (
- "fmt"
- "html/template"
- "reflect"
- "strconv"
- "strings"
- "time"
-
- jww "github.com/spf13/jwalterweatherman"
- )
-
- // ToTimeE casts an empty interface to time.Time.
- func ToTimeE(i interface{}) (tim time.Time, err error) {
- i = indirect(i)
- jww.DEBUG.Println("ToTimeE called on type:", reflect.TypeOf(i))
-
- switch s := i.(type) {
- case time.Time:
- return s, nil
- case string:
- d, e := StringToDate(s)
- if e == nil {
- return d, nil
- }
- return time.Time{}, fmt.Errorf("Could not parse Date/Time format: %v\n", e)
- default:
- return time.Time{}, fmt.Errorf("Unable to Cast %#v to Time\n", i)
- }
- }
-
- // ToDurationE casts an empty interface to time.Duration.
- func ToDurationE(i interface{}) (d time.Duration, err error) {
- i = indirect(i)
- jww.DEBUG.Println("ToDurationE called on type:", reflect.TypeOf(i))
-
- switch s := i.(type) {
- case time.Duration:
- return s, nil
- case int64:
- d = time.Duration(s)
- return
- case float64:
- d = time.Duration(s)
- return
- case string:
- d, err = time.ParseDuration(s)
- return
- default:
- err = fmt.Errorf("Unable to Cast %#v to Duration\n", i)
- return
- }
- }
-
- // ToBoolE casts an empty interface to a bool.
- func ToBoolE(i interface{}) (bool, error) {
- i = indirect(i)
- jww.DEBUG.Println("ToBoolE called on type:", reflect.TypeOf(i))
-
- switch b := i.(type) {
- case bool:
- return b, nil
- case nil:
- return false, nil
- case int:
- if i.(int) != 0 {
- return true, nil
- }
- return false, nil
- case string:
- return strconv.ParseBool(i.(string))
- default:
- return false, fmt.Errorf("Unable to Cast %#v to bool", i)
- }
- }
-
- // ToFloat64E casts an empty interface to a float64.
- func ToFloat64E(i interface{}) (float64, error) {
- i = indirect(i)
- jww.DEBUG.Println("ToFloat64E called on type:", reflect.TypeOf(i))
-
- switch s := i.(type) {
- case float64:
- return s, nil
- case float32:
- return float64(s), nil
- case int64:
- return float64(s), nil
- case int32:
- return float64(s), nil
- case int16:
- return float64(s), nil
- case int8:
- return float64(s), nil
- case int:
- return float64(s), nil
- case string:
- v, err := strconv.ParseFloat(s, 64)
- if err == nil {
- return float64(v), nil
- }
- return 0.0, fmt.Errorf("Unable to Cast %#v to float", i)
- default:
- return 0.0, fmt.Errorf("Unable to Cast %#v to float", i)
- }
- }
-
- // ToIntE casts an empty interface to an int.
- func ToIntE(i interface{}) (int, error) {
- i = indirect(i)
- jww.DEBUG.Println("ToIntE called on type:", reflect.TypeOf(i))
-
- switch s := i.(type) {
- case int:
- return s, nil
- case int64:
- return int(s), nil
- case int32:
- return int(s), nil
- case int16:
- return int(s), nil
- case int8:
- return int(s), nil
- case string:
- v, err := strconv.ParseInt(s, 0, 0)
- if err == nil {
- return int(v), nil
- }
- return 0, fmt.Errorf("Unable to Cast %#v to int", i)
- case float64:
- return int(s), nil
- case bool:
- if bool(s) {
- return 1, nil
- }
- return 0, nil
- case nil:
- return 0, nil
- default:
- return 0, fmt.Errorf("Unable to Cast %#v to int", i)
- }
- }
-
- // From html/template/content.go
- // Copyright 2011 The Go Authors. All rights reserved.
- // indirect returns the value, after dereferencing as many times
- // as necessary to reach the base type (or nil).
- func indirect(a interface{}) interface{} {
- if a == nil {
- return nil
- }
- if t := reflect.TypeOf(a); t.Kind() != reflect.Ptr {
- // Avoid creating a reflect.Value if it's not a pointer.
