add error messages to Web version

web_app/main/routes.py

@@ -1,6 +1,7 @@
 from flask.helpers import send_file
 from flask import render_template, abort, flash, Blueprint
 from web_app.main.forms import UploadJavaForm
+from errors.custom import JavaSyntaxError, ScopeNotFoundException, InterpreterException, NoPathError
 from random import randint
 import shutil
 import secrets
@@ -56,6 +57,7 @@ def generator():
 
                
             deleteFilesInFolder(str(os.path.join(os.path.abspath(os.path.join('Web', os.pardir)), './tmp/output/')))
+            try:
                 NSD = NassiShneidermanDiagram(True)
                 output_directory = output_path + '/' + outputname
                 
@@ -73,7 +75,18 @@ def generator():
                 NSD.convert_to_image(output_directory, on_conflict=behaviour)
 
                 shutil.make_archive(output_path_zip, 'zip', output_directory) 
-            
+            except JavaSyntaxError as JsE:
+                flash((str(JsE)))
+            except ScopeNotFoundException as SnFe:
+                flash((str(SnFe)))
+            except FileNotFoundError as FnFe:
+                flash(str(FnFe))
+            except InterpreterException as iE:
+                flash(str(iE))
+            except Exception as e:
+                flash(('Failed to create an image of one funktion correctly. ' + str(e)) + 'There may be some images created. ')
+            except:    
+                raise            
             deleteFilesInFolder(output_path)
             return send_file(output_path_zip + '.zip', as_attachment=True)