go-opds-pse/app/routes/routes.go

package routes

import (
	"archive/zip"
	"bytes"
	"encoding/xml"
	"fmt"
	"github.com/creasty/defaults"
	"github.com/gorilla/mux"
	"github.com/patrickmn/go-cache"
	"github.com/samber/lo"
	"github.com/urfave/cli/v2"
	"go-opds-pse/app/comicinfo"
	"go-opds-pse/app/opds"
	"go-opds-pse/app/utils"
	"golang.org/x/tools/blog/atom"
	"io"
	"io/fs"
	"net/http"
	"path/filepath"
	"slices"
	"sort"
	"strconv"
	"strings"
	"time"
)

var ctx *cli.Context
var c *cache.Cache

func Init(cctx *cli.Context, r *mux.Router, cc *cache.Cache) {
	ctx = cctx
	c = cc
	r.HandleFunc("/", Index).Methods("GET")
	r.HandleFunc("/stream/{manga:.*}/{page:[0-9]+}", Stream).Methods("GET")
}

func Index(w http.ResponseWriter, r *http.Request) {
	feed := opds.Feed{
		ID:      "feed",
		Title:   "go-opds-pse",
		Updated: atom.Time(time.Now()),
		Author: &opds.Author{
			Name: "go-opds-pse",
			URI:  "https://github.com/sclark-dev/go-opds-pse",
		},
		Link: []opds.Link{
			{
				Rel:  "start",
				Href: "/",
				Type: "application/atom+xml;profile=opds-catalog;kind=navigation",
			},
		},
	}

	feed.Entry = append(feed.Entry)

	err := filepath.WalkDir(ctx.String("manga"), func(path string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() || filepath.Ext(d.Name()) != ".cbz" {
			return err
		}

		hrefPath := strings.TrimPrefix(path, ctx.String("manga"))

		// Check if ComicInfo is cached
		var ComicInfo comicinfo.ComicInfo
		ci, found := c.Get(path)
		if found {
			ComicInfo = ci.(comicinfo.ComicInfo)
		} else {
			zf, err := zip.OpenReader(path)
			if err != nil {
				return nil
			}

			defer zf.Close()
			for i := range zf.File {
				if strings.ToLower(zf.File[i].Name) == "comicinfo.xml" {
					cif, err := zf.File[i].Open()
					if err != nil {
						return nil
					}

					cib, err := io.ReadAll(cif)
					if err != nil {
						return nil
					}

					err = cif.Close()
					if err != nil {
						return nil
					}

					err = xml.Unmarshal(cib, &ComicInfo)
					if err != nil {
						return nil
					}

					c.Set(path, ComicInfo, cache.NoExpiration)
				}
			}
		}

		entry := &opds.Entry{
			ID:    utils.FileBasename(d.Name()),
			Title: utils.FileBasename(d.Name()),
			Author: &opds.Author{
				Name: ComicInfo.Writer,
			},
			Summary:     &opds.Text{Body: ComicInfo.Summary},
			DcPublisher: ComicInfo.Publisher,
			Link: []opds.Link{
				{
					Rel:   "http://opds-spec.org/acquisition",
					Href:  "/manga" + hrefPath,
					Type:  "application/x-cbz",
					Title: utils.FileBasename(d.Name()),
				},
				{
					Rel:  "http://opds-spec.org/image",
					Href: "/stream" + hrefPath + "/0",
					Type: "image/png",
				},
				{
					Rel:  "http://opds-spec.org/image/thumbnail",
					Href: "/stream" + hrefPath + "/0",
					Type: "image/png",
				},
			},
		}

		if ComicInfo != (comicinfo.ComicInfo{}) {
			entry.Link = append(entry.Link, opds.Link{
				Rel:      "http://vaemendis.net/opds-pse/stream",
				Href:     "/stream" + hrefPath + "/{pageNumber}",
				Type:     "image/png",
				PseCount: uint(ComicInfo.PageCount),
			})
		}

		feed.Entry = append(feed.Entry, entry)

		return nil
	})

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = defaults.Set(&feed)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	data, err := xml.MarshalIndent(feed, "", "  ")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	http.ServeContent(w, r, "feed.xml", time.Now(), bytes.NewReader(data))
}

func Stream(w http.ResponseWriter, r *http.Request) {
	// Parse all variables
	vars := mux.Vars(r)
	path := ctx.String("manga") + "/" + vars["manga"]
	page, err := strconv.Atoi(vars["page"])
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Open zip file
	zf, err := zip.OpenReader(path)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	defer zf.Close()

	// Filter to just accepted image files
	pages := lo.Filter(zf.File, func(f *zip.File, i int) bool {
		if slices.Contains([]string{".png", ".jpg", ".webp"}, filepath.Ext(f.Name)) {
			return true
		}
		return false
	})

	// Check if page number exists
	if page > len(pages)-1 {
		http.Error(w, fmt.Sprintf("page %d out of range", page), http.StatusBadRequest)
		return
	}

	// Sort pages lexically
	sort.Slice(pages, func(i, j int) bool {
		return pages[i].Name < pages[j].Name
	})

	// Open page for reading
	imf, err := pages[page].Open()
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	defer imf.Close()

	// Read all data from page
	imageBytes, err := io.ReadAll(imf)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Serve page data
	http.ServeContent(w, r, pages[page].Name, time.Now(), bytes.NewReader(imageBytes))
}