graphql: directly return a connection, cleaning

1 files changed, 39 insertions, 0 deletions

diff --git a/graphql/connections/connections.go b/graphql/connections/connections.go
new file mode 100644
index 00000000..145bfbbe
--- /dev/null
+++ b/graphql/connections/connections.go
@@ -0,0 +1,39 @@
+//go:generate genny -in=connection_template.go -out=gen_bug.go gen "NodeType=bug.Snapshot EdgeType=models.BugEdge ConnectionType=models.BugConnection"
+//go:generate genny -in=connection_template.go -out=gen_operation.go gen "NodeType=bug.Operation EdgeType=models.OperationEdge ConnectionType=models.OperationConnection"
+//go:generate genny -in=connection_template.go -out=gen_comment.go gen "NodeType=bug.Comment EdgeType=models.CommentEdge ConnectionType=models.CommentConnection"
+
+package connections
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const cursorPrefix = "cursor:"
+
+type Edge interface {
+	GetCursor() string
+}
+
+// Creates the cursor string from an offset
+func OffsetToCursor(offset int) string {
+	str := fmt.Sprintf("%v%v", cursorPrefix, offset)
+	return base64.StdEncoding.EncodeToString([]byte(str))
+}
+
+// Re-derives the offset from the cursor string.
+func CursorToOffset(cursor string) (int, error) {
+	str := ""
+	b, err := base64.StdEncoding.DecodeString(cursor)
+	if err == nil {
+		str = string(b)
+	}
+	str = strings.Replace(str, cursorPrefix, "", -1)
+	offset, err := strconv.Atoi(str)
+	if err != nil {
+		return 0, fmt.Errorf("Invalid cursor")
+	}
+	return offset, nil
+}