github.com/buth/gqlgen@v0.7.2/graphql/string.go (about)

     1  package graphql
     2  
     3  import (
     4  	"fmt"
     5  	"io"
     6  	"strconv"
     7  )
     8  
     9  const encodeHex = "0123456789ABCDEF"
    10  
    11  func MarshalString(s string) Marshaler {
    12  	return WriterFunc(func(w io.Writer) {
    13  		start := 0
    14  		io.WriteString(w, `"`)
    15  
    16  		for i, c := range s {
    17  			if c < 0x20 || c == '\\' || c == '"' {
    18  				io.WriteString(w, s[start:i])
    19  
    20  				switch c {
    21  				case '\t':
    22  					io.WriteString(w, `\t`)
    23  				case '\r':
    24  					io.WriteString(w, `\r`)
    25  				case '\n':
    26  					io.WriteString(w, `\n`)
    27  				case '\\':
    28  					io.WriteString(w, `\\`)
    29  				case '"':
    30  					io.WriteString(w, `\"`)
    31  				default:
    32  					io.WriteString(w, `\u00`)
    33  					w.Write([]byte{encodeHex[c>>4], encodeHex[c&0xf]})
    34  				}
    35  
    36  				start = i + 1
    37  			}
    38  		}
    39  
    40  		io.WriteString(w, s[start:])
    41  		io.WriteString(w, `"`)
    42  	})
    43  }
    44  func UnmarshalString(v interface{}) (string, error) {
    45  	switch v := v.(type) {
    46  	case string:
    47  		return v, nil
    48  	case int:
    49  		return strconv.Itoa(v), nil
    50  	case float64:
    51  		return fmt.Sprintf("%f", v), nil
    52  	case bool:
    53  		if v {
    54  			return "true", nil
    55  		} else {
    56  			return "false", nil
    57  		}
    58  	case nil:
    59  		return "null", nil
    60  	default:
    61  		return "", fmt.Errorf("%T is not a string", v)
    62  	}
    63  }