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FileField with instance id in DRF

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0

I don't know why filefield return string that include None when post data.

like this

http://example.com/room/None/1.jpg

My instance id was null on save.

In models.py

def room_photo_path(instance, filename):
 return 'room//'.format(instance.id, filename)


class Room(models.Model):
 photo = models.FileField(upload_to=room_photo_path)

In serializers.py

class RoomSerializer(serializers.ModelSerializer):
 class Meta:
 model = Room
 fields = '__all__'

django django-models django-rest-framework

share|improve this question

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

add a comment | 

0

I don't know why filefield return string that include None when post data.

like this

http://example.com/room/None/1.jpg

My instance id was null on save.

In models.py

def room_photo_path(instance, filename):
 return 'room//'.format(instance.id, filename)


class Room(models.Model):
 photo = models.FileField(upload_to=room_photo_path)

In serializers.py

class RoomSerializer(serializers.ModelSerializer):
 class Meta:
 model = Room
 fields = '__all__'

django django-models django-rest-framework

share|improve this question

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

add a comment | 

I don't know why filefield return string that include None when post data.

like this

http://example.com/room/None/1.jpg

My instance id was null on save.

In models.py

def room_photo_path(instance, filename):
 return 'room//'.format(instance.id, filename)


class Room(models.Model):
 photo = models.FileField(upload_to=room_photo_path)

In serializers.py

class RoomSerializer(serializers.ModelSerializer):
 class Meta:
 model = Room
 fields = '__all__'

django django-models django-rest-framework

share|improve this question

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

def room_photo_path(instance, filename):
 return 'room//'.format(instance.id, filename)


class Room(models.Model):
 photo = models.FileField(upload_to=room_photo_path)

class RoomSerializer(serializers.ModelSerializer):
 class Meta:
 model = Room
 fields = '__all__'

share|improve this question

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

share|improve this question

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

asked Mar 25 at 14:47

iamdifferentiamdifferent

933 bronze badges

1 Answer
1

active

oldest

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2

id gets assigned in database so the instance needs to be saved to have an id.

upload_to function gets called before the object is saved to database so you can't access the id because there is no id yet.

You can use signals and use a post_save signal to make the changes if you really have to use ids.

Django docs: Signals

share|improve this answer

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi, I understood your answer. So, I tried this.. but It's not working for me.. Can I use override save for solve this problem? There are different between save function and post_save signal?
  
  – iamdifferent
  Mar 26 at 2:38
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can't use save either. id gets assigned after save method. Basically you won't have an id unless the database gets the data and save them which means there is nothing you can do in django level. post_save signals sends a signal to a function after save so you can make changes while you have the id too.
  
  – Navid Zarepak
  Mar 26 at 7:13
  

  
  
  
  

add a comment | 

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2

id gets assigned in database so the instance needs to be saved to have an id.

upload_to function gets called before the object is saved to database so you can't access the id because there is no id yet.

You can use signals and use a post_save signal to make the changes if you really have to use ids.

Django docs: Signals

share|improve this answer

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi, I understood your answer. So, I tried this.. but It's not working for me.. Can I use override save for solve this problem? There are different between save function and post_save signal?
  
  – iamdifferent
  Mar 26 at 2:38
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can't use save either. id gets assigned after save method. Basically you won't have an id unless the database gets the data and save them which means there is nothing you can do in django level. post_save signals sends a signal to a function after save so you can make changes while you have the id too.
  
  – Navid Zarepak
  Mar 26 at 7:13
  

  
  
  
  

add a comment | 

2

id gets assigned in database so the instance needs to be saved to have an id.

upload_to function gets called before the object is saved to database so you can't access the id because there is no id yet.

You can use signals and use a post_save signal to make the changes if you really have to use ids.

Django docs: Signals

share|improve this answer

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi, I understood your answer. So, I tried this.. but It's not working for me.. Can I use override save for solve this problem? There are different between save function and post_save signal?
  
  – iamdifferent
  Mar 26 at 2:38
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can't use save either. id gets assigned after save method. Basically you won't have an id unless the database gets the data and save them which means there is nothing you can do in django level. post_save signals sends a signal to a function after save so you can make changes while you have the id too.
  
  – Navid Zarepak
  Mar 26 at 7:13
  

  
  
  
  

add a comment | 

id gets assigned in database so the instance needs to be saved to have an id.

upload_to function gets called before the object is saved to database so you can't access the id because there is no id yet.

You can use signals and use a post_save signal to make the changes if you really have to use ids.

Django docs: Signals

share|improve this answer

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

share|improve this answer

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges

answered Mar 25 at 14:59

Navid ZarepakNavid Zarepak

1,84011 gold badge66 silver badges1818 bronze badges