web/web.go

package main

import (
    "fmt"
    "log"
    "net/http"
)

const (
    // Address server listening address
    Address = ":1312"

    // UploadRoute key uploading path
    UploadRoute = "/upload"

    // RetrievalRoute
    RetrievalRoute = "/retrieve"
)

// Pair private key and computer id
type Pair struct {
    Id  string
    Key string
}

// Keys stored in memory
var Keys = []Pair{}

func main() {
    http.HandleFunc(UploadRoute, handleUpload)
    http.HandleFunc(RetrievalRoute, handleRetrieve)

    fmt.Println("Listening on", Address)
    log.Fatal(http.ListenAndServe(Address, nil))
}

func reject(w http.ResponseWriter, r *http.Request, reason string) {
    fmt.Println("Rejecting ", r.RemoteAddr+":", reason)
    w.WriteHeader(http.StatusNotFound)
    fmt.Fprint(w, http.StatusText(http.StatusNotFound))
}

func handleUpload(w http.ResponseWriter, r *http.Request) {
    id := r.PostFormValue("i")
    key := r.PostFormValue("k")

    if r.Method != "POST" {
        reject(w, r, "HTTP method is not POST, got "+r.Method)
        return
    }

    if id == "" {
        reject(w, r, "id parameter i not set or empty")
        return
    }

    if key == "" {
        reject(w, r, "key parameter k is not set or empty")
    }

    for _, pair := range Keys {
        if pair.Id == id {
            reject(w, r, "key already exists")
            return
        }
    }

    pair := Pair{Id: id, Key: key}
    Keys = append(Keys, pair)
}

func handleRetrieve(w http.ResponseWriter, r *http.Request) {
    id := r.PostFormValue("i")

    if r.Method != "POST" {
        reject(w, r, "HTTP method is not POST, got "+r.Method)
        return
    }

    if id == "" {
        reject(w, r, "id parameter i is not set")
        return
    }

    for _, pair := range Keys {
        if pair.Id == id {
            fmt.Fprint(w, pair.Key)
            return
        }
    }

    reject(w, r, "no key found for id "+id)
}