Added /v2 in module name.

LICENSE

@@ -1,6 +1,6 @@
 The MIT License
 
-Copyright (c) 2022 Alexander "Arav" Andreev <me@arav.top>
+Copyright (c) 2022,2023 Alexander "Arav" Andreev <me@arav.su>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

Makefile

@@ -1,31 +0,0 @@
-PACKAGE_NAME=justcaptcha
-TARGET=${PACKAGE_NAME}d
-
-SYSCTL=${shell which systemctl}
-SYSDDIR_=${shell pkg-config systemd --variable=systemdsystemunitdir}
-SYSDDIR=${SYSDDIR_:/%=%}
-DESTDIR=/
-
-LDFLAGS=-ldflags "-s -w -X main.version=1.2.0" -tags osusergo,netgo
-
-all: ${TARGET}
-
-.PHONY: ${TARGET}
-
-${TARGET}:
-	go build -o bin/$@ ${LDFLAGS} cmd/$@/main.go
-
-run:
-	bin/${TARGET} -expiry 1m -listen 127.0.0.1:19134
-
-install:
-	install -Dm 0755 bin/${TARGET} ${DESTDIR}usr/bin/${TARGET}
-	install -Dm 0644 LICENSE ${DESTDIR}usr/share/licenses/${PACKAGE_NAME}/LICENSE
-
-	install -Dm 0644 init/systemd/${PACKAGE_NAME}.service ${DESTDIR}${SYSDDIR}/${PACKAGE_NAME}.service
-
-uninstall:
-	rm ${DESTDIR}usr/bin/${TARGET}
-	rm ${DESTDIR}usr/share/licenses/${PACKAGE_NAME}/LICENSE
-
-	rm ${DESTDIR}${SYSDDIR}/${PACKAGE_NAME}.service

README.md

@@ -1,73 +1,36 @@
-justcaptcha ver. 1.2.0
-======================
+justcaptcha
+===========
 
-A simple CAPTCHA service implementation.
+A simple CAPTCHA implementation.
 
-## Usage
+An example using built-in "dwelling" implementation.
 
-    justcaptchad -expiry 5m -listen /var/run/justcaptchad/j.sock
+Create a new CAPTCHA:
 
-`-expiry` takes time for CAPTCHA to be valid for in format X{s,m,h}.
+    c := dwcaptcha.NewDwellingCaptcha(expiry)
+    _, id := inmemdb.New(someAdditionalDataUsedInIDGenerationUsuallyIPAddr, c)
 
-`-listen` is `ip:port` or `/path/to/unix.sock` to listen on.
+Get an image for a CAPTCHA:
 
-## API
+    i := inmemdb.Image(captchaID, captchaStyle)
+    if i == nil {
+        ... // do something if there was no image returned
+    }
 
-### Get a new CAPTCHA
+    jpeg.Encode(w, *i, &jpeg.Options{Quality: 20})
 
-    GET /
+Solve a CAPTCHA:
 
-It will return an ID of a new CAPTCHA in plain text.
+    if ok := inmemdb.Solve(captchaID, answer); !ok {
+        ... // not solved
+    }
+    // solved
+    ...
 
-#### HTTP codes
-- `200` if created (and it always being created)
+Check is CAPTCHA was solved:
 
-### Get an image for a CAPTCHA
-
-    GET /:captcha_id/image?style=
-
-Responds with an image in JPEG format.
-
-An optional URL query parameter `style=` set a name of a CAPTCHA style if
-implemented by used CAPTCHA implementation.
-
-#### HTTP codes
-- `200` if exists
-- `404` if doesn't exist
-- `500` if for some reason an image wasn't created
-
-### Submit an answer
-
-    POST /:captcha_id
-
-Accepts `application/x-www-form-urlencoded` content type.
-
-It takes one parameter `answer=123456`.
-
-Responds with an empty body and one of the HTTP codes.
-
-#### HTTP codes
-- `200` if solved
-- `403` if not solved
-- `404` if doesn't exist
-
-### Check if captcha is solved
-
-    GET /:captcha_id?remove
-
-Responds with an empty body and one of the HTTP codes.
-
-If an optional `remove` URL query parameter without a value supplied. CAPTCHA
-will be removed without check if it is solved and a HTTP code `200` will be sent.
-Otherwise, a `403` HTTP code will be sent, and, e.g. browser will print an error
-message to console. So, in this case it helps to keep a browser's console cleaner.
-If CAPTCHA doesn't exist a `404` HTTP code still will be returned.
-
-This can be useful to remove an unused CAPTCHA from a DB without waiting for it
-to be expired. E.g. when a visitor requests for a new CAPTCHA because he struggle
-to solve it.
-
-#### HTTP codes
-- `200` if solved
-- `403` if not solved
-- `404` if doesn't exist
+    if ok := inmemdb.IsSolved(captchaID); !ok {
+	    ... // not solved
+    }
+    // solved
+    ...

