Add manual ticket search feature.

Author: ukane-philemon

webapi/admin.go

@@ -155,6 +155,13 @@ func (s *Server) adminPage(c *gin.Context) {
 func (s *Server) ticketSearch(c *gin.Context) {
 	hash := c.PostForm("hash")
 
+	// Before hitting the db, ensure this is a valid ticket hash. Ignore bool.
+	if err := validateTicketHash(hash); err != nil {
+		s.log.Errorf("ticketSearch: Invalid ticket hash (ticketHash=%s): %v", hash, err)
+		c.String(http.StatusBadRequest, "invalid ticket hash")
+		return
+	}
+
 	ticket, found, err := s.db.GetTicketByHash(hash)
 	if err != nil {
 		s.log.Errorf("db.GetTicketByHash error (ticketHash=%s): %v", hash, err)

webapi/middleware.go

@@ -6,10 +6,13 @@ package webapi
 
 import (
 	"bytes"
+	"encoding/base64"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"strings"
+	"time"
 
 	"github.com/decred/vspd/rpc"
 	"github.com/gin-gonic/gin"
@@ -18,6 +21,10 @@ import (
 	"github.com/jrick/wsrpc/v2"
 )
 
+// TicketSearchMessageFmt is the format for the message to be signed
+// in order to search for a ticket using the vspd frontend.
+const TicketSearchMessageFmt = "I want to check vspd ticket status for ticket %s at vsp with pubkey %s on window %d."
+
 // withSession middleware adds a gorilla session to the request context for
 // downstream handlers to make use of. Sessions are used by admin pages to
 // maintain authentication status.
@@ -349,3 +356,111 @@ func (s *Server) vspAuth(c *gin.Context) {
 	c.Set(knownTicketKey, ticketFound)
 	c.Set(commitmentAddressKey, commitmentAddress)
 }
+
+// ticketSearchAuth middleware reads the request form body and extracts the
+// ticket hash and signature from the base64 string provided. The commitment
+// address for the ticket is retrieved from the database if it is known, or it
+// is retrieved from the chain if not. The middleware errors out if required
+// information is not provided or the signature does not contain a message
+// signed with the commitment address. Ticket information is added to the
+// request context for downstream handlers to use.
+func (s *Server) ticketSearchAuth(c *gin.Context) {
+	funcName := "ticketSearchAuth"
+
+	encodedString := c.PostForm("encoded")
+
+	// Get information added to context.
+	dcrdClient := c.MustGet(dcrdKey).(*rpc.DcrdRPC)
+	dcrdErr := c.MustGet(dcrdErrorKey)
+	if dcrdErr != nil {
+		s.log.Errorf("%s: Could not get dcrd client: %v", funcName, dcrdErr.(error))
+		c.Set(errorKey, errInternalError)
+		return
+	}
+
+	currentBlockHeader, err := dcrdClient.GetBestBlockHeader()
+	if err != nil {
+		s.log.Errorf("%s: Error getting best block header : %v", funcName, err)
+		c.Set(errorKey, errInternalError)
+		// Average blocks per day for the current network.
+		blocksPerDay := (24 * time.Hour) / s.cfg.NetParams.TargetTimePerBlock
+		blockWindow := int(currentBlockHeader.Height) / int(blocksPerDay)
+
+		decodedByte, err := base64.StdEncoding.DecodeString(encodedString)
+		if err != nil {
+			s.log.Errorf("%s: Decoding form data error : %v", funcName, err)
+			c.Set(errorKey, errBadRequest)
+			return
+		}
+
+		data := strings.Split(string(decodedByte), ":")
+		if len(data) != 2 {
+			c.Set(errorKey, errBadRequest)
+			return
+		}
+
+		ticketHash := data[0]
+		signature := data[1]
+		vspPublicKey := s.cache.data.PubKey
+		messageSigned := fmt.Sprintf(TicketSearchMessageFmt, ticketHash, vspPublicKey, blockWindow)
+
+		// Before hitting the db or any RPC, ensure this is a valid ticket hash.
+		err = validateTicketHash(ticketHash)
+		if err != nil {
+			s.log.Errorf("%s: Invalid ticket (clientIP=%s): %v", funcName, c.ClientIP(), err)
+			c.Set(errorKey, errInvalidTicket)
+			return
+		}
+
+		// Check if this ticket already appears in the database.
+		ticket, ticketFound, err := s.db.GetTicketByHash(ticketHash)
+		if err != nil {
+			s.log.Errorf("%s: db.GetTicketByHash error (ticketHash=%s): %v", funcName, ticketHash, err)
+			c.Set(errorKey, errInternalError)
+			return
+		}
+
+		if !ticketFound {
+			s.log.Warnf("%s: Unknown ticket (clientIP=%s)", funcName, c.ClientIP())
+			c.Set(errorKey, errUnknownTicket)
+			return
+		}
+
+		// If the ticket was found in the database, we already know its
+		// commitment address. Otherwise we need to get it from the chain.
+		var commitmentAddress string
+		if ticketFound {
+			commitmentAddress = ticket.CommitmentAddress
+		} else {
+			commitmentAddress, err = getCommitmentAddress(ticketHash, dcrdClient, s.cfg.NetParams)
+			if err != nil {
+				s.log.Errorf("%s: Failed to get commitment address (clientIP=%s, ticketHash=%s): %v",
+					funcName, c.ClientIP(), ticketHash, err)
+
+				var apiErr *apiError
+				if errors.Is(err, apiErr) {
+					c.Set(errorKey, errInvalidTicket)
+				} else {
+					c.Set(errorKey, errInternalError)
+				}
+
+				return
+			}
+		}
+
+		// Validate request signature to ensure ticket ownership.
+		err = validateSignature(ticketHash, commitmentAddress, signature, messageSigned, s.db, s.cfg.NetParams)
+		if err != nil {
+			s.log.Errorf("%s: Couldn't validate signature (clientIP=%s, ticketHash=%s): %v",
+				funcName, c.ClientIP(), ticketHash, err)
+			c.Set(errorKey, errBadSignature)
+			return
+		}
+
+		// Add ticket information to context so downstream handlers don't need
+		// to access the db for it.
+		c.Set(ticketKey, ticket)
+		c.Set(knownTicketKey, ticketFound)
+		c.Set(errorKey, nil)
+	}
+}

