2 files changed, 75 insertions(+), 0 deletions(-)

A model/cursor.go
A model/filter.go

@@ 0,0 1,69 @@
+package model
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+
+	"git.sr.ht/~sircmpwn/gql.sr.ht/crypto"
+)
+
+// TODO: Add field to prevent cursor reuse across unrelated resources
+type Cursor struct {
+	Count  int    `json:"count"`
+	Next   string `json:"next"`
+	Search string `json:"search"`
+}
+
+func (cur *Cursor) UnmarshalGQL(v interface{}) error {
+	enc, ok := v.(string)
+	if !ok {
+		return fmt.Errorf("cursor must be strings")
+	}
+	plain := crypto.Decrypt([]byte(enc))
+	if plain == nil {
+		return fmt.Errorf("Invalid cursor")
+	}
+	err := json.Unmarshal(plain, cur)
+	if err != nil {
+		// This is guaranteed to be a programming error
+		panic(err)
+	}
+	return nil
+}
+
+func (cur Cursor) MarshalGQL(w io.Writer) {
+	data, err := json.Marshal(cur)
+	if err != nil {
+		panic(err)
+	}
+	w.Write([]byte("\""))
+	w.Write(crypto.Encrypt(data))
+	w.Write([]byte("\""))
+}
+
+func derefOrInt(i *int, d int) int {
+	if i != nil {
+		return *i
+	}
+	return d
+}
+
+func NewCursor(filter *Filter) *Cursor {
+	if filter != nil {
+		count := derefOrInt(filter.Count, 25)
+		if count <= 0 {
+			count = 25
+		}
+		return &Cursor{
+			Next:   "",
+			Count:  count,
+			Search: "", // TODO
+		}
+	}
+	return &Cursor{
+		Count:  25,
+		Next:   "",
+		Search: "",
+	}
+}

@@ 0,0 1,6 @@
+package model
+
+type Filter struct {
+	Count  *int    `json:"count"`
+	Search *string `json:"search"`
+}