build/archlinux/PKGBUILD

@@ -1,30 +0,0 @@
-# Maintainer: Alexander "Arav" Andreev <me@arav.top>
-pkgname=justcaptcha
-pkgver=1.2.0
-pkgrel=1
-pkgdesc="Just a CAPTCHA service"
-arch=('i686' 'x86_64' 'arm' 'armv6h' 'armv7h' 'aarch64')
-url="https://git.arav.top/Arav/justcaptcha"
-license=('MIT')
-groups=()
-depends=()
-makedepends=('go')
-provides=('justcaptcha')
-conflicts=('justcaptcha')
-replaces=()
-backup=()
-options=()
-install=
-source=('https://git.arav.top/Arav/justcaptcha/archive/1.2.0.tar.gz')
-noextract=()
-md5sums=('SKIP')
-
-build() {
-    cd "$srcdir/$pkgname"
-    make DESTDIR="$pkgdir/"
-}
-
-package() {
-    cd "$srcdir/$pkgname"
-    make DESTDIR="$pkgdir/" install
-}

captcha.go

@@ -20,7 +20,8 @@ func NewIntAnswer() Answer {
 
 // Captcha interface that should be implemented by a CAPTCHA.
 type Captcha interface {
-	// Image generates and returns a pointer to an image of CAPTCHA.
+	// Image generates an image of a CAPTCHA according to a passed style
+	// and returns a pointer to it.
 	Image(style string) *image.Image
 	// Answer returns a pregenerated answer.
 	Answer() Answer
@@ -37,14 +38,14 @@ type Captcha interface {
 // All derivatives that embed this struct only need to implement
 // an Image() method.
 type BaseCaptcha struct {
-	answer   Answer
-	solved   bool
-	expireIn time.Time
+	answer Answer
+	solved bool
+	expiry time.Time
 }
 
 func NewBaseCaptcha(expiry time.Duration) *BaseCaptcha {
 	return &BaseCaptcha{
-		expireIn: ExpiryDate(expiry),
+		expiry: time.Now().Add(expiry),
 	}
 }
 
@@ -52,8 +53,6 @@ func (c *BaseCaptcha) Image(style string) *image.Image {
 	return nil
 }
 
-// Answer generates an integer answer for a CAPTCHA or just returns
-// an existing one.
 func (c *BaseCaptcha) Answer() Answer {
 	if c.answer == "" {
 		c.answer = NewIntAnswer()
@@ -61,8 +60,6 @@ func (c *BaseCaptcha) Answer() Answer {
 	return c.answer
 }
 
-// Solve sets solved field to true if given answer is right and returns a result
-// of a check.
 func (c *BaseCaptcha) Solve(answer Answer) bool {
 	c.solved = c.answer == answer
 	return c.solved
@@ -73,11 +70,5 @@ func (c *BaseCaptcha) IsSolved() bool {
 }
 
 func (c *BaseCaptcha) Expiry() time.Time {
-	return c.expireIn
-}
-
-// ExpiryDate returns a date when CAPTCHA expires. It adds a passed
-// expiry duration to a current time.
-func ExpiryDate(expiry time.Duration) time.Time {
-	return time.Now().Add(expiry)
+	return c.expiry
 }

