grasp: spread stuff into multiple files.

khatru/grasp/read.go

@@ -0,0 +1,117 @@
+package grasp
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+
+	"fiatjaf.com/nostr"
+)
+
+func (gs *GraspServer) handleGitUploadPack(
+	w http.ResponseWriter,
+	r *http.Request,
+	pubkey nostr.PubKey,
+	repoName string,
+) {
+	repoPath := filepath.Join(gs.RepositoryDir, repoName)
+
+	// for upload-pack (pull), check if repository exists
+	if !gs.repoExists(pubkey, repoName) {
+		w.Header().Set("content-type", "text/plain; charset=UTF-8")
+		w.WriteHeader(404)
+		fmt.Fprintf(w, "repository announcement event not found during upload-pack\n")
+		return
+	}
+
+	if gs.OnRead != nil {
+		reject, msg := gs.OnRead(r.Context(), pubkey, repoName)
+		if reject {
+			w.Header().Set("content-type", "text/plain; charset=UTF-8")
+			w.WriteHeader(403)
+			fmt.Fprintf(w, "%s\n", msg)
+			return
+		}
+	}
+
+	const expectedContentType = "application/x-git-upload-pack-request"
+	contentType := r.Header.Get("Content-Type")
+	if contentType != expectedContentType {
+		w.Header().Set("content-type", "text/plain; charset=UTF-8")
+		w.WriteHeader(415)
+		fmt.Fprintf(w, "expected Content-Type: '%s', but received '%s'\n", expectedContentType, contentType)
+		return
+	}
+
+	var bodyReader io.ReadCloser = r.Body
+	if r.Header.Get("Content-Encoding") == "gzip" {
+		gzipReader, err := gzip.NewReader(r.Body)
+		if err != nil {
+			w.Header().Set("content-type", "text/plain; charset=UTF-8")
+			w.WriteHeader(500)
+			fmt.Fprintf(w, "failed to create gzip reader, handler: UploadPack, error: %v\n", err)
+			return
+		}
+		defer gzipReader.Close()
+		bodyReader = gzipReader
+	}
+
+	w.Header().Set("Content-Type", "application/x-git-upload-pack-result")
+	w.Header().Set("Connection", "Keep-Alive")
+	w.Header().Set("Cache-Control", "no-cache, max-age=0, must-revalidate")
+	w.WriteHeader(200)
+
+	if err := gs.runUploadPack(w, r, repoPath, bodyReader); err != nil {
+		w.Header().Set("content-type", "text/plain; charset=UTF-8")
+		w.WriteHeader(403)
+		fmt.Fprintf(w, "failed to execute git-upload-pack, handler: UploadPack, error: %v\n", err)
+		return
+	}
+}
+
+// runUploadPack executes git-upload-pack for pull operations
+func (gs *GraspServer) runUploadPack(w http.ResponseWriter, r *http.Request, repoPath string, bodyReader io.ReadCloser) error {
+	cmd := exec.Command("git", "upload-pack", "--stateless-rpc", ".")
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Dir = repoPath
+	cmd.Env = append(os.Environ(), fmt.Sprintf("GIT_PROTOCOL=%s", r.Header.Get("Git-Protocol")))
+
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+
+	stdoutPipe, err := cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("failed to create stdout pipe: %w", err)
+	}
+
+	stdinPipe, err := cmd.StdinPipe()
+	if err != nil {
+		return fmt.Errorf("failed to create stdin pipe: %w", err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("failed to start git-upload-pack: %w", err)
+	}
+
+	// copy input to stdin
+	go func() {
+		defer stdinPipe.Close()
+		io.Copy(stdinPipe, bodyReader)
+	}()
+
+	// copy output to response
+	io.Copy(gs.newWriteFlusher(w), stdoutPipe)
+	stdoutPipe.Close()
+
+	if err := cmd.Wait(); err != nil {
+		return fmt.Errorf("git-upload-pack failed: %w, stderr: %s", err, stderr.String())
+	}
+
+	return nil
+}