feat: add token pagination link header parser (#722)

go.mod

@@ -58,6 +58,7 @@ require (
  github.com/ory/herodot v0.9.13
  github.com/ory/jsonschema/v3 v3.0.7
  github.com/pelletier/go-toml v1.9.5
+ github.com/peterhellberg/link v1.2.0
  github.com/pkg/errors v0.9.1
  github.com/pkg/profile v1.7.0
  github.com/prometheus/client_golang v1.13.0

go.sum

@@ -752,6 +752,8 @@ github.com/pelletier/go-toml v1.9.5 h1:4yBQzkHv+7BHq2PQUZF3Mx0IYxG7LsP222s7Agd3v
 github.com/pelletier/go-toml v1.9.5/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
 github.com/pelletier/go-toml/v2 v2.0.6 h1:nrzqCb7j9cDFj2coyLNLaZuJTLjWjlaz6nvTvIwycIU=
 github.com/pelletier/go-toml/v2 v2.0.6/go.mod h1:eumQOmlWiOPt5WriQQqoM5y18pDHwha2N+QD+EUNTek=
+github.com/peterhellberg/link v1.2.0 h1:UA5pg3Gp/E0F2WdX7GERiNrPQrM1K6CVJUUWfHa4t6c=
+github.com/peterhellberg/link v1.2.0/go.mod h1:gYfAh+oJgQu2SrZHg5hROVRQe1ICoK0/HHJTcE0edxc=
 github.com/phayes/freeport v0.0.0-20180830031419-95f893ade6f2 h1:JhzVVoYvbOACxoUmOs6V/G4D5nPVUW73rKvXxP4XUJc=
 github.com/phayes/freeport v0.0.0-20180830031419-95f893ade6f2/go.mod h1:iIss55rKnNBTvrwdmkUpLnDpZoAHvWaiq5+iMmen4AE=
 github.com/phpdave11/gofpdf v1.4.2/go.mod h1:zpO6xFn9yxo3YLyMvW8HcKWVdbNqgIfOOp2dXMnm1mY=

pagination/keysetpagination/parse_header.go

@@ -0,0 +1,44 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package keysetpagination
+
+import (
+ "net/http"
+ "net/url"
+
+ "github.com/peterhellberg/link"
+)
+
+// PaginationResult represents a parsed result of the link HTTP header.
+type PaginationResult struct {
+ // NextToken is the next page token. If it's empty, there is no next page.
+ NextToken string
+
+ // FirstToken is the first page token.
+ FirstToken string
+}
+
+// ParseHeader parses the response header's Link.
+func ParseHeader(r *http.Response) *PaginationResult {
+ links := link.ParseResponse(r)
+ return &PaginationResult{
+ NextToken: findRel(links, "next"),
+ FirstToken: findRel(links, "first"),
+ }
+}
+
+func findRel(links link.Group, rel string) string {
+ for idx, l := range links {
+ if idx == rel {
+ parsed, err := url.Parse(l.URI)
+ if err != nil {
+ continue
+ }
+
+ return parsed.Query().Get("page_token")
+ }
+ }
+
+ return ""
+}

pagination/keysetpagination/parse_header_test.go

@@ -0,0 +1,49 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package keysetpagination
+
+import (
+ "net/http"
+ "net/http/httptest"
+ "net/url"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+ "github.com/stretchr/testify/require"
+)
+
+func TestParseHeader(t *testing.T) {
+ u, err := url.Parse("https://www.ory.sh/")
+ require.NoError(t, err)
+
+ t.Run("has next page", func(t *testing.T) {
+ p := &Paginator{
+ defaultToken: StringPageToken("default"),
+ token: StringPageToken("next"),
+ size: 2,
+ }
+
+ r := httptest.NewRecorder()
+ Header(r, u, p)
+
+ result := ParseHeader(&http.Response{Header: r.Header()})
+ assert.Equal(t, "next", result.NextToken, r.Header())
+ assert.Equal(t, "default", result.FirstToken, r.Header())
+ })
+
+ t.Run("is last page", func(t *testing.T) {
+ p := &Paginator{
+ defaultToken: StringPageToken("default"),
+ size: 1,
+ isLast: true,
+ }
+
+ r := httptest.NewRecorder()
+ Header(r, u, p)
+
+ result := ParseHeader(&http.Response{Header: r.Header()})
+ assert.Equal(t, "", result.NextToken, r.Header())
+ assert.Equal(t, "default", result.FirstToken, r.Header())
+ })
+}