cmd/justcaptchad/main.go

@@ -1,72 +0,0 @@
-package main
-
-import (
-	"flag"
-	"fmt"
-	"justcaptcha/internal/captcha"
-	"justcaptcha/internal/handlers"
-	"justcaptcha/pkg/server"
-	"log"
-	"net/netip"
-	"os"
-	"os/signal"
-	"strings"
-	"syscall"
-	"time"
-)
-
-var version string
-
-var listenAddress *string = flag.String("listen", "/var/run/justcaptcha/c.sock", "listen address (ip:port|unix_path)")
-var captchaExpiry *time.Duration = flag.Duration("expiry", 5*time.Minute, "CAPTCHA expiry in format XX{s,m,h}, e.g. 5m, 300s")
-var showVersion *bool = flag.Bool("v", false, "show version")
-
-func main() {
-	flag.Parse()
-	log.SetFlags(0)
-
-	if *showVersion {
-		fmt.Println("justcaptchad ver.", version, "\nCopyright (c) 2022 Alexander \"Arav\" Andreev <me@arav.top>")
-		return
-	}
-
-	captcha.Init(*captchaExpiry)
-
-	hand := handlers.New()
-	srv := server.NewHttpServer()
-
-	srv.GET("/", hand.New)
-	srv.POST("/:captcha", hand.Solve)
-	srv.GET("/:captcha", hand.IsSolved)
-	srv.GET("/:captcha/image", hand.Image)
-
-	var network string
-	if !strings.ContainsRune(*listenAddress, ':') {
-		network = "unix"
-		defer os.Remove(*listenAddress)
-	} else {
-		ap, err := netip.ParseAddrPort(*listenAddress)
-		if err != nil {
-			log.Fatalln(err)
-		}
-
-		if ap.Addr().Is4() {
-			network = "tcp4"
-		} else if ap.Addr().Is6() {
-			network = "tcp6"
-		}
-	}
-
-	if err := srv.Start(network, *listenAddress); err != nil {
-		log.Fatalln("failed to start a server:", err)
-	}
-
-	doneSignal := make(chan os.Signal, 1)
-	signal.Notify(doneSignal, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
-
-	<-doneSignal
-
-	if err := srv.Stop(); err != nil {
-		log.Fatalln("failed to properly shutdown a server:", err)
-	}
-}

db.go

@@ -0,0 +1,42 @@
+package captcha
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"image"
+	"strconv"
+	"time"
+)
+
+const DefaultExpiredScanInterval = 60 * time.Second
+
+// ID is a CAPTCHA identifier.
+type ID string
+
+// NewID generates an ID as a sha256 hash of additionalData (usually IP-address),
+// current time, answer and more, it adds a set of random bytes and encodes all
+// of it with base64 in raw URL variant.
+func NewID(additionalData string, answer Answer) ID {
+	idHash := sha256.New()
+
+	idHash.Write([]byte(additionalData))
+	idHash.Write([]byte(strconv.FormatInt(time.Now().UnixMicro(), 16)))
+	idHash.Write([]byte(answer))
+	randData := make([]byte, 32)
+	rand.Read(randData)
+	idHash.Write(randData)
+
+	return ID(base64.RawURLEncoding.EncodeToString(idHash.Sum(nil)))
+}
+
+// DB interface with all necessary methods.
+type DB interface {
+	New(data string, captcha Captcha) (Captcha, ID)
+	GetExpiry() time.Duration
+	SetExpiry(expiry time.Duration)
+	Image(id ID, style string) *image.Image
+	Solve(id ID, answer Answer) bool
+	IsSolved(id ID) bool
+	Remove(id ID)
+}

dwcaptcha/dwcaptcha_test.go

@@ -0,0 +1,30 @@
+package dwcaptcha_test
+
+import (
+	"testing"
+	"time"
+
+	"git.arav.su/Arav/justcaptcha/v2/dwcaptcha"
+)
+
+const expiry = 10 * time.Minute
+
+func TestCaptcha(t *testing.T) {
+	captcha := dwcaptcha.NewDwellingCaptcha(expiry)
+
+	if diff := time.Until(captcha.Expiry()) - expiry; diff >= 1*time.Microsecond {
+		t.Errorf("Difference %s is more than 1 microsecond", diff.String())
+	}
+
+	if captcha.Image("") == nil {
+		t.Error("image cannot be nil, but it is!")
+	}
+
+	if !captcha.Solve(captcha.Answer()) {
+		t.Error("for whatever reason, its own answer doesn't match itself O_O")
+	}
+
+	if !captcha.IsSolved() {
+		t.Error("after last test it should be true, but it is not!")
+	}
+}

dwcaptcha/dwelling_captcha.go

@@ -1,11 +1,12 @@
-package captcha
+package dwcaptcha
 
 import (
 	"image"
-	"justcaptcha/pkg/captcha"
 	"math/rand"
 	"time"
 