webapi/templates/homepage.html

@@ -22,7 +22,7 @@ <h1>VSP Overview</h1>
 
         <p class="pt-1 pb-2">A Voting Service Provider (VSP) maintains a pool of always-online voting wallets,
             and allows Decred ticket holders to use these wallets to vote their tickets in exchange for a small fee.
-            VSPs are completely non-custodial - they never hold, manage, or have access to any user funds.
+            VSPs are completely non-custodial - they never hold, manage, or have access to any user funds. <a href="/ticket" target="_blank" rel="noopener noreferrer">Click here to search tickets</a>. <br>
             Visit <a href="https://docs.decred.org/proof-of-stake/overview/" target="_blank" rel="noopener noreferrer">docs.decred.org</a>
             to find out more about VSPs, tickets, and voting.
         </p>

webapi/templates/ticket.html

@@ -0,0 +1,39 @@
+{{ template "header" . }}
+
+<div class="vsp-overview pt-4 pb-3 mb-3">
+    <div class="container">
+
+        <div class="d-flex flex-wrap">
+            <h1>Ticket Search</h1>
+        </div>
+    </div>
+</div>
+
+<div class="container">
+    <div class="row">
+        <div class="col-12 pt-2 pb-4">
+            <div class="block__content">
+                <section>
+                    <form action="/ticket" method="post">
+                        <p class="my-1 orange" style="visibility:{{ if .Error }}visible{{ else }}hidden{{ end }};">
+                            {{.Error}}</p>
+
+                        <div class="mb-3 col col-lg-8 pl-0">
+                            <label for="encodedInput" class="form-label">Encoded Base64 String</label>
+                            <input type="text" name="encoded" size="64" class="form-control shadow-none" minlength="64"
+                                maxlength="500" id="encodedInput" required placeholder="Encoded string" autocomplete="off" value="">
+                        </div>
+                        <button class="btn btn-primary d-block my-2" type="submit">Search</button>
+                    </form>
+
+                    {{ with .SearchResult }}
+                    {{ template "ticket-search-result" . }}
+                    {{ end }}
+                </section>
+            </div>
+        </div>
+    </div>
+</div>
+
+</div>
+{{ template "footer" . }}

