Initial CMS tlog implementation

politeiad/backendv2/tstorebe/plugins/cms/cmds.go

@@ -0,0 +1,392 @@
+// Copyright (c) 2021 The Decred developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package cms
+
+import (
+	"bytes"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+
+	backend "github.com/decred/politeia/politeiad/backendv2"
+	"github.com/decred/politeia/politeiad/backendv2/tstorebe/store"
+	"github.com/decred/politeia/politeiad/plugins/cms"
+	"github.com/decred/politeia/politeiad/plugins/usermd"
+	"github.com/decred/politeia/util"
+)
+
+const (
+	pluginID = cms.PluginID
+
+	// Blob entry data descriptors
+	dataDescriptorInvoiceStatus = pluginID + "-invoicestatus-v1"
+)
+
+// cmdSetInvoiceStatus sets invoice's invoice status.
+func (c *cmsPlugin) cmdSetInvoiceStatus(token []byte, payload string) (string, error) {
+	// Decode payload
+	var sbs cms.SetInvoiceStatus
+	err := json.Unmarshal([]byte(payload), &sbs)
+	if err != nil {
+		return "", err
+	}
+
+	// Verify token
+	err = tokenMatches(token, sbs.Token)
+	if err != nil {
+		return "", err
+	}
+
+	// Verify invoice status
+	switch sbs.Status {
+	case cms.InvoiceStatusApproved, cms.InvoiceStatusDisputed,
+		cms.InvoiceStatusNew, cms.InvoiceStatusNotFound, cms.InvoiceStatusPaid,
+		cms.InvoiceStatusRejected, cms.InvoiceStatusUpdated:
+	default:
+		// Invoice status is invalid
+		return "", backend.PluginError{
+			PluginID:     cms.PluginID,
+			ErrorCode:    uint32(cms.ErrorCodeInvoiceStatusInvalid),
+			ErrorContext: "invalid invoice status",
+		}
+	}
+
+	// Verify signature
+	msg := sbs.Token + string(sbs.Status) + sbs.Reason
+	err = util.VerifySignature(sbs.Signature, sbs.PublicKey, msg)
+	if err != nil {
+		return "", convertSignatureError(err)
+	}
+
+	// Ensure reason is provided when status is set to closed.
+	if sbs.Status == cms.InvoiceStatusRejected && sbs.Reason == "" {
+		return "", backend.PluginError{
+			PluginID:  cms.PluginID,
+			ErrorCode: uint32(cms.ErrorCodeInvoiceStatusChangeNotAllowed),
+			ErrorContext: "must provide a reason when setting " +
+				"invoice status to rejected",
+		}
+	}
+
+	// Ensure no invoice status already exists
+	bscs, err := c.invoiceStatusChanges(token)
+	if err != nil {
+		return "", err
+	}
+
+	// CHECK TO SEE IF THE PREVIOUSLY SET STATUS ALLOWS TO BE SET TO REQUESTED
+	switch bscs[len(bscs)-1].Status {
+	case cms.InvoiceStatusNew, cms.InvoiceStatusUpdated, cms.InvoiceStatusDisputed:
+		// These statuses allow for any updating.
+	case cms.InvoiceStatusApproved:
+		// Should we allow for the status to be updated if it was set to approved already?
+	case cms.InvoiceStatusPaid, cms.InvoiceStatusRejected:
+		return "", backend.PluginError{
+			PluginID:     cms.PluginID,
+			ErrorCode:    uint32(cms.ErrorCodeInvoiceStatusChangeNotAllowed),
+			ErrorContext: "can not set invoice status more than once",
+		}
+	}
+
+	// Save invoice status change
+	receipt := c.identity.SignMessage([]byte(sbs.Signature))
+	bsc := cms.InvoiceStatusChange{
+		Token:     sbs.Token,
+		Status:    sbs.Status,
+		Reason:    sbs.Reason,
+		PublicKey: sbs.PublicKey,
+		Signature: sbs.Signature,
+		Timestamp: time.Now().Unix(),
+		Receipt:   hex.EncodeToString(receipt[:]),
+	}
+	err = c.invoiceStatusSave(token, bsc)
+	if err != nil {
+		return "", err
+	}
+
+	// Prepare reply
+	sbsr := cms.SetInvoiceStatusReply{
+		Timestamp: bsc.Timestamp,
+		Receipt:   bsc.Receipt,
+	}
+	reply, err := json.Marshal(sbsr)
+	if err != nil {
+		return "", err
+	}
+
+	return string(reply), nil
+}
+
+// tokenMatches verifies that the command token (the token for the record that
+// this plugin command is being executed on) matches the payload token (the
+// token that the plugin command payload contains that is typically used in the
+// payload signature). The payload token must be the full length token.
