better code organization

function parameters should be lowercase

Fix crash on invalid labels import

Added invoice exporting and reduced duplicate code

Better exception handling

removed json module import

some more cleanup

Cleaned up some stuff

Added exporting contacts

lib/paymentrequest.py

@@ -40,7 +40,7 @@ except ImportError:
 from . import bitcoin
 from . import util
 from .util import print_error, bh2u, bfh
-from .util import FileImportFailed, FileImportFailedEncrypted
+from .util import export_meta, import_meta
 from . import transaction
 from . import x509
 from . import rsakey
@@ -468,27 +468,31 @@ class InvoiceStore(object):
                 continue
 
     def import_file(self, path):
-        try:
-            with open(path, 'r') as f:
-                d = json.loads(f.read())
-                self.load(d)
-        except json.decoder.JSONDecodeError:
-            traceback.print_exc(file=sys.stderr)
-            raise FileImportFailedEncrypted()
-        except BaseException:
-            traceback.print_exc(file=sys.stdout)
-            raise FileImportFailed()
+        import_meta(path, self.validate, self.on_import)
+
+    #TODO: Invoice import validation
+    def validate(self, data):
+        return data
+
+    def on_import(self, data):
+        self.load(data)
         self.save()
 
-    def save(self):
-        l = {}
+    def export_file(self, fileName):
+        export_meta(self.before_save(), fileName)
+
+    def before_save(self):
+        l= {}
         for k, pr in self.invoices.items():
             l[k] = {
                 'hex': bh2u(pr.raw),
                 'requestor': pr.requestor,
                 'txid': pr.tx
             }
-        self.storage.put('invoices', l)
+        return l
+
+    def save(self):
+        self.storage.put('invoices', self.before_save())
 
     def get_status(self, key):
         pr = self.get(key)