Tweak content type determination for resource decoders

pkg/envoy/csv/decoder.go

@@ -5,12 +5,11 @@ import (
 	"context"
 	"encoding/csv"
 	"io"
-	"os"
-	"path/filepath"
 	"strings"
 
 	"github.com/cortezaproject/corteza-server/pkg/envoy"
 	"github.com/cortezaproject/corteza-server/pkg/envoy/resource"
+	"github.com/gabriel-vasile/mimetype"
 )
 
 type (
@@ -31,8 +30,18 @@ func Decoder() *decoder {
 }
 
 // CanDecodeFile determines if the file can be determined by this decoder
-func (y *decoder) CanDecodeFile(i os.FileInfo) bool {
-	return strings.Trim(filepath.Ext(i.Name()), ".") == "csv"
+func (y *decoder) CanDecodeFile(f io.Reader) bool {
+	_, ext, err := mimetype.DetectReader(f)
+	if err != nil {
+		return false
+	}
+
+	return y.CanDecodeExt(ext)
+}
+
+func (y *decoder) CanDecodeExt(ext string) bool {
+	pt := strings.Split(ext, ".")
+	return strings.TrimSpace(pt[len(pt)-1]) == "csv"
 }
 
 // Decode decodes the given io.Reader into a generic resource dataset

pkg/envoy/directory/decode.go

@@ -14,7 +14,8 @@ import (
 
 type (
 	decoder interface {
-		CanDecodeFile(os.FileInfo) bool
+		CanDecodeExt(string) bool
+		CanDecodeFile(io.Reader) bool
 		Decode(context.Context, io.Reader, *envoy.DecoderOpts) ([]resource.Interface, error)
 	}
 )
@@ -46,22 +47,30 @@ func Decode(ctx context.Context, p string, decoders ...decoder) ([]resource.Inte
 			return nil
 		}
 
+		if f, err = os.Open(p); err != nil {
+			return err
+		}
+		defer f.Close()
+
 		for _, d = range decoders {
 			// find compatible decoder
-			if d.CanDecodeFile(info) {
+			if d.CanDecodeFile(f) {
+				break
+			}
+			// Do a fallback for extensions
+			if d.CanDecodeExt(info.Name()) {
 				break
 			}
 		}
-
 		if d == nil {
 			// no decoder found
 			return nil
 		}
 
-		if f, err = os.Open(p); err != nil {
+		_, err = f.Seek(0, 0)
+		if err != nil {
 			return err
 		}
-		defer f.Close()
 
 		dir, fn := path.Split(p)
 		do := &envoy.DecoderOpts{

pkg/envoy/json/decoder.go

@@ -5,12 +5,12 @@ import (
 	"context"
 	"encoding/json"
 	"io"
-	"os"
-	"path/filepath"
 	"strings"
 
 	"github.com/cortezaproject/corteza-server/pkg/envoy"
 	"github.com/cortezaproject/corteza-server/pkg/envoy/resource"
+	"github.com/cortezaproject/corteza-server/pkg/mime"
+	"github.com/gabriel-vasile/mimetype"
 )
 
 type (
@@ -35,8 +35,30 @@ func Decoder() *decoder {
 }
 
 // CanDecodeFile determines if the file can be decoded by this decoder
-func (d *decoder) CanDecodeFile(i os.FileInfo) bool {
-	return strings.Trim(filepath.Ext(i.Name()), ".") == "jsonl"
+func (d *decoder) CanDecodeFile(f io.Reader) bool {
+	var buff bytes.Buffer
+	tr := io.TeeReader(f, &buff)
+
+	_, ext, err := mimetype.DetectReader(tr)
+	if err != nil {
+		return false
+	}
+
+	if ext == "txt" {
+		if is, err := mime.JsonL(&buff); err != nil {
+			return false
+		} else if is {
+			ext = "jsonl"
+		}
+	}
+
+	return d.CanDecodeExt(ext)
+}
+
+func (d *decoder) CanDecodeExt(ext string) bool {
+	pt := strings.Split(ext, ".")
+	ext = strings.TrimSpace(pt[len(pt)-1])
+	return ext == "jsonl" || ext == "json"
 }
 
 // Decode decodes the given io.Reader into a generic resource dataset

pkg/envoy/yaml/decoder.go

@@ -3,8 +3,6 @@ package yaml
 import (
 	"context"
 	"io"
-	"os"
-	"path/filepath"
 	"strings"
 
 	"github.com/cortezaproject/corteza-server/pkg/envoy"
@@ -29,16 +27,18 @@ func Decoder() *decoder {
 	return &decoder{}
 }
 
-// CanDecodeFile
-func (y *decoder) CanDecodeFile(i os.FileInfo) bool {
-	switch strings.Trim(filepath.Ext(i.Name()), ".") {
-	case "yaml", "yml":
-		return true
-	}
-
+// CanDecodeFile checks if the file can be handled by this decoder
+//
+// @todo Add support for this; current library is unable to detect this.
+func (y *decoder) CanDecodeFile(f io.Reader) bool {
 	return false
 }
 
+func (y *decoder) CanDecodeExt(ext string) bool {
+	pt := strings.Split(ext, ".")
+	return strings.TrimSpace(pt[len(pt)-1]) == "yaml"
+}
+
 func (y *decoder) Decode(ctx context.Context, r io.Reader, dctx *envoy.DecoderOpts) ([]resource.Interface, error) {
 	var (
 		doc = &Document{}

pkg/mime/mime.go

@@ -3,26 +3,13 @@ package mime
 import (
 	"bufio"
 	"io"
-
-	"github.com/gabriel-vasile/mimetype"
 )
 
-func Type(file io.ReadSeeker) (mt string, ext string, err error) {
-	if _, err = file.Seek(0, 0); err != nil {
-		return
-	}
-
-	// Make sure we rewind when we're done
-	defer file.Seek(0, 0)
-	return mimetype.DetectReader(file)
-}
-
-func JsonL(file io.ReadSeeker) (bool, error) {
+func JsonL(f io.Reader) (bool, error) {
 	// ExtractMimetype fails to detect json if jsonl is used
 	// For now check if first rune is {
-	r := bufio.NewReader(file)
+	r := bufio.NewReader(f)
 	rn, _, err := r.ReadRune()
-	defer file.Seek(0, 0)
 	if err != nil {
 		return false, err
 	}