I'm working on a PUT request to be able to modify data in my JSON file, using Flask and Python. The problem is it won't save the changes made.
Below is my code:
#app.route('/updated', methods = ['POST', 'PUT' 'GET'])
def update():
try:
title = request.form['title']
print title
if request.method == 'POST':
with open("articles.json", 'r+') as json_File:
articles = json.load(json_File)
for article in articles['article']:
if title == article['title']:
print article['title']
print article['author']
print article['article_id']
article['title'] = title
article['author'] = request.form['author']
article['text'] = request.form['text']
article['article_id'] = request.form['article_id']
print article
save_article = json.dumps(article, json_File)
else:
print "article could not be added"
#json_File.close()
return render_template('updated.html', save_article = save_article, article = article)
except:
print "This didn't work."
return render_template('errorHandler.html'), 404
Example from (http://blog.luisrei.com/articles/flaskrest.html)
#app.route('/echo', methods = ['GET', 'POST', 'PATCH', 'PUT', 'DELETE'])
def api_echo():
if request.method == 'GET':
return "ECHO: GET\n"
elif request.method == 'POST':
return "ECHO: POST\n"
elif request.method == 'PATCH':
return "ECHO: PACTH\n"
elif request.method == 'PUT':
return "ECHO: PUT\n"
elif request.method == 'DELETE':
return "ECHO: DELETE"
Probably best to have a if/elif/else for each method in the decorator, prevents weird bug and edge cases.
I think you should change this part:
if request.method == 'POST' or request.method == 'PUT':
For better practices, i think you should do:
if request.method == 'POST' or request.method == 'PUT':
# do your code here, which edit into your database
if request.method == 'GET':
# do GET code here, which return data from your database
Or separate your https methods into different functions
First of all, json.dumps() "dumps" to a string, not a file. So
save_article = json.dumps(article, json_File)
will return a string which is then bound to the save_article variable, but the file is not actually modified. You probably meant to use json.dump(article, json_File) which does accept a file as the second argument.
Note: The file argument is silently ignored in Python 2, which I assume that you are using because it would show up as an error in Python 3.
There might be other problems. One is that articles will be appended to the file, but it would seem that the intention of the code is to update an existing article. It's generally impractical to update text files in place. A better method would be to iterate over the articles, updating those that match the title. Then rewrite the whole file once at the end. Here's an example:
with open("articles.json", 'r') as json_File:
articles = json.load(json_File)
# update any matching articles
for article in articles['article']:
if title == article['title']:
article['author'] = request.form['author']
article['text'] = request.form['text']
article['article_id'] = request.form['article_id']
# rewrite the whole JSON file with updated dictionary
with open("articles.json", 'w') as json_File:
json.dump(articles, json_File)
As you are updating the article data you might want to consider using a simple database to manage it. You could take a look at Flask SQLAlchemy.
Related
I have this Flask View which takes a POST and GET requests
Goal is to do something with the Data from the POST request
and use it for the GET request
for example this AJAX GET Request
$.getJSON({url: '/uploadajax'}).done(result =>console.log(result));
which waits to return the processed data from the POST request
I was able to pass the data to the AJAX call by
declaring the global variable result and changed it in the function
and use it as a return value for the GET Request
Question here: is there a cleaner way to perform this task ?
result = 0
# ------------upload-file-----------------------------------------#
#flask_class.route('/uploadajax', methods=['POST', 'GET'])
def receave_file():
if request.method == 'POST':
uploaded_file = request.files['file']
# filename = secure_filename(uploaded_file.filename)
if uploaded_file.filename != "":
filename = secure_filename(uploaded_file.filename)
file_ext = os.path.splitext(filename)[1] # was macht das ?
if file_ext not in Config.ALLOWED_EXTENSIONS:
abort(400)
# file kann auch net gespeichert werden
uploaded_file.save(os.path.join(flask_class.instance_path, 'uploads', filename))
# ------------------------------------- #
df = pd.read_excel(uploaded_file)
columns = df.columns.to_list()
global result
result = json.dumps(columns)
# return result
print("shoud return somehting")
# ---------------------------------------- #
return '', 204
# ---------------------------------------- #
else:
return "false"
else:
# GET REQUEST
if len(result) > 1:
return result
else:
return '', 404
# return render_template('index.html')
Yes, there is :)
Have a look at the following code:
class LocalStore:
def __call__(self, f: callable):
f.__globals__[self.__class__.__name__] = self
return f
# ------------upload-file-----------------------------------------#
#flask_class.route('/uploadajax', methods=['POST', 'GET'])
#LocalStore() # creates store for this unique method only
def receave_file():
if request.method == 'POST':
LocalStore.post_headers= request.headers
LocalStore.post_body = request.body
LocalStore.post_json = request.get_json()
LocalStore.post_params = request.params
LocalStore.answer_to_everything = 42
print("POST request stored.")
