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98 lines
2.4 KiB
98 lines
2.4 KiB
package terse
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import (
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"bufio"
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"fmt"
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"log"
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"net/http"
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"net/url"
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"strings"
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"github.com/golang/groupcache/lru"
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)
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type Handler struct {
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cache *lru.Cache
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serverURL *url.URL
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}
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func (handler *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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switch r.Method {
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case "GET":
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handler.HandleGet(w, r)
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case "POST":
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handler.HandlePost(w, r)
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default:
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log.Printf("%s 405", r.Method)
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http.Error(w, fmt.Sprintf("Method \"%s\" Not Allowed", r.Method), http.StatusMethodNotAllowed)
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}
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}
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func (handler *Handler) HandleGet(w http.ResponseWriter, r *http.Request) {
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url := strings.Trim(r.URL.Path, "/")
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// If they gave us something like `/<shortcode>/<who knows>`
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// then jst grab the first part
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code := strings.SplitN(url, "/", 2)[0]
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value, ok := handler.cache.Get(code)
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// If the url exists in the cache and is a string, redirect to it
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if ok {
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log.Printf("GET \"%s\" 301 \"%s\"", code, value.(string))
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http.Redirect(w, r, value.(string), http.StatusMovedPermanently)
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return
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}
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log.Printf("GET \"%s\" 404", code)
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http.NotFound(w, r)
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}
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func (handler *Handler) HandlePost(w http.ResponseWriter, r *http.Request) {
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// Parse url from body
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reader := bufio.NewScanner(r.Body)
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reader.Scan()
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rawurl := reader.Text()
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// Ensure url given is a real url
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cleanUrl, err := CleanURL(rawurl)
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if err != nil {
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log.Printf("POST \"%s\" 400", rawurl)
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http.Error(w, fmt.Sprintf("Invalid url \"%s\"", rawurl), http.StatusBadRequest)
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return
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}
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// Generate short code and store in cache
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code := GetShortCode([]byte(cleanUrl))
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// If the short code exists, and the urls are different, complain about the conflict
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value, ok := handler.cache.Get(code)
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if ok {
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if value.(string) != cleanUrl {
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log.Printf("POST \"%s\" 409", rawurl)
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msg := fmt.Sprintf("Short code conflict \"%s\" already registered as \"%s\"", code, value.(string))
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http.Error(w, msg, http.StatusConflict)
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return
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}
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} else {
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handler.cache.Add(code, cleanUrl)
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}
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// Generate response url
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codeUrl := handler.serverURL
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codeUrl.Path = "/" + code
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log.Printf("POST \"%s\" 201 created \"%s\"", rawurl, code)
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w.WriteHeader(http.StatusCreated)
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fmt.Fprintf(w, codeUrl.String())
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}
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func NewServer(bind string, maxEntries int, serverURL string) (*http.Server, error) {
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parsedURL, err := url.ParseRequestURI(serverURL)
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if err != nil {
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return nil, err
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}
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return &http.Server{
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Addr: bind,
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Handler: &Handler{
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cache: lru.New(maxEntries),
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serverURL: parsedURL,
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},
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}, nil
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}
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