+func tokenMatches(cmdToken []byte, payloadToken string) error {
+	pt, err := tokenDecode(payloadToken)
+	if err != nil {
+		return backend.PluginError{
+			PluginID:     cms.PluginID,
+			ErrorCode:    uint32(cms.ErrorCodeTokenInvalid),
+			ErrorContext: util.TokenRegexp(),
+		}
+	}
+	if !bytes.Equal(cmdToken, pt) {
+		return backend.PluginError{
+			PluginID:  cms.PluginID,
+			ErrorCode: uint32(cms.ErrorCodeTokenInvalid),
+			ErrorContext: fmt.Sprintf("payload token does not "+
+				"match command token: got %x, want %x",
+				pt, cmdToken),
+		}
+	}
+	return nil
+}
+
+// cmdSummary returns the cms summary of a invoice.
+func (c *cmsPlugin) cmdSummary(token []byte) (string, error) {
+	// Get record metadata
+	r, err := c.recordAbridged(token)
+	if err != nil {
+		return "", err
+	}
+	var (
+		mdState  = r.RecordMetadata.State
+		mdStatus = r.RecordMetadata.Status
+
+		bsc *cms.InvoiceStatusChange
+	)
+
+	invoiceStatus, err := invoiceStatus(mdState, mdStatus, bsc)
+	if err != nil {
+		return "", err
+	}
+
+	// Prepare reply
+	sr := cms.SummaryReply{
+		Summary: cms.InvoiceSummary{
+			Status: invoiceStatus,
+		},
+	}
+	reply, err := json.Marshal(sr)
+	if err != nil {
+		return "", err
+	}
+
+	return string(reply), nil
+}
+
+// cmdInvoiceStatusChanges returns the invoice status changes of a invoice.
+func (c *cmsPlugin) cmdInvoiceStatusChanges(token []byte) (string, error) {
+	// Get invoice status changes
+	bscs, err := c.invoiceStatusChanges(token)
+	if err != nil {
+		return "", err
+	}
+
+	// Prepare reply
+	bscsr := cms.InvoiceStatusChangesReply{
+		InvoiceStatusChanges: bscs,
+	}
+	reply, err := json.Marshal(bscsr)
+	if err != nil {
+		return "", err
+	}
+
+	return string(reply), nil
+}
+
+// statusChangesDecode decodes and returns the StatusChangeMetadata from the
+// metadata streams if one is present.
+func statusChangesDecode(metadata []backend.MetadataStream) ([]usermd.StatusChangeMetadata, error) {
+	statuses := make([]usermd.StatusChangeMetadata, 0, 16)
+	for _, v := range metadata {
+		if v.PluginID != usermd.PluginID ||
+			v.StreamID != usermd.StreamIDStatusChanges {
+			// Not the mdstream we're looking for
+			continue
+		}
+		d := json.NewDecoder(strings.NewReader(v.Payload))
+		for {
+			var sc usermd.StatusChangeMetadata
+			err := d.Decode(&sc)
+			if errors.Is(err, io.EOF) {
+				break
+			} else if err != nil {
+				return nil, err
+			}
+			statuses = append(statuses, sc)
+		}
+		break
+	}
+	return statuses, nil
+}
+
+// invoiceStatus combines record metadata and plugin metadata in order to
+// create a unified map of the various paths a invoice can take throughout
+// the invoice process.
+func invoiceStatus(state backend.StateT, status backend.StatusT, bsc *cms.InvoiceStatusChange) (cms.InvoiceStatusT, error) {
+	switch state {
+	case backend.StateUnvetted:
+		return cms.InvoiceStatusInvalid, nil // Just say invalid, since they shouldn't be here?
+	case backend.StateVetted:
+		switch status {
+		case backend.StatusArchived:
+			return cms.InvoiceStatusInvalid, nil // Just say invalid, since they shouldn't be here?
+		case backend.StatusCensored:
+			return cms.InvoiceStatusInvalid, nil // Just say invalid, since they shouldn't be here?
+		case backend.StatusPublic:
+			return bsc.Status, nil
+		}
+	}
+	// Shouldn't happen return an error
+	return cms.InvoiceStatusInvalid,
+		errors.Errorf(
+			"couldn't determine invoice status: invoice state: %v, "+
+				"invoice status %v", state, status)
+}
+
+// recordAbridged returns a record with all files omitted.