- return a
- }
- v := reflect.ValueOf(a)
- for v.Kind() == reflect.Ptr && !v.IsNil() {
- v = v.Elem()
- }
- return v.Interface()
- }
-
- // From html/template/content.go
- // Copyright 2011 The Go Authors. All rights reserved.
- // indirectToStringerOrError returns the value, after dereferencing as many times
- // as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
- // or error,
- func indirectToStringerOrError(a interface{}) interface{} {
- if a == nil {
- return nil
- }
-
- var errorType = reflect.TypeOf((*error)(nil)).Elem()
- var fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
-
- v := reflect.ValueOf(a)
- for !v.Type().Implements(fmtStringerType) && !v.Type().Implements(errorType) && v.Kind() == reflect.Ptr && !v.IsNil() {
- v = v.Elem()
- }
- return v.Interface()
- }
-
- // ToStringE casts an empty interface to a string.
- func ToStringE(i interface{}) (string, error) {
- i = indirectToStringerOrError(i)
- jww.DEBUG.Println("ToStringE called on type:", reflect.TypeOf(i))
-
- switch s := i.(type) {
- case string:
- return s, nil
- case bool:
- return strconv.FormatBool(s), nil
- case float64:
- return strconv.FormatFloat(i.(float64), 'f', -1, 64), nil
- case int:
- return strconv.FormatInt(int64(i.(int)), 10), nil
- case []byte:
- return string(s), nil
- case template.HTML:
- return string(s), nil
- case template.URL:
- return string(s), nil
- case nil:
- return "", nil
- case fmt.Stringer:
- return s.String(), nil
- case error:
- return s.Error(), nil
- default:
- return "", fmt.Errorf("Unable to Cast %#v to string", i)
- }
- }
-
- // ToStringMapStringE casts an empty interface to a map[string]string.
- func ToStringMapStringE(i interface{}) (map[string]string, error) {
- jww.DEBUG.Println("ToStringMapStringE called on type:", reflect.TypeOf(i))
-
- var m = map[string]string{}
-
- switch v := i.(type) {
- case map[string]string:
- return v, nil
- case map[string]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToString(val)
- }
- return m, nil
- case map[interface{}]string:
- for k, val := range v {
- m[ToString(k)] = ToString(val)
- }
- return m, nil
- case map[interface{}]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToString(val)
- }
- return m, nil
- default:
- return m, fmt.Errorf("Unable to Cast %#v to map[string]string", i)
- }
- }
-
- // ToStringMapStringSliceE casts an empty interface to a map[string][]string.
- func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
- jww.DEBUG.Println("ToStringMapStringSliceE called on type:", reflect.TypeOf(i))
-
- var m = map[string][]string{}
-
- switch v := i.(type) {
- case map[string][]string:
- return v, nil
- case map[string][]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToStringSlice(val)
- }
- return m, nil
- case map[string]string:
- for k, val := range v {
- m[ToString(k)] = []string{val}
- }
- case map[string]interface{}:
- for k, val := range v {
- m[ToString(k)] = []string{ToString(val)}
- }
- return m, nil
- case map[interface{}][]string:
- for k, val := range v {
- m[ToString(k)] = ToStringSlice(val)
- }
- return m, nil
- case map[interface{}]string:
- for k, val := range v {
- m[ToString(k)] = ToStringSlice(val)
- }
- return m, nil
- case map[interface{}][]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToStringSlice(val)
- }
- return m, nil
- case map[interface{}]interface{}:
- for k, val := range v {
- key, err := ToStringE(k)
- if err != nil {
- return m, fmt.Errorf("Unable to Cast %#v to map[string][]string", i)
- }
- value, err := ToStringSliceE(val)
- if err != nil {
- return m, fmt.Errorf("Unable to Cast %#v to map[string][]string", i)
- }
- m[key] = value
- }
- default:
- return m, fmt.Errorf("Unable to Cast %#v to map[string][]string", i)
- }
- return m, nil
- }
-
- // ToStringMapBoolE casts an empty interface to a map[string]bool.
