Fetching GDPR Vendor Lists

Gopkg.toml

@@ -81,6 +81,10 @@
   name = "github.com/chasex/log"
   branch = "analytics"
 
+[[constraint]]
+  name = "github.com/prebid/go-gdpr"
+  version = "0.3.0"
+
 [prune]
   go-tests = true
   unused-packages = true

gdpr/gdpr.go

@@ -0,0 +1,31 @@
+package gdpr
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/prebid/prebid-server/config"
+	"github.com/prebid/prebid-server/openrtb_ext"
+)
+
+type Permissions interface {
+	// Determines whether or not the host company is allowed to read/write cookies.
+	HostCookiesAllowed(ctx context.Context, consent string) (bool, error)
+
+	// Determines whether or not the given bidder is allowed to user personal info for ad targeting.
+	BidderSyncAllowed(ctx context.Context, bidder openrtb_ext.BidderName, consent string) (bool, error)
+}
+
+// NewPermissions gets an instance of the Permissions for use elsewhere in the project.
+func NewPermissions(ctx context.Context, cfg config.GDPR, vendorIDs map[openrtb_ext.BidderName]uint16, client *http.Client) Permissions {
+	// If the host doesn't buy into the IAB GDPR consent framework, then save some cycles and let all syncs happen.
+	if cfg.HostVendorID == 0 {
+		return alwaysAllow{}
+	}
+
+	return &permissionsImpl{
+		cfg:             cfg,
+		vendorIDs:       vendorIDs,
+		fetchVendorList: newVendorListFetcher(ctx, client, vendorListURLMaker),
+	}
+}

gdpr/impl.go

@@ -0,0 +1,104 @@
+package gdpr
+
+import (
+	"context"
+	"encoding/base64"
+
+	"github.com/prebid/go-gdpr/consentconstants"
+	"github.com/prebid/go-gdpr/vendorconsent"
+	"github.com/prebid/go-gdpr/vendorlist"
+	"github.com/prebid/prebid-server/config"
+	"github.com/prebid/prebid-server/openrtb_ext"
+)
+
+// This file implements GDPR permissions for the app.
+// For more info, see https://github.com/prebid/prebid-server/issues/501
+//
+// Nothing in this file is exported. Public APIs can be found in gdpr.go
+
+type permissionsImpl struct {
+	cfg             config.GDPR
+	vendorIDs       map[openrtb_ext.BidderName]uint16
+	fetchVendorList func(ctx context.Context, id uint16) (vendorlist.VendorList, error)
+}
+
+func (p *permissionsImpl) HostCookiesAllowed(ctx context.Context, consent string) (bool, error) {
+	// If we're not given a consent string, respect the preferences in the app config.
+	if consent == "" {
+		return p.cfg.UsersyncIfAmbiguous, nil
+	}
+
+	data, err := base64.RawURLEncoding.DecodeString(consent)
+	if err != nil {
+		return false, err
+	}
+
+	parsedConsent, err := vendorconsent.Parse([]byte(data))
+	if err != nil {
+		return false, err
+	}
+
+	vendorList, err := p.fetchVendorList(ctx, parsedConsent.VendorListVersion())
+	if err != nil {
+		return false, err
+	}
+
+	// Config validation makes uint16 conversion safe here
+	return hasPermissions(parsedConsent, vendorList, uint16(p.cfg.HostVendorID), consentconstants.InfoStorageAccess), nil
+}
+
+func (p *permissionsImpl) BidderSyncAllowed(ctx context.Context, bidder openrtb_ext.BidderName, consent string) (bool, error) {
+	// If we're not given a consent string, respect the preferences in the app config.
+	if consent == "" {
+		return p.cfg.UsersyncIfAmbiguous, nil
+	}
+
+	id, ok := p.vendorIDs[bidder]
+	if !ok {
+		return false, nil
+	}
+
+	data, err := base64.RawURLEncoding.DecodeString(consent)
+	if err != nil {
+		return false, err
+	}
+
+	parsedConsent, err := vendorconsent.Parse([]byte(data))
+	if err != nil {
+		return false, err
+	}
+
+	vendorList, err := p.fetchVendorList(ctx, parsedConsent.VendorListVersion())
+	if err != nil {
+		return false, err
+	}
+
+	return hasPermissions(parsedConsent, vendorList, id, consentconstants.AdSelectionDeliveryReporting), nil
+}
+
+func hasPermissions(consent vendorconsent.VendorConsents, vendorList vendorlist.VendorList, vendorID uint16, purpose consentconstants.Purpose) bool {
+	vendor := vendorList.Vendor(vendorID)
+	if vendor == nil {
+		return false
+	}
+	if vendor.LegitimateInterest(purpose) {
+		return true
+	}
+
+	// If the host declared writing cookies to be a "normal" purpose, only do the sync if the user consented to it.
+	if vendor.Purpose(purpose) && consent.PurposeAllowed(purpose) && consent.VendorConsent(vendorID) {
+		return true
+	}
+
+	return false
+}
+
+type alwaysAllow struct{}
+
+func (a alwaysAllow) HostCookiesAllowed(ctx context.Context, consent string) (bool, error) {
+	return true, nil
+}
+
+func (a alwaysAllow) BidderSyncAllowed(ctx context.Context, bidder openrtb_ext.BidderName, consent string) (bool, error) {
+	return true, nil
+}

