Go 语言做的几个验证码
1、http://www.oschina.net/code/snippet_173630_12006 ：
效果：
源代码：
2、https://github.com/dchest/captcha
它比较强大，可以生成图片的验证码或者音频验证码。
[mw_shl_code=erlang,true]package main import ( "image" "image/color" "image/png" "io" "net/http" "math/rand" crand "crypto/rand" "time" "fmt" "strconv" ) const ( stdWidth = 100 stdHeight = 40 maxSkew = 2 ) const ( fontWidth = 5 fontHeight = 8 blackChar = 1 ) var font = [][]byte{ { // 0 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, }, { // 1 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, }, { // 2 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, }, { // 3 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, }, { // 4 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, }, { // 5 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, }, { // 6 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, }, { // 7 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, }, { // 8 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, }, { // 9 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, }, } type Image struct { *image.NRGBA color *color.NRGBA width int //a digit width height int //a digit height dotsize int } func init(){ rand.Seed(int64(time.Second)) } func NewImage(digits []byte, width, height int) *Image { img := new(Image) r := image.Rect(img.width, img.height, stdWidth, stdHeight) img.NRGBA = image.NewNRGBA(r) img.color = &color.NRGBA{ uint8(rand.Intn(129)), uint8(rand.Intn(129)), uint8(rand.Intn(129)), 0xFF, } // Draw background (10 random circles of random brightness) img.calculateSizes(width, height, len(digits)) img.fillWithCircles(10, img.dotsize) maxx := width - (img.width+img.dotsize)*len(digits) - img.dotsize maxy := height - img.height - img.dotsize*2 x := rnd(img.dotsize*2, maxx) y := rnd(img.dotsize*2, maxy) // Draw digits. for _, n := range digits { img.drawDigit(font[n], x, y) x += img.width + img.dotsize } // Draw strike-through line. img.strikeThrough() return img } func (img *Image) WriteTo(w io.Writer) (int64, error) { return 0, png.Encode(w, img) } func (img *Image) calculateSizes(width, height, ncount int) { // Goal: fit all digits inside the image. var border int if width > height { border = height / 5 } else { border = width / 5 } // Convert everything to floats for calculations. w := float64(width - border*2) //268 h := float64(height - border*2) //48 // fw takes into account 1-dot spacing between digits. fw := float64(fontWidth) + 1 //6 fh := float64(fontHeight) //8 nc := float64(ncount) //7 // Calculate the width of a single digit taking into account only the // width of the image. nw := w / nc //38 // Calculate the height of a digit from this width. nh := nw * fh / fw //51 // Digit too high? if nh > h { // Fit digits based on height. nh = h //nh = 44 nw = fw / fh * nh } // Calculate dot size. img.dotsize = int(nh / fh) // Save everything, making the actual width smaller by 1 dot to account // for spacing between digits. img.width = int(nw) img.height = int(nh) - img.dotsize } func (img *Image) fillWithCircles(n, maxradius int) { color := img.color maxx := img.Bounds().Max.X maxy := img.Bounds().Max.Y for i := 0; i < n; i++ { setRandomBrightness(color, 255) r := rnd(1, maxradius) img.drawCircle(color, rnd(r, maxx-r), rnd(r, maxy-r), r) } } func (img *Image) drawHorizLine(color color.Color, fromX, toX, y int) { for x := fromX; x <= toX; x++ { img.Set(x, y, color) } } func (img *Image) drawCircle(color color.Color, x, y, radius int) { f := 1 - radius dfx := 1 dfy := -2 * radius xx := 0 yy := radius img.Set(x, y+radius, color) img.Set(x, y-radius, color) img.drawHorizLine(color, x-radius, x+radius, y) for xx < yy { if f >= 0 { yy-- dfy += 2 f += dfy } xx++ dfx += 2 f += dfx