Write additional metadata back into the source sheet

README.md

@@ -66,6 +66,7 @@ This server can be configured with these following parameters:
 | `HOME_REDIRECT` | (optional) which url to redirect when root url (`/`) is visited
 | `LISTEN_ADDR` | (optional) which network address to listen on (default `""` which means all interfaces) |
 | `PORT` | (optional) http port to listen on (default `8080`).
+| `REDIRECT_STATUS` | (optional) HTTP status code to return upon redirect. (default `301`, Moved Permanently).
 
 ## Disclaimer
 

main.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -21,6 +22,7 @@ func main() {
 	googleSheetsID := os.Getenv("GOOGLE_SHEET_ID")
 	sheetName := os.Getenv("SHEET_NAME")
 	homeRedirect := os.Getenv("HOME_REDIRECT")
+	redirectStatus := os.Getenv("REDIRECT_STATUS")
 
 	ttlVal := os.Getenv("CACHE_TTL")
 	ttl := time.Second * 5
@@ -32,16 +34,30 @@ func main() {
 		ttl = v
 	}
 
-	srv := &server{
-		db: &cachedURLMap{
-			ttl: ttl,
-			sheet: &sheetsProvider{
-				googleSheetsID: googleSheetsID,
-				sheetName:      sheetName,
-			},
+	urlMap := &cachedURLMap{
+		ttl: ttl,
+		sheet: &sheetsProvider{
+			googleSheetsID: googleSheetsID,
+			sheetName:      sheetName,
 		},
+	}
+	if err := urlMap.Init(); err != nil {
+		log.Fatalf("failed to initialize url map: %v", err)
+	}
+
+	srv := &server{
+		db:           urlMap,
 		homeRedirect: homeRedirect,
 	}
+	if redirectStatus != "" {
+		s, err := strconv.Atoi(redirectStatus)
+		if err != nil {
+			log.Fatalf("failed to parse REDIRECT_STATUS as int: %v", err)
+		}
+		srv.redirectStatus = s
+	} else {
+		srv.redirectStatus = http.StatusMovedPermanently
+	}
 
 	http.HandleFunc("/", srv.handler)
 
@@ -52,11 +68,18 @@ func main() {
 }
 
 type server struct {
-	db           *cachedURLMap
-	homeRedirect string
+	db             *cachedURLMap
+	homeRedirect   string
+	redirectStatus int
 }
 
-type URLMap map[string]*url.URL
+type mapData struct {
+	url      *url.URL
+	hitCount int
+	rowIndex int
+}
+
+type URLMap map[string]*mapData
 
 type cachedURLMap struct {
 	sync.RWMutex
@@ -67,7 +90,14 @@ type cachedURLMap struct {
 	sheet *sheetsProvider
 }
 
-func (c *cachedURLMap) Get(query string) (*url.URL, error) {
+func (c *cachedURLMap) Init() error {
+	if err := c.sheet.Init(); err != nil {
+		return fmt.Errorf("failed to initialize sheet: %v", err)
+	}
+	return nil
+}
+
+func (c *cachedURLMap) Get(query string) (*mapData, error) {
 	if err := c.refresh(); err != nil {
 		return nil, err
 	}
@@ -132,11 +162,12 @@ func (s *server) redirect(w http.ResponseWriter, req *http.Request) {
 	}
 
 	log.Printf("redirecting=%q to=%q", req.URL, redirTo.String())
-	http.Redirect(w, req, redirTo.String(), http.StatusMovedPermanently)
+	http.Redirect(w, req, redirTo.String(), s.redirectStatus)
+
 }
 
 func (s *server) findRedirect(req *url.URL) (*url.URL, error) {
-	path := strings.TrimPrefix(req.Path, "/")
+	path := strings.TrimPrefix(strings.ToLower(req.Path), "/")
 