+	captcha "git.arav.su/Arav/justcaptcha/v2"
+
 	"github.com/fogleman/gg"
 )
 

go.mod

@@ -1,13 +1,10 @@
-module justcaptcha
+module git.arav.su/Arav/justcaptcha/v2
 
-go 1.18
+go 1.12
 
-require (
-	github.com/fogleman/gg v1.3.0
-	github.com/julienschmidt/httprouter v1.3.0
-)
+require github.com/fogleman/gg v1.3.0
 
 require (
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
-	golang.org/x/image v0.0.0-20220722155232-062f8c9fd539 // indirect
+	golang.org/x/image v0.11.0 // indirect
 )

go.sum

@@ -2,9 +2,36 @@ github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
 github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
-github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
-github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=
-golang.org/x/image v0.0.0-20220722155232-062f8c9fd539 h1:/eM0PCrQI2xd471rI+snWuu251/+/jpBpZqir2mPdnU=
-golang.org/x/image v0.0.0-20220722155232-062f8c9fd539/go.mod h1:doUCurBvlfPMKfmIpRIywoHmhN3VyhnoFDbvIEWF4hY=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/image v0.11.0 h1:ds2RoQvBvYTiJkwpSFDwCcDFNX7DqjL2WsUgTNk0Ooo=
+golang.org/x/image v0.11.0/go.mod h1:bglhjqbqVuEb9e9+eNR45Jfu7D+T4Qan+NhQk8Ck2P8=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

init/systemd/justcaptcha.service

@@ -1,39 +0,0 @@
-[Unit]
-Description=A simple CAPTCHA service for your website
-After=network.target
-
-[Service]
-Type=simple
-Restart=on-failure
-DynamicUser=yes
-ExecStart=/usr/bin/justcaptchad -expiry 5m -listen /var/run/justcaptcha/j.sock
-
-ReadOnlyPaths=/
-# Set here path to directory where uploads are stored.
-NoExecPaths=/
-ExecPaths=/usr/bin/justcaptchad
-
-RuntimeDirectory=justcaptcha
-
-AmbientCapabilities=
-CapabilityBoundingSet=
-
-LockPersonality=true
-MemoryDenyWriteExecute=true
-NoNewPrivileges=true
-PrivateDevices=true
-ProtectClock=true
-ProtectControlGroups=true
-ProtectHome=true
-ProtectKernelLogs=true
-ProtectKernelModules=true
-ProtectKernelTunables=true
-ProtectSystem=strict
-RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
-RestrictNamespaces=true
-RestrictRealtime=true
-RestrictSUIDSGID=true
-SystemCallArchitectures=native
-
-[Install]
-WantedBy=multi-user.target