gdpr/impl_test.go

@@ -0,0 +1,185 @@
+package gdpr
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"testing"
+
+	"github.com/prebid/prebid-server/config"
+	"github.com/prebid/prebid-server/openrtb_ext"
+
+	"github.com/prebid/go-gdpr/vendorlist"
+)
+
+func TestNoConsentButAllowByDefault(t *testing.T) {
+	perms := permissionsImpl{
+		cfg: config.GDPR{
+			HostVendorID:        3,
+			UsersyncIfAmbiguous: true,
+		},
+		vendorIDs:       nil,
+		fetchVendorList: failedListFetcher,
+	}
+	allowSync, err := perms.BidderSyncAllowed(context.Background(), openrtb_ext.BidderAppnexus, "")
+	assertBoolsEqual(t, true, allowSync)
+	assertNilErr(t, err)
+	allowSync, err = perms.HostCookiesAllowed(context.Background(), "")
+	assertBoolsEqual(t, true, allowSync)
+	assertNilErr(t, err)
+}
+
+func TestNoConsentAndRejectByDefault(t *testing.T) {
+	perms := permissionsImpl{
+		cfg: config.GDPR{
+			HostVendorID:        3,
+			UsersyncIfAmbiguous: false,
+		},
+		vendorIDs:       nil,
+		fetchVendorList: failedListFetcher,
+	}
+	allowSync, err := perms.BidderSyncAllowed(context.Background(), openrtb_ext.BidderAppnexus, "")
+	assertBoolsEqual(t, false, allowSync)
+	assertNilErr(t, err)
+	allowSync, err = perms.HostCookiesAllowed(context.Background(), "")
+	assertBoolsEqual(t, false, allowSync)
+	assertNilErr(t, err)
+}
+
+func TestAllowedSyncs(t *testing.T) {
+	vendorListData := mockVendorListData(t, 1, map[uint16]*purposes{
+		2: &purposes{
+			purposes: []uint8{1}, // cookie reads/writes
+		},
+		3: &purposes{
+			purposes: []uint8{3}, // ad personalization
+		},
+	})
+	perms := permissionsImpl{
+		cfg: config.GDPR{
+			HostVendorID: 2,
+		},
+		vendorIDs: map[openrtb_ext.BidderName]uint16{
+			openrtb_ext.BidderAppnexus: 2,
+			openrtb_ext.BidderPubmatic: 3,
+		},
+		fetchVendorList: listFetcher(map[uint16]vendorlist.VendorList{
+			1: parseVendorListData(t, vendorListData),
+		}),
+	}
+
+	allowSync, err := perms.HostCookiesAllowed(context.Background(), "BON3PCUON3PCUABABBAAABoAAAAAMw")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, true, allowSync)
+
+	allowSync, err = perms.BidderSyncAllowed(context.Background(), openrtb_ext.BidderPubmatic, "BON3PCUON3PCUABABBAAABoAAAAAMw")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, true, allowSync)
+}
+
+func TestProhibitedPurposes(t *testing.T) {
+	vendorListData := mockVendorListData(t, 1, map[uint16]*purposes{
+		2: &purposes{
+			purposes: []uint8{1}, // cookie reads/writes
+		},
+		3: &purposes{
+			purposes: []uint8{3}, // ad personalization
+		},
+	})
+	perms := permissionsImpl{
+		cfg: config.GDPR{
+			HostVendorID: 2,
+		},
+		vendorIDs: map[openrtb_ext.BidderName]uint16{