img.drawHorizLine(color, x-xx, x+xx, y+yy) img.drawHorizLine(color, x-xx, x+xx, y-yy) img.drawHorizLine(color, x-yy, x+yy, y+xx) img.drawHorizLine(color, x-yy, x+yy, y-xx) } } func (img *Image) strikeThrough() { r := 0 maxx := img.Bounds().Max.X maxy := img.Bounds().Max.Y y := rnd(maxy/3, maxy-maxy/3) for x := 0; x < maxx; x += r { r = rnd(1, img.dotsize/3) y += rnd(-img.dotsize/2, img.dotsize/2) if y <= 0 || y >= maxy { y = rnd(maxy/3, maxy-maxy/3) } img.drawCircle(img.color, x, y, r) } } func (img *Image) drawDigit(digit []byte, x, y int) { skf := rand.Float64() * float64(rnd(-maxSkew, maxSkew)) xs := float64(x) minr := img.dotsize / 2 // minumum radius maxr := img.dotsize/2 + img.dotsize/4 // maximum radius y += rnd(-minr, minr) for yy := 0; yy < fontHeight; yy++ { for xx := 0; xx < fontWidth; xx++ { if digit[yy*fontWidth+xx] != blackChar { continue } // Introduce random variations. or := rnd(minr, maxr) ox := x + (xx * img.dotsize) + rnd(0, or/2) oy := y + (yy * img.dotsize) + rnd(0, or/2) img.drawCircle(img.color, ox, oy, or) } xs += skf x = int(xs) } } func setRandomBrightness(c *color.NRGBA, max uint8) { minc := min3(c.R, c.G, c.B) maxc := max3(c.R, c.G, c.B) if maxc > max { return } n := rand.Intn(int(max-maxc)) - int(minc) c.R = uint8(int(c.R) + n) c.G = uint8(int(c.G) + n) c.B = uint8(int(c.B) + n) } func min3(x, y, z uint8) (o uint8) { o = x if y < o { o = y } if z < o { o = z } return } func max3(x, y, z uint8) (o uint8) { o = x if y > o { o = y } if z > o { o = z } return } // rnd returns a random number in range [from, to]. func rnd(from, to int) int { //println(to+1-from) return rand.Intn(to+1-from) + from } const ( // Standard length of uniuri string to achive ~95 bits of entropy. StdLen = 16 // Length of uniurl string to achive ~119 bits of entropy, closest // to what can be losslessly converted to UUIDv4 (122 bits). UUIDLen = 20 ) // Standard characters allowed in uniuri string. var StdChars = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") // New returns a new random string of the standard length, consisting of // standard characters. func New() string { return NewLenChars(StdLen, StdChars) } // NewLen returns a new random string of the provided length, consisting of // standard characters. func NewLen(length int) string { return NewLenChars(length, StdChars) } // NewLenChars returns a new random string of the provided length, consisting // of the provided byte slice of allowed characters (maximum 256). func NewLenChars(length int, chars []byte) string { b := make([]byte, length) r := make([]byte, length+(length/4)) // storage for random bytes. clen := byte(len(chars)) maxrb := byte(256 - (256 % len(chars))) i := 0 for { if _, err := io.ReadFull(crand.Reader, r); err != nil { panic("error reading from random source: " + err.Error()) } for _, c := range r { if c >= maxrb { // Skip this number to avoid modulo bias. continue } b = chars[c%clen] i++ if i == length { return string(b) } } } panic("unreachable") } func pic(w http.ResponseWriter, req *http.Request) { d := make([]byte, 4) s := NewLen(4) ss := "" d = []byte(s) for v := range d { d[v] %= 10 ss += strconv.FormatInt(int64(d[v]), 32) } w.Header().Set("Content-Type", "image/png") NewImage(d, 100, 40).WriteTo(w) fmt.Println(ss) } func index(w http.ResponseWriter, req *http.Request) { str := "<meta charset=\"utf-8\"><h3>golang 图片验证码例子</h3><img border=\"1\" src=\"/pic\" alt=\"图片验证码\" onclick=\"this.src='/pic'\" />" w.Header().Set("Content-Type", "text/html") w.Write([]byte(str)) } func main() { http.HandleFunc("/pic", pic) http.HandleFunc("/", index) s := &http.Server{ Addr: ":8080", ReadTimeout: 30*time.Second, WriteTimeout: 30*time.Second, MaxHeaderBytes: 1 << 20, } s.ListenAndServe() }[/mw_shl_code]
