Programatically reset all camera_input / file_uploader

🎈 Using Streamlit
1

Summary

I need to be able to clear the photos uploaded either using camera_input or file_uploader programatically via python.

I saw this other post: How to Clear uploaded images when using st.file_uploader, accepting multiple files and how to clear other outputs? - :cloud: Streamlit Community Cloud - Streamlit. However it does not apply to me because I need to be able to perform different action depending on the photos uploaded. One of them being to clear all uploaded photos and retake.

Steps to reproduce

import streamlit as st

st.camera_input("Photo 1", key="photo1")
st.camera_input("Photo 2", key="photo2")
st.camera_input("Photo 3", key="photo3")

st.file_uploader("Upload your photos", key="photo4")
st.file_uploader("Upload your photos", key="photo5")
st.file_uploader("Upload your photos", key="photo6")


if st.button("Clear Photos"):
    st.session_state.pop("photo1")
    st.session_state.pop("photo2")
    st.session_state.pop("photo3")
    st.session_state.pop("photo4")
    st.session_state.pop("photo5")
    st.session_state.pop("photo6")
    st.session_state.photo1 = None
    st.session_state.photo2 = None
    st.session_state.photo3 = None
    st.session_state.photo4 = None
    st.session_state.photo5 = None
    st.session_state.photo6 = None

st.session_state

Expected behavior:

Reset all photos uploaded using both camera_input and file_uploaded. Including resetting the widget itself to its clean slate.

Actual behavior:

Although the st.session_state is reset, the widget is still displayed in it’s state before I change the session_state

image

image

Alternative Method tested

Alternative i tried to make use of st.empty(). Code as follows:

import streamlit as st

placeholder = st.empty()

with placeholder.container():
    st.camera_input("Photo 1", key="photo1")
    st.camera_input("Photo 2", key="photo2")
    st.camera_input("Photo 3", key="photo3")
    st.file_uploader("Upload your photos", key="photo4")
    st.file_uploader("Upload your photos", key="photo5")
    st.file_uploader("Upload your photos", key="photo6")


if st.button("Clear Photos"):
    placeholder.empty()
    for key, value in st.session_state.items():
        if "photo" in key:
            st.session_state.pop(key)

    st.session_state

    with placeholder.container():
        st.camera_input("Photo 1", key="photo1")
        st.camera_input("Photo 2", key="photo2")
        st.camera_input("Photo 3", key="photo3")
        st.file_uploader("Upload your photos", key="photo4")
        st.file_uploader("Upload your photos", key="photo5")
        st.file_uploader("Upload your photos", key="photo6")

However i run into another error as follows:

DuplicateWidgetID: There are multiple widgets with the same key='photo1'.

To fix this, please make sure that the key argument is unique for each widget you create.

Traceback:

File "C:\Users\User\Desktop\work\test\app.py", line 23, in <module>
    st.camera_input("Photo 1", key="photo1")

Debug info

  • Streamlit version: 1.21.0
  • Python version: 3.9.16
2

Hey @erjieyong,

Thanks for sharing this question!

I know you mentioned that the solution in this thread doesn’t work because you don’t always want to clear all the photos, but have you considered making the submit button for the form just a button that says “Clear Photos”, and then you could have another button outside the form that would be used for the other use case?

Alternatively, I think the reason that your uploaded photos are still in the UI is because the app isn’t rerunning after you’re clearing the photos from session state, so you might be able to use st.experimental_rerun to rerun the app/get the UI to refresh.