inmemdb/inmemdb.go

@@ -0,0 +1,159 @@
+package inmemdb
+
+import (
+	"image"
+	"sync"
+	"time"
+
+	captcha "git.arav.su/Arav/justcaptcha/v2"
+)
+
+// InMemoryDB implementation that lives in a memory (map).
+type InMemoryDB struct {
+	sync.Mutex
+
+	db                 map[captcha.ID]captcha.Captcha
+	expiry             time.Duration
+	expiryScanInterval time.Duration
+}
+
+// NewInMemoryDB returns an initialised instance of an InMemoryDB.
+// An expiry is a scan interval for expired CAPTCHAs (if passed a longer one,
+// resets to a default (captcha.DefaultExpiredScanInterval)).
+func NewInMemoryDB(expiry time.Duration) *InMemoryDB {
+	db := &InMemoryDB{
+		db:     make(map[captcha.ID]captcha.Captcha),
+		expiry: expiry}
+
+	if expiry < captcha.DefaultExpiredScanInterval {
+		db.expiryScanInterval = expiry
+	} else {
+		db.expiryScanInterval = captcha.DefaultExpiredScanInterval
+	}
+
+	go db.cleanExpired()
+
+	return db
+}
+
+// New accepts a CAPTCHA instance, generates an ID and store it in a database.
+// A data string is an additional random data used to generate an ID,
+// e.g. an IP-address.
+func (imcdb *InMemoryDB) New(data string, cptcha captcha.Captcha) (captcha.Captcha, captcha.ID) {
+	id := captcha.NewID(data, cptcha.Answer())
+
+	imcdb.Lock()
+	imcdb.db[id] = cptcha
+	imcdb.Unlock()
+
+	return cptcha, id
+}
+
+// GetExpiry returns an expiry for a CAPTCHA.
+func (imcdb *InMemoryDB) GetExpiry() time.Duration {
+	return imcdb.expiry
+}
+
+// SetExpiry changes an expiry for a CAPTCHA and a scan interval. Scan interval
+// cannot be longer than a default, so if it is, then resets to a default.
+func (imcdb *InMemoryDB) SetExpiry(expiry time.Duration) {
+	imcdb.expiry = expiry
+	if expiry < captcha.DefaultExpiredScanInterval {
+		imcdb.expiryScanInterval = expiry
+	} else {
+		imcdb.expiryScanInterval = captcha.DefaultExpiredScanInterval
+	}
+}
+
+// Image returns a freshly generated image for a CAPTCHA with style if
+// applicable.
+func (imcdb *InMemoryDB) Image(id captcha.ID, style string) *image.Image {
+	imcdb.Lock()
+	defer imcdb.Unlock()
+	if c, ok := imcdb.db[id]; ok {
+		return c.Image(style)
+	}
+	return nil
+}
+
+// Solve compares given answer with a stored one and if failed
+// deletes a CAPTCHA from database.
+func (imcdb *InMemoryDB) Solve(id captcha.ID, answer captcha.Answer) bool {
+	imcdb.Lock()
+	defer imcdb.Unlock()
+	if c, ok := imcdb.db[id]; ok {
+		ok = c.Solve(answer)
+		if !ok {
+			delete(imcdb.db, id)
+		}
+		return ok
+	}
+	return false
+}
+
+// IsSolved checks if CAPTCHA was solved and removes it
+// from a database.
+func (imcdb *InMemoryDB) IsSolved(id captcha.ID) bool {
+	imcdb.Lock()
+	defer imcdb.Unlock()
+	if c, ok := imcdb.db[id]; ok {
+		delete(imcdb.db, id)
+		return c.IsSolved()
+	}
+	return false
+}
+
+// Remove a CAPTCHA from a database.
+func (imcdb *InMemoryDB) Remove(id captcha.ID) {
+	imcdb.Lock()
+	defer imcdb.Unlock()
+	delete(imcdb.db, id)
+}
+
+// cleanExpired removes expired CAPTCHAs in a loop.
+func (imcdb *InMemoryDB) cleanExpired() {
+	for {
+		sleepFor := imcdb.expiryScanInterval - (time.Duration(time.Now().Second()) % imcdb.expiryScanInterval)
+		time.Sleep(sleepFor)
+
+		imcdb.Lock()
+		for id, captcha := range imcdb.db {
+			if time.Since(captcha.Expiry()) >= imcdb.expiry {
+				delete(imcdb.db, id)
+			}
+		}
+		imcdb.Unlock()
+	}
+}
+
+// An instance of InMemoryDB
+
+var imcdb = NewInMemoryDB(captcha.DefaultExpiredScanInterval)
+
+func GetExpiry() time.Duration {
+	return imcdb.GetExpiry()
+}
+
+func SetExpiry(expiry time.Duration) {
+	imcdb.SetExpiry(expiry)
+}
+
+func New(data string, captcha captcha.Captcha) (captcha.Captcha, captcha.ID) {
+	return imcdb.New(data, captcha)
+}
+
+func Image(id captcha.ID, style string) *image.Image {
+	return imcdb.Image(id, style)
+}
+
+func Solve(id captcha.ID, answer captcha.Answer) bool {
+	return imcdb.Solve(id, answer)
+}
+
+func IsSolved(id captcha.ID) bool {
+	return imcdb.IsSolved(id)
+}
+
+func Remove(id captcha.ID) {
+	imcdb.Remove(id)
+}

