chore: use shortie as a internal package
This commit is contained in:
307
internal/shortie/shortie.go
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307
internal/shortie/shortie.go
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@ -0,0 +1,307 @@
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package shortie
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import (
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"encoding/json"
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"fmt"
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"html/template"
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"io/ioutil"
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"log"
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"math/rand"
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"net/http"
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"net/url"
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"regexp"
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"strings"
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"time"
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"github.com/asaskevich/govalidator"
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"github.com/patrickmn/go-cache"
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"github.com/valyala/fasthttp"
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)
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type body struct {
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FullHeader bool
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IsGhost bool
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HasForm bool
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IsLink bool
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H1 string
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H3 string
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Line1 string
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Line2 string
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}
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const (
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letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" // Base strings for randStringBytesMaskImprSrc
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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var (
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// Src tiny entropy Pool
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Src = rand.NewSource(time.Now().UnixNano())
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// Pool KV memory DB
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Pool *cache.Cache
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// URLSize is the default size of the shortened URL
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URLSize int = 10
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// Port is the listening port address
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Port int = 8080
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// Exp is the expiration time of the shortened URL
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Exp time.Duration = 240 * time.Hour
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// Cleanup is the clean up time interval
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Cleanup time.Duration = 1 * time.Hour
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// Proto is the shortened URL protocol
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Proto string = "https"
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// Domain is the shortened URL domain
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Domain string = "localhost"
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// Path is the shortened URL prefix path
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Path string = ""
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// DumpFile is the file to dump URL data
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DumpFile string = "urls.json"
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)
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// get executes the GET command
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func get(key string) (string, bool) {
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value, status := Pool.Get(key)
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if !status {
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return "", status
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}
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return value.(string), status
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}
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// set executes the redis SET command
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func set(key, suffix string) {
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Pool.Set(suffix, key, 0)
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}
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// randStringBytesMaskImprSrc Generate random string of n size
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func randStringBytesMaskImprSrc(n int) string {
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b := make([]byte, n)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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for i, cache, remain := n-1, Src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = Src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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b[i] = letterBytes[idx]
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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return string(b)
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}
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// redirect receives a key searches the kv database for it and if
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// found returns the value, or a error if not found
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func redirect(k string) (string, error) {
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rgx, _ := regexp.Compile("[a-zA-Z0-9]+")
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key := rgx.FindString(k)
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key, status := get(key)
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if !status {
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return "", fmt.Errorf("Not Found")
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}
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u, _ := url.Parse(key)
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if u.Scheme == "" {
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u.Scheme = "https"
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}
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return u.String(), nil
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}
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// shortener receive a url, validates the url, generate a random suffix string
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// of urlSize size, checks if the suffix string is ensure on the kv database
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// and then writes the kv pair (suffix, url) to the database, returning the suffix
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func shortener(u []byte, s int) (string, error) {
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var su string
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us := string(u)
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if !govalidator.IsURL(string(us)) {
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return su, fmt.Errorf("Bad Request")
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}
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pu, _ := url.Parse(us)
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for {
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su = randStringBytesMaskImprSrc(s)
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_, status := get(su)
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if !status {
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break
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}
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}
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set(pu.String(), su)
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return su, nil
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}
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// dumpDbToFile dumps the kv pairs from the in memory database to file
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func dumpDbTOFile() (int, error) {
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i := Pool.Items()
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dumpObj, _ := json.Marshal(i)
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return len(i), ioutil.WriteFile(DumpFile, dumpObj, 0644)
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}
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// loadFromFile loads kv pairs from the dumpFile json to the in memory database
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func loadFromFile() (int, error) {
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dumpObj := make(map[string]cache.Item)
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jsonFile, err := ioutil.ReadFile(DumpFile)
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if err != nil {
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return 0, err
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}
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err = json.Unmarshal([]byte(jsonFile), &dumpObj)
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if err != nil {
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return 0, err
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}
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Pool = cache.NewFrom(Exp, Cleanup, dumpObj)
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return len(dumpObj), err
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}
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// itemsFromPost loads kv pairs from a json POST to the in memory database
