feat: add create short url

internal/api/handler.go

@@ -7,18 +7,20 @@ import (
 
 	"github.com/babariviere/short/internal/db"
 	"github.com/babariviere/short/internal/oas"
+	"github.com/babariviere/short/internal/url"
 	"github.com/jackc/pgx/v5"
 )
 
 var _ oas.Handler = (*handler)(nil)
 
 type handler struct {
-	oas.UnimplementedHandler
+	serverUrl string
 	queries   *db.Queries
 }
 
-func NewHandler(queries *db.Queries) *handler {
+func NewHandler(serverUrl string, queries *db.Queries) *handler {
 	return &handler{
+		serverUrl: serverUrl,
 		queries:   queries,
 	}
 }
@@ -36,3 +38,28 @@ func (h *handler) RedirectLongURL(ctx context.Context, params oas.RedirectLongUR
 		Location: oas.NewOptString(res.LongUrl),
 	}, nil
 }
+
+func (h *handler) CreateShortURL(ctx context.Context, req *oas.CreateShortURLReq) (oas.CreateShortURLRes, error) {
+	hash, err := url.GenerateHash(req.URL)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate hash for url %s: %w", req.URL, err)
+	}
+
+	res, err := h.queries.InsertURL(ctx, db.InsertURLParams{
+		Hash:    hash,
+		LongUrl: req.URL,
+	})
+	if err != nil {
+		// No row == conflict since we do a "ON CONFLICT DO NOTHING"
+		if errors.Is(err, pgx.ErrNoRows) {
+			return &oas.CreateShortURLBadRequest{
+				Message: oas.NewOptString("URL already exist."),
+			}, nil
+		}
+		return nil, fmt.Errorf("failed to insert url: %w", err)
+	}
+
+	return &oas.CreateShortURLCreated{
+		Shorten: h.serverUrl + "/" + res.Hash,
+	}, nil
+}

internal/db/query.sql.go

@@ -20,3 +20,22 @@ func (q *Queries) GetURLByHash(ctx context.Context, hash string) (Url, error) {
 	err := row.Scan(&i.ID, &i.Hash, &i.LongUrl)
 	return i, err
 }
+
+const insertURL = `-- name: InsertURL :one
+INSERT INTO urls (hash, long_url)
+VALUES ($1, $2)
+ON CONFLICT (hash) DO NOTHING
+RETURNING id, hash, long_url
+`
+
+type InsertURLParams struct {
+	Hash    string
+	LongUrl string
+}
+
+func (q *Queries) InsertURL(ctx context.Context, arg InsertURLParams) (Url, error) {
+	row := q.db.QueryRow(ctx, insertURL, arg.Hash, arg.LongUrl)
+	var i Url
+	err := row.Scan(&i.ID, &i.Hash, &i.LongUrl)
+	return i, err
+}

internal/oas/oas_json_gen.go

@@ -85,10 +85,8 @@ func (s *CreateShortURLCreated) Encode(e *jx.Encoder) {
 // encodeFields encodes fields.
 func (s *CreateShortURLCreated) encodeFields(e *jx.Encoder) {
 	{
-		if s.Shorten.Set {
 		e.FieldStart("shorten")
-			s.Shorten.Encode(e)
-		}
+		e.Str(s.Shorten)
 	}
 }
 
@@ -101,13 +99,16 @@ func (s *CreateShortURLCreated) Decode(d *jx.Decoder) error {
 	if s == nil {
 		return errors.New("invalid: unable to decode CreateShortURLCreated to nil")
 	}
+	var requiredBitSet [1]uint8
 
 	if err := d.ObjBytes(func(d *jx.Decoder, k []byte) error {
 		switch string(k) {
 		case "shorten":
+			requiredBitSet[0] |= 1 << 0
 			if err := func() error {
-				s.Shorten.Reset()
-				if err := s.Shorten.Decode(d); err != nil {
+				v, err := d.Str()
+				s.Shorten = string(v)
+				if err != nil {
 					return err
 				}
 				return nil
@@ -121,6 +122,38 @@ func (s *CreateShortURLCreated) Decode(d *jx.Decoder) error {
 	}); err != nil {
 		return errors.Wrap(err, "decode CreateShortURLCreated")
 	}
+	// Validate required fields.
+	var failures []validate.FieldError
+	for i, mask := range [1]uint8{
+		0b00000001,
+	} {
+		if result := (requiredBitSet[i] & mask) ^ mask; result != 0 {
+			// Mask only required fields and check equality to mask using XOR.
+			//
+			// If XOR result is not zero, result is not equal to expected, so some fields are missed.
+			// Bits of fields which would be set are actually bits of missed fields.
+			missed := bits.OnesCount8(result)
+			for bitN := 0; bitN < missed; bitN++ {
+				bitIdx := bits.TrailingZeros8(result)
+				fieldIdx := i*8 + bitIdx
+				var name string
+				if fieldIdx < len(jsonFieldsNameOfCreateShortURLCreated) {
+					name = jsonFieldsNameOfCreateShortURLCreated[fieldIdx]
+				} else {
+					name = strconv.Itoa(fieldIdx)
+				}
+				failures = append(failures, validate.FieldError{
+					Name:  name,
+					Error: validate.ErrFieldRequired,
+				})
+				// Reset bit.
+				result &^= 1 << bitIdx
+			}
+		}
+	}
+	if len(failures) > 0 {
+		return &validate.Error{Fields: failures}
+	}
 
