feat: add coder_workspace_ls MCP tool (coder#19652)

Author: code-asher

agent/ls.go

@@ -11,23 +11,39 @@ import (
 	"strings"
 
 	"github.com/shirou/gopsutil/v4/disk"
+	"github.com/spf13/afero"
 	"golang.org/x/xerrors"
 
 	"github.com/coder/coder/v2/coderd/httpapi"
 	"github.com/coder/coder/v2/codersdk"
+	"github.com/coder/coder/v2/codersdk/workspacesdk"
 )
 
 var WindowsDriveRegex = regexp.MustCompile(`^[a-zA-Z]:\\$`)
 
-func (*agent) HandleLS(rw http.ResponseWriter, r *http.Request) {
+func (a *agent) HandleLS(rw http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 
-	var query LSRequest
-	if !httpapi.Read(ctx, rw, r, &query) {
+	// An absolute path may be optionally provided, otherwise a path split into an
+	// array must be provided in the body (which can be relative).
+	query := r.URL.Query()
+	parser := httpapi.NewQueryParamParser()
+	path := parser.String(query, "", "path")
+	parser.ErrorExcessParams(query)
+	if len(parser.Errors) > 0 {
+		httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
+			Message:     "Query parameters have invalid values.",
+			Validations: parser.Errors,
+		})
 		return
 	}
 
-	resp, err := listFiles(query)
+	var req workspacesdk.LSRequest
+	if !httpapi.Read(ctx, rw, r, &req) {
+		return
+	}
+
+	resp, err := listFiles(a.filesystem, path, req)
 	if err != nil {
 		status := http.StatusInternalServerError
 		switch {
@@ -46,66 +62,74 @@ func (*agent) HandleLS(rw http.ResponseWriter, r *http.Request) {
 	httpapi.Write(ctx, rw, http.StatusOK, resp)
 }
 
-func listFiles(query LSRequest) (LSResponse, error) {
-	var fullPath []string
-	switch query.Relativity {
-	case LSRelativityHome:
-		home, err := os.UserHomeDir()
-		if err != nil {
-			return LSResponse{}, xerrors.Errorf("failed to get user home directory: %w", err)
+func listFiles(fs afero.Fs, path string, query workspacesdk.LSRequest) (workspacesdk.LSResponse, error) {
+	absolutePathString := path
+	if absolutePathString != "" {
+		if !filepath.IsAbs(path) {
+			return workspacesdk.LSResponse{}, xerrors.Errorf("path must be absolute: %q", path)
 		}
-		fullPath = []string{home}
-	case LSRelativityRoot:
-		if runtime.GOOS == "windows" {
-			if len(query.Path) == 0 {
-				return listDrives()
+	} else {
+		var fullPath []string
+		switch query.Relativity {
+		case workspacesdk.LSRelativityHome:
+			home, err := os.UserHomeDir()
+			if err != nil {
+				return workspacesdk.LSResponse{}, xerrors.Errorf("failed to get user home directory: %w", err)
 			}
-			if !WindowsDriveRegex.MatchString(query.Path[0]) {
-				return LSResponse{}, xerrors.Errorf("invalid drive letter %q", query.Path[0])
+			fullPath = []string{home}
+		case workspacesdk.LSRelativityRoot:
+			if runtime.GOOS == "windows" {
+				if len(query.Path) == 0 {
+					return listDrives()
+				}
+				if !WindowsDriveRegex.MatchString(query.Path[0]) {
+					return workspacesdk.LSResponse{}, xerrors.Errorf("invalid drive letter %q", query.Path[0])
+				}
+			} else {
+				fullPath = []string{"/"}
 			}
-		} else {
-			fullPath = []string{"/"}
+		default:
+			return workspacesdk.LSResponse{}, xerrors.Errorf("unsupported relativity type %q", query.Relativity)
 		}
-	default:
-		return LSResponse{}, xerrors.Errorf("unsupported relativity type %q", query.Relativity)
-	}
 
-	fullPath = append(fullPath, query.Path...)
-	fullPathRelative := filepath.Join(fullPath...)
-	absolutePathString, err := filepath.Abs(fullPathRelative)
-	if err != nil {
-		return LSResponse{}, xerrors.Errorf("failed to get absolute path of %q: %w", fullPathRelative, err)
+		fullPath = append(fullPath, query.Path...)
+		fullPathRelative := filepath.Join(fullPath...)
+		var err error
+		absolutePathString, err = filepath.Abs(fullPathRelative)
+		if err != nil {
+			return workspacesdk.LSResponse{}, xerrors.Errorf("failed to get absolute path of %q: %w", fullPathRelative, err)
+		}
 	}
 