return jsonify({"response": "Thanks for your POST!"})
else:
try:
print("This is a GET request.")
print("POST headers were:", LocalStore.post_headers)
print("POST params were :", LocalStore.post_params)
print("POST body was :", LocalStore.post_body)
print("The answer is :", LocalStore.answer_to_everything)
return jsonify({"postHeadersWere": LocalStore.post_headers})
except AttributeError:
return jsonify({"response":"You have to make a POST first!"})
I created a special class which "injects" its reference into the __globals__ dictionary of the method. If you type the class name in the method, it will be the object reference, not the class reference. Be aware of that!
You then just need to add #LocalStore underneath the #app.route(...) of your application because the store needs to be routed with the method...
I think it's a quite elegant way that saves you the definition of 5 global variables for 5 different methods
#app.route('/predict', methods=['GET', 'POST'])
def predict1():
# radio = 0
if request.method == 'POST':
value = request.get_json()
if(value['radioValue'] == 'word'):
radio = 0
return "ok"
elif(value['radioValue'] == 'sentence'):
radio = 1
return "ok"
else:
if(radio==0):
lists = ["my","word"]
elif(radio==1):
lists = ["my","sentence"]
return jsonify({'prediction': lists})
Hello, I am new to Flask and web development. So, here is my question, I am getting two radio button value named word and sentence. I want to pass lists = ["my","word"] if value is word else lists = ["my","sentence"].
But here jsonify() is not returning anything. So what am I doing wrong here?
Though it return lists if I declare radio variable outside if-else block as you can see I commented them out.
Also if I don't return anything inside post what I did as return "ok" it doesn't return anything even if I declare radio = 0 or 1 outside if-else block.
A short explanation will be really helpful.
If you check your debug log, you will probably see a NameError where radio is not defined. This is due to radio being a local variable, and not a session variable as you probably intended.
To store variables for further usage in Flask, you need to use sessions.
from flask import session
#app.route('/predict', methods=['GET', 'POST'])
def predict1():
if request.method == 'POST':
value = request.get_json()
if(value['radioValue'] == 'word'):
session["radio"] = 0
return "ok"
elif(value['radioValue'] == 'sentence'):
session["radio"] = 1
return "ok"
else:
if(session["radio"]==0):
lists = ["my","word"]
elif(session["radio"]==1):
lists = ["my","sentence"]
return jsonify({'prediction': lists})
POST data not always making to my logic, despite updating the django model properly
def new_record(request):
form = RecordForm(request.POST or None)
if request.method == 'POST':
if form.is_valid():
form.save()
return HttpResponseRedirect('/new_record')
else:
form = RecordForm()
item1 = request.POST.getlist('checkbox_1')
item2 = request.POST.getlist('checkbox_2')
item3 = request.POST.getlist('checkbox_3')
print(item1)
print(item2)
print(item3)
if 'on' in item1:
print("Checkbox 1 is true")
write_pdf_view(textobject='textobject', exam_record_number='123')
else:
print("Checkbox 1 is False")
if 'on' in item2:
print("Checkbox 2 is true")
else:
print("Checkbox 2 is False")
if 'on' in item3:
print("Checkbox 3 is true")
else:
print("Checkbox 3 is False")
return render(request=request,
template_name='main/new_record.html',
context={"form": form}
)
What I'm hoping to do is basically check if a checkbox is selected and pass a value into a function if this is true, for now I've fixed y write_pdf_view values to something I know exists and that's not working either (I imported that above)
I feel like this might be trivial for someone with experience, I'm a new hobbyist just looking to learn! Any help much appreciated.
Your if statements are executing during GET and not POST.
