From 264e40388269fa518c971fc3ab67389213df164c Mon Sep 17 00:00:00 2001
From: "Alexander \"Arav\" Andreev" <me@arav.top>
Date: Mon, 7 Feb 2022 04:49:21 +0400
Subject: [PATCH] Handlers.

---
 internal/handlers/handlers.go | 191 ++++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 internal/handlers/handlers.go

diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
new file mode 100644
index 0000000..bd6a7a4
--- /dev/null
+++ b/internal/handlers/handlers.go
@@ -0,0 +1,191 @@
+package handlers
+
+import (
+	"crypto/sha256"
+	"dwelling-upload/internal/configuration"
+	"dwelling-upload/pkg/server"
+	"dwelling-upload/pkg/utils"
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"html/template"
+	"io"
+	"io/fs"
+	"log"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"time"
+
+	"github.com/eknkc/amber"
+)
+
+var defaultAmberOptions = amber.Options{PrettyPrint: false, LineNumbers: false}
+
+var compiledTemplates map[string]*template.Template
+
+type IndexData struct {
+	MainSite         string
+	FileMaxSz        string
+	StorageCapacity  int64
+	StorageUsed      int64
+	StorageAvailable int64
+	StorageCapStr    string
+	StorageUsedStr   string
+	StorageAvailStr  string
+}
+
+type UploadedData struct {
+	MainSite     string
+	DownloadURL  string
+	KeepForHours int
+}
+
+type UploadHandlers struct {
+	conf *configuration.Configuration
+}
+
+func NewUploadHandlers(conf *configuration.Configuration) *UploadHandlers {
+	compiledTemplates = amber.MustCompileDir(conf.WebDir+"/templates",
+		amber.DefaultDirOptions, defaultAmberOptions)
+	return &UploadHandlers{
+		conf: conf}
+}
+
+func (h *UploadHandlers) Index(w http.ResponseWriter, r *http.Request) {
+	var storCapacity int64 = h.conf.Uploads.Limits.Storage << 20
+	var fMaxSize int64 = h.conf.Uploads.Limits.FileSize << 20
+	var storSize int64 = 0
+
+	filepath.Walk(h.conf.Uploads.Directory, func(_ string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		storSize += info.Size()
+
+		return nil
+	})
+
+	_, _, capStr := utils.ConvertFileSize(storCapacity)
+	_, _, usedStr := utils.ConvertFileSize(storSize)
+	_, _, availStr := utils.ConvertFileSize(storCapacity - storSize)
+	_, _, fMaxSzStr := utils.ConvertFileSize(fMaxSize)
+
+	if err := compiledTemplates["index"].Execute(w, &IndexData{
+		MainSite:         utils.MainSite(r.Host),
+		FileMaxSz:        fMaxSzStr,
+		StorageCapacity:  storCapacity,
+		StorageCapStr:    capStr,
+		StorageAvailable: storCapacity - storSize,
+		StorageAvailStr:  availStr,
+		StorageUsed:      storSize,
+		StorageUsedStr:   usedStr,
+	}); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		log.Fatalln("failed to execute Index template:", err)
+	}
+}
+
+func (h *UploadHandlers) Upload(w http.ResponseWriter, r *http.Request) {
+	var fMaxSizeBytes int64 = h.conf.Uploads.Limits.FileSize << 20
+
+	r.Body = http.MaxBytesReader(w, r.Body, fMaxSizeBytes)
+
+	if err := r.ParseMultipartForm(fMaxSizeBytes); err != nil {
+		log.Println("failed to parse form:", err)
+		http.Error(w, "request too big", http.StatusExpectationFailed)
+		return
+	}
+
+	f, fHandler, err := r.FormFile("file")
+	if err != nil {
+		log.Println("failed to open incoming file:", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	defer func() {
+		os.Remove(fHandler.Filename)
+		f.Close()
+	}()
+
+	s256 := sha256.New()
+	if _, err := io.Copy(s256, f); err != nil {
+		log.Println("failed to compute SHA-256 hash:", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	fSha256 := hex.EncodeToString(s256.Sum(nil))
+	s256.Write([]byte(h.conf.HashSalt))
+	fSaltedHash := base64.RawURLEncoding.EncodeToString(s256.Sum(nil))
+
+	f.Seek(0, io.SeekStart)
+
+	fPath := path.Join(h.conf.Uploads.Directory, fSaltedHash)
+
+	_, err = os.Stat(fPath)
+	if os.IsNotExist(err) {
+		fDst, err := os.Create(fPath)
+		if err != nil {
+			log.Println("failed to open file for writing", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		n, err := io.Copy(fDst, f)
+		if err != nil {
+			log.Println("failed to copy uploaded file to destination:", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		fmt.Println(n, err)
+		fDst.Sync()
+		fDst.Close()
+
+		log.Printf("| %s | %s | %s | SHA256 %s | %s | %d", r.RemoteAddr, utils.NetworkType(r.Host),
+			fHandler.Filename, fSha256, fSaltedHash, fHandler.Size)
+
+		w.WriteHeader(http.StatusCreated)
+	} else {
+		os.Chtimes(fPath, time.Now(), time.Now())
+	}
+
+	downloadURL := path.Join("/f", fSaltedHash, fHandler.Filename)
+
+	if err := compiledTemplates["uploaded"].Execute(w, &UploadedData{
+		MainSite:     utils.MainSite(r.Host),
+		DownloadURL:  downloadURL,
+		KeepForHours: h.conf.Uploads.Limits.KeepForHours,
+	}); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		log.Fatalln("failed to execute Index template:", err)
+	}
+}
+
+func (h *UploadHandlers) Download(w http.ResponseWriter, r *http.Request) {
+	saltedHash := server.GetURLParam(r, "hash")
+	name := server.GetURLParam(r, "name")
+
+	path := path.Join(h.conf.Uploads.Directory, saltedHash)
+
+	stat, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	w.Header().Add("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", name))
+	// w.Header().Add("Content-Type", "application/octet-stream")
+
+	fd, err := os.Open(path)
+	if err != nil {
+		log.Println("failed to open file to read:", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	defer fd.Close()
+
+	http.ServeContent(w, r, path, stat.ModTime(), fd)
+}