 	return nil
 }

internal/oas/oas_schemas_gen.go

@@ -20,16 +20,16 @@ func (*CreateShortURLBadRequest) createShortURLRes() {}
 
 type CreateShortURLCreated struct {
 	// Created shorten URL. Going to this URL should redirect to URL from request body.
-	Shorten OptString `json:"shorten"`
+	Shorten string `json:"shorten"`
 }
 
 // GetShorten returns the value of Shorten.
-func (s *CreateShortURLCreated) GetShorten() OptString {
+func (s *CreateShortURLCreated) GetShorten() string {
 	return s.Shorten
 }
 
 // SetShorten sets the value of Shorten.
-func (s *CreateShortURLCreated) SetShorten(val OptString) {
+func (s *CreateShortURLCreated) SetShorten(val string) {
 	s.Shorten = val
 }
 

internal/url/hash.go

@@ -0,0 +1,34 @@
+package url
+
+import (
+	"hash/fnv"
+	"strings"
+)
+
+// GenerateHash hash the `url` param into a 8 characters base62 using fnv algorithm.
+func GenerateHash(url string) (string, error) {
+	hasher := fnv.New32a()
+	_, err := hasher.Write([]byte(url))
+	if err != nil {
+		return "", err
+	}
+	return encodeToBase62(hasher.Sum32()), nil
+}
+
+var base62 = [62]rune{
+	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
+	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+}
+
+func encodeToBase62(hash uint32) string {
+	var sb strings.Builder
+	sb.Grow(8)
+
+	for hash > 0 {
+		sb.WriteRune(base62[hash%62])
+		hash /= 62
+	}
+
+	return sb.String()
+}

main.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"strings"
 
 	"github.com/babariviere/short/internal/api"
 	"github.com/babariviere/short/internal/db"
@@ -19,13 +20,20 @@ func main() {
 		log.Fatalln("DATABASE_URL is not configured.")
 	}
 
+	serverUrl := os.Getenv("SERVER_URL")
+	if serverUrl == "" {
+		serverUrl = "http://localhost:8080"
+	}
+
+	serverUrl = strings.TrimSuffix(serverUrl, "/")
+
 	psql, err := pgx.Connect(context.Background(), psqlUrl)
 	if err != nil {
 		log.Fatalf("cannot connect to database: %v", err)
 	}
 
 	queries := db.New(psql)
-	handler := api.NewHandler(queries)
+	handler := api.NewHandler(serverUrl, queries)
 
 	srv, err := oas.NewServer(handler)
 	if err != nil {

openapi.yaml

@@ -4,17 +4,17 @@ info:
   version: 0.1.0
   description: An URL shortener service.
 paths:
-  "/{hash}":
+  '/{hash}':
     get:
       responses:
-        "307":
+        '307':
           description: Redirect client to long URL.
           headers:
             Location:
               schema:
                 type: string
               description: Long URL
-        "404":
+        '404':
           description: Not Found
       description: Redirect client to long URL.
       operationId: redirectLongURL
@@ -38,11 +38,11 @@ paths:
                 url:
                   type: string
                   description: URL to shorten
-                  example: "https://example.com"
+                  example: 'https://example.com'
               required:
                 - url
       responses:
-        "201":
+        '201':
           description: Succesfully created shorten URL.
           content:
             application/json:
@@ -52,7 +52,9 @@ paths:
                   shorten:
                     type: string
                     description: Created shorten URL. Going to this URL should redirect to URL from request body.
-        "400":
+                required:
+                  - shorten
+        '400':
           description: Bad Request
           content:
             application/json:

sql/query.sql

@@ -1,3 +1,9 @@
 -- name: GetURLByHash :one
 SELECT * FROM urls
 WHERE hash = $1;
+
+-- name: InsertURL :one
+INSERT INTO urls (hash, long_url)
+VALUES ($1, $2)
+ON CONFLICT (hash) DO NOTHING
+RETURNING *;