Python Flask, custom status of background process as response
I'm having trouble returning a custom response from a background process that takes a long time and its being called from a view function in Flask. I use the EventSource method from the html to display the status of the process to the user. The process is encapsulated in an object instanced in the view function and I need a way to signalize the status of the process.
The significant parts of the object are:
class MyObject:
self.status = 0
def signal_status(self):
yield self.status
def doSomeProcess(self):
self.status = 1
self.foo()
self.status = 2
self.bar()
self.status = 3
def process_call(self):
Thread(target=self.async_process, args=(app, data)).start()
def async_process(self, app, data):
with app.app_context():
self.doSomeProcess(data)
And from the routes:
myObj = MyObject()
@app.route('/process/<data>')
def process(data):
global myObject
myObject.process_call(data)
return render_template('process.html')
@app.route('/progress')
def progress():
global myObject
return Response(myObject.signal_status(), mimetype='text/event-stream')
Then I'm trying to reveive the code in js from the response like this:
<script>
var source = new EventSource("/progress");
source.onmessage = function(event) {
console.log(event.data);
}
</script>
However nothing appears in the console more than a 200 response message. I've tried casting to str the yield response from signal_status(). If I print the call to signal_status() the number is displayed normaly, so i don't think the threading is the issue.
Am I using the right approach to this issue, or Is there any other way I could display the status of the process in the client?
javascript python jquery flask response
asked Nov 13 '18 at 18:27
jevisanjevisan
62
add a comment |
I'm having trouble returning a custom response from a background process that takes a long time and its being called from a view function in Flask. I use the EventSource method from the html to display the status of the process to the user. The process is encapsulated in an object instanced in the view function and I need a way to signalize the status of the process.
The significant parts of the object are:
class MyObject:
self.status = 0
def signal_status(self):
yield self.status
def doSomeProcess(self):
self.status = 1
self.foo()
self.status = 2
self.bar()
self.status = 3
def process_call(self):
Thread(target=self.async_process, args=(app, data)).start()
def async_process(self, app, data):
with app.app_context():
self.doSomeProcess(data)
And from the routes:
myObj = MyObject()
@app.route('/process/<data>')
def process(data):
global myObject
myObject.process_call(data)
return render_template('process.html')
@app.route('/progress')
def progress():
global myObject
return Response(myObject.signal_status(), mimetype='text/event-stream')
Then I'm trying to reveive the code in js from the response like this:
<script>
var source = new EventSource("/progress");
source.onmessage = function(event) {
console.log(event.data);
}
</script>
However nothing appears in the console more than a 200 response message. I've tried casting to str the yield response from signal_status(). If I print the call to signal_status() the number is displayed normaly, so i don't think the threading is the issue.
Am I using the right approach to this issue, or Is there any other way I could display the status of the process in the client?
javascript python jquery flask response
asked Nov 13 '18 at 18:27
jevisanjevisan
62
Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22
add a comment |
I'm having trouble returning a custom response from a background process that takes a long time and its being called from a view function in Flask. I use the EventSource method from the html to display the status of the process to the user. The process is encapsulated in an object instanced in the view function and I need a way to signalize the status of the process.
The significant parts of the object are:
class MyObject:
self.status = 0
def signal_status(self):
yield self.status
def doSomeProcess(self):
self.status = 1
self.foo()
self.status = 2
self.bar()
self.status = 3
def process_call(self):
Thread(target=self.async_process, args=(app, data)).start()
def async_process(self, app, data):
with app.app_context():
self.doSomeProcess(data)
And from the routes:
myObj = MyObject()
@app.route('/process/<data>')
def process(data):
global myObject
myObject.process_call(data)
return render_template('process.html')
@app.route('/progress')
def progress():
global myObject
return Response(myObject.signal_status(), mimetype='text/event-stream')
Then I'm trying to reveive the code in js from the response like this:
<script>
var source = new EventSource("/progress");
source.onmessage = function(event) {
console.log(event.data);
}
</script>
However nothing appears in the console more than a 200 response message. I've tried casting to str the yield response from signal_status(). If I print the call to signal_status() the number is displayed normaly, so i don't think the threading is the issue.
Am I using the right approach to this issue, or Is there any other way I could display the status of the process in the client?
javascript python jquery flask response
asked Nov 13 '18 at 18:27
jevisanjevisan
62
I'm having trouble returning a custom response from a background process that takes a long time and its being called from a view function in Flask. I use the EventSource method from the html to display the status of the process to the user. The process is encapsulated in an object instanced in the view function and I need a way to signalize the status of the process.
The significant parts of the object are:
class MyObject:
self.status = 0
def signal_status(self):
yield self.status
def doSomeProcess(self):
self.status = 1
self.foo()
self.status = 2
self.bar()
self.status = 3
def process_call(self):
Thread(target=self.async_process, args=(app, data)).start()
def async_process(self, app, data):
with app.app_context():
self.doSomeProcess(data)
And from the routes:
myObj = MyObject()
@app.route('/process/<data>')
def process(data):
global myObject
myObject.process_call(data)
return render_template('process.html')
@app.route('/progress')
def progress():
global myObject
return Response(myObject.signal_status(), mimetype='text/event-stream')
Then I'm trying to reveive the code in js from the response like this:
<script>
var source = new EventSource("/progress");
source.onmessage = function(event) {
console.log(event.data);
}
</script>
However nothing appears in the console more than a 200 response message. I've tried casting to str the yield response from signal_status(). If I print the call to signal_status() the number is displayed normaly, so i don't think the threading is the issue.
Am I using the right approach to this issue, or Is there any other way I could display the status of the process in the client?
javascript python jquery flask response
javascript python jquery flask response
asked Nov 13 '18 at 18:27
jevisanjevisan
62
asked Nov 13 '18 at 18:27
jevisanjevisan
62
asked Nov 13 '18 at 18:27
jevisanjevisan
62
asked Nov 13 '18 at 18:27
jevisanjevisan
62
asked Nov 13 '18 at 18:27
jevisanjevisan
62
62
Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22
add a comment |
Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22
Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22
Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22
add a comment |
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Have you considered to use a distributed task queue like Celery? My gut feels like you should not implement asynch processing by your own, if something like celery can help you. I personally have collected some good experience with it!
– Lennart Blom
Nov 13 '18 at 21:22