I would recommend structuring your code using the class-based view structure, as follows:
from django.views import View
class NewRecord(View):
def get(self, request):
return render(request, 'main/new_record.html', {'form': RecordForm})
def post(self, request):
form = RecordForm(request.POST)
if form.is_valid():
form.save()
item1 = request.POST.get('checkbox_1', None)
##place the rest of your logic here
return HttpResponseRedirect('/new_record')
I'm currently learning Django however I'm torn on how to structure the equivalent of add method using it. I'm creating a URL shortener and I'm between the following methods to implement in creating the shortened URL:
def shorten(request):
if request.method == 'POST':
http_url = request.POST.get("http_url","")
if http_url: # test if not blank
short_id = get_short_code()
new_url = Urls(http_url=http_url, short_id=short_id)
new_url.save()
return HttpResponseRedirect(reverse('url_shortener:index'))
else:
error_message = "You didn't provide a valid url"
return render(request, 'url_shortener/shorten.html', { 'error_message' : error_message })
return render(request, 'url_shortener/shorten.html')
vs.
def shorten(request):
http_url = request.POST["http_url"]
if http_url:
short_id = get_short_code()
new_url = Urls(http_url=http_url, short_id=short_id)
new_url.save()
return HttpResponseRedirect(reverse('url_shortener:index'))
else:
error_message = "You didn't provide a valid url"
return render(request, 'url_shortener/shorten.html', { 'error_message' : error_message })
return render(request, 'url_shortener/shorten.html')
Specifically, I want to know the best practice on the following:
Is it best practice to explicity test if method is post or http_url = request.POST["http_url"] is enough
Is http_url = request.POST.get("http_url","") recommended to be used or this is just suppressing the error?
If (2) is not recommended, how can I make the http_url required and throw an error? I also tried the following but the except block is not triggered when I submit a blank form
def shorten(request):
if request.method == 'POST':
try:
http_url = request.POST["http_url"]
short_id = get_short_code()
new_url = Urls(http_url=http_url, short_id=short_id)
new_url.save()
return HttpResponseRedirect(reverse('url_shortener:index'))
except KeyError:
error_message = "You didn't provide a valid url"
return render(request, 'url_shortener/shorten.html', { 'error_message' : error_message })
return render(request, 'url_shortener/shorten.html')
request.POST["key"]
will throw a KeyError when the key is not present in the dictionary. You can use a try...catch clause to handle the error.
Generally though, its idiomatic and perfectly normal to do:
request.POST.get("key")
More about get here.
I'm facing this exception error and I'm puzzled by it, as this method worked in similar system, appreciate any help or pointers. Many Thanks!
Exception Value: The view Project.qna.views.add_vote didn't return an HttpResponse object.
def add_vote(request):
if request.method == "POST":
q_id = request.POST['vote_form_q_id']
a_id = request.POST['vote_form_a_id']
vote_value = request.POST['vote_form_value']
ok = False
vote_num = None
name = None
if q_id:
try:
question = Question.objects.get(id=q_id)
question.num_vote += int(vote_value)
question.save()
vote_num = question.num_vote
name = 'Question_'+str(q_id)
ok = True
except Question.DoesNotExist:
pass
elif a_id:
try:
answer = Answer.objects.get(id=a_id)
answer.num_vote += int(vote_value)
answer.save()
vote_num = answer.num_vote
name = 'Answer_'+str(a_id)
ok = True
except Answer.DoesNotExist:
pass
if ok and request.is_ajax:
result = simplejson.dumps({
"vote_num": vote_num,
}, cls=LazyEncoder)
response = HttpResponse(result, mimetype='application/javascript')
response.set_cookie(name, datetime.now)
return response
Fix your indention please, also you seem to have a lot of workarounds that could be simplified.
Every django view should return a HttpResponse object, you seem to have a lot of places where this would not be the case. To narrow down your problem change every pass to a print statement to see where your code actually fails. It would be quite helpful if you could present your POST data.
Well it's hard to tell without seeing what kind of request you are making to the view. But are you sending a POST request? Because you don't handle GET requests in any way. Also the indentation is wrong. But that might just be cutting and pasting gone awry.
This is untested, but it's a cleaner and more robust design, which I believe fits in with your logic and highlights the points where returning an HttpResponse is necessary:
def add_vote(request):
if not (request.method == 'POST' and request.is_ajax):
return # Some suitable response here
try:
vote_value = int(request.POST.get('vote_form_value',''))
except ValueError as e:
pass # Some suitable response here
def saveobj(model, key, val): # helper function to reduce code repetition
item = model.objects.get(id=key)
item.num_vote += val
item.save()
return item.num_vote, '%s_%s' % (model.__class__.__name__, key)
for model, key in [(Question, 'vote_form_q_id'), (Answer, 'vote_form_a_id')]):
try:
new_vote_value, name = saveobj(model, request.POST[key], vote_value)
break
except (KeyError, ObjectDoesNotExist) as e:
continue # or error out
else:
pass # neither question or answer found - so suitable response here
# return ajax response here....