88 lines
2.5 KiB
Go
88 lines
2.5 KiB
Go
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package survey
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import (
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"errors"
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"fmt"
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"reflect"
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)
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// Required does not allow an empty value
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func Required(val interface{}) error {
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// the reflect value of the result
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value := reflect.ValueOf(val)
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// if the value passed in is the zero value of the appropriate type
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if isZero(value) && value.Kind() != reflect.Bool {
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return errors.New("Value is required")
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}
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return nil
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}
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// MaxLength requires that the string is no longer than the specified value
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func MaxLength(length int) Validator {
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// return a validator that checks the length of the string
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return func(val interface{}) error {
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if str, ok := val.(string); ok {
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// if the string is longer than the given value
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if len([]rune(str)) > length {
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// yell loudly
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return fmt.Errorf("value is too long. Max length is %v", length)
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}
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} else {
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// otherwise we cannot convert the value into a string and cannot enforce length
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return fmt.Errorf("cannot enforce length on response of type %v", reflect.TypeOf(val).Name())
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}
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// the input is fine
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return nil
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}
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}
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// MinLength requires that the string is longer or equal in length to the specified value
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func MinLength(length int) Validator {
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// return a validator that checks the length of the string
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return func(val interface{}) error {
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if str, ok := val.(string); ok {
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// if the string is shorter than the given value
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if len([]rune(str)) < length {
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// yell loudly
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return fmt.Errorf("value is too short. Min length is %v", length)
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}
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} else {
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// otherwise we cannot convert the value into a string and cannot enforce length
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return fmt.Errorf("cannot enforce length on response of type %v", reflect.TypeOf(val).Name())
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}
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// the input is fine
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return nil
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}
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}
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// ComposeValidators is a variadic function used to create one validator from many.
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func ComposeValidators(validators ...Validator) Validator {
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// return a validator that calls each one sequentially
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return func(val interface{}) error {
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// execute each validator
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for _, validator := range validators {
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// if the answer's value is not valid
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if err := validator(val); err != nil {
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// return the error
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return err
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}
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}
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// we passed all validators, the answer is valid
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return nil
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}
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}
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// isZero returns true if the passed value is the zero object
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func isZero(v reflect.Value) bool {
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switch v.Kind() {
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case reflect.Slice, reflect.Map:
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return v.Len() == 0
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}
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// compare the types directly with more general coverage
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return reflect.DeepEqual(v.Interface(), reflect.Zero(v.Type()).Interface())
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}
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