+func (c *cmsPlugin) recordAbridged(token []byte) (*backend.Record, error) {
+	reqs := []backend.RecordRequest{
+		{
+			Token:        token,
+			OmitAllFiles: true,
+		},
+	}
+	rs, err := c.backend.Records(reqs)
+	if err != nil {
+		return nil, err
+	}
+	r, ok := rs[hex.EncodeToString(token)]
+	if !ok {
+		return nil, backend.ErrRecordNotFound
+	}
+
+	return &r, nil
+}
+
+// convertSignatureError converts a util SignatureError to a backend
+// PluginError that contains a cms plugin error code.
+func convertSignatureError(err error) backend.PluginError {
+	var e util.SignatureError
+	var s cms.ErrorCodeT
+	if errors.As(err, &e) {
+		switch e.ErrorCode {
+		case util.ErrorStatusPublicKeyInvalid:
+			s = cms.ErrorCodePublicKeyInvalid
+		case util.ErrorStatusSignatureInvalid:
+			s = cms.ErrorCodeSignatureInvalid
+		}
+	}
+	return backend.PluginError{
+		PluginID:     cms.PluginID,
+		ErrorCode:    uint32(s),
+		ErrorContext: e.ErrorContext,
+	}
+}
+
+// invoiceStatusSave saves a InvoiceStatusChange to the backend.
+func (c *cmsPlugin) invoiceStatusSave(token []byte, bsc cms.InvoiceStatusChange) error {
+	// Prepare blob
+	be, err := invoiceStatusEncode(bsc)
+	if err != nil {
+		return err
+	}
+
+	// Save blob
+	return c.tstore.BlobSave(token, *be)
+}
+
+// invoiceStatusChanges returns the invoice status changes of a proposal.
+func (c *cmsPlugin) invoiceStatusChanges(token []byte) ([]cms.InvoiceStatusChange, error) {
+	// Retrieve blobs
+	blobs, err := c.tstore.BlobsByDataDesc(token,
+		[]string{dataDescriptorInvoiceStatus})
+	if err != nil {
+		return nil, err
+	}
+
+	// Decode blobs
+	statusChanges := make([]cms.InvoiceStatusChange, 0, len(blobs))
+	for _, v := range blobs {
+		a, err := invoiceStatusDecode(v)
+		if err != nil {
+			return nil, err
+		}
+		statusChanges = append(statusChanges, *a)
+	}
+
+	// Sanity check. They should already be sorted from oldest to
+	// newest.
+	sort.SliceStable(statusChanges, func(i, j int) bool {
+		return statusChanges[i].Timestamp < statusChanges[j].Timestamp
+	})
+
+	return statusChanges, nil
+}
+
+// invoiceStatusEncode encodes a InvoiceStatusChange into a BlobEntry.
+func invoiceStatusEncode(bsc cms.InvoiceStatusChange) (*store.BlobEntry, error) {
+	data, err := json.Marshal(bsc)
+	if err != nil {
+		return nil, err
+	}
+	hint, err := json.Marshal(
+		store.DataDescriptor{
+			Type:       store.DataTypeStructure,
+			Descriptor: dataDescriptorInvoiceStatus,
+		})
+	if err != nil {
+		return nil, err
+	}
+	be := store.NewBlobEntry(hint, data)
+	return &be, nil
+}
+
+// invoiceStatusDecode decodes a BlobEntry into a InvoiceStatusChange.
+func invoiceStatusDecode(be store.BlobEntry) (*cms.InvoiceStatusChange, error) {
+	// Decode and validate data hint
+	b, err := base64.StdEncoding.DecodeString(be.DataHint)
+	if err != nil {
+		return nil, fmt.Errorf("decode DataHint: %v", err)
+	}
+	var dd store.DataDescriptor
+	err = json.Unmarshal(b, &dd)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshal DataHint: %v", err)
+	}
+	if dd.Descriptor != dataDescriptorInvoiceStatus {
+		return nil, fmt.Errorf("unexpected data descriptor: got %v, "+
+			"want %v", dd.Descriptor, dataDescriptorInvoiceStatus)
+	}
+
+	// Decode data
+	b, err = base64.StdEncoding.DecodeString(be.Data)
+	if err != nil {
+		return nil, fmt.Errorf("decode Data: %v", err)
+	}
+	digest, err := hex.DecodeString(be.Digest)
+	if err != nil {
+		return nil, fmt.Errorf("decode digest: %v", err)
+	}
+	if !bytes.Equal(util.Digest(b), digest) {
+		return nil, fmt.Errorf("data is not coherent; got %x, want %x",
+			util.Digest(b), digest)
+	}
+	var bsc cms.InvoiceStatusChange
+	err = json.Unmarshal(b, &bsc)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshal AuthDetails: %v", err)
+	}
+
+	return &bsc, nil
+}