+			openrtb_ext.BidderAppnexus: 2,
+			openrtb_ext.BidderPubmatic: 3,
+		},
+		fetchVendorList: listFetcher(map[uint16]vendorlist.VendorList{
+			1: parseVendorListData(t, vendorListData),
+		}),
+	}
+
+	allowSync, err := perms.HostCookiesAllowed(context.Background(), "BON3PCUON3PCUABABBAAABAAAAAAMw")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, false, allowSync)
+
+	allowSync, err = perms.BidderSyncAllowed(context.Background(), openrtb_ext.BidderPubmatic, "BON3PCUON3PCUABABBAAABAAAAAAMw")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, false, allowSync)
+}
+
+func TestProhibitedVendors(t *testing.T) {
+	vendorListData := mockVendorListData(t, 1, map[uint16]*purposes{
+		2: &purposes{
+			purposes: []uint8{1}, // cookie reads/writes
+		},
+		3: &purposes{
+			purposes: []uint8{3}, // ad personalization
+		},
+	})
+	perms := permissionsImpl{
+		cfg: config.GDPR{
+			HostVendorID: 2,
+		},
+		vendorIDs: map[openrtb_ext.BidderName]uint16{
+			openrtb_ext.BidderAppnexus: 2,
+			openrtb_ext.BidderPubmatic: 3,
+		},
+		fetchVendorList: listFetcher(map[uint16]vendorlist.VendorList{
+			1: parseVendorListData(t, vendorListData),
+		}),
+	}
+
+	allowSync, err := perms.HostCookiesAllowed(context.Background(), "BON3PCUON3PCUABABBAAABoAAAAANA")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, false, allowSync)
+
+	allowSync, err = perms.BidderSyncAllowed(context.Background(), openrtb_ext.BidderPubmatic, "BON3PCUON3PCUABABBAAABoAAAAANA")
+	assertNilErr(t, err)
+	assertBoolsEqual(t, false, allowSync)
+}
+
+func parseVendorListData(t *testing.T, data string) vendorlist.VendorList {
+	t.Helper()
+	parsed, err := vendorlist.ParseEagerly([]byte(data))
+	if err != nil {
+		t.Fatalf("Failed to parse vendor list data. %v", err)
+	}
+	return parsed
+}
+
+func listFetcher(lists map[uint16]vendorlist.VendorList) func(context.Context, uint16) (vendorlist.VendorList, error) {
+	return func(ctx context.Context, id uint16) (vendorlist.VendorList, error) {
+		data, ok := lists[id]
+		if ok {
+			return data, nil
+		} else {
+			return nil, fmt.Errorf("vendorlist id=%d not found", id)
+		}
+	}
+}
+
+func failedListFetcher(ctx context.Context, id uint16) (vendorlist.VendorList, error) {
+	return nil, errors.New("vendor list can't be fetched")
+}
+
+func assertNilErr(t *testing.T, err error) {
+	t.Helper()
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+}
+
+func assertErr(t *testing.T, err error) {
+	t.Helper()
+	if err == nil {
+		t.Errorf("Expected error did not occur.")
+	}
+}
+
+func assertBoolsEqual(t *testing.T, expected bool, actual bool) {
+	t.Helper()
+	if expected != actual {
+		t.Errorf("Expected %t, got %t", expected, actual)
+	}
+}