Allow reading package query for -filter option from a file.

cmd/mirror_edit.go

@@ -2,6 +2,10 @@ package cmd
 
 import (
 	"fmt"
+        "bufio"
+        "io/ioutil"
+        "os"
+        "strings"
 
 	"github.com/aptly-dev/aptly/pgp"
 	"github.com/aptly-dev/aptly/query"
@@ -9,6 +13,37 @@ import (
 	"github.com/smira/flag"
 )
 
+func getContent(filterarg string) (string, error) {
+	var err error
+        // Check if filterarg starts with '@'
+        if strings.HasPrefix(filterarg, "@") {
+                // Remove the '@' character from filterarg
+                filterarg = strings.TrimPrefix(filterarg, "@")
+                if filterarg == "-" {
+                	// If filterarg is "-", read from stdin
+                        scanner := bufio.NewScanner(os.Stdin)
+						scanner.Split(bufio.ScanLines)
+						scanner.Buffer(make([]byte, 1024*1024), 1024*1024)
+                        var content strings.Builder
+                        for scanner.Scan() {
+                                content.WriteString(scanner.Text() + "\n")
+                        }
+                        err = scanner.Err()
+			if err == nil {
+                                filterarg = content.String()
+                        }
+                } else {
+                	// Read the file content into a byte slice
+			var data []byte
+                	data, err = ioutil.ReadFile(filterarg)
+                	if err == nil {
+                        	filterarg = string(data)
+                	}
+		}
+        }
+        return filterarg, err
+}
+
 func aptlyMirrorEdit(cmd *commander.Command, args []string) error {
 	var err error
 	if len(args) != 1 {
@@ -28,11 +63,13 @@ func aptlyMirrorEdit(cmd *commander.Command, args []string) error {
 	}
 
 	fetchMirror := false
+	filter := false
 	ignoreSignatures := context.Config().GpgDisableVerify
 	context.Flags().Visit(func(flag *flag.Flag) {
 		switch flag.Name {
 		case "filter":
-			repo.Filter = flag.Value.String()
+			repo.Filter, err = getContent(flag.Value.String())
+			filter = true
 		case "filter-with-deps":
 			repo.FilterWithDeps = flag.Value.Get().(bool)
 		case "with-installer":
@@ -49,6 +86,10 @@ func aptlyMirrorEdit(cmd *commander.Command, args []string) error {
 		}
 	})
 
+	if filter && err != nil {
+		return fmt.Errorf("unable to read package query from file %s: %w", repo.Filter, err)
+	}
+
 	if repo.IsFlat() && repo.DownloadUdebs {
 		return fmt.Errorf("unable to edit: flat mirrors don't support udebs")
 	}