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func loadFromJSON(j []byte) (int, error) {
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dumpObj := make(map[string]cache.Item)
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err := json.Unmarshal(j, &dumpObj)
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if err != nil {
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return 0, err
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}
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Pool = cache.NewFrom(Exp, Cleanup, dumpObj)
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return len(dumpObj), nil
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}
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func internalError(msg string, err error) body {
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log.Println(err)
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return body{
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FullHeader: true,
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IsGhost: true,
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HasForm: true,
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H1: "500",
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H3: msg,
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Line1: "Boo, the ghost is broken :(",
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Line2: "His last words where: " + err.Error(),
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}
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}
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// IndexHandler return a fasthttp.RequestHandler function that genetares the index page
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func IndexHandler(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, body{
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HasForm: true,
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Line1: "Welcome to Short, the simple URL shortener,",
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Line2: "Type an URL below to shorten it",
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})
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}
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}
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// Short return a fasthttp.RequestHandler function that genetares the shortener page
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func Short(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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suf, err := shortener(ctx.FormValue("url"), URLSize)
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if err != nil {
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ctx.SetStatusCode(fasthttp.StatusBadRequest)
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t.Execute(ctx, body{
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FullHeader: true,
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IsGhost: true,
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HasForm: true,
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H1: "400",
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H3: err.Error(),
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Line1: "Boo, looks like this ghost stole this page!",
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Line2: "But you can type an URL below to shorten it",
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})
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return
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}
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ru, _ := url.Parse(fmt.Sprintf("%s://%s:%v/%s%s", Proto, Domain, Port, Path, suf))
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t.Execute(ctx, body{
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IsLink: true,
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Line1: ru.String(),
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})
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}
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}
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// Redir return a fasthttp.RequestHandler function that genetares the shortener redirect page
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func Redir(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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key := ctx.UserValue("key")
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if Path != "" {
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key = strings.Replace(key.(string), Path, "", 1)
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}
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u, err := redirect(key.(string))
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if err != nil {
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ctx.SetStatusCode(fasthttp.StatusNotFound)
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t.Execute(ctx, body{
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FullHeader: true,
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IsGhost: true,
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HasForm: true,
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H1: "404",
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H3: err.Error(),
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Line1: "Boo, looks like this ghost stole this page!",
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Line2: "But you can type an URL below to shorten it",
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})
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return
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}
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ctx.Redirect(u, fasthttp.StatusFound)
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}
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}
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// ToFile return a fasthttp.RequestHandler function that dumps the contents of the
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// KV db to the DumpFile file
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func ToFile(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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i, err := dumpDbTOFile()
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if err != nil {
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ctx.SetStatusCode(http.StatusInternalServerError)
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, internalError("Failed to dump kv DB to file", err))
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return
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}
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, body{Line1: fmt.Sprintf("Exported %v items to %v", i, DumpFile)})
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}
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}
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// FromFile return a fasthttp.RequestHandler function that loads the content of the DumpFile into the
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// KV db
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func FromFile(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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i, err := loadFromFile()
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if err != nil {
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ctx.SetStatusCode(http.StatusInternalServerError)
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, internalError("Error loading DB from file", err))
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return
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}
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, body{Line1: fmt.Sprintf("Imported %v items to the DB", i)})
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}
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}
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// Dump return a fasthttp.RequestHandler function that dumps the contents of the
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// KV db to the ctx handler
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func Dump(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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dumpObj, err := json.Marshal(Pool.Items())
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if err != nil {
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ctx.SetStatusCode(http.StatusInternalServerError)
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, internalError("Unable to dump key value db: ", err))
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return
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}
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fmt.Fprintf(ctx, "%s", dumpObj)
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}
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}
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// FromPost return a fasthttp.RequestHandler function that loads the content of the JSON POST into the
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// KV db
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func FromPost(t *template.Template) func(ctx *fasthttp.RequestCtx) {
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return func(ctx *fasthttp.RequestCtx) {
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i, err := loadFromJSON(ctx.PostBody())
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if err != nil {
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ctx.SetStatusCode(http.StatusInternalServerError)
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, internalError("Error loading DB", err))
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return
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}
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ctx.Response.Header.SetCanonical([]byte("Content-Type"), []byte("text/html"))
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t.Execute(ctx, body{Line1: fmt.Sprintf("Imported %v items to the DB", i)})
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}
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}
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