Add http proxy mode (ozkatz#6)

README.md

@@ -41,6 +41,12 @@ Downloading and extracting a specific object from within a zip file:
 cz cat s3://example-bucket/path/to/archive.zip images/cat.png > cat.png
 ```
 
+HTTP proxy mode (see below):
+
+```shell
+cz http s3://example-bucket/path
+```
+
 Mounting (See below):
 
 ```shell
@@ -102,6 +108,17 @@ Reading a file from the remote zip involves another HTTP range request: once we
 
 Because zip files store each file (whether compressed or not) independently, this is enough to uncompress and write the file to `stdout`.
 
+#### ⚠️ Experimental: `cz http`
+
+CloudZip can run in proxy mode, allowing you to read archived files directly HTTP client (usually a browser). 
+
+```shell
+cz http s3://example-bucket/path
+```
+
+This will open an HTTP server on a random port (use `--listen` to bind to another address). The server will map the requested path relative to the supplied S3 url argument. A single query argument `filename` should be supplied, referencing the file within the zip file. E.g. `GET /a/b/c.zip?filename=foobar.png` will serve `foobar.png` from within the `s3://example-bucket/path/a/b/c.zip` archive.
+
+
 #### ⚠️ Experimental: `cz mount`
 
 Instead of listing and downloading individual files from the remote zip, you can now mount it to a local directory.

cmd/common.go

@@ -35,7 +35,7 @@ func die(fstring string, args ...interface{}) {
 func setupLogging() {
 	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
 		AddSource: true,
-		Level:     slog.LevelError,
+		Level:     slog.LevelWarn,
 	})))
 	if os.Getenv("CLOUDZIP_LOGGING") == "DEBUG" {
 		slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{

cmd/http.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net"
+	"net/http"
+	"strings"
+
+	"github.com/ozkatz/cloudzip/pkg/remote"
+	"github.com/ozkatz/cloudzip/pkg/zipfile"
+	"github.com/spf13/cobra"
+)
+
+var httpCmd = &cobra.Command{
+	Use:     "http",
+	Short:   "Run HTTP proxy server mode",
+	Example: "http s3://example-bucket/path",
+	Args:    cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		remotePath := strings.TrimSuffix(args[0], "/")
+		bindAddress, err := cmd.Flags().GetString("listen")
+		if err != nil {
+			die("Could not parse command flag listen: %v\n", err)
+		}
+
+		http.HandleFunc("/",
+			func(w http.ResponseWriter, r *http.Request) {
+				internalPath := r.URL.Query().Get("filename")
+				slog.Debug("HTTP Handler", "objectPath", r.URL.Path, "internalPath", internalPath)
+				obj, err := remote.Object(remotePath + r.URL.Path)
+				if err != nil {
+					slog.Warn("could not open zip file", "error", err)
+					w.WriteHeader(http.StatusInternalServerError)
+					return
+				}
+				zip := zipfile.NewCentralDirectoryParser(zipfile.NewStorageAdapter(r.Context(), obj))
+				reader, err := zip.Read(internalPath)
+				if errors.Is(err, remote.ErrDoesNotExist) || errors.Is(err, zipfile.ErrFileNotFound) {
+					w.WriteHeader(http.StatusNotFound)
+					return
+				} else if err != nil {
+					w.WriteHeader(http.StatusBadGateway)
+					slog.Warn("Error reading zip file from upstream", "error", err)
+					return
+				}
+				io.Copy(w, reader)
+			})
+
+		listener, err := net.Listen("tcp", bindAddress)
+		if err != nil {
+			die("Failed to bind port: %v\n", err)
+		}
+		fmt.Printf("HTTP server listening on %s\n", listener.Addr().String())
+		err = http.Serve(listener, nil)
+		if err != nil {
+			slog.Error("Error running HTTP server", "error", err)
+		}
+	},
+}
+
+func init() {
+	httpCmd.Flags().StringP("listen", "l", "127.0.0.1:0", "address to listen on")
+	rootCmd.AddCommand(httpCmd)
+}

pkg/remote/s3.go

@@ -54,7 +54,8 @@ func s3IsNotFoundErr(err error) bool {
 		return false
 	}
 	var nf *types.NotFound
-	return errors.As(err, &nf)
+	var nosuchkey *types.NoSuchKey
+	return errors.As(err, &nf) || errors.As(err, &nosuchkey)
 }
 
 func s3parseUri(uri string) (*s3ParsedUri, error) {