webapi/ticket.go

@@ -0,0 +1,72 @@
+// Copyright (c) 2022 The Decred developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package webapi
+
+import (
+	"net/http"
+
+	"github.com/decred/vspd/database"
+	"github.com/gin-gonic/gin"
+)
+
+// ticketPage is the handler for "GET /ticket"
+func (s *Server) ticketPage(c *gin.Context) {
+	c.HTML(http.StatusOK, "ticket.html", gin.H{
+		"WebApiCache": s.cache.getData(),
+		"WebApiCfg":   s.cfg,
+	})
+}
+
+// ticketErrPage returns error message to the ticket page.
+func (s *Server) ticketErrPage(c *gin.Context, status int, message string) {
+	c.HTML(status, "ticket.html", gin.H{
+		"WebApiCache": s.cache.getData(),
+		"WebApiCfg":   s.cfg,
+		"Error":       message,
+	})
+
+}
+
+// manualTicketSearch is the handler for "POST /ticket".
+func (s *Server) manualTicketSearch(c *gin.Context) {
+
+	// Get values which have been added to context by middleware.
+	err := c.MustGet(errorKey)
+	if err != nil {
+		apiErr := err.(apiError)
+		s.ticketErrPage(c, apiErr.httpStatus(), apiErr.String())
+		return
+	}
+
+	ticket := c.MustGet(ticketKey).(database.Ticket)
+	knownTicket := c.MustGet(knownTicketKey).(bool)
+
+	voteChanges, err := s.db.GetVoteChanges(ticket.Hash)
+	if err != nil {
+		s.log.Errorf("db.GetVoteChanges error (ticket=%s): %v", ticket.Hash, err)
+		s.ticketErrPage(c, http.StatusBadRequest, "Error getting vote changes from database")
+		return
+	}
+
+	altSignAddrData, err := s.db.AltSignAddrData(ticket.Hash)
+	if err != nil {
+		s.log.Errorf("db.AltSignAddrData error (ticket=%s): %v", ticket.Hash, err)
+		s.ticketErrPage(c, http.StatusBadRequest, "Error getting alternate signature from database")
+		return
+	}
+
+	c.HTML(http.StatusOK, "ticket.html", gin.H{
+		"SearchResult": searchResult{
+			Hash:            ticket.Hash,
+			Found:           knownTicket,
+			Ticket:          ticket,
+			AltSignAddrData: altSignAddrData,
+			VoteChanges:     voteChanges,
+			MaxVoteChanges:  s.cfg.MaxVoteChangeRecords,
+		},
+		"WebApiCache": s.cache.getData(),
+		"WebApiCfg":   s.cfg,
+	})
+}

webapi/webapi.go

@@ -62,6 +62,7 @@ const (
 	ticketKey            = "Ticket"
 	knownTicketKey       = "KnownTicket"
 	commitmentAddressKey = "CommitmentAddress"
+	errorKey             = "Error"
 )
 
 type Server struct {
@@ -244,6 +245,8 @@ func (s *Server) router(cookieSecret []byte, dcrd rpc.DcrdConnect, wallets rpc.W
 	// Website routes.
 
 	router.GET("", s.homepage)
+	router.GET("/ticket", s.ticketPage)
+	router.POST("/ticket", s.withDcrdClient(dcrd), s.ticketSearchAuth, s.manualTicketSearch)
 
 	login := router.Group("/admin").Use(
 		s.withSession(cookieStore),