inmemdb/inmemdb_test.go

@@ -0,0 +1,48 @@
+package inmemdb_test
+
+import (
+	"testing"
+	"time"
+
+	captcha "git.arav.su/Arav/justcaptcha/v2"
+	"git.arav.su/Arav/justcaptcha/v2/dwcaptcha"
+	"git.arav.su/Arav/justcaptcha/v2/inmemdb"
+)
+
+const expiry = 10 * time.Minute
+const testData = "192.168.0.1"
+
+func TestInMemDBDefaultInstance(t *testing.T) {
+	if inmemdb.GetExpiry() != captcha.DefaultExpiredScanInterval {
+		t.Errorf("expiration is different from a default one (%v != %v)",
+			inmemdb.GetExpiry(), captcha.DefaultExpiredScanInterval)
+	}
+
+	inmemdb.SetExpiry(expiry)
+
+	if expiry != inmemdb.GetExpiry() {
+		t.Errorf("Expected %v, but got %v", expiry, inmemdb.GetExpiry())
+	}
+
+	captcha, captchaID := inmemdb.New(testData, dwcaptcha.NewDwellingCaptcha(expiry))
+
+	if inmemdb.Image(captchaID, "") == nil {
+		t.Error("nil returned instead of an image.Image struct")
+	}
+
+	if !inmemdb.Solve(captchaID, captcha.Answer()) {
+		t.Error("CAPTCHA not solved. Looks like provided ID wasn't found")
+	}
+
+	if !inmemdb.IsSolved(captchaID) {
+		t.Error("last test solved a CAPTCHA, but IsSolved() returned false")
+	}
+}
+
+func TestInMemDBNewInstance(t *testing.T) {
+	db := inmemdb.NewInMemoryDB(expiry)
+
+	if db.GetExpiry() != expiry {
+		t.Errorf("expected expiry %v, but got %v", expiry, db.GetExpiry())
+	}
+}

internal/captcha/instance.go

@@ -1,38 +0,0 @@
-package captcha
-
-import (
-	"image"
-	"justcaptcha/pkg/captcha"
-	"time"
-)
-
-var captchaDb captcha.CaptchaDB
-
-func Init(expiry time.Duration) {
-	captchaDb = captcha.NewInMemoryCaptchaDB(expiry)
-}
-
-func New(data string) (captcha.Captcha, captcha.ID) {
-	dc := NewDwellingCaptcha(captchaDb.GetExpiry())
-	return captchaDb.New(data, dc)
-}
-
-func Image(id captcha.ID, style string) (*image.Image, error) {
-	return captchaDb.Image(id, style)
-}
-
-func Solve(id captcha.ID, answer captcha.Answer) (bool, error) {
-	return captchaDb.Solve(id, answer)
-}
-
-func IsSolved(id captcha.ID) (bool, error) {
-	return captchaDb.IsSolved(id)
-}
-
-func Remove(id captcha.ID) error {
-	return captchaDb.Remove(id)
-}
-
-func GetExpiry() time.Duration {
-	return captchaDb.GetExpiry()
-}