 	segments := strings.Split(path, "/")
 	var discard []string
@@ -147,7 +178,13 @@ func (s *server) findRedirect(req *url.URL) (*url.URL, error) {
 			return nil, err
 		}
 		if v != nil {
-			return prepRedirect(v, strings.Join(discard, "/"), req.Query()), nil
+			go s.db.sheet.Write("C", v.rowIndex,
+				[]interface{}{
+					strconv.Itoa(v.hitCount + 1),
+					time.Now().Format(time.RFC3339),
+				})
+			v.hitCount++
+			return prepRedirect(v.url, strings.Join(discard, "/"), req.Query()), nil
 		}
 		discard = append([]string{segments[len(segments)-1]}, discard...)
 		segments = segments[:len(segments)-1]
@@ -173,7 +210,7 @@ func prepRedirect(base *url.URL, addPath string, query url.Values) *url.URL {
 
 func urlMap(in [][]interface{}) URLMap {
 	out := make(URLMap)
-	for _, row := range in {
+	for i, row := range in {
 		if len(row) < 2 {
 			continue
 		}
@@ -185,6 +222,18 @@ func urlMap(in [][]interface{}) URLMap {
 		if !ok || v == "" {
 			continue
 		}
+		hitCount := 0
+		if len(row) >= 3 {
+			h, ok := row[2].(string)
+			if !ok || v == "" {
+				continue
+			}
+			hc, err := strconv.Atoi(h)
+			if err != nil {
+				log.Printf("warn: %s=%s hitCount invalid", k, h)
+			}
+			hitCount = hc
+		}
 
 		k = strings.ToLower(k)
 		u, err := url.Parse(v)
@@ -197,7 +246,7 @@ func urlMap(in [][]interface{}) URLMap {
 		if exists {
 			log.Printf("warn: shortcut %q redeclared, overwriting", k)
 		}
-		out[k] = u
+		out[k] = &mapData{u, hitCount, i + 1}
 	}
 	return out
 }

sheetsprovider.go

@@ -4,34 +4,63 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"sync"
 
 	"google.golang.org/api/sheets/v4"
 )
 
 type sheetsProvider struct {
+	sync.RWMutex
+	client         *sheets.Service
 	googleSheetsID string
 	sheetName      string
 }
 
-func (s *sheetsProvider) Query() ([][]interface{}, error) {
+func (s *sheetsProvider) Init() error {
 	if s.googleSheetsID == "" {
-		return nil, fmt.Errorf("GOOGLE_SHEET_ID not set")
+		return fmt.Errorf("GOOGLE_SHEET_ID not set")
 	}
 
 	srv, err := sheets.NewService(context.TODO())
 	if err != nil {
-		return nil, fmt.Errorf("unable to retrieve Sheets client: %v", err)
+		return fmt.Errorf("unable to retrieve Sheets client: %v", err)
 	}
+	s.client = srv
+	return nil
+}
 
+func (s *sheetsProvider) Query() ([][]interface{}, error) {
 	log.Println("querying sheet")
-	readRange := "A:B"
+	readRange := "A:D"
 	if s.sheetName != "" {
 		readRange = s.sheetName + "!" + readRange
 	}
-	resp, err := srv.Spreadsheets.Values.Get(s.googleSheetsID, readRange).Do()
+	resp, err := s.client.Spreadsheets.Values.Get(s.googleSheetsID, readRange).Do()
 	if err != nil {
 		return nil, fmt.Errorf("unable to retrieve data from sheet: %v", err)
 	}
 	log.Printf("queried %d rows", len(resp.Values))
 	return resp.Values, nil
 }
+
+// Write will write the values rowwise, starting at the given column and row index.
+func (s *sheetsProvider) Write(column string, rowIndex int, values []interface{}) error {
+	s.Lock()
+	defer s.Unlock()
+	log.Printf("writing %s to row %v", values, rowIndex)
+	writeRange := fmt.Sprintf("%s%d", column, rowIndex)
+	if s.sheetName != "" {
+		writeRange = s.sheetName + "!" + writeRange
+	}
+	_, err := s.client.Spreadsheets.Values.Update(s.googleSheetsID, writeRange, &sheets.ValueRange{
+		Values: [][]interface{}{values},
+	}).ValueInputOption("USER_ENTERED").Do()
+	if err != nil {
+		return fmt.Errorf("unable to write data to sheet: %v", err)
+	}
+	return nil
+}
+
+func New() *sheetsProvider {
+	return &sheetsProvider{}
+}