 	// codeql[go/path-injection] - The intent is to allow the user to navigate to any directory in their workspace.
-	f, err := os.Open(absolutePathString)
+	f, err := fs.Open(absolutePathString)
 	if err != nil {
-		return LSResponse{}, xerrors.Errorf("failed to open directory %q: %w", absolutePathString, err)
+		return workspacesdk.LSResponse{}, xerrors.Errorf("failed to open directory %q: %w", absolutePathString, err)
 	}
 	defer f.Close()
 
 	stat, err := f.Stat()
 	if err != nil {
-		return LSResponse{}, xerrors.Errorf("failed to stat directory %q: %w", absolutePathString, err)
+		return workspacesdk.LSResponse{}, xerrors.Errorf("failed to stat directory %q: %w", absolutePathString, err)
 	}
 
 	if !stat.IsDir() {
-		return LSResponse{}, xerrors.Errorf("path %q is not a directory", absolutePathString)
+		return workspacesdk.LSResponse{}, xerrors.Errorf("path %q is not a directory", absolutePathString)
 	}
 
 	// `contents` may be partially populated even if the operation fails midway.
-	contents, _ := f.ReadDir(-1)
-	respContents := make([]LSFile, 0, len(contents))
+	contents, _ := f.Readdir(-1)
+	respContents := make([]workspacesdk.LSFile, 0, len(contents))
 	for _, file := range contents {
-		respContents = append(respContents, LSFile{
+		respContents = append(respContents, workspacesdk.LSFile{
 			Name:               file.Name(),
 			AbsolutePathString: filepath.Join(absolutePathString, file.Name()),
 			IsDir:              file.IsDir(),
 		})
 	}
 
 	// Sort alphabetically: directories then files
-	slices.SortFunc(respContents, func(a, b LSFile) int {
+	slices.SortFunc(respContents, func(a, b workspacesdk.LSFile) int {
 		if a.IsDir && !b.IsDir {
 			return -1
 		}
@@ -117,35 +141,35 @@ func listFiles(query LSRequest) (LSResponse, error) {
 
 	absolutePath := pathToArray(absolutePathString)
 
-	return LSResponse{
+	return workspacesdk.LSResponse{
 		AbsolutePath:       absolutePath,
 		AbsolutePathString: absolutePathString,
 		Contents:           respContents,
 	}, nil
 }
 
-func listDrives() (LSResponse, error) {
+func listDrives() (workspacesdk.LSResponse, error) {
 	// disk.Partitions() will return partitions even if there was a failure to
 	// get one. Any errored partitions will not be returned.
 	partitionStats, err := disk.Partitions(true)
 	if err != nil && len(partitionStats) == 0 {
 		// Only return the error if there were no partitions returned.
-		return LSResponse{}, xerrors.Errorf("failed to get partitions: %w", err)
+		return workspacesdk.LSResponse{}, xerrors.Errorf("failed to get partitions: %w", err)
 	}
 
-	contents := make([]LSFile, 0, len(partitionStats))
+	contents := make([]workspacesdk.LSFile, 0, len(partitionStats))
 	for _, a := range partitionStats {
 		// Drive letters on Windows have a trailing separator as part of their name.
 		// i.e. `os.Open("C:")` does not work, but `os.Open("C:\\")` does.
 		name := a.Mountpoint + string(os.PathSeparator)
-		contents = append(contents, LSFile{
+		contents = append(contents, workspacesdk.LSFile{
 			Name:               name,
 			AbsolutePathString: name,
 			IsDir:              true,
 		})
 	}
 
-	return LSResponse{
+	return workspacesdk.LSResponse{
 		AbsolutePath:       []string{},
 		AbsolutePathString: "",
 		Contents:           contents,
@@ -163,36 +187,3 @@ func pathToArray(path string) []string {
 	}
 	return out
 }
-
-type LSRequest struct {
-	// e.g. [], ["repos", "coder"],
-	Path []string `json:"path"`
-	// Whether the supplied path is relative to the user's home directory,
-	// or the root directory.
-	Relativity LSRelativity `json:"relativity"`
-}
-
-type LSResponse struct {
-	AbsolutePath []string `json:"absolute_path"`
-	// Returned so clients can display the full path to the user, and
-	// copy it to configure file sync
-	// e.g. Windows: "C:\\Users\\coder"
-	//      Linux: "/home/coder"
-	AbsolutePathString string   `json:"absolute_path_string"`
-	Contents           []LSFile `json:"contents"`
-}
-
-type LSFile struct {
-	Name string `json:"name"`
-	// e.g. "C:\\Users\\coder\\hello.txt"
-	//      "/home/coder/hello.txt"
-	AbsolutePathString string `json:"absolute_path_string"`
-	IsDir              bool   `json:"is_dir"`
-}
-
-type LSRelativity string
-
-const (
-	LSRelativityRoot LSRelativity = "root"
-	LSRelativityHome LSRelativity = "home"
-)