internal/handlers/handlers.go

@@ -1,82 +0,0 @@
-package handlers
-
-import (
-	"fmt"
-	"image/jpeg"
-	"justcaptcha/internal/captcha"
-	pcaptcha "justcaptcha/pkg/captcha"
-	"justcaptcha/pkg/server"
-	"net/http"
-)
-
-type CaptchaHandlers struct{}
-
-func New() *CaptchaHandlers {
-	return &CaptchaHandlers{}
-}
-
-func (h *CaptchaHandlers) New(w http.ResponseWriter, r *http.Request) {
-	_, id := captcha.New(r.RemoteAddr)
-
-	fmt.Fprint(w, id)
-}
-
-func (h *CaptchaHandlers) Image(w http.ResponseWriter, r *http.Request) {
-	captchaID := pcaptcha.ID(server.GetURLParam(r, "captcha"))
-	captchaStyle := r.URL.Query().Get("style")
-
-	captchaImage, err := captcha.Image(captchaID, captchaStyle)
-	if err != nil {
-		w.WriteHeader(http.StatusNotFound)
-		return
-	}
-
-	if captchaImage == nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	w.Header().Add("Content-Disposition", "inline; filename=\""+string(captchaID)+"\"")
-
-	jpeg.Encode(w, *captchaImage, &jpeg.Options{Quality: 20})
-}
-
-func (h *CaptchaHandlers) Solve(w http.ResponseWriter, r *http.Request) {
-	r.ParseForm()
-
-	captchaID := pcaptcha.ID(server.GetURLParam(r, "captcha"))
-	answer := pcaptcha.Answer(r.FormValue("answer"))
-
-	ok, err := captcha.Solve(captchaID, answer)
-	if err != nil {
-		w.WriteHeader(http.StatusNotFound)
-		return
-	}
-
-	if !ok {
-		w.WriteHeader(http.StatusForbidden)
-	}
-}
-
-func (h *CaptchaHandlers) IsSolved(w http.ResponseWriter, r *http.Request) {
-	captchaID := pcaptcha.ID(server.GetURLParam(r, "captcha"))
-	isJustRemove := r.URL.Query().Has("remove")
-
-	if isJustRemove {
-		err := captcha.Remove(captchaID)
-		if err != nil {
-			w.WriteHeader(http.StatusNotFound)
-		}
-		return
-	}
-
-	solved, err := captcha.IsSolved(captchaID)
-	if err != nil {
-		w.WriteHeader(http.StatusNotFound)
-		return
-	}
-
-	if !solved {
-		w.WriteHeader(http.StatusForbidden)
-	}
-}

pkg/captcha/db.go

@@ -1,147 +0,0 @@
-package captcha
-
-import (
-	"crypto/sha256"
-	"encoding/base64"
-	"errors"
-	"image"
-	"strconv"
-	"sync"
-	"time"
-)
-
-var errorNotFound = errors.New("captcha not found")
-
-var defaultExpiredScanInterval = 60 * time.Second
-
-type ID string
-
-// NewID generates an ID as a sha256 hash of additionalData, current time
-// and answer encoded with base64 in raw URL variant.
-func NewID(additionalData string, answer Answer) ID {
-	idHash := sha256.New()
-
-	idHash.Write([]byte(additionalData))
-	idHash.Write([]byte(strconv.FormatInt(time.Now().UnixMicro(), 16)))
-	idHash.Write([]byte(answer))
-
-	return ID(base64.RawURLEncoding.EncodeToString(idHash.Sum(nil)))
-}
-
-type CaptchaDB interface {
-	New(data string, captcha Captcha) (Captcha, ID)
-	GetExpiry() time.Duration
-	Image(id ID, style string) (*image.Image, error)
-	Solve(id ID, answer Answer) (bool, error)
-	IsSolved(id ID) (bool, error)
-	Remove(id ID) error
-	cleanExpired()
-}
-
-type InMemoryCaptchaDB struct {
-	sync.Mutex
-
-	db                 map[ID]Captcha
-	expireIn           time.Duration
-	expireScanInterval time.Duration
-}
-
-func NewInMemoryCaptchaDB(expire time.Duration) *InMemoryCaptchaDB {
-	db := &InMemoryCaptchaDB{
-		db:       make(map[ID]Captcha),
-		expireIn: expire}
-
-	if expire < defaultExpiredScanInterval {
-		db.expireScanInterval = expire
-	} else {
-		db.expireScanInterval = defaultExpiredScanInterval
-	}
-
-	db.cleanExpired()
-
-	return db
-}
-
-// New accepts an Captcha instance, generates an ID and store it in a database.
-// `data` string is an additional random data used to generate an ID,
-// e.g. IP-address.
-func (cdb *InMemoryCaptchaDB) New(data string, captcha Captcha) (Captcha, ID) {
-	id := NewID(data, captcha.Answer())
-
-	cdb.Lock()
-	cdb.db[id] = captcha
-	cdb.Unlock()
-
-	return captcha, id
-}
-
-// cleanExpired starts a goroutine that deletes expired CAPTCHAs.
-func (cdb *InMemoryCaptchaDB) cleanExpired() {
-	go func() {
-		for {
-			sleepFor := cdb.expireScanInterval - (time.Duration(time.Now().Second()) % cdb.expireScanInterval)
-			time.Sleep(sleepFor)
-
-			cdb.Lock()
-			for id, captcha := range cdb.db {
-				if time.Since(captcha.Expiry()) >= cdb.expireIn {
-					delete(cdb.db, id)
-				}
-			}
-			cdb.Unlock()
-		}
-	}()
-}
-
-// GetExpiry returns time for how long CAPTCHA will last.
-func (cdb *InMemoryCaptchaDB) GetExpiry() time.Duration {
-	return cdb.expireIn
-}
-
-// Image returns image for a CAPTCHA.
-func (cdb *InMemoryCaptchaDB) Image(id ID, style string) (*image.Image, error) {
-	cdb.Lock()
-	defer cdb.Unlock()
-	if c, ok := cdb.db[id]; ok {
-		return c.Image(style), nil
-	}
-	return nil, errorNotFound
-}
-
-// Solve compares given answer with a stored one and if failed
-// deletes a CAPTCHA from database.
-func (cdb *InMemoryCaptchaDB) Solve(id ID, answer Answer) (bool, error) {
-	cdb.Lock()
-	defer cdb.Unlock()
-	if c, ok := cdb.db[id]; ok {
-		ok = c.Solve(answer)
-		if !ok {
-			delete(cdb.db, id)
-		}
-		return ok, nil
-	}
-	return false, errorNotFound
-}
-
-// IsSolved checks if CAPTCHA was solved and removes it
-// from a database.
-func (cdb *InMemoryCaptchaDB) IsSolved(id ID) (bool, error) {
-	cdb.Lock()
-	defer cdb.Unlock()
-	if c, ok := cdb.db[id]; ok {
-		delete(cdb.db, id)
-		return c.IsSolved(), nil
-	}
-	return false, errorNotFound
-}
-
-// Remove a CAPTCHA from a database.
-func (cdb *InMemoryCaptchaDB) Remove(id ID) error {
-	cdb.Lock()
-	defer cdb.Unlock()
-	if _, ok := cdb.db[id]; ok {
-		delete(cdb.db, id)
-		return nil
-	}
-	return errorNotFound
-}