- func ToStringMapBoolE(i interface{}) (map[string]bool, error) {
- jww.DEBUG.Println("ToStringMapBoolE called on type:", reflect.TypeOf(i))
-
- var m = map[string]bool{}
-
- switch v := i.(type) {
- case map[interface{}]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToBool(val)
- }
- return m, nil
- case map[string]interface{}:
- for k, val := range v {
- m[ToString(k)] = ToBool(val)
- }
- return m, nil
- case map[string]bool:
- return v, nil
- default:
- return m, fmt.Errorf("Unable to Cast %#v to map[string]bool", i)
- }
- }
-
- // ToStringMapE casts an empty interface to a map[string]interface{}.
- func ToStringMapE(i interface{}) (map[string]interface{}, error) {
- jww.DEBUG.Println("ToStringMapE called on type:", reflect.TypeOf(i))
-
- var m = map[string]interface{}{}
-
- switch v := i.(type) {
- case map[interface{}]interface{}:
- for k, val := range v {
- m[ToString(k)] = val
- }
- return m, nil
- case map[string]interface{}:
- return v, nil
- default:
- return m, fmt.Errorf("Unable to Cast %#v to map[string]interface{}", i)
- }
- }
-
- // ToSliceE casts an empty interface to a []interface{}.
- func ToSliceE(i interface{}) ([]interface{}, error) {
- jww.DEBUG.Println("ToSliceE called on type:", reflect.TypeOf(i))
-
- var s []interface{}
-
- switch v := i.(type) {
- case []interface{}:
- for _, u := range v {
- s = append(s, u)
- }
- return s, nil
- case []map[string]interface{}:
- for _, u := range v {
- s = append(s, u)
- }
- return s, nil
- default:
- return s, fmt.Errorf("Unable to Cast %#v of type %v to []interface{}", i, reflect.TypeOf(i))
- }
- }
-
- // ToStringSliceE casts an empty interface to a []string.
- func ToStringSliceE(i interface{}) ([]string, error) {
- jww.DEBUG.Println("ToStringSliceE called on type:", reflect.TypeOf(i))
-
- var a []string
-
- switch v := i.(type) {
- case []interface{}:
- for _, u := range v {
- a = append(a, ToString(u))
- }
- return a, nil
- case []string:
- return v, nil
- case string:
- return strings.Fields(v), nil
- case interface{}:
- str, err := ToStringE(v)
- if err != nil {
- return a, fmt.Errorf("Unable to Cast %#v to []string", i)
- }
- return []string{str}, nil
- default:
- return a, fmt.Errorf("Unable to Cast %#v to []string", i)
- }
- }
-
- // ToIntSliceE casts an empty interface to a []int.
- func ToIntSliceE(i interface{}) ([]int, error) {
- jww.DEBUG.Println("ToIntSliceE called on type:", reflect.TypeOf(i))
-
- if i == nil {
- return []int{}, fmt.Errorf("Unable to Cast %#v to []int", i)
- }
-
- switch v := i.(type) {
- case []int:
- return v, nil
- }
-
- kind := reflect.TypeOf(i).Kind()
- switch kind {
- case reflect.Slice, reflect.Array:
- s := reflect.ValueOf(i)
- a := make([]int, s.Len())
- for j := 0; j < s.Len(); j++ {
- val, err := ToIntE(s.Index(j).Interface())
- if err != nil {
- return []int{}, fmt.Errorf("Unable to Cast %#v to []int", i)
- }
- a[j] = val
- }
- return a, nil
- default:
- return []int{}, fmt.Errorf("Unable to Cast %#v to []int", i)
- }
- }
-
- // StringToDate casts an empty interface to a time.Time.
- func StringToDate(s string) (time.Time, error) {
- return parseDateWith(s, []string{
- time.RFC3339,
- "2006-01-02T15:04:05", // iso8601 without timezone
- time.RFC1123Z,
- time.RFC1123,
- time.RFC822Z,
- time.RFC822,
- time.ANSIC,
- time.UnixDate,
- time.RubyDate,
- "2006-01-02 15:04:05Z07:00",
- "02 Jan 06 15:04 MST",
- "2006-01-02",
- "02 Jan 2006",
- "2006-01-02 15:04:05 -07:00",
- "2006-01-02 15:04:05 -0700",
- })
- }
-
- func parseDateWith(s string, dates []string) (d time.Time, e error) {
- for _, dateType := range dates {
- if d, e = time.Parse(dateType, s); e == nil {
- return
- }
- }
- return d, fmt.Errorf("Unable to parse date: %s", s)
- }
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