From 0ae4019a1a2ba5f51dabe57e051d9568ecbd315f Mon Sep 17 00:00:00 2001
From: Damien De Paoli <ddp@depaoli.id.au>
Date: Thu, 31 Dec 2020 11:31:15 +1100
Subject: [PATCH] handle DB errors

---
 author.py | 49 +++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/author.py b/author.py
index f694109..85e7f2b 100644
--- a/author.py
+++ b/author.py
@@ -2,6 +2,8 @@ from wtforms import SubmitField, StringField, HiddenField, validators, Form
 from flask_wtf import FlaskForm
 from flask import request, render_template, redirect
 from __main__ import db, app, ma
+from sqlalchemy import Sequence
+from sqlalchemy.exc import SQLAlchemyError
 from status import st, Status
 
 ################################################################################
@@ -50,15 +52,20 @@ def authors():
 @app.route("/author", methods=["GET", "POST"])
 def new_author():
     form = AuthorForm(request.form)
+    page_title='Create new Author'
     if 'surname' not in request.form:
-        return render_template("edit_id_name.html", form=form, page_title='Create new Author' )
+        return render_template("edit_id_name.html", form=form, page_title=page_title )
     else:
         author = Author( surname=request.form["surname"], firstnames=request.form["firstnames"] )
-        db.session.add(author)
-        db.session.commit()
-        st.SetMessage( "Created new Author ({})".format(author) )
-        return redirect( '/authors' )
-
+        try:
+            db.session.add(author)
+            db.session.commit()
+            st.SetMessage( "Created new Author ({})".format(author) )
+            return redirect( '/authors' )
+        except SQLAlchemyError as e:
+            st.SetAlert( "danger" )
+            st.SetMessage( "<b>Failed to add Author:</b>&nbsp;{}".format( e.orig) )
+            return render_template("edit_id_name.html", form=form, page_title=page_title, alert=st.GetAlert(), message=st.GetMessage() )
 
 ################################################################################
 # /author/<id> -> GET/POST(save or delete) -> shows/edits/delets a single author
@@ -67,22 +74,28 @@ def new_author():
 def author(id):
     ### DDP: should this be request.form or request.values?
     form = AuthorForm(request.form)
+    page_title='Edit Author'
     if request.method == 'POST' and form.validate():
-        author = Author.query.get(id)
-        if 'delete' in request.form:
-            st.SetMessage("Successfully deleted Author: ({})".format( author ) )
-            author = Author.query.filter(Author.id==id).delete()
-        if 'submit' in request.form:
-            st.SetMessage("Successfully Updated Author: (From: {}".format(author) )
-            author.surname = request.form['surname']
-            author.firstnames = request.form['firstnames']
-            st.AppendMessage(" To: {}".format(author) )
-        db.session.commit()
-        return redirect( '/authors' )
+        try:
+            author = Author.query.get(id)
+            if 'delete' in request.form:
+                st.SetMessage("Successfully deleted Author: ({})".format( author ) )
+                author = Author.query.filter(Author.id==id).delete()
+            if 'submit' in request.form:
+                st.SetMessage("Successfully Updated Author: (From: {}".format(author) )
+                author.surname = request.form['surname']
+                author.firstnames = request.form['firstnames']
+                st.AppendMessage(" To: {}".format(author) )
+            db.session.commit()
+            return redirect( '/authors' )
+        except SQLAlchemyError as e:
+            st.SetAlert( "danger" )
+            st.SetMessage( "<b>Failed to modify Author:</b>&nbsp;{}".format(e.orig) )
+            return render_template("edit_id_name.html", form=form, page_title=page_title, alert=st.GetAlert(), message=st.GetMessage() )
     else:
         author = Author.query.get(id)
         form = AuthorForm(request.values, obj=author)
-    return render_template("edit_id_name.html", object=author, form=form)
+    return render_template("edit_id_name.html", object=author, form=form, page_title = page_title, alert=st.GetAlert(), message=st.GetMessage() )
 
 ################################################################################
 # helper fund to GetAuthors -> author_list -> jinja2 for author drop-down in book.html