pkg/server/http.go

@@ -1,76 +0,0 @@
-package server
-
-import (
-	"context"
-	"log"
-	"net"
-	"net/http"
-	"os"
-	"time"
-
-	"github.com/julienschmidt/httprouter"
-)
-
-type HttpServer struct {
-	server *http.Server
-	router *httprouter.Router
-}
-
-func NewHttpServer() *HttpServer {
-	r := httprouter.New()
-	return &HttpServer{
-		server: &http.Server{
-			ReadTimeout:  3 * time.Second,
-			WriteTimeout: 3 * time.Second,
-			Handler:      r,
-		},
-		router: r,
-	}
-}
-
-func (s *HttpServer) GET(path string, handler http.HandlerFunc) {
-	s.router.Handler(http.MethodGet, path, handler)
-}
-
-func (s *HttpServer) POST(path string, handler http.HandlerFunc) {
-	s.router.Handler(http.MethodPost, path, handler)
-}
-
-func (s *HttpServer) SetNotFoundHandler(handler http.HandlerFunc) {
-	s.router.NotFound = handler
-}
-
-// GetURLParam wrapper around underlying router for getting URL parameters.
-func GetURLParam(r *http.Request, param string) string {
-	return httprouter.ParamsFromContext(r.Context()).ByName(param)
-}
-
-func (s *HttpServer) Start(network, address string) error {
-	listener, err := net.Listen(network, address)
-	if err != nil {
-		return err
-	}
-
-	if listener.Addr().Network() == "unix" {
-		os.Chmod(address, 0777)
-	}
-
-	go func() {
-		if err = s.server.Serve(listener); err != nil && err != http.ErrServerClosed {
-			log.Fatalln(err)
-		}
-	}()
-
-	return nil
-}
-
-func (s *HttpServer) Stop() error {
-	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-	defer cancel()
-
-	if err := s.server.Shutdown(ctx); err != nil {
-		return err
-	}
-
-	return nil
-}