github.com/jepp2078/gqlgen@v0.7.2/example/starwars/model.go (about)

     1  package starwars
     2  
     3  import (
     4  	"context"
     5  	"encoding/base64"
     6  	"fmt"
     7  	"strconv"
     8  	"strings"
     9  	"time"
    10  )
    11  
    12  type CharacterFields struct {
    13  	ID        string
    14  	Name      string
    15  	FriendIds []string
    16  	AppearsIn []Episode
    17  }
    18  
    19  type Human struct {
    20  	CharacterFields
    21  	StarshipIds  []string
    22  	heightMeters float64
    23  	Mass         float64
    24  }
    25  
    26  func (h *Human) Height(unit LengthUnit) float64 {
    27  	switch unit {
    28  	case "METER", "":
    29  		return h.heightMeters
    30  	case "FOOT":
    31  		return h.heightMeters * 3.28084
    32  	default:
    33  		panic("invalid unit")
    34  	}
    35  }
    36  
    37  func (Human) IsCharacter()    {}
    38  func (Human) IsSearchResult() {}
    39  
    40  type Review struct {
    41  	Stars      int
    42  	Commentary *string
    43  	Time       time.Time
    44  }
    45  
    46  type Droid struct {
    47  	CharacterFields
    48  	PrimaryFunction string
    49  }
    50  
    51  func (Droid) IsCharacter()    {}
    52  func (Droid) IsSearchResult() {}
    53  
    54  func (r *Resolver) resolveFriendConnection(ctx context.Context, ids []string, first *int, after *string) (FriendsConnection, error) {
    55  	from := 0
    56  	if after != nil {
    57  		b, err := base64.StdEncoding.DecodeString(*after)
    58  		if err != nil {
    59  			return FriendsConnection{}, err
    60  		}
    61  		i, err := strconv.Atoi(strings.TrimPrefix(string(b), "cursor"))
    62  		if err != nil {
    63  			return FriendsConnection{}, err
    64  		}
    65  		from = i
    66  	}
    67  
    68  	to := len(ids)
    69  	if first != nil {
    70  		to = from + *first
    71  		if to > len(ids) {
    72  			to = len(ids)
    73  		}
    74  	}
    75  
    76  	return FriendsConnection{
    77  		ids:  ids,
    78  		from: from,
    79  		to:   to,
    80  	}, nil
    81  }
    82  
    83  type FriendsConnection struct {
    84  	ids  []string
    85  	from int
    86  	to   int
    87  }
    88  
    89  func (f *FriendsConnection) TotalCount() int {
    90  	return len(f.ids)
    91  }
    92  
    93  func (f *FriendsConnection) PageInfo() PageInfo {
    94  	return PageInfo{
    95  		StartCursor: encodeCursor(f.from),
    96  		EndCursor:   encodeCursor(f.to - 1),
    97  		HasNextPage: f.to < len(f.ids),
    98  	}
    99  }
   100  
   101  func encodeCursor(i int) string {
   102  	return base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("cursor%d", i+1)))
   103  }